JVA Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 
Search Issue | RSS Feeds RSS
Previous Issue

Nov 1999

Volume 17, Issue 6, pp. 3157-3530

back to top
RSS Feeds

Cathodic plasma polymerization and treatment by anode magnetron torch: II. The influence of operating parameters on the argon sputtering rate distribution

J. G. Zhao and H. Yasuda

J. Vac. Sci. Technol. A 17, 3157 (1999); http://dx.doi.org/10.1116/1.582065 (9 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
In this study, the distribution of argon sputtering rate on the cathode surface was used to investigate the anode magnetron torch plasma system, which was developed for large substrate surface treatment. The Ar sputtering rate was estimated using the colorimetric method. The experimental results showed that a uniform sputtering rate could be achieved by adjusting the distance between the two electrodes, because a suitable electrode distance creates a uniform magnetic field near the cathode surface. A small gap distance can increase the Ar sputtering rate in the focused area, but also creates deposition near the vicinity or outside of the edge of the glass tube, which is used to focus the gas flow. The optimum gap distance is equal to the cathodic dark space thickness at the edge of the glass tube; this configuration maintains a high sputtering rate in the focused area, but does not allow deposition to occur near the vicinity or outside of the edge of the glass tube. A higher Ar sputtering rate can be achieved under low system pressure. At low system pressure, a high magnetic-field strength is important for increasing the Ar sputtering rate, as it improves the magnetic confinement of electrons. © 1999 American Vacuum Society.  
Show PACS
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
82.35.-x Polymers: properties; reactions; polymerization
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

Moisture stability and structure relaxation processes in plasma-deposited SiOF films

V. Pankov, J. C. Alonso, and A. Ortiz

J. Vac. Sci. Technol. A 17, 3166 (1999); http://dx.doi.org/10.1116/1.582111 (6 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Fluorinated silicon dioxide (SiOF) films have been prepared by remote plasma enhanced chemical vapor deposition using SiF4, O2, H2, and He gases. Fourier transform infrared spectroscopy has been used to study structural changes in SiOF films caused by interaction with atmospheric moisture. It is shown that the increased incorporation of fluorine into the SiOF network during film deposition gradually increases the value of the average Si–O–Si angle in the SiOF network, 〈θ〉, from 138° to 153°. It is concluded that the value of about 144° corresponds to nearly relaxed SiOF network and therefore can be considered as an equilibrium angle for SiOF films. Subsequent increase in the fluorine concentration in the film results in 〈θ ) larger than the equilibrium 〈θ〉 (“overequilibrium”) and causes structural relaxation of the SiOF network towards the equilibrium 〈θ〉 during the post-deposition period. Both “under-” and “overequilibrium” values of 〈θ〉 seem to be the sources of SiOF film structural instability and increased reactivity with moisture. However, film hydrolysis and structural relaxation processes in the SiOF films characterized by “underequilibrium” values of 〈θ〉 are effectively suppressed by F presence in moderate concentrations. On the contrary, SiOF films characterized by “overequilibrium” 〈θ〉 have low density network and heavily absorb atmospheric water, which strongly promotes both structural relaxation and hydrolysis during the post-deposition period. © 1999 American Vacuum Society.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
77.55.-g Dielectric thin films
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
68.55.-a Thin film structure and morphology
68.55.Nq Composition and phase identification
85.40.Sz Deposition technology
78.30.Hv Other nonmetallic inorganics
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
82.30.Nr Association, addition, insertion, cluster formation
78.66.Nk Insulators

Surface dependent electron and negative ion density in inductively coupled discharges

G. A. Hebner, M. G. Blain, T. W. Hamilton, C. A. Nichols, and R. L. Jarecki

J. Vac. Sci. Technol. A 17, 3172 (1999); http://dx.doi.org/10.1116/1.582040 (7 pages) | Cited 19 times

Full Text: | Download PDF

Show Abstract
Electron and negative ion density have been measured in a modified Applied Materials decoupled plasma source commercial metal etch chamber using gas mixtures of BCl3, Cl2 and Ar. Measurements were performed for four different substrate types to examine the influence of surface material on the bulk plasma properties: aluminum, alumina, photoresist, and 50% patterned aluminum/photoresist. Electron densities in the Cl2/BCl3 mixtures varied from 0.25 to 4×1011 cm−3. Photodetachment measurements of the negative ion density indicate that the negative ion density was smaller than the electron density and that the electron to negative ion density ratio varied between 1 and 6. The presence of photoresist had a dominant influence on the electron and negative ion density compared to alumina and aluminum surfaces. In most cases, the electron density above wafers covered with photoresist was a factor of 2 lower, while the negative ion density was a factor of 2 higher than the aluminum or alumina surfaces. © 1999 American Vacuum Society.
Show PACS
52.80.-s Electric discharges
52.25.-b Plasma properties
52.70.Ds Electric and magnetic measurements
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning

Highly selective etching of silicon nitride over silicon and silicon dioxide

B. E. E. Kastenmeier, P. J. Matsuo, and G. S. Oehrlein

J. Vac. Sci. Technol. A 17, 3179 (1999); http://dx.doi.org/10.1116/1.582097 (6 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
A highly selective dry etching process for the removal of silicon nitride (Si3N4) layers from silicon and silicon dioxide (SiO2) is described and its mechanism examined. This new process employs a remote O2/N2 discharge with much smaller flows of CF4 or NF3 as a fluorine source as compared to conventional Si3N4 removal processes. Etch rates of Si3N4 of more than 30 nm/min were achieved for CF4 as a source of fluorine, while simultaneously the etch rate ratio of Si3N4 to polycrystalline silicon was as high as 40, and SiO2 was not etched at all. For NF3 as a fluorine source, Si3N4 etch rates of 50 nm/min were achieved, while the etch rate ratios to polycrystalline silicon and SiO2 were approximately 100 and 70, respectively. In situ ellipsometry shows the formation of an approximately 10-nm-thick reactive layer on top of the polycrystalline silicon. This oxidized reactive layer suppresses etching reactions of the reactive gas phase species with the silicon. © 1999 American Vacuum Society.    
Show PACS
81.65.Cf Surface cleaning, etching, patterning
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology

Monolayer-level controlled incorporation of nitrogen at Si–SiO2 interfaces using remote plasma processing

H. Niimi and G. Lucovsky

J. Vac. Sci. Technol. A 17, 3185 (1999); http://dx.doi.org/10.1116/1.582041 (12 pages) | Cited 28 times

Full Text: | Download PDF

Show Abstract
We demonstrate three different ways to incorporate nitrogen at Si–SiO2 interfaces: (i) an O2/He plasma oxidation of the Si surface followed by an N2/He plasma nitridation, (ii) an N2/He plasma nitridation of the Si surface, and (iii) a Si3N4 film deposition on to the Si surface. The two-step interface formation, the O2/He plasma oxidation followed by the N2/He plasma nitridation, is shown to yield significantly better interface device properties than the other two approaches. These differences in interface properties are explained by an application of constraint theory based on comparisons of the average bonding coordination of the dielectric layer at the interface with the Si substrate. © 1999 American Vacuum Society.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.72.uf Ge and Si
85.40.Ry Impurity doping, diffusion and ion implantation technology
81.65.Lp Surface hardening: nitridation, carburization, carbonitridation
81.05.Cy Elemental semiconductors
81.65.Mq Oxidation

Atomic hydrogen temperature in silane plasmas used for the deposition of a-Si:H films

K. Miyazaki, T. Kajiwara, K. Uchino, K. Muraoka, T. Okada, and M. Maeda

J. Vac. Sci. Technol. A 17, 3197 (1999); http://dx.doi.org/10.1116/1.582042 (5 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
Atomic hydrogen temperature in a silane plasma used for the deposition of a-Si:H films was measured using a two-photon laser-induced fluorescence technique. The temperature was found to be 2200±600 K and higher than both the parent-gas temperature and the atomic hydrogen temperature in a hydrogen plasma. We considered the mechanism of atomic hydrogen temperature determination in the plasma as follows. Hydrogen atoms generated by the dissociation of gas molecules due to electron impact in the plasma have a kinetic energy of several eV, which they then lose through collisions with gas molecules. At the same time, they disappear from the plasma due to chemical reactions and diffusion before thermal equilibrium with gas molecules has been established. Thus, an atomic hydrogen temperature higher than that of gas molecules becomes the equilibrium value in the plasma. We show, in the new experiment, that this model provides a good estimation of atomic hydrogen temperature in the plasma under various conditions of silane-hydrogen mixtures. © 1999 American Vacuum Society.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
81.05.Cy Elemental semiconductors
81.05.Gc Amorphous semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
52.25.Fi Transport properties
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions
52.20.Fs Electron collisions
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)

Properties of a-Si:H films deposited from silane diluted with hydrogen and helium using modified pulse plasma technique

C. Mukherjee, C. Anandan, T. Seth, P. N. Dixit, and R. Bhattacharyya

J. Vac. Sci. Technol. A 17, 3202 (1999); http://dx.doi.org/10.1116/1.582043 (7 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Hydrogenated amorphous silicon films were deposited in a modified square wave modulated pulsed plasma discharge at 13.56 MHz using silane diluted with hydrogen, helium, and their mixtures at two different modulation frequencies. The deposition rate is found to be higher in helium diluted plasmas and also at 10 Hz modulation. Increasing the modulation frequency from 2 to 10 Hz increases the deposition rate at all dilutions with helium or helium and hydrogen. At 2 Hz modulation, the deposition rate in helium diluted silane is higher and tends to saturate with increasing dilution whereas with hydrogen dilution it decreases. In helium diluted discharge with 10 Hz modulation the material properties deteriorate. However, the addition of hydrogen to helium diluted silane improves the film properties. The decrease in the deposition rate in hydrogen, and hydrogen and helium diluted plasmas is attributed to atomic hydrogen mediated etching of the growth surface which also explains the improvements in optoelectronic properties of these films. Hydrogen content, hydrogen bonding configurations, and the defect density also depend on the dilution ratio and modulation frequency. © 1999 American Vacuum Society.
Show PACS
81.05.Cy Elemental semiconductors
81.05.Gc Amorphous semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.-a Thin film structure and morphology

Absolute intensities of the vacuum ultraviolet spectra in a metal-etch plasma processing discharge

J. R. Woodworth, M. G. Blain, R. L. Jarecki, T. W. Hamilton, and B. P. Aragon

J. Vac. Sci. Technol. A 17, 3209 (1999); http://dx.doi.org/10.1116/1.582044 (9 pages) | Cited 20 times

Full Text: | Download PDF

Show Abstract
In this article we report absolute intensities of vacuum ultraviolet (VUV) and near ultraviolet emission lines (4.8–18 eV) for discharges used to etch aluminum in a commercial inductively coupled plasma reactor. We report line intensities as functions of wafer type, pressure, gas mixture, and radio frequency excitation level. In a standard aluminum etching mixture containing Cl2 and BCl3 almost all the light emitted at energies exceeding 8.8 eV was due to neutral atomic chlorine. Optical trapping of the VUV radiation in the discharge complicates calculations of VUV fluxes to the wafer. However, we measured total photon fluxes to the wafer at energies above 8.8 eV on the order of 4×1014 photons/cm2 s with a nonreactive wafer and 0.7×1014 photons/cm2 s with a reactive wafer. The majority of the radiation was between 8.9 and 9.3 eV. At these energies, the photons have enough energy to create electron-hole pairs in SiO2 and may penetrate up to a micron into the SiO2 before being absorbed. Relevance of these measurements to VUV photon-induced damage of SiO2 during etching is discussed. © 1999 American Vacuum Society.
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
81.05.Bx Metals, semimetals, and alloys

Influence of surface material on the boron chloride density in inductively coupled discharges

G. A. Hebner, M. G. Blain, and T. W. Hamilton

J. Vac. Sci. Technol. A 17, 3218 (1999); http://dx.doi.org/10.1116/1.582045 (7 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
The relative density of BCl radicals has been measured in a modified Applied Materials decoupled plasma source commercial metal etch chamber using laser-induced fluorescence. In plasmas containing mixtures of BCl3 with Cl2, Ar, and/or N2, the relative BCl density was measured as a function of source and bias power, pressure, flow rate, BCl3/Cl2 ratio, and argon addition. To determine the influence of surface materials on the bulk plasma properties, the relative BCl density was measured using four different substrate types; aluminum, alumina, photoresist, and photoresist-patterned aluminum. In most cases, the relative BCl density was highest above photoresist-coated wafers and lowest above blanket aluminum wafers. The BCl density increased with increasing source power and the ratio of BCl3 to Cl2, while the addition of N2 to a BCl3/Cl2 plasma resulted in a decrease in BCl density. The BCl density was relatively insensitive to changes in the other plasma parameters. © 1999 American Vacuum Society.
Show PACS
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

Production of highly uniform electron cyclotron resonance plasmas by distribution control of the microwave electric field

Muneo Furuse, Seiichi Watanabe, Hitoshi Tamura, and Osamu Fukumasa

J. Vac. Sci. Technol. A 17, 3225 (1999); http://dx.doi.org/10.1116/1.582046 (5 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
We have developed the apparatus that can measure the three-dimensional distribution of microwave electric field intensity in electron cyclotron resonance (ECR) plasmas to investigate production and control of ECR plasmas. The relationship between the plasma properties of ECR plasmas and the microwave electric field intensity in plasmas is studied. We have confirmed that the pattern of the radial distribution of the ion saturation current at the electrode is the same as that of the microwave electric field intensity at the ECR zone. If the distribution of microwave electric field intensity at the ECR zone is uniform, the distribution of plasma density on the electrode becomes uniform, even if the distribution of microwave electric field intensity of the other zone is not uniform. Therefore, in order to obtain the optimum distribution of plasma density on the electrode, the distribution of microwave electric field intensity at the ECR zone must be controlled. © 1999 American Vacuum Society.
Show PACS
52.50.Dg Plasma sources

Deposition and 1.54 μm Er3+ luminescent properties of erbium-doped hydrogenated amorphous silicon thin films by electron cyclotron resonance plasma enhanced chemical vapor deposition of SiH4 with concurrent sputtering of erbium

Jung H. Shin and Mun-Jun Kim

J. Vac. Sci. Technol. A 17, 3230 (1999); http://dx.doi.org/10.1116/1.582047 (5 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
Erbium-doped hydrogenated amorphous silicon (a-Si:H) thin films were deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition of SiH4 with concurrent sputtering of erbium. The oxygen and carbon contamination levels in all films were 1×1019 and 3×1019 cm−3, respectively, and the erbium concentrations could be controlled from 0.13 to 1.1 at. % by adjusting the erbium bias voltage. The half width Γ/2 of the Raman transverse-optic peak of the deposited films ranged from 32±1 to 36±1 cm−1, increasing with the increasing Er concentration. Strong 1.54 μm Er3+ luminescence with little temperature quenching was observed from all samples. The most intense Er3+ luminescence was observed from the as-deposited film with a deposition temperature of 380 °C and an erbium concentration of 0.13 at. %, showing that using the present method, erbium-doped a-Si:H films with good erbium optical activity and low structural disorder can be deposited directly while avoiding excessive contamination. © 1999 American Vacuum Society.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
78.66.Jg Amorphous semiconductors; glasses
78.66.Db Elemental semiconductors and insulators
78.55.Ap Elemental semiconductors
78.30.Am Elemental semiconductors and insulators
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
78.35.+c Brillouin and Rayleigh scattering; other light scattering

Effects of deposition conditions on the fluorine and hydrogen concentration in tantalum pentoxide (Ta2O5) thin films prepared by plasma enhanced chemical vapor deposition using a tantalum pentafluoride (TaF5) source

E. Z. Luo, B. Sundaravel, H. Y. Guo, I. H. Wilson, S. Four, and R. A. B. Devine

J. Vac. Sci. Technol. A 17, 3235 (1999); http://dx.doi.org/10.1116/1.582048 (5 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Using Rutherford backscattering spectrometry, nuclear reaction analysis, and elastic recoil detection analysis, we have analyzed the fluorine (F) and hydrogen (H) incorporated in thin tantalum pentoxide (Ta2O5) films on Si substrates prepared by plasma enhanced chemical vapor deposition using a tantalum pentafluoride (TaF5) source. It is shown that both F and H contents depend strongly on the deposition conditions, especially on the microwave power. Narrow resonant reaction 19F(α,p)22Ne analysis shows that there is considerable diffusion of F into the Si substrate. © 1999 American Vacuum Society.
Show PACS
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.S- Impurities in crystals
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis

Effects of silicon–hydrogen bond characteristics on the crystallization of hydrogenated amorphous silicon films prepared by plasma enhanced chemical vapor deposition

Hae-Yeol Kim, Jae-Beom Choi, and Jai-Young Lee

J. Vac. Sci. Technol. A 17, 3240 (1999); http://dx.doi.org/10.1116/1.582049 (6 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
The crystallization behavior of hydrogenated amorphous silicon (a-Si:H) films prepared by plasma enhanced chemical vapor deposition is investigated in view of the silicon–hydrogen (Si–Hn) bond characteristics. A-Si:H films deposited at various pressures (0.1–1.0 Torr) are annealed to polycrystalline silicon (poly-Si) films in a conventional vacuum furnace at 600 °C. The final grain size in the poly-Si films increases with the deposition pressure, up to 1.6 μm in the case of the films deposited at 1.0 Torr. The Si–Hn bond characteristics are analyzed by Fourier transform infrared spectroscopy and modified gas chromatography for hydrogen thermal evolution experiment. Finally, the Si–Hn bond characteristics are suggested to be an important factor affecting the crystallization behavior of a-Si:H films, which is also related to the film stress as well as the structural disorder in a-Si network. © 1999 American Vacuum Society.
Show PACS
68.55.-a Thin film structure and morphology
61.43.Dq Amorphous semiconductors, metals, and alloys
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
82.80.Bg Chromatography
78.35.+c Brillouin and Rayleigh scattering; other light scattering
78.66.Jg Amorphous semiconductors; glasses
78.66.Db Elemental semiconductors and insulators
81.05.Cy Elemental semiconductors
81.05.Gc Amorphous semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Low-energy xenon ion sputtering of ceramics investigated for stationary plasma thrusters

Y. Garnier, V. Viel, J.-F. Roussel, and J. Bernard

J. Vac. Sci. Technol. A 17, 3246 (1999); http://dx.doi.org/10.1116/1.582050 (9 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
The low-energy sputtering of boron nitride, magnesium oxide, boron nitride and aluminum nitride (BNAlN), and boron nitride and silicon oxide (BNSiO2) by xenon ions of bombarding energies 350, 500 eV, and 1 keV was studied experimentally. In order to measure the ion current without being significantly disturbed by slow ions, only planar probes were used during short duration sputtering experiments (of the order of 10 h). Moreover, slow ion current contribution was estimated by numerical simulations and subtracted from each ion current measurement. It was found that the ion-beam incidence effect on sputtering yields was not as important as for theoretical results or experimental results on quasinonrough solid surfaces, for which it is possible to observe a more pronounced angular dependence of the sputtering yield. This phenomenon is due to surface irregularities of ceramic materials and because of surface roughness the macroscopic sputtering yield should actually result from the convolution of the microscopic sputtering yield by the angular distribution of surface facet incidences. The irregular surface structure of ceramics like BNSiO2 or BNAlN seems to be sputtered differently due to a differential erosion from grain to grain and from grain to surrounding matrix. This uneven erosion may be explained by the wide angular distribution of facet incidences of surface microprofiles and the various binding energies in the selvage of material. Finally, the dependence of sputtering yield at normal incidence on ion energy, in the range 0.35–1 keV, is almost a linear one. © 1999 American Vacuum Society.
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.65.-b Surface treatments

Dynamic mixing deposition/implantation in a plasma immersion configuration

X. B. Tian, T. Zhang, Z. M. Zeng, B. Y. Tang, and P. K. Chu

J. Vac. Sci. Technol. A 17, 3255 (1999); http://dx.doi.org/10.1116/1.582051 (5 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
A surface layer consisting of titanium, nitrogen, and oxygen is implanted/deposited onto SS304 stainless steel using dynamic mixing and plasma immersion ion implantation. Titanium is introduced into a nitrogen glow discharge plasma from a metal arc plasma source. Dynamic mixing is achieved via the co-implantation of Ti ions with high charge states as well as nitrogen and oxygen ions in the plasma. The resulting surface layer possesses superior tribological properties and corrosion resistance. The observed improvement in the wear resistance is more than a factor of 10. The enhancement in the surface properties is believed to be due to the synergistic effects of the coexistence and dynamic mixing of titanium, nitrogen, and oxygen at the interface. © 1999 American Vacuum Society.
Show PACS
81.05.Bx Metals, semimetals, and alloys
61.82.Bg Metals and alloys
61.80.Jh Ion radiation effects
64.75.-g Phase equilibria
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Kn Corrosion protection
62.20.Qp Friction, tribology, and hardness
81.40.Pq Friction, lubrication, and wear
61.72.up Other materials

Silicon oxide selective etching process keeping harmony with environment by using radical injection technique

Kazushi Fujita, Masafumi Ito, Masaru Hori, and Toshio Goto

J. Vac. Sci. Technol. A 17, 3260 (1999); http://dx.doi.org/10.1116/1.582052 (5 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
A novel radical control method using a radical injection technique was proposed for preventing global warming. This system consists of a new fluorocarbon radical source where the polytetrafluoroethylene was ablated by a CO2 laser resulting in producing fluorocarbon radicals working as etching species and a radical filter set in front of the radical source which controls radicals generated from the radical source. Therefore, this system does not employ any fluorocarbon feed gases causing the global warming. The system was successfully applied to SiO2 over Si selective etching process employing an electron cyclotron resonance plasma. CFx (x=1–3) radical densities, F atom densities and higher species were successfully controlled by using the radical filter, which was confirmed by an infrared diode laser absorption spectroscopy and an actinometric optical emission spectroscopy. From these results, it was found that this technique was applicable to SiO2 over Si selective etching process keeping harmony with the environment, particularly for preventing global warming. © 1999 American Vacuum Society.
Show PACS
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning

Plasma chemistry in fluorocarbon film deposition from pentafluoroethane/argon mixtures

Sairam Agraharam, Dennis W. Hess, Paul A. Kohl, and Sue A. Bidstrup Allen

J. Vac. Sci. Technol. A 17, 3265 (1999); http://dx.doi.org/10.1116/1.582053 (7 pages) | Cited 29 times

Full Text: | Download PDF

Show Abstract
Plasma-enhanced deposition of fluorocarbon films was performed at 120 °C from a mixture of pentafluoroethane (CF3CHF2) and argon in a parallel plate plasma reactor. Mass spectrometry of the reactor effluent was used to gain an understanding of the plasma chemistry of this monomer. The monomer primarily dissociated into CF3• and CHF2• in the plasma. The results from mass spectrometry indicated that CHF2∗ was the primary precursor for deposition and that the fluorine radicals in the plasma were primarily scavenged as CF4 and HF. Monomer conversion (fraction of monomer fragmented) in the plasma was determined based on mass spectrometer partial pressure analysis of CH3CHF+ fragments (parent molecule: CF3CHF2) before and after plasma ignition. The conversion correlated directly with both the applied power and the deposition rate. The overall gas phase reactions did not change significantly with rf power within our range of operation, indicating a common reaction mechanism at all powers. No significant change in the composition of the deposited films was found, as measured by x-ray photoelectron spectroscopy (XPS), supporting the common mechanism conclusion. Further, XPS studies showed a fluorine-to-carbon ratio between 1.05 and 1.15 suggesting extensive crosslinking of the polymer. Infrared spectra of the deposited films showed negligible CHx concentration despite the presence of hydrogen in the monomer. © 1999 American Vacuum Society.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
85.40.Ls Metallization, contacts, interconnects; device isolation

Effect of capacitive coupling on inductively coupled fluorocarbon plasma processing

M. Schaepkens, N. R. Rueger, J. J. Beulens, X. Li, T. E. F. M. Standaert, P. J. Matsuo, and G. S. Oehrlein

J. Vac. Sci. Technol. A 17, 3272 (1999); http://dx.doi.org/10.1116/1.582054 (9 pages) | Cited 19 times

Full Text: | Download PDF

Show Abstract
This article describes results obtained using various plasma and surface diagnostics in a study of inductively coupled fluorocarbon plasmas in which the amount of capacitive coupling was systematically varied. It is found that the plasma density decreases while the electron temperature increases as the amount of capacitive coupling is increased at a constant source power level. The rate at which the dielectric coupling window is eroded is found to scale with both the peak-to-peak rf voltage and the ion current density, and the dielectric window erosion is found to influence the resulting plasma gas-phase chemistry. The changes in plasma electrical and chemical characteristics have a large impact on the surface processes occurring in inductively coupled fluorocarbon plasmas such as fluorocarbon deposition, fluorocarbon etching, SiO2 etching and Si etching. Further, we show how the selective SiO2-to-Si etch process changes with varying capacitive coupling. © 1999 American Vacuum Society.
Show PACS
52.25.-b Plasma properties
52.70.-m Plasma diagnostic techniques and instrumentation
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
85.40.Sz Deposition technology
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Electrical control of the spatial uniformity of reactive species in plasmas

Mark A. Sobolewski and Kristen L. Steffens

J. Vac. Sci. Technol. A 17, 3281 (1999); http://dx.doi.org/10.1116/1.582055 (12 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
We report a new method for controlling the spatial distribution of reactive chemical species in a parallel-plate plasma reactor, by means of a variable-impedance load placed between the unpowered electrode and ground. The technique was demonstrated in 89% CF4/11% O2 and 51% C2F6/49% O2 chamber-cleaning plasmas at 13.3–133 Pa (0.1–1.0 Torr) in a Gaseous Electronics Conference Reference Cell. The rf current and voltage at both electrodes were measured, and plasma spatial characteristics were observed using two-dimensional (2D) planar laser-induced fluorescence of the CF2 radical and 2D broadband optical emission measurements. By adjusting the load impedance to cancel the impedance of stray capacitances in parallel with the load, or the sheath capacitance in series with the load, the rf current at the load electrode could be made higher or lower than the current received when the electrode is grounded. When the rf current at the load electrode was minimized, regions of intense optical emission and high CF2 density were shifted radially outward from the center of the reactor. When the rf current at the load electrode was maximized, regions of intense optical emission and high CF2 density shifted radially inward, and the distribution of CF2 across the electrode surfaces became more uniform. These results suggest that variable loads could be used to direct reactive species in chamber-cleaning plasmas to the surfaces most in need of cleaning, or to increase the radial uniformity of reactive species in etching plasmas.
Show PACS
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
52.70.Kz Optical (ultraviolet, visible, infrared) measurements

Hardmask charging during Cl2 plasma etching of silicon

M. A. Vyvoda, M. Li, and D. B. Graves

J. Vac. Sci. Technol. A 17, 3293 (1999); http://dx.doi.org/10.1116/1.582056 (15 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Feature profile evolution simulations of plasma etching rely to first order on the accurate prediction of ion fluxes to all points on the evolving surface. Previous experimental and theoretical work strongly suggests that dielectric charging effects play a key role in a type of anomolous feature evolution known as “notchings.” This involves charging of newly exposed gate dielectric material, subsequent ion trajectory bending, and notch formation due to localized ion flux enhancement. Few researchers, however, have considered charging of masking dielectrics (e.g., SiO2 hardmasks) and its associated effects on feature evolution, even though such charging is likely to occur in modern high-density plasma etching systems. In this article, we develop a combined reactor- and feature-scale model of Cl2 plasma etching of crystalline silicon, allowing for the possibility of hardmask charging and ion trajectory deflection. We show via comparison of simulation results to cross-sectional scanning electron micrographs of silicon trenches that these charging effects can explain the formation of wide, “triangular,” microtrenches seen when etching silicon at 2 mTorr pressure and low rf-bias power. Furthermore, the model correctly predicts the disappearance of these microtrenches when the rf-bias power is raised. © 1999 American Vacuum Society.
Show PACS
81.05.Cy Elemental semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning

Study of CN films synthesized by facing target sputtering

Yi Wang, E. Y. Jiang, H. L. Bai, and P. Wu

J. Vac. Sci. Technol. A 17, 3308 (1999); http://dx.doi.org/10.1116/1.582057 (4 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
CN films were made by a facing target sputtering system. X-ray diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy spectra were measured to investigate the structure and the binding state of the film. The films are amorphous and the N/C increases as the N2 partial pressure increases and it reaches 0.46 when the N2 pressure is 100%. The N incorporated C forms N-sp2 C and N-sp3 C mainly and there is a small amount of CN. The incorporated N causes structural disorder of the C films and a reduction in the friction coefficient of the films. © 1999 American Vacuum Society.
Show PACS
61.43.Er Other amorphous solids
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
79.60.Ht Disordered structures
78.66.Nk Insulators
78.35.+c Brillouin and Rayleigh scattering; other light scattering
62.20.Qp Friction, tribology, and hardness
81.40.Pq Friction, lubrication, and wear

Fine control of deposition film compositions using radio-frequency reactive sputtering with periodic gas additions

Shoji Kimura, Takuya Honda, and Daigo Fukushi

J. Vac. Sci. Technol. A 17, 3312 (1999); http://dx.doi.org/10.1116/1.582058 (5 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Thin films of titanium nitride are prepared on metallic substrates using rf reactive sputtering. A pure titanium target and argon plasma are used with reactive gas of nitrogen in the sputter. The pressure of Ar is 0.53 Pa, and the input power 300 W. The reactive gas is periodically added to a constant plasma supporting Ar flow as a form of square waves, and this is called the modulation method. Wide atomic ratios of N to Ti, 0.3 to unity, are obtained by changing the duty ratio or period, where the stoichiometric ratio of TiN is unity. The variation of the atomic ratio is slower than that of the continuous nitrogen gas addition and this promises easy handling for producing a film with a particular atomic ratio. Moreover, the deposition rates are maintained within a factor of 30% decrease. These results indicate possible application to bulky material preparations such as functionally gradient materials (FGMs) and FGM-like intermediate layers for composite materials. © 1999 American Vacuum Society.
Show PACS
81.15.Cd Deposition by sputtering
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)

Glow discharge mass spectrometry study of the deposition of TiO2 thin films by direct current reactive magnetron sputtering of a Ti target

V. Vancoppenolle, P.-Y. Jouan, M. Wautelet, J.-P. Dauchot, and M. Hecq

J. Vac. Sci. Technol. A 17, 3317 (1999); http://dx.doi.org/10.1116/1.582059 (5 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
The properties of titanium oxide thin films deposited by direct current magnetron sputtering of a Ti target are strongly dependent on the sputtering conditions. The aim of the present work is to investigate the discharge parameters such as plasma potential, discharge voltage, deposition rate, and ion composition of the discharge as a function of the oxygen partial pressure. The plasma potential, relative to the ground, is determined from the ion energy distribution. Working in the constant current discharge mode, we observe, with increasing oxygen partial pressure, a drop of the plasma potential, an increase of the discharge voltage, a drop of the deposition rate, and an inversion of the Ti+–TiO+ intensities. For a given discharge current and pressure, the drop of the plasma potential and the increase of the discharge voltage occur at the same gas composition while the drop of the deposition rate and the ion intensity inversion happen at an oxygen richer gas composition. Both transitions are linearly correlated and depend on the discharge current. For larger oxygen partial pressure, a third transition appears corresponding to an inversion between TiO+ and TiO2+ intensities. These results lead us to consider three regimes in the reactive sputtering of a Ti target. © 1999 American Vacuum Society.
Show PACS
81.15.Cd Deposition by sputtering
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
52.70.Nc Particle measurements
52.80.Hc Glow; corona

Pulsed bias magnetron sputtering of thin films on insulators

Edward Barnat and T.-M. Lu

J. Vac. Sci. Technol. A 17, 3322 (1999); http://dx.doi.org/10.1116/1.582060 (5 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
It is shown that a pulsed direct current (dc) bias is capable of discharging insulating surfaces and providing a good means of controlling the energy of the ions extracted from the sputter magnetron plasma. Numerical calculations were made for surface potentials of an insulating thin film exposed to a plasma, placed on a conductor with a pulsed dc bias. Surface potentials are calculated as a function of time for pulses of variable frequency and duty. Average ion energy is shown to converge to applied dc biases at higher frequencies. Thin aluminum films were deposited on SiO2 substrates as a function of pulse frequency. Atomic force microscopy scans of the surface show that increasing the frequency of the pulses produces drastic changes in resulting film surface morphology. © 1999 American Vacuum Society.
Show PACS
81.15.Cd Deposition by sputtering
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.05.Bx Metals, semimetals, and alloys
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

Material characteristics and thermal stability of cosputtered Ta–Ru thin films

D. S. Wuu, C. C. Chan, and R. H. Horng

J. Vac. Sci. Technol. A 17, 3327 (1999); http://dx.doi.org/10.1116/1.582061 (6 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Ta–Ru alloy films were studied for use as a heater material in thermal ink-jet printheads. Thin films with different Ta/Ru compositions were deposited on oxidized Si substrates by cosputtering. The Ru/Ta ratio in the alloy was found to strongly affect the structure, resistivity, stress, and thermal stability. From x-ray and transmission electron microscopy examinations, the Ta1Ru1 phase has formed and dominated in the compositions exceeding 54 at. % Ru. With increasing the Ru content above 13 at. %, the resistivities of the Ta–Ru thin films begin to rise and can reach a maximum of ∼320 μΩ cm in the composition range between 35 and 54 at. % Ru. It is found that the films with small Ru ratios (⩽22%) exhibit poor thermal stability and the compressive stress increases after each thermal cycle (from 25 to 450 °C) in air, while the films with larger Ru atomic ratios show good stability. The measured stress-temperature behavior was investigated by Auger depth profiling analysis and x-ray photoelectron spectroscopy. The oxygen content of samples after repeated thermal cycling is largely related to the alloy composition. The observed preferential oxidation of Ta in the Ta–Ru samples can be further interpreted by thermodynamic calculations. The Ta-rich surface oxide is believed to be responsible for the oxidation resistance of the Ru atom at high temperatures. This results in the Ru of the metallic state though the oxidation of Ta occurs. Finally, an open pool test environment is arranged such that the liquid pool can be regarded as an infinite reservoir for the heater, from the standpoint of both momentum and energy transport. A lifetime over 1×107 driving pulses can be obtained for the Ta–Ru thin-film heater with 54 at. % Ru content. © 1999 American Vacuum Society.
Show PACS
68.60.Dv Thermal stability; thermal effects
73.61.At Metal and metallic alloys
68.55.-a Thin film structure and morphology
68.55.Nq Composition and phase identification
81.65.Mq Oxidation

Hollow cathode magnetrons with target gas feed

J. W. Bradley, D. M. Willett, and Y. Aranda Gonzalvo

J. Vac. Sci. Technol. A 17, 3333 (1999); http://dx.doi.org/10.1116/1.582062 (7 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
The plasma properties in a magnetron sputtering source can be modified by inducing the hollow cathode effect in a groove machined into the cathode target. Neutral gas is fed directly into the groove supplied from a reservoir behind the target and this is found to significantly increase the discharge current. Langmuir probe measurements made above the sputter trench show a much denser plasma is formed and the proportion of hot electrons in the plasma bulk is increased when gas is fed to the groove rather than to the vacuum chamber. The new design allows low downstream working pressures to be achieved but still maintaining high discharge currents, and gives the ability to run the discharge in one gas while introducing a second (i.e., reactive gas) to the chamber close to the substrate. © 1999 American Vacuum Society.
Show PACS
52.80.Hc Glow; corona
52.70.Ds Electric and magnetic measurements
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Ion-enhanced etching of Si(100) with molecular chlorine: Reaction mechanisms and product yields

Rory S. Goodman, N. Materer, and Stephen R. Leone

J. Vac. Sci. Technol. A 17, 3340 (1999); http://dx.doi.org/10.1116/1.582063 (11 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
Laser single-photon ionization time-of-flight mass spectrometry is used to measure silicon etch products that evolve during argon ion-enhanced etching of room temperature Si(100) with molecular chlorine over an ion energy range of 275–975 eV. The etch products are examined as a function of ion energy, ion flux, and molecular chlorine flux. The neutral Si atom, SiCl, and SiCl2 are the only product species observed with the 118 nm ionization and are detected directly without fragmentation. The Si and SiCl species are the main products, with the latter having much greater yield. The yield of each product increases with increasing ion energy. The SiCl/Si yield ratio increases with decreasing ion kinetic energy, indicating an increase in the chlorine surface coverage at lower ion energies. A simple kinetic model, including chlorine adsorption and sputtering of the resulting silicon chloride surface moieties, is proposed to describe the formation of Si and SiCl etch products. A model describing the chlorine pressure dependence of Si atom sputtering is developed in which the sputtering of Si atoms occurs from two different precursor states, one from an unchlorinated site and another from a partially chlorinated site. Using this kinetic model, the sputtering yield for SiCl per Ar+ is estimated from the molecular chlorine flux dependence of the SiCl signals and ranges from 3.2±0.8 to 4.9±0.9. © 1999 American Vacuum Society.
Show PACS
81.05.Cy Elemental semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Nanoscratch characterization of dual-ion-beam deposited C-doped boron nitride films

K. F. Chan, C. W. Ong, and C. L. Choy

J. Vac. Sci. Technol. A 17, 3351 (1999); http://dx.doi.org/10.1116/1.582064 (7 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Boron nitride (BN) films with carbon (C) contents varying from 3–11.8 at. % were fabricated using dual-ion-beam deposition. Films with low C contents (⩽6.2 at. %) consist mainly of the c-BN structure. The hardness of these films is as high as 43 GPa, and the coefficient of friction μ is described by the formula μ=0.14 W0.25, where W is the normal load in millinewtons. The critical load of damage is above 50 mN. Because of the existence of high internal stresses, the films peel off readily from the substrates, and delamination occurs immediately once a scratch track is produced. When more C is added, the formation of the c-BN structure is suppressed, while a graphite-like structure becomes dominant. The hardness and critical load drop to 8.6 GPa and 6.8 mN, respectively, when the C content is 11.8 at. %. The values of μ remain unchanged. The internal stresses are partially released, thereby leading to improved film adhesion. We have found an optimum C content of 7.2 at. %, at which both the mechanical and adhesion properties are satisfactory. © 1999 American Vacuum Society.
Show PACS
68.60.Bs Mechanical and acoustical properties
81.15.Jj Ion and electron beam-assisted deposition; ion plating
62.20.Qp Friction, tribology, and hardness
62.20.D- Elasticity
62.20.M- Structural failure of materials

Enhancement of the etch rate of LiNbO3 by prior bombardment with MeV O2+ ions

Patrick W. Leech and Mark C. Ridgway

J. Vac. Sci. Technol. A 17, 3358 (1999); http://dx.doi.org/10.1116/1.582066 (4 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The implantation of LiNbO3 with 5 MeV O2+ ions has been examined as a means of increasing the rate of subsequent reactive ion etching in CF4/CHF3 plasmas. The etch rate of LiNbO3 implanted at a dose sufficient to amorphize the substrate (1×1015–5×1015 ions cm−2) was ⩽3 times higher than in unimplanted substrates. The measured etch rates in CF4/CHF3 plasmas were essentially independent of the implant dose below 3×1014 ions cm−2 but increased significantly at and above 1×1015 ions cm−2. This transition was correlated with the onset of amorphization. In an Ar plasma, the etch rate of LiNbO3 was unaffected by prior million electron volt implantation and was an order of magnitude lower than in the CF4/CHF3 plasmas. These results have suggested that the damage induced by million electron volt implantation acted to accelerate the process of ion-enhanced chemical etching in LiNbO3 but had no significant influence on the process of physical sputtering in an Ar plasma. © 1999 American Vacuum Society.
Show PACS
61.72.up Other materials
81.65.Cf Surface cleaning, etching, patterning
77.80.-e Ferroelectricity and antiferroelectricity
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
85.40.Ry Impurity doping, diffusion and ion implantation technology
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

X-ray photoelectron spectroscopy studies of modified surfaces of α-Al2O3, SiO2, and Si3N4 by low energy reactive ion beam irradiation

Won-Kook Choi, Seok-Keun Koh, and Hyung-Jin Jung

J. Vac. Sci. Technol. A 17, 3362 (1999); http://dx.doi.org/10.1116/1.582067 (6 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
Reactions of N2+ ion beams with oxide surfaces of α-Al2O3(0001) single crystal and chemical vapor deposition (CVD) SiO2, and reactions of O2+ ion beams with a nitride surface of Si-rich CVD Si3N4 were investigated as a function of ion beam energy (200–1000 V) and dose (1×1015–1×1017/cm2). The thickness modified by the irradiation of a reactive low kinetic energy ion beam was measured using high resolution cross-sectional images of transmission electron microscopy (HR-XTEM), and the formation of new bonding induced by chemical reaction was analyzed by x-ray photoelectron spectroscopy (XPS). New bonding of Al–O–N on α-Al2O3(0001) started to be observed at 600 V N2+ ion energy and a dose of 1×1016/cm2, and Al–N bonding could be found at an ion beam energy of 1 keV. The thickness of the aluminum oxynitride layer after 800 V N2+ bombardment has been determined to be 10–50 Å by HR-XTEM analysis. In the case of CVD SiO2 surface modification, new bonding related to nitrogen was not clearly resolved in the XPS spectra, irrespective of the change of ion beam energy from 200 to 1000 V and ion dose from 1×1015 to 1×1017/cm2. However, widening of the full width at half maximum of Si 2p core-level XPS spectra for the modified SiO2 surface and the peak position of N 1s around 399 eV were evidence of the existence of nitrogen-related bonding like Si–O–N in the modified CVD SiO2 surfaces. Moreover, it was very interesting that the Si 2p peak of elemental Si appeared in the sample irradiated at a dose of 1×1017/cm2. Its occurrence was considered to be due mainly to the preferential sputtering effect, and was found to be largely dependent on the ion beam energy as well as on the ion dose. In the surface modification of low-pressure CVD Si3N4 by direct ken O2+ ion irradiation, Si–O–N bonding could be successfully created at an ion beam energy of 200 V and it evolved significantly at ion beam energies higher than 500 V. From the above results, low energy reactive ion beam irradiation can successfully create new bonding structures on oxide and nitride surfaces due to a surface chemical reaction like nitridation or oxidation, and is expected to be very useful for the formation of new ultrathin functional layers on ceramic surfaces. © 1999 American Vacuum Society.
Show PACS
61.80.Jh Ion radiation effects
79.60.Bm Clean metal, semiconductor, and insulator surfaces
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Reaction layer dynamics in ion-assisted Si/XeF2 etching: Ion flux dependence

P. G. M. Sebel, L. J. F. Hermans, and H. C. W. Beijerinck

J. Vac. Sci. Technol. A 17, 3368 (1999); http://dx.doi.org/10.1116/1.582068 (11 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
The etch rate of Si by XeF2 can be enhanced by more than a factor of 8 by ion bombardment. This enhancement is studied in a multiple-beam setup by looking at the response of reaction product signals upon ion pulses on time scales of 1–100 s in a multiple-beam setup. On a time scale of 100 s, it is found that ion bombardment causes fluorine depletion of the reaction layer and changes the structure of the reaction layer. This lower fluorine content results in a lower contribution of the spontaneous SiF4 production during ion bombardment. For the enhanced SiF4 production two processes are found from pulse measurements on the time scale of 1–10 s. First, ion bombardment creates weakly bound surface species, e.g., SiF2, that can react in the reaction layer to SiF4. Second, XeF2 reacts with these species with a higher reaction probability, thus enhancing the SiF4 production. The relative importance of both mechanisms is determined. Further, the limiting steps during spontaneous and ion-assisted etching are discussed, revealing that the creation of dangling bonds is the reason for the higher sticking probability of XeF2 during ion-assisted etching. © 1999 American Vacuum Society.
Show PACS
81.05.Cy Elemental semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning

Mechanism of columnar microstructure growth in titanium oxide thin films deposited by ion-beam assisted deposition

Qi Tang, Kazuo Kikuchi, Shigetaro Ogura, and Angus Macleod

J. Vac. Sci. Technol. A 17, 3379 (1999); http://dx.doi.org/10.1116/1.582069 (6 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
The microstructure of titanium oxide thin films deposited by ion-assisted deposition was studied as a function of various process parameters such as the ratio of oxygen to argon in the ion beam, the ion/evaporant arrival ratio, and the substrate temperature. By changing the ratio of oxygen and argon ions, amorphous-like and different types of columnar microstructure could be induced in the films. The columnar microstructure was investigated by means of transmission and scanning electron microscopes. Crystal structures were investigated by x-ray diffraction and transmission electron microscopy. Growth models of columnar microstructure are proposed and the mechanism of columnar microstructure growth and the resulting optical properties are also discussed. © 1999 American Vacuum Society.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Jj Ion and electron beam-assisted deposition; ion plating
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.66.Li Other semiconductors

Laser-induced particle formation and coalescence in a methane discharge

W. W. Stoffels, E. Stoffels, G. Ceccone, and F. Rossi

J. Vac. Sci. Technol. A 17, 3385 (1999); http://dx.doi.org/10.1116/1.582070 (8 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
Laser-induced formation of submicrometer dust particles and the subsequent coalescence phenomena in a low-pressure methane radio-frequency plasma have been analyzed. Six distinct phases can be distinguished: (a) nanoparticle synthesis by laser interaction with the plasma species, (b) particle conglomeration and the formation of ordered Coulomb lattices at the plasma–sheath region above the powered electrode, (c) coalescence of grains within the Coulomb lattice and formation of submillimeter strings, (d) condensation of the strings in the discharge and the formation of V-shaped structures, (e) condensation of the V structures into a single network of several centimeters in diameter suspended in the plasma, (f) deposition of the network on the electrode and its subsequent growth on the surface. Large carbon structures as well as nanoparticles have been analyzed in situ by He–Ne laser light scattering and laser ablation and ex situ by an optical and a scanning electron microscope, and by micro-Raman spectroscopy. © 1999 American Vacuum Society.
Show PACS
52.27.Lw Dusty or complex plasmas; plasma crystals
52.80.Pi High-frequency and RF discharges
52.38.-r Laser-plasma interactions
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.40.Hf Plasma-material interactions; boundary layer effects

Growth of single crystal MgO on TiN/Si heterostructure by pulsed laser deposition

A. K. Sharma, A. Kvit, and J. Narayan

J. Vac. Sci. Technol. A 17, 3393 (1999); http://dx.doi.org/10.1116/1.582071 (4 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
High quality epitaxial films of MgO have been grown on a Si (100) surface with TiN as a buffer layer by pulsed laser deposition. The electron diffraction patterns of these films confirmed the single crystal nature of the films with cube-on-cube epitaxy. It is difficult to grow high quality MgO films directly on Si due to large differences in lattice constants and thermal expansion coefficients of the two materials. The high resolution microscopy on our films revealed sharp interfaces between MgO/TiN and TiN/Si with no indication of interfacial reaction. Raman spectrum of MgO films revealed sharp peaks characteristic of MgO and TiN, indicating a good crystallinity. Further, superconducting YBa2Cu3O7−x films were grown on this heterostructure with a sharp transition at 88 K, indicating a high quality of the grown structure. This work opens a way for the growth of a variety of high quality perovskite structures for integration with silicon devices. © 1999 American Vacuum Society.
Show PACS
81.15.Fg Pulsed laser ablation deposition
68.55.-a Thin film structure and morphology
81.15.Kk Vapor phase epitaxy; growth from vapor phase
78.30.Hv Other nonmetallic inorganics
78.66.Nk Insulators
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors

Properties of Y2O3 nanocluster films deposited by Cu-vapor laser at room temperature

L. N. Dinh, K. D. Frischknecht, M. A. Schildbach, T. Anklam, and W. McLean

J. Vac. Sci. Technol. A 17, 3397 (1999); http://dx.doi.org/10.1116/1.582072 (4 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The dependence of stoichiometry, grain size, and surface morphology of yttrium oxide films, deposited by a Cu-vapor laser at room temperature, as a function of oxygen ambient pressure during synthesis were investigated. Auger electron spectroscopy showed that films with a O/Y ratio close to stoichiometry were obtained at oxygen pressures >3×10−1 Torr. X-ray diffraction revealed that pulsed laser deposited yttrium oxide films were composed mainly of nanocrystals, the average grain size of which grew from about 9.3 to 22.1 nm as the oxygen pressure was increased from 1.5×10−2 to 5 Torr. The surface morphology of the films, as determined by secondary electron microscopy, also exhibited increasing roughness as the grain size increased. Films deposited in an oxygen background pressure up to 1.5×10−2 Torr were oxygen deficient but exhibited good adhesion to substrates, while those deposited at higher oxygen background were powdery. © 1999 American Vacuum Society.
Show PACS
68.55.-a Thin film structure and morphology
61.66.Bi Elemental solids
61.66.Dk Alloys
61.46.-w Structure of nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.15.Fg Pulsed laser ablation deposition
68.35.Gy Mechanical properties; surface strains
68.60.Bs Mechanical and acoustical properties

INA-X: A novel instrument for electron-gas secondary neutral mass spectrometry with optional in situ x-ray photoelectron spectroscopy

Hans Oechsner and Matthias Müller

J. Vac. Sci. Technol. A 17, 3401 (1999); http://dx.doi.org/10.1116/1.582073 (5 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
A novel instrument for electron-gas secondary neutral mass spectrometry (SNMS) is described which is designed to enable in situ x-ray photoelectron spectroscopy measurements as an option. By operating the postionizing SNMS plasma inside an UHV chamber, residual gas signals are reduced to the mass-independent background in the order of a few 10−1 cps. A comparison between SNMS spectra taken with the existing INA-3 and the novel INA-X instrument reveal an increased detection power down to some 100 ppb. C and O as examples of analytically difficult elements become detectable down to the 10 ppm regime. © 1999 American Vacuum Society.
Show PACS
07.75.+h Mass spectrometers
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
07.81.+a Electron and ion spectrometers

Preparation and mechanical properties of composite diamond-like carbon thin films

Q. Wei, R. J. Narayan, A. K. Sharma, J. Sankar, and J. Narayan

J. Vac. Sci. Technol. A 17, 3406 (1999); http://dx.doi.org/10.1116/1.582074 (9 pages) | Cited 33 times

Full Text: | Download PDF

Show Abstract
We have investigated mechanical properties of diamond-like carbon (DLC) thin films, particularly the internal compressive stress and ways to alleviate it. Foreign atoms such as copper, titanium, and silicon were incorporated into the DLC films during pulsed laser deposition. The chemical composition of the doped films was determined using Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy (XPS). Optical microscopy of the doped films showed that DLC films containing Cu exhibit much less particulate density as compared to the films containing Ti and Si. Visible Raman spectroscopy was used to characterize the films. The effect of dopants on the Raman spectrum was analyzed in terms of peak shape and position. Optical microscopy of the pure DLC of a certain thickness showed severe buckling. The mechanisms of adhesion associated with DLC coatings were discussed. Qualitative scratch tests on the specimens showed that pure DLC films have relatively poor adhesion due to a large compressive stress, while the doped DLC films exhibit much improved adhesion. Wear tests show improved wear resistance in the doped DLC coatings. Nanoindentation results suggest that pure DLC has an average hardness above 40 GPa and effective Young’s modulus above 200 GPa. The doped DLC films showed slightly decreased hardness and Young’s modulus as compared to pure DLC films. These results can be rationalized by analyzing the internal stress reduction as derived from Raman G-peak shift to lower wavenumbers. A preliminary interpretation of the stress reduction mechanism is discussed. © 1999 American Vacuum Society.
Show PACS
81.15.Fg Pulsed laser ablation deposition
68.60.Bs Mechanical and acoustical properties
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
62.20.Qp Friction, tribology, and hardness
81.40.Pq Friction, lubrication, and wear
62.20.D- Elasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.F- Deformation and plasticity
81.40.Lm Deformation, plasticity, and creep
78.30.Hv Other nonmetallic inorganics
78.66.-w Optical properties of specific thin films
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.55.Nq Composition and phase identification

Metal overlayers on organic functional groups of self-assembled monolayers: VIII. X-ray photoelectron spectroscopy of the Ni/COOH interface

G. C. Herdt and A. W. Czanderna

J. Vac. Sci. Technol. A 17, 3415 (1999); http://dx.doi.org/10.1116/1.582075 (4 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
The interaction of vacuum deposited Ni with the COOH organic functional groups of mercaptoundecanoic acid [HS(CH2)10COOH] self-assembled monolayers formed on an Au substrate has been characterized with in situ x-ray photoelectron spectroscopy. Steady loss and complete disappearance of the hydroxyl component of O 1s peak at 532.8 eV provides evidence for the formation of a Ni–O bond at the Ni/COOH interface. Further evidence for interfacial compound formation is provided by a binding energy shift in the high binding energy component of the Ni 2p3/2 peak from 854.8 to 854.4 eV for Ni coverages below ∼0.2 nm. These results are consistent with the donation of electrons from the deposited Ni to the COOH oxygens at low Ni coverages. The absence of the characteristic satellite feature in the Ni 2p peak excludes the possibility that a full electron charge is donated to each COOH organic functional group as a bidentate complex. However, the data are consistent with a two step reaction mechanism in which Ni initially reacts weakly with the oxygens in COOH below one monolayer coverage and then forms a complex above this coverage. © 1999 American Vacuum Society.
Show PACS
68.35.Ct Interface structure and roughness
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Fourier transform infrared spectroscopy of effluents from pulsed plasmas of 1,1,2,2-tetrafluoroethane, hexafluoropropylene oxide, and difluoromethane

Catherine B. Labelle, Simon M. Karecki, Rafael Reif, and Karen K. Gleason

J. Vac. Sci. Technol. A 17, 3419 (1999); http://dx.doi.org/10.1116/1.582076 (10 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
Gas-phase Fourier transform infrared spectroscopy (FTIR) has been used to analyze the effluents from C2H2F4, hexafluoropropylene oxide (CF3CFOCF2, HFPO), and CH2F2 pulsed plasmas. A series of reference spectra for possible effluent species was used to identify the major species in each. The major species in pulsed C2H2F4 plasmas were found to be: C2H2F4, HF, C2F4, C2HF5, CHF3, and SiF4 (formed from free fluorine). For HFPO pulsed plasmas, the major effluents are: HFPO, CF3COF3, COF2, C2F4, C2F6, CO, CF4, and C3F8, whereas for CH2F2 pulsed plasmas, the major effluents are: CH2F2, HF, SiF4, and CHF3. Reaction sets were postulated for each precursor to account for the observed effluents, and these sets were used to explain the trends of species concentrations with pulse on and pulse off time. In each case, most of the effluent concentration trends could be traced back to competition between dissociation pathways of a particular molecule. For both C2H2F4 and CH2F2, the main reactions were the competition between CF2 production and HF elimination from the original precursor. For C2H2F4 pulsed plasmas, the competition between these pathways was found to be ∼1:1, whereas for CH2F2 pulsed plasmas, the HF elimination pathway is dominant. For HFPO, the key reactions are the three dissociation pathways of CF3COF, a main product of the initial dissociation of HFPO into CF2+CF3COF. The global warming impact of each of the pulsed plasma enhanced chemical vapor deposition processes was gauged by the million metric tons of carbon equivalent (MMTCE) metric. CH2F2 pulsed plasmas were found to have the lowest MMTCE (min=2.1×106), whereas HFPO pulsed plasmas had the highest MMTCE (max=7.7×107). For all three precursors, the MMTCE impact is reduced by decreasing the exposure to plasma excitation through increasing the off time at a fixed on time. © 1999 American Vacuum Society.
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Interface analysis of naphthyl-substituted benzidine derivative and tris-8-(hydroxyquinoline) aluminum using ultraviolet and x-ray photoemission spectroscopy

E. W. Forsythe, V.-E. Choong, T. Q. Le, and Yongli Gao

J. Vac. Sci. Technol. A 17, 3429 (1999); http://dx.doi.org/10.1116/1.582077 (4 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
We have studied the interface between naphthyl-substituted benzidine derivative (NPB) and tris-8-(hydroxyquinoline) aluminum (Alq3). Ultraviolet photoemission and x-ray photoemission spectroscopy (UPS, XPS) are used to distinguish contributions from NPB and Alq3 and reveal an interface formation region of approximately one to two monolayers. The UPS results show the highest occupied molecular orbital (HOMO) level offset is 0.3 eV, whereas the lowest unoccupied molecular orbitial offset is 0.8 eV, which confines electrons in the emissive Alq3 layer of the heterostructure. From the UPS difference spectrum, the gradual modification of the HOMO levels are revealed. Within the interface region, the energy levels bend by more than 0.3 eV. The Alq3 and NPB HOMO level increases are consistent with the vacuum level shift as well as the observed core level shifts from XPS. Further, the XPS and UPS results show no chemical interactions or wave function overlap at the interface. © 1999 American Vacuum Society.
Show PACS
79.60.Jv Interfaces; heterostructures; nanostructures
73.20.At Surface states, band structure, electron density of states

Optoelectronic properties of polycrystalline CdInTe films

A. Iribarren, I. Riech, M. P. Hernández, R. Castro-Rodríguez, J. L. Peña, and M. Zapata-Torres

J. Vac. Sci. Technol. A 17, 3433 (1999); http://dx.doi.org/10.1116/1.582078 (4 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
Close-spaced vapor transport combined with free evaporation was used for the growth of polycrystalline CdInTe films on glass substrates. The optoelectronic properties of the films were investigated by absorption at 77 and 300 K, and photoluminescence at 77 K with the indium concentration ranged from 0 to 22 at. %. The band-gap energy was found to vary linearly, and the band-gap temperature coefficient increases as the indium concentration increases. It was found that the ionization energy of indium displaced from the cationic sites of the CdTe lattice corresponds to a donor level at ED>32 meV (ED≃36 meV) below the conduction-band bottom. This level and the acceptor level associated with Cd vacancies stay at the same energy distance of their corresponding bands for all the indium concentrations studied. The relation between Eg and the lattice parameter is also shown. © 1999 American Vacuum Society.
Show PACS
78.66.Li Other semiconductors
78.55.Hx Other solid inorganic materials
61.72.J- Point defects and defect clusters
71.55.Ht Other nonmetals
78.40.Fy Semiconductors

Low-energy cathodoluminescence spectroscopy of erbium-doped gallium nitride surfaces

T. M. Levin, A. P. Young, J. Schäfer, L. J. Brillson, J. D. MacKenzie, and C. R. Abernathy

J. Vac. Sci. Technol. A 17, 3437 (1999); http://dx.doi.org/10.1116/1.582079 (6 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
We have used cathodoluminescence spectroscopy with variable incident beam energies to study the energy levels and activation of Er impurities in GaN as a function of depth below the free surface. The GaN films were doped in situ during either metalorganic molecular-beam epitaxy (MOMBE) or molecular-beam epitaxy (MBE). Besides the well-known Er3+ luminescence at 0.80 eV, we observe emissions at 1.2, 1.8, 2.2, and 2.3 eV, corresponding to higher energy Er 4f shell transitions. For unannealed MOMBE-grown GaN:Er, these higher energy emissions appear only for excitation depths of hundreds of nanometers. The MOMBE-grown GaN;Er annealed to 500 °C shows a dramatic increase in the 1.8, 2.2, and 2.3 eV peak intensities at shallow probe depths, with its yield increasing with increasing depth. These three features become pronounced at all depths after a 700 °C anneal. MBE-grown GaN:Er grown with lower C and O impurity levels than the MOMBE-grown sample exhibits strong emission at all these energies without annealing. The decreased emission at shallow (tens of nanometer) probe depths suggests a depletion of activation Er in the near-surface region. Enhancement of near-surface Er3+ luminescence with annealing may be due to lattice reordering as well as impurity redistribution. © 1999 American Vacuum Society.
Show PACS
78.66.Fd III-V semiconductors
68.55.-a Thin film structure and morphology
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.60.Hk Cathodoluminescence, ionoluminescence

Low-energy Ar+ ion induced angularly resolved Al(100) and Al(110) sputtering measurements

P. C. Smith and D. N. Ruzic

J. Vac. Sci. Technol. A 17, 3443 (1999); http://dx.doi.org/10.1116/1.582080 (6 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
An apparatus and analysis method to obtain both the angular distribution of sputtered atoms and the total sputtering yield for materials of interest to physical vapor deposition (PVD) has been created. Total yield is determined by collecting the sputtered material on a quartz crystal oscillator (QCO) microbalance. The sputtered material is also collected on a pyrolytic graphite witness plate. By mapping the concentrations of the sputtered material on this plate, both polar and azimuthal angular distributions of the sputtered material can be determined. Utilizing this setup, data have been obtained for (200–500 eV) Ar+ normally incident on polycrystalline aluminum sputtering targets with strong (100) and (110) crystallographic orientations. The overall yields of these samples compare well to the available data as well as empirical formulas. Crystallographic effects in the angular distributions are clearly seen. The Al(100) sample shows 12% enhanced sputtering along the 〈110〉 direction at all energies. © 1999 American Vacuum Society.
Show PACS
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Ni–Cr passivation of very thin Ag films for low-emissivity multilayer coatings

R. J. Martín-Palma and J. M. Martínez-Duart

J. Vac. Sci. Technol. A 17, 3449 (1999); http://dx.doi.org/10.1116/1.582081 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
In the present work, the optical properties in the visible and infrared ranges of glass/SnO2(380 Å)/Ni–Cr(15 Å)/Ag(90 Å)/Ni–Cr(25 Å)/SnO2(380 Å) and glass/SnO2(380 Å)/Ni–Cr(15 Å)/Ag(90 Å)/SnO2(380 Å) systems are compared in order to determine the influence of the external Ni–Cr film on the optical behavior of low-emissivity multilayer coatings for energy saving applications. It has been observed that the lack of either one Ni–Cr film results in the hampering of the low-emissivity behavior (from 2.5% to 49.5% at λ=10 μm), as a result of the diminution of the reflectance values in the infrared range (from 97.5% to 50.5% at λ=10 μm). The lack of the Ni–Cr film also affects the optical performance in the visible range, by decreasing the transmittance from approximately 80% to 60% at λ=550 nm, and increasing the reflectance from about 5% to 30%. This behavior is attributed to the partial oxidation of the silver layer which might result both in a variation of the chemical and structural properties of this film. © 1999 American Vacuum Society.
Show PACS
81.65.Rv Passivation
42.79.Wc Optical coatings
78.66.Bz Metals and metallic alloys
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
81.65.Mq Oxidation
42.70.Ce Glasses, quartz
81.05.Bx Metals, semimetals, and alloys

Problems of determining true equilibrium pressures of hydrogen getters over a wide range of getter temperature and hydrogen sorption

F. Ghezzi and M. De Angeli

J. Vac. Sci. Technol. A 17, 3452 (1999); http://dx.doi.org/10.1116/1.582082 (11 pages)

Full Text: | Download PDF

Show Abstract
We have assessed a conventionally configured apparatus to measure hydrogen equilibrium pressures of getter alloys over the temperature range of 25 to 400 °C and hydrogen concentration range of 0.02 to 1 H/A. An in situ approach has been proposed to correlate the measurements of different gauges using one of the precisely calibrated gauges as a standard reference. The pressure range of interest was 10−7–105 Pa and was covered using a Bayart–Alpert gauge, a spinning rotor gauge, and different capacitance gauges. The approach involves measuring the characteristic response of these instruments prior to determining hydrogen equilibrium pressures over the relevant range of wall and getter bed temperature. To evaluate the accuracy of the measurements, we performed an error propagation analysis. The use of a porous filter to avoid fines contamination and the adsorption/desorption kinetics of the walls of the system were both addressed. © 1999 American Vacuum Society.
Show PACS
07.30.Cy Vacuum pumps
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
07.30.Bx Degasification, residual gas

Oxygen doping effect on Ge–Sb–Te phase change optical disks

Atsushi Ebina, Masao Hirasaka, and Kenji Nakatani

J. Vac. Sci. Technol. A 17, 3463 (1999); http://dx.doi.org/10.1116/1.582083 (4 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
High performance phase change optical recording disk has been developed by using an oxygen-doped Ge–Sb–Te recording layer. The 5×105 overwrite cycles were achieved with this 6 at. % oxygen-doped phase change optical recording disk. The transmission electron microscope observation shows that the crystal grain size was enlarged and the “self-sharpening effect” disappeared with increasing of oxygen concentration. It is thought that the oxygen doping made it easy to grow the uniform large grain size without the self-sharpening effect around the amorphous mark and therefore, the overwrite cyclability of the phase change optical recording disk was improved. © 1999 American Vacuum Society.
Show PACS
42.79.Vb Optical storage systems, optical disks

Separation of electron-stimulated-desorption neutrals from outgassing originating from the grid surface of emission-controlled gauges: Studies with a heated-grid gauge

Fumio Watanabe and Maki Suemitsu

J. Vac. Sci. Technol. A 17, 3467 (1999); http://dx.doi.org/10.1116/1.582084 (6 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
With the construction of a heated-grid gauge, whose grid temperature can be varied independent of the electron emission, the two major barriers against precise pressure measurements in the extremely high vacuum (XHV) region, i.e., electron-stimulated-desorption neutrals and outgassing, have been successfully separated. In XHV, these two processes are both dominated by hydrogen molecules, while their strengths depend strongly on the grid temperature and the grid material. At elevated temperatures, outgassing caused by the out-diffusion of hydrogen atoms dissolved in the grid begin to dominate. This suggests use of a metal with low hydrogen solubility for XHV-compatible grid material. © 1999 American Vacuum Society.
Show PACS
07.30.Bx Degasification, residual gas
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
07.30.Dz Vacuum gauges

Growth habit of rhombohedral Bi thin films on zinc-blende CdTe substrates with various orientations

Yunki Kim, Sunglae Cho, Antonio DiVenere, George K. Wong, and John B. Ketterson

J. Vac. Sci. Technol. A 17, 3473 (1999); http://dx.doi.org/10.1116/1.582085 (4 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Rhombohedral Bi thin films have been grown on zinc-blende (111), (211) and (100) CdTe substrates by molecular beam epitaxy. Reflection high-energy electron diffraction patterns showed that Bi grew layer-by-layer on the CdTe substrates without any reconstruction. X-ray diffraction θ−2θ scans revealed that the Bi films grown on (111) CdTe are (00.l) oriented and that the Bi films on (100) CdTe are (10.4) oriented. X-ray pole figures from the Bi films and the CdTe substrates indicated that Bi (00.l) on (211) CdTe grew along the CdTe (111) direction, like in the case of the Bi films on (111) CdTe. Most Bi grains on (100) CdTe select one particular direction out of the four possible directions in the presence of an off-axis tilt relative to the (100) substrate surface normal.© 1999 American Vacuum Society.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
68.55.-a Thin film structure and morphology

Surface reaction pathways of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione on clean and pre-oxidized Ni(110) surfaces

H. L. Nigg and R. I. Masel

J. Vac. Sci. Technol. A 17, 3477 (1999); http://dx.doi.org/10.1116/1.582086 (4 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Ni contamination of Si surfaces is an increasing problem for very large scale integrated manufacturers seeking sub-0.25 μm features. Dry etching methods are considered important, potential processes for removal of this contaminant. We and others have recently proposed a chemical vapor etching (CVE) treatment using oxygen and hexafluoropentanedione that could be used to remove Ni. In this article, we have used temperature programmed desorption to examine the surface kinetic pathways of Ni removal by CVE. Ni was successfully dry etched from the pre-oxidized surface by the desorption of Ni(CF3COCHCOCF3)2 between 280 and 480 K with a maximum desorption rate around 390 K. However, above 500 K, a variety of decomposition products appeared and etching ceased. Analysis of the clean (i.e., fully reduced surface) showed these products to be a result of the scission of bonds attached to the β-carbon: C–CF3, C–CH and C=O. Furthermore, stabilization of radical species like CF3 on the clean surface resulted in some unexpected decomposition products observed desorbing between 360 and 540 K. Otherwise, some Ni-fluoride desorption was observed on both surfaces above 800 K and Auger revealed carbon on both surfaces after flashing to 900 K. From these results, it is clear that we need to understand the β-scission process better before we can determine how clean etching can be achieved. © 1999 American Vacuum Society.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.43.-h Chemisorption/physisorption: adsorbates on surfaces

In situ atomic force microscope observation of initial stages of corrosion at 18Cr–8Ni stainless steel

F. Katsuki, M. Matsuda, M. Matsumoto, and T. Tomida

J. Vac. Sci. Technol. A 17, 3481 (1999); http://dx.doi.org/10.1116/1.582087 (5 pages)

Full Text: | Download PDF

Show Abstract
Atomic force microscope (AFM) was applied to the investigation of the initial stages of corrosion at 18Cr–8Ni stainless steel. Surfaces of electrochemically or mechanically polished specimens were in situ observed by AFM in a 0.89 M NaCl solution or a 1 M buffered Na2SO4 solution while measuring potentiostatic polarization curves. The mechanical polishing resulted in a substantial increase in corrosion rates, and a dramatic change in surface morphology to a facet structure has been observed in a 0.89 M NaCl solution during an anodic potential sweep up to 0.5 V. The electrochemical polish or the anodic polarization in 1 M buffered Na2SO4 leads to a lower corrosion rate, and the transition from passive to transpassive corrosion states has been clearly detected by AFM as well as in potentiostatic polarization curves. The detailed in situ observation has revealed that the transpassive film is formed on the surface with an oriented rectangle morphology. © 1999 American Vacuum Society.
Show PACS
81.65.Ps Polishing, grinding, surface finishing
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
68.35.B- Structure of clean surfaces (and surface reconstruction)
82.45.-h Electrochemistry and electrophoresis

Tau–Charm factory vacuum chamber design

V. Antropov, E. Perelstein, M. Sazonov, B. Garke, N. Schindler, and C. Edelmann

J. Vac. Sci. Technol. A 17, 3486 (1999); http://dx.doi.org/10.1116/1.582088 (9 pages)

Full Text: | Download PDF

Show Abstract
The present article gives a description of the vacuum chamber required for a high luminosity electron e+−e− collider Tau–Charm factory. The beam lifetime, which is limited by the single particle collisions with molecules of the residual gas, is estimated. The synchrotron radiation gas loading is studied for the Tau–Charm factory vacuum chamber. The effect of various cleaning procedures on the outgassing behavior of samples of the chamber wall is studied. It is shown that a cleaning procedure by a suitable NaOH etching gives the best results of the tested techniques for minimizing of contaminations and outgassing rates. © 1999 American Vacuum Society.
Show PACS
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials
29.20.db Storage rings and colliders
07.30.Bx Degasification, residual gas

Excitation states of titanium and nitrogen gas in an electron beam evaporation sustained arc

S. Q. Xiao, K. Tsuzuki, H. Sugimura, and O. Takai

J. Vac. Sci. Technol. A 17, 3495 (1999); http://dx.doi.org/10.1116/1.582089 (5 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
The arc discharge studied in this work was sustained by titanium vapor evaporated by an electron beam in nitrogen atmosphere. Optical emission spectroscopy and Langmuir probe diagnostics were carried out to study the excitation of titanium and nitrogen. It was found that with increasing arc current, Ti and nitrogen gas exhibited an opposite tendency of excitation. When arc current increased from 20 to 60 A, Ti was highly excited to Ti+, while the excitation of nitrogen was lowered; this is completely different from that for a conventional cathodic arc, where both Ti and N2 are highly ionized. By Langmuir probe diagnostics, the electron energy distribution followed a two-Maxwellian distribution at an arc current of 60 A; the electron temperatures were 0.98 and 10.1 eV, and the corresponding electron densities were 2.7×1011 and 3.9×109 cm3, respectively. This result provided a theoretical explanation for the difference of excitation between titanium and nitrogen in this arc. © 1999 American Vacuum Society.
Show PACS
52.80.Mg Arcs; sparks; lightning; atmospheric electricity
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.70.Ds Electric and magnetic measurements

Development of an all-metal vacuum bellows following twist motion

Yusuke Suetsugu, Masamitsu Shiraishi, Takashi Mishiba, and Yuici Ohno

J. Vac. Sci. Technol. A 17, 3500 (1999); http://dx.doi.org/10.1116/1.582090 (5 pages)

Full Text: | Download PDF

Show Abstract
A novel all-metal vacuum bellows that can follow a twist motion around the axis was designed and developed. The bellows, called here a “twist bellows,” consists of two normal bellows sections and one special bellows section whose corrugation is oblique to the axis. A trial model with a total length of 400 mm and an inner diameter of 100 mm is able to absorb the twist up to about ±22° (44° total) within a twist torque of about 12 N m (120 kg cm) while keeping the total length constant. The twist bellows can also follow the usual bending, shifting, expanding and contracting motion easily like a conventional bellows. The twist bellows allows an unobstructed direct view along the axis and is especially useful for vacuum system of accelerators or synchrotron light beam lines. © 1999 American Vacuum Society.
Show PACS
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials

Innovation of the fore pump and roughing pump for high-gas-flow semiconductor processing

Isao Akutsu and Tadahiro Ohmi

J. Vac. Sci. Technol. A 17, 3505 (1999); http://dx.doi.org/10.1116/1.582091 (4 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
A new screw pump has been developed as a useful backing pump for high-gas-flow semiconductor processing. The characteristic features of the screws are unequal lead and unequal slant angle, which realize higher pumping speed and smaller volume of the pumping system. This pump has a very wide dynamic range of 10−3–760 Torr with a high pumping speed and low electric power consumption by gradational lead screw structure and check valve at outlet. Furthermore, this pump is free from byproduct deposition, corrosion of inner surface and oil degradation. The backdiffusion of oils can be suppressed by admitting the N2 purge gas flow larger than 10 sccm to the inlet side of the pump. © 1999 American Vacuum Society.
Show PACS
07.30.Cy Vacuum pumps
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Influence of vacuum environment on the aging of phosphors at low electron energies

C. H. Seager, D. R. Tallant, L. Shea, K. R. Zavadil, B. Gnade, P. H. Holloway, J. S. Bang, X. M. Zhang, A. Vecht, C. S. Gibbons, P. Trwoga, C. Summers, B. Wagner, and J. Penczek

J. Vac. Sci. Technol. A 17, 3509 (1999); http://dx.doi.org/10.1116/1.582032 (7 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Screened samples of two different commercial phosphors were aged at 1.5 keV under nominally identical conditions in five different vacuum systems. After aging to doses of ∼5 C/cm2 the changes in cathodoluminescence (CL) spectral output and photoluminescence properties were determined, and x-ray photoemission spectroscopy (XPS) and Auger analyses were performed. We observed that while the CL degradation was similar for all systems at low electron doses, the aging rates diverged at high doses, suggesting an increasing importance of the vacuum environment. Post-aged CL spectra showed distinct redshifts in all cases, and the most heavily degraded samples displayed XPS-determined increases in surface carbon levels. The data suggest an extrinsic CL aging mechanism; a model involving the conversion of surface hydrocarbons to a metallic graphite phase agrees with the data. © 1999 American Vacuum Society.
Show PACS
78.55.Hx Other solid inorganic materials
81.40.Gh Other heat and thermomechanical treatments
81.40.Tv Optical and dielectric properties related to treatment conditions
61.80.Fe Electron and positron radiation effects
78.60.Hk Cathodoluminescence, ionoluminescence
79.60.Bm Clean metal, semiconductor, and insulator surfaces
79.20.Fv Electron impact: Auger emission

Surface perturbation target for the Rayleigh–Taylor instability in inertial-confinement fusion experiments

Bin Zhou, Jue Wang, Jun Shen, Zhongsheng Deng, Zhenquan Lai, Lingyan Chen, and Yulong Zhang

J. Vac. Sci. Technol. A 17, 3516 (1999); http://dx.doi.org/10.1116/1.582092 (5 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
A preparation process of a surface perturbation target was introduced in this article. Through laser interference and a nickel-electroplate process, sinusoidal surface perturbation on the photoresist and nickel plate mold with sinusoidal surface perturbation were obtained. We transferred sinusoidal perturbation on brominated polystyrene foils by a spin-coating process. By removing the brominated polystyrene foils from the nickel-plate mold, the brominated polystyrene sinusoidal surface perturbation target was obtained. The transfer precision of the sinusoidal perturbation was measured by scanning electron microscopy. The measurements showed that the surface perturbation was transferred precisely. The surface roughness on the surface perturbation target was about 15.0 nm, analyzed by an α-step apparatus. © 1999 American Vacuum Society.
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.57.-z Laser inertial confinement

Role of boundary conditions at the anode in the development of an electric field induced avalanche in a gas at low pressure

V. Pletnev and S. Zukotynski

J. Vac. Sci. Technol. A 17, 3521 (1999); http://dx.doi.org/10.1116/1.582093 (4 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
A dc glow discharge configuration was investigated that includes a flat semitransparent anode situated between two symmetrically positioned cathodes. The transparency of the anode increases the electron path length for ionizing collisions. This leads to a significant increase in the number of free electrons in the discharge volume. The simplicity of the discharge configuration makes it possible to model the electron avalanche in its early stage with proper boundary conditions and without the use of adjustable parameters in both elastic and nonelastic scattering cross sections. The results obtained for hydrogen indicate that the number of free electrons in the discharge can be increased by several orders of magnitude in comparison with a similar discharge configuration but with an opaque anode. © 1999 American Vacuum Society.
Show PACS
52.80.Hc Glow; corona
back to top
RSS Feeds

High quality low roughness niobium thin films made by electron cyclotron resonance technique

Antonio Esposito, Hiroshi Nakagawa, Hiroshi Akoh, and Susumu Takada

J. Vac. Sci. Technol. A 17, 3525 (1999); http://dx.doi.org/10.1116/1.582094 (4 pages)

Full Text: | Download PDF

Show Abstract
We performed growth of body-centered-cubic Nb thin films using an electron cyclotron resonance (ECR) technique on {100} Si substrates. We deposited Nb films using both Ar and Xe plasmas. Reflection high-energy electron diffraction and atomic force microscopy analyses have been performed in order to observe the surface topography. We found that the surface roughness of films deposited by ECR is 4–5 times smoother than films deposited by magnetron sputtering systems. We obtained this result even at room temperature deposition conditions.© 1999 American Vacuum Society.
Show PACS
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.-a Thin film structure and morphology
back to top
RSS Feeds

Low-cost alternative to motorized linear and rotary motion feedthroughs

P. R. McCabe and A. L. Utz

J. Vac. Sci. Technol. A 17, 3529 (1999); http://dx.doi.org/10.1116/1.582095 (1 page)

Full Text: | Download PDF

Show Abstract
A simple adapter converts a manual motion feedthrough device into its motorized equivalent. © 1999 American Vacuum Society.
Show PACS
06.60.Sx Positioning and alignment; manipulating, remote handling
back to top
RSS Feeds

Erratum: “Temperature dependence of reflection high-energy electron diffraction intensity from Si(111)-7×7 superlattice” [J. Vac. Sci. Technol. A 15, 2569 (1997)]

K. Yamaguchi, H. Mitsui, and Y. Shigeta

J. Vac. Sci. Technol. A 17, 3530 (1999); http://dx.doi.org/10.1116/1.582096 (1 page) | Cited 8 times

Full Text: | Download PDF

Abstract Unavailable
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
99.10.Cd Errata
Close

© 2013 AVS Science & Technology of Materials, Interfaces, and Processing Help | Contact
close