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

Nov 1997

Volume 15, Issue 6, pp. 2831-3170


Fabrication of excess PbO-doped Pb(Zr0.52Ti0.48)O3 thin films using radio frequency magnetron sputtering method

Tae Song Kim, Dong Joo Kim, Jeon Kook Lee, and Hyung Jin Jung

J. Vac. Sci. Technol. A 15, 2831 (1997); http://dx.doi.org/10.1116/1.580835 (5 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
As a method for lowering deposition temperature, the effect of 50% excess Pb addition in Pb(Zr0.52T0.48)O3 ceramic target on Pb(Zr0.52T0.48)O3 thin films (4000–5000 Å thickness) was studied. The PZT thin films were grown on Pt/Ti/SiO2/Si(100) substrates by using radio frequency magnetron sputtering method. The existing phase of PZT thin films was confirmed with x-ray diffraction analysis, and growth morphologies were studied with scanning electron microscopy. At the substrate temperature of 440 °C, only the pyrochlore phase existed, and as the substrate temperature was increased, the amount of perovskite phase also increased. It was finally found that the PZT thin films without pyrochlore phase could be fabricated at the temperature as low as 520 °C. It was also observed that the quality of the final phases after the postannealing process severely depends on the initial perovskite phase purity during deposition. The electrical properties of PZT thin films were characterized through P–E hysteresis curves, dielectric constant and loss, and fatigue measurements. It was confirmed that the electrical properties of PZT thin films were closely related to the crystallographic microstructure of PZT thin films. © 1997 American Vacuum Society.
Show PACS
81.15.Cd Deposition by sputtering
77.55.-g Dielectric thin films
77.80.Dj Domain structure; hysteresis
77.22.Gm Dielectric loss and relaxation
68.55.-a Thin film structure and morphology
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
62.20.M- Structural failure of materials
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
77.22.Ch Permittivity (dielectric function)

Properties of crystallized Si1−xGex thin films deposited by sputtering

Emil V. Jelenkovic, K. Y. Tong, Z. Sun, C. L. Mak, and W. Y. Cheung

J. Vac. Sci. Technol. A 15, 2836 (1997); http://dx.doi.org/10.1116/1.580836 (6 pages) | Cited 20 times

Full Text: | Download PDF

Show Abstract
Si1−xGex were deposited by a radio frequency magnetron sputtering system and were furnace crystallized at a temperature of 550 °C. The crystallization process was characterized by x-ray diffraction (XRD), Raman spectra, electron spin resonance transmission electron microscopy. The effect of germanium content in the films was studied for samples with germanium from 19% to 53%. Doping of Si1−xGex films by phosphorous was investigated through measurement of sheet resistance and carrier mobility. It was found that sputtered Si1−xGex films can be useful for thin film transistors with low temperature budget. No significant clustering of pure Ge or Si in Si1−xGex films was deduced from the recorded XRD and Raman spectra. © 1997 American Vacuum Society.
Show PACS
68.55.-a Thin film structure and morphology
81.05.Hd Other semiconductors
81.15.Cd Deposition by sputtering
73.61.Le Other inorganic semiconductors
78.30.Hv Other nonmetallic inorganics
78.66.Li Other semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance
76.30.-v Electron paramagnetic resonance and relaxation
61.72.up Other materials

Direct current magnetron sputtered W–AlN cermet solar absorber films

Qi-Chu Zhang

J. Vac. Sci. Technol. A 15, 2842 (1997); http://dx.doi.org/10.1116/1.580837 (5 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
W–AlN cermet selective surfaces have been investigated using a special direct current (dc) magnetron sputtering technology. During the deposition of the W–AlN cermet layer, both Al and W targets were run simultaneously in a gas mixture of argon and nitrogen. The total sputtering gas pressure was 1 Pa and the reactive nitrogen gas partial pressure was chosen at 2.5×10−2 Pa, which is beyond the transition point from metal phase to dielectric phase in the deposited material. The ceramic AlN component was deposited by dc reactive sputtering and the metallic W component by dc sputtering due to the excellent nitriding resistance of metallic tungsten. By substrate movement a multi-sublayer system, consisting of alternating W and AlN sublayers, was deposited. This deposited multi-sublayer system can be considered as a macro-homogeneous W–AlN cermet layer with metal volume fraction determined by controlling the thickness of the sublayers. W–AlN cermet selective surfaces with a double cermet layer film structure were deposited. The typical film structure from surface to bottom substrate is an AlN anti-reflection layer on a double W–AlN cermet layer on an Al metal infrared reflection layer. A solar absorptance of 0.92–0.94 with emittance of 0.03–0.05 at room temperature and 0.08–0.10 at 350°C has been achieved for such W–AlN cermet selective surfaces. The W–AlN cermet has excellent thermal stability in vacuum at high operating temperature. © 1997 American Vacuum Society.
Show PACS
42.79.Ek Solar collectors and concentrators
81.05.Mh Cermets, ceramic and refractory composites
81.15.Cd Deposition by sputtering
42.79.Wc Optical coatings

Simulation of sputter deposition at high pressures

T. Smy, L. Tan, S. S. Winterton, S. K. Dew, and M. J. Brett

J. Vac. Sci. Technol. A 15, 2847 (1997); http://dx.doi.org/10.1116/1.580838 (7 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Sputtering, although often optimized by trial and error, increasingly needs sound modeling techniques because of the high capital investment. Usually the simulation problem is broken down into three stages: emission at the target, transport through the host gas, and deposition at the substrate. It turns out that these stages are necessarily linked and must be properly decoupled. Here we are mainly interested in the transport through the vapor phase, which may be simulated by our Monte Carlo model, SIMSPUD. However, at high operating pressures, significant deposition takes place onto the target. To modify our Monte Carlo routine, rather than emitting particles in proportion to the erosion profile of the target and waiting for some of these to completely escape, all particles which land on the target are re-emitted until they ultimately escape to the substrate or chamber walls. This modification makes the net emission rate equal to the target erosion rate. At sufficiently high pressures, the Monte Carlo routine becomes very slow. In fact, the problem then becomes a diffusion problem best handled by numerical solution of the Laplace equation. At any rate, it is shown that when SIMSPUD has been modified in this way, good agreement with experiment is obtained over a wide range of working pressures. © 1997 American Vacuum Society.
Show PACS
81.15.Cd Deposition by sputtering
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Time dependence and spatial distribution of the deposition rate of YBa2Cu3O7 thin films in 90° off-axis sputtering

P. G. Quigley, R. A. Rao, and C. B. Eom

J. Vac. Sci. Technol. A 15, 2854 (1997); http://dx.doi.org/10.1116/1.580839 (5 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
We have examined the time dependence and spatial distribution of the deposition rate of YBa2Cu3O7 (YBCO) thin films in 90° off-axis radio frequency planar magnetron sputtering throughout the life of a target. We have found that although the amount of YBCO sputtered from the target is constant, the amount of YBCO deposited on the substrate decreases linearly over time. Furthermore, the time dependence of the deposition rate changes at different positions on the substrate. The changes in the deposition rate at any point along the substrate as a function of time can be explained by the change in the angular distribution of the sputtered particles that is caused by changes in the target erosion groove geometry, and the decrease in the kinetic energy of sputtered particles that is indicated by the decrease in the self-bias voltage over time. © 1997 American Vacuum Society.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
81.15.Cd Deposition by sputtering
74.72.-h Cuprate superconductors

Mass and energy measurements of the species responsible for cBN growth in rf bias sputter conditions

Osamu Tsuda, Yoshinao Tatebayashi, Yukiko Yamada-Takamura, and Toyonobu Yoshida

J. Vac. Sci. Technol. A 15, 2859 (1997); http://dx.doi.org/10.1116/1.580840 (5 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Mass and energy measurements of ions and neutrals impinging on a substrate surface were performed during radio frequency (rf) bias sputter deposition of cubic boron nitride (cBN) thin films in a pure Ar discharge. The sampling system was rf driven to measure the correct energy of ions impinging to the rf driven substrate. The ion energy distributions showed asymmetric bimodal shapes and the energy spreads varied with the masses of ions and the negative substrate bias voltage (Vs). Ar+ was the most dominant ion, and the average energy and energy spread changed with Vs from 90 to 310 eV and from 40 to 140 eV, respectively. The flux ratio of Ar+ to B (Φi/ΦB) increased from 1.0 to 2.3 with a decrease in the target power input. cBN could be deposited above a threshold of the total momentum transfer per depositing boron atoms; 138 (eV amu)1/2, which is comparable to the values reported in the ion beam assisted depositions. Therefore, argon ions with an energy of 135 to 380 eV are considered to be equally contributory for cBN formation. Moreover, nucleation of cBN depends on Φi/ΦB, namely, the flux ratio of ion to boron, and requires accumulation of a certain surface state caused by ion bombardment effects, such as defects generation or densification. © 1997 American Vacuum Society.
Show PACS
81.05.Ea III-V semiconductors
81.15.Cd Deposition by sputtering
61.80.Jh Ion radiation effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Discharge disruptions in a helicon plasma source

K. P. Shamrai, V. F. Virko, H.-O. Blom, V. P. Pavlenko, V. B. Taranov, L. B. Jonsson, C. Hedlund, and S. Berg

J. Vac. Sci. Technol. A 15, 2864 (1997); http://dx.doi.org/10.1116/1.580841 (11 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
We study experimentally and theoretically stable regimes and discharge disruptions in a helicon plasma source. At fixed input power and gas pressure, stable operation of the source is possible below some critical value of magnetic field Bcr. The plasma density increases with the magnetic field and reaches a maximum value nmax at Bcr; after which the discharge disruption occurs. Both Bcr and nmax increase almost linearly with the input power and the rate of increase is increasing with the pressure. Matching of the plasma load to the rf power source improves when approaching the disruption point, and becomes perfect at the critical field. The theory of discharge disruptions assumes the power absorption in a helicon source to arise from the linear conversion of helicon waves into electrostatic waves at the plasma edge. The calculated dependence of the absorbed power on the plasma density turns out to be nonmonotonic with minima at antiresonances of the electrostatic wave excitation. This explains qualitatively principal peculiarities of discharge disruptions. The calculated plasma impedance is in agreement with experimental value within a factor of 2. © 1997 American Vacuum Society.
Show PACS
52.50.Dg Plasma sources
52.80.-s Electric discharges
52.25.-b Plasma properties
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.40.Hf Plasma-material interactions; boundary layer effects

Development of an energetic ion assisted mixing and deposition process for TiNx and diamondlike carbon films, using a co-axial geometry in plasma source ion implantation

Shamim M. Malik, R. P. Fetherston, and J. R. Conrad

J. Vac. Sci. Technol. A 15, 2875 (1997); http://dx.doi.org/10.1116/1.580842 (5 pages) | Cited 19 times

Full Text: | Download PDF

Show Abstract
Plasma source ion implantation (PSII) is a relatively simple technique for the ion implantation/deposition of materials. In PSII a substrate is immersed in a plasma, and high negative voltage pulses are applied to accelerate ions into the substrate resulting in modification of the properties of the material in the near surface region. A technique was developed to produce uniform diamondlike carbon coatings and TiNx films inside and outside a hollow cylinder (substrate). A description of apparatus, experimental methods for this type of deposition process, and preliminary results are presented in this article. © 1997 American Vacuum Society.
Show PACS
61.72.up Other materials
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Jj Ion and electron beam-assisted deposition; ion plating
68.35.Fx Diffusion; interface formation
61.80.Jh Ion radiation effects
85.40.Ry Impurity doping, diffusion and ion implantation technology

Influence on selective SiO2/Si etching of carbon atoms produced by CH4 addition to a C4F8 permanent magnet electron cyclotron resonance etching plasma

Shoji Den, Tatsushi Kuno, Masafumi Ito, Masaru Hori, Toshio Goto, Patrick O’Keeffe, Yuzo Hayashi, and Yuichi Sakamoto

J. Vac. Sci. Technol. A 15, 2880 (1997); http://dx.doi.org/10.1116/1.580843 (5 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Changes in the densities of fluorocarbon radicals and fluorine atoms in a size-scalable large-area compact permanent magnet electron cyclotron resonance etching plasma source employing C4F8 gas with CH4 addition have been investigated. Measurements using infrared laser absorption spectroscopy and actinometric optical emission spectroscopy show that, for a pure C4F8 plasma, the dominant species is CF2 radicals with a density of the order of 1013 cm−3, followed by fluorine atoms, CF3 and CF2 radicals which have a density an order of magnitude lower at 1012 cm−3. The densities of the different fluorocarbon radical species were found to display different dependencies on increasing CH4 gas addition. Hollow cathode absorption spectroscopy was used to estimate the carbon atom density for the first time, to the best of our knowledge, in an etching plasma. The carbon atom density in the plasma increases linearly with CH4 gas addition between 20 and 80%. Analysis of actual SiO2/Si etching revealed that the etch selectivity and carbon atom to fluorine atom ratio follows a similar trend indicating a direct correlation between the carbon atom density in the plasma and the etch selectivity. © 1997 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
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
52.25.-b Plasma properties
82.30.Cf Atom and radical reactions; chain reactions; molecule-molecule reactions
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
52.50.Dg Plasma sources
52.70.Kz Optical (ultraviolet, visible, infrared) measurements

Characterization of an azimuthally symmetric helicon wave high density plasma source

G. R. Tynan, A. D. Bailey, G. A. Campbell, R. Charatan, A. de Chambrier, G. Gibson, D. J. Hemker, K. Jones, A. Kuthi, C. Lee, T. Shoji, and M. Wilcoxson

J. Vac. Sci. Technol. A 15, 2885 (1997); http://dx.doi.org/10.1116/1.580844 (8 pages) | Cited 60 times

Full Text: | Download PDF

Show Abstract
A cylindrically symmetric (azimuthal mode number m=0) resonant inductive (MO̸RITM) radio frequency (rf) helicon wave high density plasma source is described. The source consists of an antenna and bell jar generator immersed in a diverging magnetic field. Plasma is generated in this upstream region and then is transported along the field lines into the low-field downstream processing chamber. A propagating wave is observed in the plasma with rf spatial distribution and propagation characteristics that obey the theoretical m=0 helicon wave dispersion relation. By varying the divergence of the source magnetic field, the wafer etch rate and etch uniformity can be controlled. Spatially resolved optical emission spectroscopy shows that molecular gases are almost completely dissociated near the plasma center and have a uniform radial distribution. Highly uniform plasma and neutral distributions are then produced at the wafer location, and have been used in a variety of etch applications. © 1997 American Vacuum Society.
Show PACS
52.50.Dg Plasma sources
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
52.40.Fd Plasma interactions with antennas; plasma-filled waveguides
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.35.Hr Electromagnetic waves (e.g., electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid)
52.25.-b Plasma properties
81.65.Cf Surface cleaning, etching, patterning
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)

Structure and chemical composition of fluorinated SiO2 films deposited using SiF4/O2 plasmas

Sang M. Han and Eray S. Aydil

J. Vac. Sci. Technol. A 15, 2893 (1997); http://dx.doi.org/10.1116/1.580845 (12 pages) | Cited 40 times

Full Text: | Download PDF

Show Abstract
Attenuated total reflection Fourier transform infrared spectroscopy and spectroscopic ellipsometry were employed for chemical and structural analysis of fluorinated SiO2 deposited in SiF4 and O2 plasmas. Isotopic substitution of 16O2 with 18O2 in the feed gas mixture was used to determine whether F is bonded to Si or O atoms in the film. Isotopic substitution experiments revealed that infrared active SiO–F stretching mode in SiO2 matrix appears at 1372 cm-1 but only when the SiF4-to-O2 ratio of the feed gas mixture is reduced below 0.1. The SiOF species in fluorinated SiO2 result from insertion of O into SiF bonds, which have been already incorporated into the film. Deposition experiments using 16O2 and 18O2 also helped identify silicon mono- and di-fluorides (O3SiF and O2SiF2), which were most abundant in fluorinated SiO2. The stretching mode of O3Si–F appears at 950 cm-1, whereas the antisymmetric and symmetric stretching modes of O2Si–F2 appear at 990 cm-1 and 920 cm-1, respectively. The concentration of silicon fluorides increase monotonically with increasing SiF4-to-O2 ratio. The increase in silicon fluoride concentration causes the Si–O–Si phonon peaks to blueshift and narrow by relaxing the Si–O–Si bond angle and by decreasing the film density. Narrowing of the SiO2 phonon at 1080 cm-1 is due to SiOSi bond angle relaxation and not due to a more homogenous and ordered fluorinated SiO2 structure than unfluorinated SiO2 as suggested in previous reports. This bond angle relaxation and density reduction are accompanied by a decrease in the refractive index. Although the low refractive index signals low dielectric constant, the chemical susceptibility of SiF to O2 and H2O limits the maximum allowable silicon fluoride concentration in SiOF films to approximately 11 at. %. © 1997 American Vacuum Society.
Show PACS
78.66.Nk Insulators
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
77.22.Ch Permittivity (dielectric function)
68.55.-a Thin film structure and morphology
77.55.-g Dielectric thin films
78.30.Hv Other nonmetallic inorganics
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
63.20.-e Phonons in crystal lattices
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.)

Characteristics of spray pyrolytic ZnO:In thin films grown from zinc acetate and indium nitrate

A. Maldonado, M. de la L. Olvera, R. Asomoza, E. P. Zironi, J. Cañetas-Ortega, and J. Palacios-Gómez

J. Vac. Sci. Technol. A 15, 2905 (1997); http://dx.doi.org/10.1116/1.580883 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
The structural, electrical and optical properties of indium doped zinc oxide films, grown by spray pyrolysis are reported. The starting solution was zinc acetate diluted in a mixture of isopropyl alcohol and water to 0.1 M, the doping solution was an aqueous solution of indium nitrate. The films were grown at substrate temperatures ranging from 675 K to 800 K. X-ray diffraction and micrographs indicate that the films are polycrystalline with textured surfaces having a predominance of the (002) and (101) reflections, depending on the substrate temperature. They have a resistivity as low as 6×10−5Ω m and a transmittance better than 85% in the visible range. © 1997 American Vacuum Society.
Show PACS
81.05.Dz II-VI semiconductors
81.15.Rs Spray coating techniques
73.61.Ga II-VI semiconductors
78.66.Hf II-VI semiconductors
68.55.-a Thin film structure and morphology
78.40.Fy Semiconductors
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)

Structure of fluorine-doped silicon oxide films deposited by plasma-enhanced chemical vapor deposition

M. Yoshimaru, S. Koizumi, and K. Shimokawa

J. Vac. Sci. Technol. A 15, 2908 (1997); http://dx.doi.org/10.1116/1.580884 (7 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
The Fourier transform infrared (FTIR) spectra and Raman spectra of fluorine-doped silicon oxide films capped by silicon nitride thin film to prevent water absorption from the air were measured as a function of the fluorine concentration in the films. It was found that fluorine doping diminishes the Si–OH bonds in films. Films without fluorine show a clear OH band attributable to Si–OH bonds, but films with 7.6 at % (F) or more exhibit no OH band in FTIR spectra. The FTIR spectra also show that fluorine in films forms new absorption bands at frequencies ranging from 990 to 920 cm−1. These absorption bands are assigned as silicon monofluoride sites (940 cm−1) and as silicon difluoride sites (925 and 985 cm−1). While the silicon difluoride sites increase linearly with increasing fluorine source gas flow, the increase in silicon monofluoride sites saturate at a certain fluorine source gas flow [i.e., a fluorine concentration in film of about 7.6 at % (F)]. The Raman spectra show that fluorine doping reduces the planar threefold ring structures in the films. It is surmised that fluorine interchanges preferentially with oxygen in strained Si–O–Si bonds, forming silicon monofluoride and silicon difluoride sites. © 1997 American Vacuum Society.
Show PACS
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.-a Thin film structure and morphology
78.30.Am Elemental semiconductors and insulators
78.40.Ha Other nonmetallic inorganics
78.66.Nk Insulators
61.50.Lt Crystal binding; cohesive energy
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology

Interaction between water and fluorine-doped silicon oxide films deposited by plasma-enhanced chemical vapor deposition

M. Yoshimaru, S. Koizumi, and K. Shimokawa

J. Vac. Sci. Technol. A 15, 2915 (1997); http://dx.doi.org/10.1116/1.580885 (8 pages) | Cited 22 times

Full Text: | Download PDF

Show Abstract
The interaction between water and fluorine-doped silicon oxide (SiOF) films has been studied using Fourier transform infrared spectroscopy and thermal desorption spectroscopy. The effects of the interaction on the relative dielectric constant of films were also studied using capacitance–voltage measurements. It was found that SiOF films with high fluorine concentration have three absorption bands attributable to Si–Fn stretching vibration, however, the SiOF films have only one absorption band after humidification. The residual band is assumed to be attributable to silicon monofluoride [Si(O–)3F] sites and the disappearing bands are attributable to silicon difluoride [Si(O–)2F2] sites. Si(O–)2F2 sites are hydrided during humidification and generate Si–OH bonds and HF in the film. In addition, Si(O–)2F2 sites increase the water absorbed in film. The relative dielectric constant of SiOF films capped by silicon nitride decreased steadily with increased fluorine concentration, from 4.5 (SiO2) to less than 2.8 [11.5 at. % (F)], however, that of uncapped SiOF films saturated the decrease at about 3.6 in films having 7.6 at. % (F) or more. This saturation is caused by the increase of Si(O–)2F2 sites in film because the ratio of Si(O–)2F2 sites to total fluorine bonding sites increases markedly at a fluorine concentration above 7.6 at. % (F). Si(O–)2F2 sites increase Si–OH bonds and water absorbed in film, and both, in turn, increase the film dielectric constant. © 1997 American Vacuum Society.
Show PACS
73.61.Ng Insulators
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.
81.65.-b Surface treatments
78.30.Am Elemental semiconductors and insulators
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
77.22.Ch Permittivity (dielectric function)

Parametrization of the Laframboise theory for cylindrical Langmuir probe analysis

Michael Mausbach

J. Vac. Sci. Technol. A 15, 2923 (1997); http://dx.doi.org/10.1116/1.580886 (7 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
In this investigation we parametrize the numerical results of Laframboise with the function f(χ)=a(b+χ)c, where a, b, and c are fit parameters and χ is the normalized probe potential. The fits show a clear relation between these fitting parameters and the probe characteristic. With these parameters we construct a self-consistent algorithm to fit measured cylindrical probe characteristics of a Maxwellian plasma without any assumption for the relation of the characteristic Langmuir probe dimension to the Debye length. The measured probe characteristics of an anodic Cu-vapor vacuum arc are analyzed by means of this nonlinear fitting algorithm. From the determined plasma parameters we obtain clear indications for hot ions. The mean deviation of the calculated theoretical probe characteristic from the measured characteristic is <2%. © 1997 American Vacuum Society.
Show PACS
52.70.Ds Electric and magnetic measurements
52.80.Vp Discharge in vacuum
52.80.Mg Arcs; sparks; lightning; atmospheric electricity

Electrical characterization of a processing plasma chamber

Weston C. Roth, Robert N. Carlile, and John F. O’Hanlon

J. Vac. Sci. Technol. A 15, 2930 (1997); http://dx.doi.org/10.1116/1.580887 (8 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
In this article, we discuss techniques for electrically characterizing a plasma processing tool for the purpose of measuring the plasma impedance at the fundamental frequency. This was accomplished by building a “probe station” containing commercially available current and voltage probes which can be inserted into the radio frequency (rf) coaxial cable through which rf power is supplied to the driven electrode. We have applied our techniques to a specific tool, the Tegal modified MCR-1 etch system. We find that an essential part of the characterization is the measurement of the impedance of the device when the plasma is extinguished, which is in parallel with the plasma impedance. We find that this impedance is an inductance in series with a capacitance, similar to that found for the GEC reference cell; thus, this equivalent circuit may be universal although the element values will be machine dependent. Measurement of plasma impedance at harmonic frequencies is discussed. For the Tegal tool, we find that when the rf power is applied as a step function at t=0, the plasma impedance exhibits a transient for both its resistance and reactance. The transient occurs during the first 4 min after rf power is applied, during which the resistance and reactance decrease by 10%–20%, and then finally achieve a value that thereafter is nearly invariant in time. We have ruled out contamination, temperature effects, and plasma chemistry as the source of the transient. The impedance transient correlates well with a similar transient that we observe in the density of water vapor molecules that are present in the chamber, and we speculate that there may be a correlation between the two. The transient should be of concern to processing engineers who may find processing parameters changing during the process time, which is usually comparable to 4 min. © 1997 American Vacuum Society.  
Show PACS
52.70.-m Plasma diagnostic techniques and instrumentation
84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning

Investigation of stored energy in plasma deposited TiNx films

H. Wulff and C. Eggs

J. Vac. Sci. Technol. A 15, 2938 (1997); http://dx.doi.org/10.1116/1.580888 (7 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Thin TiNx films were deposited using a hollow cathode arc evaporation device (HCAED) for studying the influence of low energy ion bombardment on film growth and film properties. Films were deposited at various nitrogen gas flows and negative substrate voltages and investigated by x-ray photoelectron spectroscopy (XPS) and thin film x-ray diffraction. The plasma was analyzed by Langmuir probe measurements and energy resolved mass spectrometry. From both the results of nitrogen flow experiments and the negative substrate voltage experiments it can be concluded that the ion concentration as well as the ion energy determine the film properties. The data obtained from plasma monitoring and Langmuir probe measurements were used to calculate the energy flux to the growing film in relation to the deposition parameters. XPS provides information about the chemical composition. From shifting and broadening of x-ray line profiles concentrations of interstitials, dislocation densities, and domain sizes in the films were calculated. The stored energy in the films induced by low energy ion bombardment was calculated using the energy of individual interstices and dislocations and from the fraction of atoms associated with grain boundaries. The estimation of stored energy in grain boundaries was based on a simple model concerning domain sizes and melting heat. These results were compared with investigations of the energy transfer to the substrate during the film deposition in a HCAED. The stored energy is four orders of magnitude smaller than the total ion energy flux. © 1997 American Vacuum Society.
Show PACS
68.55.-a Thin film structure and morphology
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.15.Jj Ion and electron beam-assisted deposition; ion plating
61.80.Jh Ion radiation effects
79.60.Bm Clean metal, semiconductor, and insulator surfaces
52.70.-m Plasma diagnostic techniques and instrumentation
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
61.72.J- Point defects and defect clusters
61.72.Mm Grain and twin boundaries

Effect of grain size and Pb dopant on luminescence in BaTiO3

R. S. Katiyar, J. F. Meng, and Brajesh K. Rai

J. Vac. Sci. Technol. A 15, 2945 (1997); http://dx.doi.org/10.1116/1.580889 (4 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
Photoluminescence spectra of Ba1−xPbxTiO3 with grain sizes of 60 nm have been obtained. Different emission bands for pure BaTiO3 have been separately obtained against two excitation lines of 488.0 and 514.5 nm. Based on the dependence of the visible emission band upon Pb content and excitation power, a model that describes the origin of visible emission has been suggested. © 1997 American Vacuum Society.
Show PACS
78.55.Hx Other solid inorganic materials
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
61.46.-w Structure of nanoscale materials

Experimental test of the propagation of a He pressure front in a long, cryogenically cooled tube

E. Wallén

J. Vac. Sci. Technol. A 15, 2949 (1997); http://dx.doi.org/10.1116/1.580890 (10 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
A series of measurements on the propagation speed of a He pressure front in a cryogenically cooled 75.3 m long, 4.3 cm i.d. stainless steel tube at 1.9 K and 4.25 K and a theoretical model for the phenomenon of limited propagation speed of such a He pressure front are described. The measurements have shown that it took 20 h for a He leak of 5.7×10−5 Torr l/s to be detected at the other end of the 75.3 m tube at 1.9 K and if the leak was increased to 1.4×10−4 Torr l/s, still at 1.9 K, the time for the He to be detected at the distant end was reduced to 8.7 h. With the tube at 4.25 K, it took 5.0 h for a He leak of 7.0×10−5 Torr l/s to be detected at the other end. The He travels through the tube in the form of a pressure front with a steep leading pressure gradient. A model involving the adsorption isotherm for He on stainless steel which is able to predict the time of arrival of the He pressure front at the distant end within 17% is described. © 1997 American Vacuum Society.
Show PACS
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
07.30.Hd Vacuum testing methods; leak detectors

Transition metal cleaning using thermal beams

Jane P. Chang, Zhe Zhang, Han Xu, Herbert H. Sawin, and Jeffery W. Butterbaugh

J. Vac. Sci. Technol. A 15, 2959 (1997); http://dx.doi.org/10.1116/1.580891 (9 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
The cleaning of transition metals including copper, nickel and iron from silicon surfaces at ambient temperature was demonstrated using various thermal beams. Sputter-deposited copper was found in two forms on silicon surfaces: uniformly dispersed copper and copper islands. At room temperature, a ClF3 beam removed the uniformly dispersed copper, but not the copper islands. Since copper–halides are not volatile at room temperature, the observation of uniformly dispersed copper removal suggested the formation of a volatile silicon–copper–halogen species. To remove the copper islands, a hot thermal dichlorosilane SiCl2H2 (DCS) beam which pyrolytically produces SiCl2 was used as a reactive silicon source. The DCS beam alone deposited SiClx on wafer surfaces suppressing complete copper removal. Exposure of this surface to ClF3 removed the SiClx deposition and copper islands from the wafer surface at room temperature. Beams containing DCS+Cl2 or DCS+F2 in which the F2 or Cl2 was also pyrolytically dissociated at 1000 °C to form F and Cl atoms, were tested. The combination of DCS with Cl2 at a beam temperature of 1000 °C reduced the deposition rate, but did not remove all of the copper islands from the wafer surface. A F2 beam at 1000 °C alone did not remove the SiClx deposition as ClF3 did; however, the mixed DCS+F2 beam at 1000 °C removed copper to below the detection limit of x-ray photoelectron spectroscopy without any observable deposition. These results validated the proposed copper removal mechanism in which a volatile copper–halogen–silicon compound was formed. The mixed DCS+F2 beam was also capable of removing other transition metals such as nickel and iron at room temperature. © 1997 American Vacuum Society.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
81.05.Cy Elemental semiconductors
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Doping of amorphous and microcrystalline silicon films deposited by hot-wire chemical vapor deposition using phosphine and trimethylboron

P. Brogueira, V. Chu, A. C. Ferro, and J. P. Conde

J. Vac. Sci. Technol. A 15, 2968 (1997); http://dx.doi.org/10.1116/1.580892 (15 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
The optical, electronic and structural properties of n-type and p-type doped amorphous (a-Si:H) and microcrystalline (μc-Si:H) silicon films prepared by hot-wire chemical vapor deposition are studied. Intrinsic a-Si:H films deposited at filament temperatures Tfil∼1900 °C and 2500 °C using equal silane and hydrogen flow rates, and intrinsic μc-Si:H films deposited either by increasing the hydrogen dilution (FH2/FSiH4⩾10) or decreasing the filament temperature (Tfil∼1500 °C), were doped using phosphine (PH3, n-type doping) or trimethylboron (B(CH3)3, p-type doping). The dependence of the properties of the doped films on Tfil, dopant-to-silane gas flow ratio, and hydrogen dilution is studied. Both p-type and n-type μc-Si:H films were prepared and showed dark conductivities σd∼1  Ω−1 cm−1 and activation energies of σd, Ea,σd∼0.05 eV. N-type a-Si:H films were prepared and showed σd∼10−2  Ω−1 cm−1, Ea,σd∼0.25 eV, whereas p-type doping was less efficient, showing σd∼2×10−6  Ω−1 cm−1, Ea,σd∼0.45 eV. High growth rates (rd⩾15 Å/s) were obtained for all the a-Si:H doped samples. Tungsten (W) contamination of the amorphous samples was kept below the detection limit of the secondary ion mass spectroscopy analysis (∼5×1017 atoms/cm3) for all Tfil. The μc-Si:H samples showed W incorporation close to the detection limit (5–7×1017 atoms/cm3) for Tfil⩾1900 °C. The deep defect density dependence on the dopant-to-silane flow rate ratio was found to be consistent with the defect equilibrium doping model. © 1997 American Vacuum Society.
Show PACS
81.05.Cy Elemental semiconductors
61.72.uf Ge and Si
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
72.20.Fr Low-field transport and mobility; piezoresistance
72.80.Cw Elemental semiconductors
72.80.Ng Disordered solids
73.61.Jc Amorphous semiconductors; glasses
78.66.Jg Amorphous semiconductors; glasses
81.05.Gc Amorphous semiconductors
73.61.Cw Elemental semiconductors
71.55.Jv Disordered structures; amorphous and glassy solids
71.55.Cn Elemental semiconductors

Characterization of carbon nitride produced by high-current vacuum arc deposition

J. Hartmann, P. Siemroth, B. Schultrich, and B. Rauschenbach

J. Vac. Sci. Technol. A 15, 2983 (1997); http://dx.doi.org/10.1116/1.580893 (5 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
Carbon nitride thin films were deposited using the high-current arc (HCA) evaporation technique varying the pressure in the chamber and the position of the samples with respect to the evaporation source. At direct deposition the nitrogen content in the films measured by elastic recoil detection analysis saturates at an atomic ratio of 0.18 due to chemical sputtering. At positions where the substrates are shaded from the carbon plasma by the sample holder the nitrogen content increases up to 48 at. %. This observation can be explained by a decreased energy of the carbon ions, a higher arrival ratio of nitrogen to carbon ions and the high degree of ionization using the HCA technique. Varying the sample position the binding character of nitrogen to carbon atoms in the films changes from sp3 to sp2. When the energy of the deposited particles is reduced graphitic clusters are formed in an amorphous matrix. © 1997 American Vacuum Society.
Show PACS
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.Nq Composition and phase identification
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Diamond films grown by hot filament chemical vapor deposition from a solid carbon source

H. K. Woo, S. T. Lee, C. S. Lee, I. Bello, and Y. W. Lam

J. Vac. Sci. Technol. A 15, 2988 (1997); http://dx.doi.org/10.1116/1.580894 (5 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
Continuous diamond films have been grown on mirror-polished silicon, polycrystalline copper, SiC and high oriented pyrolytic graphite substrates using hot filament assisted chemical vapor deposition. Instead of using conventional gaseous carbon source, a graphite plate was used as the carbon source with hydrogen as the only feeding gas. No substrate pretreatment such as diamond powder scratching or negative biasing was needed. When carbon-13 was used as the carbon source, only diamond-12 was detected on carbon-13 indicating that deposition rather than direct conversion of carbon to diamond occurred. High nucleation density and conversion efficiency were obtained for the present growing process. Diamond films grown by this method were found to be particularly pure in diamond content. © 1997 American Vacuum Society.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.05.ub Fullerenes and related materials
81.05.Cy Elemental semiconductors
68.55.-a Thin film structure and morphology

Dependence of atomic layer-deposited Al2O3 films characteristics on growth temperature and Al precursors of Al(CH3)3 and AlCl3

Sun Jin Yun, Kyung-Ho Lee, Jarmo Skarp, Hae-Rim Kim, and Kee-Soo Nam

J. Vac. Sci. Technol. A 15, 2993 (1997); http://dx.doi.org/10.1116/1.580895 (5 pages) | Cited 33 times

Full Text: | Download PDF

Show Abstract
The materials characteristics of Al2O3 films grown on a Si (100) substrate by traveling wave reactor atomic layer deposition were investigated in the growth temperature ranging from 250 to 500 °C. The Al2O3 films grown using Al(CH3)3 trimethylaluminum (TMA) and H2O as precursors were characterized and also compared with the films grown using AlCl3 and H2O. Both samples grown with different precursors revealed identical chemical binding state of oxidized Al and very flat surface morphology. In the study of impurity incorporation, the films grown using TMA showed the C and H count rates of secondary ion mass spectrometry (SIMS) approximately six and 10 times higher than those of the film grown using AlCl3, respectively. For the Al2O3 films grown using TMA, the results showed that the impurity contents and the growth rate of the films decreased and the refractive index increased with the growth temperature. The content of impurities could be also lowered by increasing the N2 purge time after TMA pulse. However, the effect of purge time increase on the impurity incorporation was very small compared to that of growth temperature. The refractive indices were 1.64 and 1.68 at the growth temperatures of 250 and 400 °C, respectively. The rough estimation of H content using refractive indices and SIMS data indicated that the H content decreased from approximately 8.5 to 3.0 at. % as the substrate temperature increased from 250 to 400 °C. The Al2O3 film grown using AlCl3 and H2O at 500 °C, which contained approximately 0.5 at. % Cl, revealed a refractive index of 1.65. © 1997 American Vacuum Society.
Show PACS
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
78.66.Nk Insulators

Kinetics of adsorption and photodesorption of hydrogen on copper surfaces

W. H. Bailey, T. S. Rahman, M. Strongin, and J. W. Davenport

J. Vac. Sci. Technol. A 15, 2998 (1997); http://dx.doi.org/10.1116/1.580896 (7 pages)

Full Text: | Download PDF

Show Abstract
The kinetics of adsorption and photodesorption of hydrogen on a Cu surface is discussed for the next generation of high energy proton colliders. The equilibrium solution of a rate equation describing the surface kinetics leads to an expression for the gas pressure, which we estimate to be about 10−8 Torr for proton beam colliders like the now defunct 20-TeV superconducting super collider. Using classical molecular dynamics simulations with reliable interatomic potentials we find the fractional energy loss of hydrogen on Cu(100), for incident energies ranging from 0.1–1.0 eV, to be between 1%–6%. This leads to an estimate of 10−4 s for the average lifetime of the hydrogen molecule in the beam tube. © 1997 American Vacuum Society.
Show PACS
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
79.20.La Photon- and electron-stimulated desorption
82.20.Wt Computational modeling; simulation

Surface processes occurring on TiSi2 and CoSi2 in fluorine-based plasmas. Reactive ion etching in CF4/CHF3 plasmas

M. R. Baklanov, S. Vanhaelemeersch, W. Storm, Y-B. Kim, W. Vandervorst, and K. Maex

J. Vac. Sci. Technol. A 15, 3005 (1997); http://dx.doi.org/10.1116/1.580897 (10 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The kinetics of TiSi2 and CoSi2 etching in CF4/CHF3 plasmas are studied. X-ray photoelectron spectroscope studies show that after the reactive ion etching (RIE) etching of TiSi2 and CoSi2 with different gas composition, complex protective films, containing both CFx polymers and metal fluorides, are formed. The relative amount of metal fluoride and polymer depends on the gas composition. A phenomenological model describing the RIE of the metal silicides in the carbon–fluoride plasmas is established. It is shown that in the case of TiSi2, selective etching of SiO2 can be obtained by increasing the polymer precursor radical concentration in the plasma. Effective ways for the removal of the post-dry-etch residues from the TiSi2 and CoSi2 surfaces have been developed. It is shown that the use of a complex cleaning procedure, including both the SPM (H2SO4:H2O2=4:1) and O2–plasma treatments, provides practically clean surfaces of both the Ti and Co silicides without the metal fluorides and polymers. © 1997 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
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
82.20.Hf Product distribution
79.60.Jv Interfaces; heterostructures; nanostructures
82.30.Cf Atom and radical reactions; chain reactions; molecule-molecule reactions

Ion distribution functions in inductively coupled radio frequency discharges in argon–chlorine mixtures

J. R. Woodworth, M. E. Riley, P. A. Miller, C. A. Nichols, and T. W. Hamilton

J. Vac. Sci. Technol. A 15, 3015 (1997); http://dx.doi.org/10.1116/1.580898 (9 pages) | Cited 33 times

Full Text: | Download PDF

Show Abstract
We report on measurements of positive ion energies, current densities, and angular distributions at the grounded electrode of inductively coupled discharges in mixtures of argon and chlorine. We also report on ion species and Langmuir probe measurements for these discharges. The inductive drive in our gaseous electronics conference reference cell produced high plasma densities (1011–1012/cm3) and stable plasma potentials. As a result, ion energy distributions consisted of a single peak well separated from zero energy. At pressures of 2.5–20 mTorr and constant rf power, the addition of Cl2 to an Ar discharge lowered ion current densities, reduced ion energies, and reduced the width of the ion energy distributions. Half-widths of the ion angular distributions ranged from 4.5° to 8.5° with the distributions broadening with increases in pressure or rf power. The addition of Cl2 to Ar discharges made the angular distributions less sensitive to total pressure. Cl+ replaced Ar+ as the dominant ionized species when small amounts of chlorine were added to Ar discharges. © 1997 American Vacuum Society.
Show PACS
52.80.Pi High-frequency and RF discharges
52.70.Ds Electric and magnetic measurements
52.25.-b Plasma properties

Analysis of the etching of silicon in an inductively coupled chlorine plasma using laser thermal desorption

Jae Y. Choe, Irving P. Herman, and Vincent M. Donnelly

J. Vac. Sci. Technol. A 15, 3024 (1997); http://dx.doi.org/10.1116/1.580899 (8 pages) | Cited 25 times

Full Text: | Download PDF

Show Abstract
The etching of silicon by a chlorine inductively coupled plasma (ICP) was studied using laser desorption laser-induced fluorescence (LD-LIF) analysis to determine the surface coverage of chlorine during steady-state etching. Laser interferometry was used to measure etch rates, and optical emission actinometry and Langmuir probe analysis were used to characterize the plasma. The ICP operated in the dim mode for radio frequency (rf) powers ≲ 350 W and in the bright mode for higher powers. Under typical operating conditions in the ICP bright mode, the ion density was about 4× 1011/cm3, the electron temperature was 2.8 eV, and about 90% of the Cl2 was dissociated. The chlorine surface coverage in the dim and bright modes was ∼2.0× that with chlorine flow and the plasma off, and increased slowly with power. This coverage ratio monotonically increased from ∼1.6× to 2.5× that with the plasma off as the ion energy was increased from 16 to 116 eV by increasing the rf substrate bias voltage during bright mode operation. Since roughly equivalent adlayer chlorine contents were measured by LD-LIF under high ion current/fast etch conditions (ICP bright mode), and low ion current/slow etch conditions [ICP dim mode and reactive ion etching mode (substrate stage powered and no ICP power)], both the adlayer chlorine content and the etch rate seem be controlled by the ion current to the wafer. © 1997 American Vacuum Society.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
81.05.Cy Elemental semiconductors
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
79.20.Ds Laser-beam impact phenomena
78.55.Ap Elemental semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
78.66.Db Elemental semiconductors and insulators

Ge growth on Si(001) studied by x-ray photoelectron spectroscopy peak shape analysis and atomic force microscopy

M. Schleberger, A. Cohen Simonsen, S. Tougaard, J. L. Hansen, and A. Nylandsted Larsen

J. Vac. Sci. Technol. A 15, 3032 (1997); http://dx.doi.org/10.1116/1.580900 (4 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
We investigated the nanostructure of Ge deposited on Si(001) at T=560 °C with x-ray photoelectron spectroscopy using peak shape analysis and with atomic force microscopy. Analyzing the Ge 2p as well as the Si KLL spectra, we find strong island growth. The Ge deposited is equal to a 14-monolayer-thick film. In agreement with the x-ray photoelectron spectroscopy results, the atomic force microscope pictures show strong island formation. About 50% of the Si surface is covered by Ge islands. The islands are distributed regularly and have an average height of 50 Å. We find some variation in height ranging from ≃20 to ≃80 Å. © 1997 American Vacuum Society.
Show PACS
81.05.Cy Elemental semiconductors
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.55.-a Thin film structure and morphology
79.60.Bm Clean metal, semiconductor, and insulator surfaces
68.35.B- Structure of clean surfaces (and surface reconstruction)

Reflectance anisotropy of the Si(100)1×2-As surface: Discrete dipole calculation

C. H. Patterson and D. Herrendörfer

J. Vac. Sci. Technol. A 15, 3036 (1997); http://dx.doi.org/10.1116/1.580901 (8 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
The reflectance anisotropy (RA) spectrum of the Si(100)1×2-As surface is calculated using the discrete dipole model. The semiconductor is treated as a slab of pointlike dipole-polarisable bonds coupled by dipolar electrostatic fields. The response of the polarisable bonds to light in normal incidence is expressed in terms of the normal modes of the polarisable bonds which are called dipole waves. These may be classified as surface-localised, surface resonance and bulk dipole waves. We give an analysis of the optical response of this surface in terms of dipole moments localised on bonds that would be too cumbersome to implement using a band structure. The discrete dipole RA spectrum is compared to the experimental spectrum for this surface and a density functional calculation of the spectrum. The discrete dipole spectrum contains the same features as experiment. The origin of the peaks in the RA spectrum is discussed in terms of excitation of dipole waves polarised parallel and perpendicular to the arsenic dimer axes and also in terms of excitation of dipole moments in particular bonds. Parameters for the calculation were obtained from ab initio calculations on clusters. © 1997 American Vacuum Society.
Show PACS
78.20.-e Optical properties of bulk materials and thin films
73.20.At Surface states, band structure, electron density of states

Na impurity chemistry in photovoltaic CIGS thin films: Investigation with x-ray photoelectron spectroscopy

David W. Niles, Kannan Ramanathan, Falah Hasoon, Rommel Noufi, Brian J. Tielsch, and Julia E. Fulghum

J. Vac. Sci. Technol. A 15, 3044 (1997); http://dx.doi.org/10.1116/1.580902 (6 pages) | Cited 34 times

Full Text: | Download PDF

Show Abstract
Thermal processing of Cu(In1−xGax)Se2 thin-films grown as part of photovoltaic devices on soda-lime glass leads to the incorporation of Na impurity atoms in the Cu(In1−xGax)Se2. Na contamination increases the photovoltaic efficiency of Cu(In1−xGax)Se2-based devices. The purpose of this investigation is to develop a model for the chemistry of Na in Cu(In1−xGax)Se2 in an effort to understand how it improves performance. An analysis of x-ray photoelectron spectroscopy data shows that the Na concentration is ∼0.1 at. % in the bulk of Cu(In1−xGax)Se2 thin films and that the Na is bound to Se. The authors propose a model invoking the replacement of column III elements by Na during the growth of Cu(In1−xGax)Se2 thin films. Na on In and Ga sites would act as acceptor states to enhance photovoltaic device performance. © 1997 American Vacuum Society.
Show PACS
73.61.Le Other inorganic semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
73.50.Pz Photoconduction and photovoltaic effects
61.72.up Other materials
81.05.Hd Other semiconductors
79.60.Bm Clean metal, semiconductor, and insulator surfaces
72.40.+w Photoconduction and photovoltaic effects
85.40.Ry Impurity doping, diffusion and ion implantation technology

X-ray photoelectron spectroscopy characterization of semiconductor thin films using simultaneous Mg/Zr excitation

Daniel F. Allgeyer

J. Vac. Sci. Technol. A 15, 3050 (1997); http://dx.doi.org/10.1116/1.580846 (10 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
This article presents a method for determining the interfacial chemical composition of semiconductor thin films. Some of the materials and interfaces characterized by this technique are tungsten silicide, titanium nitride, silicon nitride, titanium silicide, and aluminum. These thin film materials are typically supported on conductive (silicon, polysilicon) and nonconductive (boron-doped phosphosilicate glass) substrates. The determination of their interfacial chemical compositions is enhanced by using the zirconium anode (2042.4 eV). The simultaneous use of magnesium and zirconium anodes allows the analysis of the photoelectrons as well as the corresponding higher energy Auger electrons for such materials as silicon and aluminum. The kinetic energies of the Al KLL and Si KLL are beyond the Fermi level (zero binding energy) of either the magnesium (1253.6 eV) or aluminum (1486.6 eV) anodes. The photoelectron used in conjunction with thin film Auger electrons provides the energy necessary for determining Auger parameters, which are independent of localized sample charging and provide their chemical identification. Charging is common to many of these materials and is especially prevalent when analyzed using an increasingly common monochromatized aluminum source for excitation. Thus, the simultaneous use of the magnesium (1253.6 eV) and zirconium (2042.4 eV) anodes is charge independent and provides interfacial chemical identification. © 1997 American Vacuum Society.
Show PACS
79.60.Jv Interfaces; heterostructures; nanostructures
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
68.35.Ct Interface structure and roughness
79.20.Fv Electron impact: Auger emission

Preparation and optical studies on flash evaporated Sb2S3 thin films

S. Mahanty, J. M. Merino, and M. León

J. Vac. Sci. Technol. A 15, 3060 (1997); http://dx.doi.org/10.1116/1.580847 (5 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Thin films of Sb2S3 were prepared by flash evaporation. As-deposited films were found to be amorphous and highly resistive (R>106Ω) in nature. An amorphous-crystalline phase transition occurs at 498 K on subsequent annealing in nitrogen atmosphere. The fundamental optical transition is direct in nature and the optical band gaps (Eg) lie in the region 1.70–2.07 and 1.42–1.65 eV for amorphous and crystalline films, respectively. A near-linear decrease in Eg with decreasing S/Sb ratio was observed suggesting the dependence of the band gap on film composition. © 1997 American Vacuum Society.
Show PACS
81.05.Hd Other semiconductors
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
78.66.Li Other semiconductors
61.66.Bi Elemental solids
61.66.Dk Alloys
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Reflection adsorption infrared spectroscopy of the oxidation of thin films of boron and hafnium diboride grown on Hf(0001)

Michael Belyansky and Michael Trenary

J. Vac. Sci. Technol. A 15, 3065 (1997); http://dx.doi.org/10.1116/1.580848 (4 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
The oxidation of thin films of boron and hafnium diboride grown on a Hf(0001) single crystal surface was studied with reflection absorption infrared spectroscopy (RAIRS). For both the boron and hafnium diboride films an intense broad band near 1500 cm−1 as well as features near 750 and 1250 cm−1 were detected. These vibrational features are characteristic of solid B2O3. The formation of B2O3 is also indicated by x-ray photoelectron spectroscopy (XPS) by the appearance of a chemically shifted B(1s) peak at a binding energy of 193.1 eV. However, the sensitivity for detecting surface oxide formation is considerably higher for RAIRS than for XPS. © 1997 American Vacuum Society.
Show PACS
81.65.Mq Oxidation
78.30.Hv Other nonmetallic inorganics
78.66.-w Optical properties of specific thin films
79.60.Dp Adsorbed layers and thin films

Ultrahigh vacuum deposition–reflectometer system for the in situ investigation of Y/Mo extreme-ultraviolet multilayer mirrors

Claude Montcalm, Brian T. Sullivan, Martial Ranger, and Henri Pépin

J. Vac. Sci. Technol. A 15, 3069 (1997); http://dx.doi.org/10.1116/1.580849 (13 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
An ultrahigh vacuum deposition–reflectometer system was constructed to allow the deposition and subsequent in situ reflectance measurement of extreme-ultraviolet multilayer mirrors. In this article various aspects of the deposition chamber and the reflectance measurement setup are discussed. To demonstrate the capabilities of this system, Y/Mo multilayer mirrors were studied in detail by varying deposition conditions and measuring their subsequent in situ reflectance. By optimizing the deposition conditions, reflectances of 21.3%, 34.7%, and 46.1% were obtained for the Y/Mo mirrors at wavelengths of 7.9, 9.7, and 11.4 nm, respectively. © 1997 American Vacuum Society.
Show PACS
81.05.Bx Metals, semimetals, and alloys
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.66.Bz Metals and metallic alloys
42.79.Bh Lenses, prisms and mirrors
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors

Low temperature deposition of epitaxial titanium carbide on MgO(001) by co-evaporation of C60 and Ti

L. Norin, S. McGinnis, U. Jansson, and J.-O. Carlsson

J. Vac. Sci. Technol. A 15, 3082 (1997); http://dx.doi.org/10.1116/1.580850 (4 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Films of epitaxial titanium carbide were grown on MgO(001) at 400 and 500 °C using a novel method based on the co-evaporation of Ti and C60. Mirrorlike, adhesive films of TiC1-x (0.2<x<0.4) were deposited at growth rates of approximately 0.1 μm/h. X-ray diffraction showed that the crystal orientation relationship between the film and the substrate was TiC(001)//MgO(001) and TiC[100]//MgO[100]. Transmission electron microscopy and low energy electron diffraction were also used to verify the epitaxial growth of the films. © 1997 American Vacuum Society.
Show PACS
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
61.50.-f Structure of bulk crystals

Roles of ion irradiation for crystalline growth and internal stresses in nickel films onto silicon substrates prepared by the ion beam and vapor deposition method

Naoto Kuratani, Yasuo Murakami, Osamu Imai, Akinori Ebe, Satoshi Nishiyama, and Kiyoshi Ogata

J. Vac. Sci. Technol. A 15, 3086 (1997); http://dx.doi.org/10.1116/1.580851 (7 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The roles of ion irradiation for crystalline growth and internal stresses in Ni films prepared by the ion beam and vapor deposition method were studied. Ni films were prepared on Si〈100〉 wafers by evaporation of Ni metal and simultaneous irradiation with inert gas ions, Ne, Ar, Kr, and Xe. The energies of inert gas ions were changed in the range of 0.5–10.0 keV. Transport ratios of vaporized Ni atoms to inert gas ions to substrates were kept at 15. Ion beam current densities and ion irradiation directions were fixed at 40 μA/cm2 and perpendicular to the substrate surface, respectively. From the x-ray analyses, crystallinities and preferred orientation were changed by ion irradiation conditions. On the other hand, internal stresses were also changed from compressive to tensile depending on ion energies and ion species. It is understood that the variations of crystalline growth and internal stresses in Ni films were caused by the difference of nuclear and electronic energy transfer abilities of irradiating ions. © 1997 American Vacuum Society.
Show PACS
81.05.Bx Metals, semimetals, and alloys
81.15.Jj Ion and electron beam-assisted deposition; ion plating
68.60.Bs Mechanical and acoustical properties
73.40.Ns Metal-nonmetal contacts
73.61.At Metal and metallic alloys

Temperature dependence of the electron induced gas desorption yields on stainless steel, copper, and aluminum

J. Gómez-Goñi and A. G. Mathewson

J. Vac. Sci. Technol. A 15, 3093 (1997); http://dx.doi.org/10.1116/1.580852 (11 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Electron induced gas desorption yields from stainless steel, copper, and aluminum surfaces have been measured for electrons of 300 eV energy. The main gases desorbed were H2, CH4, H2O, CO, and CO2. The effect of increasing the temperature on the gas desorption yields was measured and the only yields affected were those of H2O and H2, while the others remained essentially constant. The dependence on the dose and the temperature using two identical samples was also measured and the yields were found to be proportional to the dose to the power— α, with α positive. No big differences with temperature were seen. The value of the exponent for H2 is bigger than that expected for a diffusion model. The dependence with coverage and temperature was also analyzed, showing that the cleaning effect is quicker at higher temperatures, especially for H2. A diffusion model for H2 was applied to interpret the experimental results, showing that the model explains the results, if we consider that the H2 concentration across the bulk of the material, decreases exponentially. © 1997 American Vacuum Society.
Show PACS
79.20.La Photon- and electron-stimulated desorption
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.35.Fx Diffusion; interface formation
81.65.Cf Surface cleaning, etching, patterning

Surface kinetic study of ion-induced chemical vapor deposition of copper for focused ion beam applications

T. P. Chiang, H. H. Sawin, and C. V. Thompson

J. Vac. Sci. Technol. A 15, 3104 (1997); http://dx.doi.org/10.1116/1.580853 (11 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
A systematic surface kinetic study of ion-induced chemical vapor deposition (II-CVD) of Cu from Cu(I) hexafluoroacetylacetonate vinyltrimethylsilane was performed using quartz crystal microbalance mass deposition rate measurements, x-ray photoelectron spectroscopy compositional analysis, and laser-induced thermal desorption coverage measurements in a multibeam scattering apparatus. With the above, a phenomenological surface kinetic model describing the adsorption, deposition (both of the desired source metal and of unwanted impurities), byproduct desorption, and sputtering processes involved in II-CVD was formulated. The surface kinetic model predicts the deposition rate, composition, and precursor coverage dependencies in agreement with experimental results. © 1997 American Vacuum Society.
Show PACS
81.05.Bx Metals, semimetals, and alloys
68.55.Nq Composition and phase identification
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
82.20.Hf Product distribution
82.20.Pm Rate constants, reaction cross sections, and activation energies
79.60.Bm Clean metal, semiconductor, and insulator surfaces
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
79.20.La Photon- and electron-stimulated desorption
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
81.15.Cd Deposition by sputtering

Deconvolution of the Gaussian-convoluted profiles of mercury ions implanted into nickel

Bo-Rong Shi, N. Cue, and Ke-Ming Wang

J. Vac. Sci. Technol. A 15, 3115 (1997); http://dx.doi.org/10.1116/1.580854 (5 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Based on a nonlinear least squares optimisation, a deconvolution method is proposed to remove the system resolution from the ion implantation profiles measured. The method is applied to the range distributions of 200 keV Hg ions implanted into nickel at various tilt angles. The results show that the range straggling is markedly reduced after the deconvolution, the skewness and kurtosis are slightly larger than those of the experimental measured profiles, and they all can be represented by a Pearson IV distribution that is different from the Pearson I distribution predicted by TRIM. The longitudinal and lateral range straggling for normal incidence could be deduced from the angular dependence of the deconvoluted range straggling. © 1997 American Vacuum Society.
Show PACS
61.72.up Other materials
61.82.Bg Metals and alloys
61.80.Jh Ion radiation effects
61.72.S- Impurities in crystals
61.85.+p Channeling phenomena (blocking, energy loss, etc.)

Kinetics of F atoms and fluorocarbon radicals studied by threshold ionization mass spectrometry in a microwave CF4 plasma

A. Tserepi, W. Schwarzenbach, J. Derouard, and N. Sadeghi

J. Vac. Sci. Technol. A 15, 3120 (1997); http://dx.doi.org/10.1116/1.580855 (7 pages) | Cited 34 times

Full Text: | Download PDF

Show Abstract
The absolute concentration of fluorine atoms (F), a parameter of great importance for the characterization and modeling of etching plasmas, was measured by means of threshold ionization mass spectrometry in a CF4 microwave plasma (p=15–100 mTorr). The kinetics of these atoms and those of CF2 and CF3 radicals were studied by pulsing the plasma and time-resolved detection of these radicals with mass spectrometer. Sticking coefficients of F atoms on the different surrounding surfaces were estimated, as a function of the discharge parameters and the nature of the surfaces interacting with the plasma. It was found that the sticking of F atoms on hexatriacontane polymer surface is highly activated by the plasma generated ions and/or ultraviolet radiations. © 1997 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
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
78.47.-p Spectroscopy of solid state dynamics
52.70.Nc Particle measurements
52.25.Dg Plasma kinetic equations

Static secondary ion mass spectrometry study of the decomposition of triethylgallium on GaAs (100)

K. C. Wong, M. S. Jackson, M. T. McEllistrem, R. D. Culp, and J. G. Ekerdt

J. Vac. Sci. Technol. A 15, 3127 (1997); http://dx.doi.org/10.1116/1.580856 (7 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
The decomposition of triethylgallium (TEGa-d0) and perdeuterated triethylgallium (TEGa-d15) on Ga-rich GaAs (100) was studied using temperature programmed static secondary ion mass spectrometry (SSIMS) and temperature programmed desorption (TPD). Isothermal and temperature programmed SSIMS spectra of the TEGa-dosed surface feature three dominant hydrocarbon ions, CH3+, C2H3+, and C2H5+, whose behavior indicates the presence of two distinct ethyl ligands. The TEGa-d15 results were equivalent to the TEGa-d0 results, with the ion masses shifted by the D and H mass differences. Both CH3+ and C2H3+ SSIMS signals exhibit the same temperature dependence, staying rather constant between 140–530 K and then decreasing rapidly between 530 and 650 K. The CH3+ and C2H3+ signals disappear over the same temperature range in which C2H4 forms and desorbs from the surface in TPD; these SSIMS signals are attributed to the surface ethyl ligands that are responsible for C2H4 formation. Ethyl ligands reacting to ethylene are likely bound to Ga atom lattice sites. The C2H3+ signal is well established at 140 K, suggesting that TEGa is dissociated at temperatures as low as 140 K. The C2H5+ SSIMS signal decays in parallel with the diethylgallium ion SSIMS signal, and it then disappears in parallel with the CH3+ and C2H3+ signals; the C2H5+ SSIMS signal is associated with both ethyl ligands bound to adsorbed triethylgallium and/or diethylgallium, and with ethyl ligands bound to lattice sites. © 1997 American Vacuum Society.
Show PACS
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Plasma fluorination of polyimide thin films

Kazuhiko Endo and Toru Tatsumi

J. Vac. Sci. Technol. A 15, 3134 (1997); http://dx.doi.org/10.1116/1.580857 (4 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
The surface of polyimide films was fluorinated and a CF3 surface layer formed. The dielectric constant of the polyimide films decreased to a minimum of 2.5 as the treatment time increased. The leakage current of the polyimide films was also decreased significantly by the fluorination. The measurement of electrical properties and secondary ion mass spectroscopy revealed that the fluorine atoms diffused into the polyimide films from the fluorinated surface layer. The current–voltage characteristics indicated that reduction in the leakage current was due to fewer ionic impurities. This confirms that the fluorine diffused into the polyimide and it eliminated impurity ions. © 1997 American Vacuum Society.
Show PACS
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
81.65.-b Surface treatments
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
61.41.+e Polymers, elastomers, and plastics
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
77.22.Ch Permittivity (dielectric function)
68.60.Dv Thermal stability; thermal effects

Improved growth and thermal stability of Parylene films

Seshadri Ganguli, Hemant Agrawal, Bin Wang, Jack F. McDonald, Toh -M. Lu, G.-R. Yang, and William N. Gill

J. Vac. Sci. Technol. A 15, 3138 (1997); http://dx.doi.org/10.1116/1.580858 (5 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
Experimental results for the deposition of low dielectric constant Parylene-N and Parylene-F films are explained by a mechanism based on bulk phase diffusion reaction in the film. The deposition rate of Parylene-F decreases significantly as time increases and ultimately achieves steady state. Very favorable agreement with experiments at a substrate temperature of −10 °C is obtained for parylene-F with a rate constant of kf=5×10−5/s, and a diffusion coefficient Df=1.3×10−8 cm2/s. In contrast, the much higher rate constant at room temperature for Parylene-N films is kf=0.16/s and the predicted deposition rate is constant after a very small period of time (tss<4/kf=25 s). This prediction is confirmed by the experiments. The model predicts correctly that low deposition temperatures improve both the deposition rate and thermal stability of Parylene films. Our experiments confirm this prediction and one obtains both high growth rates and high molecular weight films at lower deposition temperatures. Furthermore, experiments show that the longer chains formed at low temperatures significantly improve the thermal stability of the films. The deposition rate also can be improved by using higher reactor pressures. However, the pressure that can be employed is limited to about 100 mTorr to maintain high quality films. At liquid nitrogen temperature (77 K), the deposition rate is three orders of magnitude larger than the film deposition rate at room temperature. The increased monomer concentration on the substrate due to higher condensation leads to this increased deposition rate. © 1997 American Vacuum Society.
Show PACS
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.-a Thin film structure and morphology
68.60.Dv Thermal stability; thermal effects
77.22.Ch Permittivity (dielectric function)
77.55.-g Dielectric thin films
66.30.H- Self-diffusion and ionic conduction in nonmetals

Electrical properties of metal–insulator–semiconductor structures with silicon nitride dielectrics deposited by low temperature plasma enhanced chemical vapor deposition distributed electron cyclotron resonance

M. C. Hugon, F. Delmotte, B. Agius, and J. L. Courant

J. Vac. Sci. Technol. A 15, 3143 (1997); http://dx.doi.org/10.1116/1.580859 (11 pages) | Cited 25 times

Full Text: | Download PDF

Show Abstract
The present article reports a study of current–voltage (J–E) and capacitance–voltage (C–V) measurements on metal–insulator–semiconductor diodes, using SiNx:H as an insulator layer and Si or InP as semiconductors. We have deposited SiNx:H films by distributed electron cyclotron resonance plasma enhanced chemical vapor deposition at floating temperature, with physical properties similar to films prepared at 800 °C by low pressure chemical vapor deposition. Silane and nitrogen were used as the reactive gases. The experimental results show that the resistivity (ρ) and the critical field (EC) are a strong function of the dielectric composition. For films deposited under optimum conditions, ρ was equal to 1016 Ω cm and EC reached 3.65 or 4.5 MV/cm for Al/SiNx:H/Si and Al/SiNx:H/InP diodes, respectively. The dominant mode of electronic conduction appears to be the Poole–Frenkel emission. The postmetallization annealing (PMA) has no significant effect on these bulk properties (ρ, EC and electronic conduction). On the contrary, PMA has been shown to mainly affect the properties of both SiNx:H/Si and SiNx:H/InP interfaces. The optimized Al/SiNx:H/Si fabrication procedure induced a midgap interface state density (Dit) of 6×1010 eV−1 cm−2 evaluated by high frequency and quasistatic C–V characteristics. In the case of Al/SiNx:H/InP diodes, we have found that the carrier trapping by direct tunneling near the SiNx:H/InP interface is dominant. © 1997 American Vacuum Society.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
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.)
73.50.Fq High-field and nonlinear effects
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ng Insulators
61.72.Cc Kinetics of defect formation and annealing
73.20.At Surface states, band structure, electron density of states

Analysis and characterization of native oxide growth on epitaxial Si1−xGex films after a chemical clean

I.-M. Lee and C. G. Takoudis

J. Vac. Sci. Technol. A 15, 3154 (1997); http://dx.doi.org/10.1116/1.580860 (4 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
Ellipsometry, contact angle goniometry, atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) are used to study native oxide growth on SiGe films (with Ge content of 0%, 20%, 40%, and 100%) after a chemical clean. Ellipsometry suggests that the presence of Ge affects the initial oxide thickness right after the clean but it does not affect the rate of native oxide growth. Roughness of SiGe samples as measured by AFM does not appear to be affected by the native oxide growth or the Ge content in the film. The decrease in advancing (and receding) contact angles of SiGe samples after the chemical clean is apparently the result of both increasing oxide thickness and oxide solid phase composition. XPS results suggest that increasing Ge content in the film increases the oxidation of SiGe surface atoms. The chemical shifts in the Si 2p and Ge 3d spectra suggest that both Si and Ge react with oxygen to form SiO2 and GeO2. Such data suggests that contact angle measurements could be a rapid method to determine the state and passivation characteristics of a silicon substrate surface as a function of time; however, such a technique would not be as effective for SiGe films, the chemical composition of their native oxides of which would also change as a function of time. © 1997 American Vacuum Society.
Show PACS
81.65.Mq Oxidation
68.35.B- Structure of clean surfaces (and surface reconstruction)
79.60.Bm Clean metal, semiconductor, and insulator surfaces
68.55.Nq Composition and phase identification

Energy spectra of secondary neutrals obtained by means of the electrostatic energy filter of a commercial low-pressure HF-plasma secondary neutral mass spectrometer

Holger Jenett and Vasile-Dan Hodoroaba

J. Vac. Sci. Technol. A 15, 3158 (1997); http://dx.doi.org/10.1116/1.580861 (5 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The ion optics system of the commercially available HF-plasma secondary neutral mass spectrometry apparatus INA3 was found to enable ion energy spectroscopy with good performance: for sufficiently high (2 keV) primary ion energies, the energy distributions of postionized Cu, Al, and Mo atoms almost show the theoretically expected behavior up to 300 eV. Maxima are found at the energies expected from collision cascade emissions. Since ionization occurs on a plasma potential between +35 and 40 V, all ion energies are shifted accordingly. Tuning of the ion optics was accomplished in the secondary ion mass spectroscopy mode by using a sputtered H3BO3/Cu powder pellet as a B+ and BO2− ion source. © 1997 American Vacuum Society.
Show PACS
07.75.+h Mass spectrometers
41.85.-p Beam optics

Corrosion resistance of titanium nitride and mixed titanium/titanium nitride coatings on iron in humid SO2-containing atmospheres

A. C. Agudelo, J. R. Gancedo, J. F. Marco, and Darko Hanžel

J. Vac. Sci. Technol. A 15, 3163 (1997); http://dx.doi.org/10.1116/1.580862 (7 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
The corrosion behavior in humid SO2-polluted atmospheres of three different TiN coatings on iron [single layer TiN (1000 nm), bilayer Ti(100 nm)/TiN(1000 nm) and multilayer Ti(100 nm)/TiN(100 nm)/Ti(100 nm)/TiN(100 nm)] have been investigated by means of x-ray photoelectron spectroscopy. Only the single layer coating shows some degradation in low concentration (0.001% v/v) SO2 atmospheres after 14 days of exposure, the other two coatings remaining stable. Exposure to higher SO2 concentration (0.04% v/v) for 7 days results in the total degradation of the single layer coating. Exposure to this latter atmosphere for 14 days brings about a considerable degradation of the bilayer and multilayer coatings, the results showing that the multilayer coating, even with the lowest total thickness, presents the highest resistance against these corrosion conditions. Corrosion of the TiN coatings results in the formation of TiO2 and several N species [probably of the type (NH4)2SO4 and species containing N–O bonds]. The degradation of the coatings results in the corrosion of the underlying iron. Fe2+ sulphates and sulphites, as well as FeOOH, are the main iron corrosion products. © 1997 American Vacuum Society.
Show PACS
81.65.Kn Corrosion protection
79.60.Jv Interfaces; heterostructures; nanostructures

Erratum: “Three-dimensional deposition of TiN film using low frequency (50 Hz) plasma chemical vapor deposition” [J. Vac. Sci. Technol. A 15, 1897 (1997)]

M. Shimozuma, H. Date, T. Iwasaki, H. Tagashira, M. Yoshino, and K. Yoshida

J. Vac. Sci. Technol. A 15, 3170 (1997); http://dx.doi.org/10.1116/1.580863 (1 page)

Full Text: | Download PDF

Abstract Unavailable
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
62.20.Qp Friction, tribology, and hardness
79.20.Fv Electron impact: Auger emission
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
73.61.-r Electrical properties of specific thin films
68.60.Bs Mechanical and acoustical properties
99.10.Cd Errata
Close

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