JVA Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

Mar 2013

Volume 31, Issue 2, Articles (02xxxx)

Issue Cover Spotlight Figure

J. Vac. Sci. Technol. A 31, 020605 (2013); http://dx.doi.org/10.1116/1.4791669 (5 pages)

Peter J. Cumpson, Jose F. Portoles, and Naoko Sano
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Modulation of Ni valence in p-type NiO films via substitution of Ni by Cu

Wei-Yu Chen, Jiann-Shing Jeng, Kuo-Lun Huang, and Jen-Sue Chen

J. Vac. Sci. Technol. A 31, 021501 (2013); http://dx.doi.org/10.1116/1.4774209 (4 pages)

Online Publication Date: 7 January 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
10 and 18 at. % copper incorporated NiO films were deposited by reactively sputtering from Ni targets covered with Cu strips of different sizes. A change in the valence of Ni from Ni2+ to Ni3+ is found by x-ray absorption near edge structure analysis after incorporating Cu into the films. All NiO films exhibit p-type conductivity, either without or with Cu additives. However, as compared with the pure NiO films, the carrier concentration of the films incorporating Cu increases, while the resistivity and mobility decrease. This study not only discusses the connections among the physical properties of the NiO films with different Cu contents but also clarifies the role of Cu additives in the NiO films.
Show PACS
73.61.Le Other inorganic semiconductors
78.70.Dm X-ray absorption spectra
81.15.Cd Deposition by sputtering
68.55.ag Semiconductors
72.20.Fr Low-field transport and mobility; piezoresistance
73.50.Dn Low-field transport and mobility; piezoresistance

Structural, surface, and thermomechanical properties of intrinsic and argon implanted tetrahedral amorphous carbon

Edison F. Motta, Gustavo A. Viana, Douglas S. Silva, Andresa D. S. Côrtes, Fernando L. Freire, Jr., and Francisco C. Marques

J. Vac. Sci. Technol. A 31, 021502 (2013); http://dx.doi.org/10.1116/1.4774326 (8 pages)

Online Publication Date: 11 January 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The structural, surface, and thermomechanical properties of intrinsic and argon incorporated tetrahedral amorphous carbon films deposited using the filtered cathodic vacuum arc process are reported. Argon atoms were simultaneously incorporated during the deposition of the films using an argon ion gun in the energy range of 0–180 eV. Contact angle measurements revealed that all of the deposited films are hydrophobic, regardless of the substrate bias voltage that was applied during the depositions. Thermal desorption spectroscopy measurements revealed that high argon bombarding energy favors films that are structurally more compact and thermally more stable. An investigation unbinding the mechanism of argon effusion and intrinsic stress relief is presented.
Show PACS
68.55.-a Thin film structure and morphology
68.60.Bs Mechanical and acoustical properties
81.40.Gh Other heat and thermomechanical treatments
68.35.bt Other materials
61.43.Er Other amorphous solids
68.43.Vx Thermal desorption

Atomic layer deposition of TiN for the fabrication of nanomechanical resonators

Nathan Nelson-Fitzpatrick, Csaba Guthy, Somayyeh Poshtiban, Eric Finley, Kenneth D. Harris, Brian J. Worfolk, and Stephane Evoy

J. Vac. Sci. Technol. A 31, 021503 (2013); http://dx.doi.org/10.1116/1.4790132 (7 pages)

Online Publication Date: 5 February 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Films of titanium nitride were grown by atomic layer deposition (ALD) over a range of temperatures from 120 °C to 300 °C, and their deposition rates were characterized by ellipsometry and reflectometry. The stress state of the films was evaluated by interferometry using a wafer bowing technique and varied from compressive (−18 MPa) to tensile (650 MPa). The crystal structure of the films was assessed by x-ray diffraction. The grain size varied with temperature in the range of 2–9 nm. The chemical composition of the films was ascertained by high-resolution x-ray photoelectron spectroscopy and showed the presence of O, Cl, and C contaminants. A mildly tensile (250 MPa) stressed film was employed for the fabrication (by electron beam lithography and reactive ion etching) of doubly clamped nanoresonator beams. The resonance frequency of resonators was assayed using an interferometric resonance testing apparatus. The devices exhibited sharp mechanical resonance peaks in the 17–25 MHz range. The uniformity and controllable deposition rate of ALD films make them ideal candidate materials for the fabrication of ultranarrow (<50 nm) nanobeam structures.
Show PACS
68.55.Nq Composition and phase identification
68.60.Bs Mechanical and acoustical properties
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.65.Cf Surface cleaning, etching, patterning
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Growth and structure of ZnO thin films on polar (√3 × √3)R30° reconstructed and unreconstructed MgO(111) surfaces by atomic layer deposition

Kallol Pradhan and Paul F. Lyman

J. Vac. Sci. Technol. A 31, 021504 (2013); http://dx.doi.org/10.1116/1.4791667 (9 pages)

Online Publication Date: 8 February 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polar heterointerfaces of MgO(111) and the II–VI semiconductor ZnO are of technological interest for transparent conducting electrode applications. Growth and structure of thin films on polar surfaces can be different than on nonpolar surfaces due to the large surface energy of polar surfaces. The authors have grown ZnO on unreconstructed MgO(111)-(1 × 1)-OH terminated and reconstructed MgO(111)-(√3 × √3)R30° polar oxide surfaces using atomic layer deposition (ALD). A homemade ultrahigh vacuum-interfaced viscous-flow ALD reactor with in situ quartz crystal monitor was used to grow ZnO thin films on the MgO(111) substrates. In the ALD process temperature window, the growth rate was found to be ∼2.3 Å/cycle. Atomic force microscopy revealed that the surface roughness increases with ZnO film thickness and that reconstructed MgO(111) is a better substrate for production of smooth ZnO films. X-ray diffraction analysis revealed that ZnO thin films grown at 130 °C are polycrystalline, having the wurtzite structure, with preferential growth along the c-axis. ZnO grown on MgO(111)-(√3 × √3)R30° substrates shows strong preferential growth along the (002) direction. In contrast, growth along the (100) and (101) directions is also observed when grown on MgO(111)-(1 × 1) substrates. These observations indicate that the crystal orientation during ALD ZnO growth depends not only on temperature but also on the surface terminations of the substrates. Optical transmittance spectra were used to find the bandgap of 3.27 eV and sharp ultraviolet cutoff of 380 nm for ALD-grown ZnO thin films. The optical transmission was found to be more then 80% in the visible region.
Show PACS
68.55.ag Semiconductors
68.35.Md Surface thermodynamics, surface energies
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.40.Fy Semiconductors
78.66.Hf II-VI semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Three dimensional reciprocal space measurement by x-ray diffraction using linear and area detectors: Applications to texture and defects determination in oriented thin films and nanoprecipitates

Simon Gaudet, Koen De Keyser, Samuel Lambert-Milot, Jean Jordan-Sweet, Christophe Detavernier, Christian Lavoie, and Patrick Desjardins

J. Vac. Sci. Technol. A 31, 021505 (2013); http://dx.doi.org/10.1116/1.4789984 (13 pages)

Online Publication Date: 13 February 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors present a method for the fast and efficient measurement of volumes of reciprocal space by x-ray diffraction using linear and area detectors. The goal of this technique is to obtain a complete overview of the reciprocal space to detect and characterize the nature and orientation of all the phases present. They first explain the detailed procedures and scan strategies required for transforming raw scattering data into three-dimensional maps of reciprocal space and present a complete open-source software package for advanced data processing, analysis, and visualization. Several case studies, chosen to highlight the overall capabilities of the technique, are then introduced. First, thermal diffuse scattering from a monocrystalline Si substrate is characterized by the presence of lines linking diffraction peaks in reciprocal space. Second, a detailed investigation of texture in multiphase thin layers permits us to reveal the unambiguous presence of fiber, axiotaxial, and epitaxial components in oriented films. The visualization of a significant fraction of reciprocal space has allowed us to identify an unexpected metastable phase, which could not be deduced from measurements carried out in the Bragg–Brentano geometry. The technique is then used to study planar defects in nickel silicides formed by solid-state reactions and micro twins in a GaP matrix containing coherent MnP precipitates. Overall, the authors show that the systematic acquisition of significant volumes of reciprocal space permits us to observe behaviors that might otherwise remain undetected when analyses are restricted to typical measurement scans.
Show PACS
81.07.-b Nanoscale materials and structures: fabrication and characterization
68.55.jm Texture
61.46.-w Structure of nanoscale materials

Characterization of metal oxide layers grown on CVD graphene

Akitomo Matsubayashi, Joseph Abel, Dhiraj Prasad Sinha, Ji Ung Lee, and Vincent P. LaBella

J. Vac. Sci. Technol. A 31, 021506 (2013); http://dx.doi.org/10.1116/1.4792068 (6 pages) | Cited 1 time

Online Publication Date: 14 February 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Growth of a fully oxidized aluminum oxide layer with low surface roughness on graphene grown by chemical vapor deposition is demonstrated. This is accomplished by the deposition of a 0.2 nm thick titanium seed layer on the graphene prior to the deposition of the aluminum under ultra high vacuum conditions, which was subsequently oxidized. The stoichiometry and surface roughness of the oxide layers were measured for a range of titanium and aluminum depositions utilizing ex situ x-ray photoelectron spectrometry and atomic force microscopy. These fully oxidized films are expected to produce good dielectric layers for use in graphene based electronic devices.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
68.35.bt Other materials
77.55.-g Dielectric thin films
79.60.Dp Adsorbed layers and thin films

On the change of preferential growth orientation in chemical vapor deposition of titanium carbide by aromatic hydrocarbon precursors

Henrik Pedersen, Ching-Chi Lin, and Lars Ojamäe

J. Vac. Sci. Technol. A 31, 021507 (2013); http://dx.doi.org/10.1116/1.4792723 (5 pages)

Online Publication Date: 15 February 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thin films of titanium carbide grown by chemical vapor deposition exhibit a strong preferential (111) growth direction if aromatic hydrocarbons, such as benzene, are used as a carbon precursor. If aliphatic hydrocarbons such as methane are used, growth on the (100) surface is preferred. In this study, quantum chemical computations are used to study the adsorption of benzene and methane on the (100) and (111) surfaces to provide an explanation for the changed growth behavior. The adsorption energy of benzene is found to be approximately twice as high on the (111) surface as compared to the (100) surface, and adsorption studies further suggest that benzene chemisorbs on the (111) surface, while it physisorbs on the (100) surface. The studies reveal no significant differences in adsorption energy or behavior for methane on the two surfaces. The authors propose that the higher benzene adsorption energy and different adsorption behavior on the (111) surface are the explanations for the preferential growth orientation.
Show PACS
68.55.A- Nucleation and growth
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
68.43.Mn Adsorption kinetics

Relative lability of gold-oxide thin films in contact with air, solvents, or electrolyte solutions

Kevin M. Cook and Gregory S. Ferguson

J. Vac. Sci. Technol. A 31, 021508 (2013); http://dx.doi.org/10.1116/1.4791687 (5 pages)

Online Publication Date: 19 February 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The lability of gold-oxide thin films in contact with air, pure solvents, or electrolyte solutions was investigated by monitoring film thicknesses using spectroscopic ellipsometry. Surface compositions were monitored using low-energy ion scattering. The oxide was inert in air over 24 h, but decomposed partially in tetrahydrofuran (THF) and water, and completely in ethanol, within the same period. The film thicknesses decreased significantly in THF solutions of Bu4NPF6 and Bu4NBF4, but were more inert in solutions of Bu4NClO4 and LiClO4 in the same solvent, making the latter more suitable choices as supporting electrolytes in electrochemical studies.
Show PACS
68.55.-a Thin film structure and morphology
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
82.45.Fk Electrodes
82.45.Gj Electrolytes
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Effects of substrate doping on Gd2O3(100)/Si(100) heterostructure

Wattaka Sitaputra and Raphael Tsu

J. Vac. Sci. Technol. A 31, 021509 (2013); http://dx.doi.org/10.1116/1.4793264 (4 pages)

Online Publication Date: 21 February 2013

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Among the three major orientations, i.e., (100), (110), and (111), Gd2O3(100) is known from the energy point of view to be least favorable on Si(100), unless accompanied by an energy reduction mechanism with a subsequent transfer of electrons across the interface into the silicon substrate. Although the growth on p-type Si(100) results in the best structural consideration from XRD, sufficiently satisfactory stability is demonstrated with Gd2O3(100)/n-type Si(100) with a significantly higher mobility enhancement at high carrier concentration with features most desirable for CMOS applications.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.72.uf Ge and Si
72.20.Fr Low-field transport and mobility; piezoresistance
Return to All Sections
Close

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