jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

SECTION LISTING

BROWSE VOLUMES

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

15 May 2005

Volume 97, Issue 10, Articles (10xxxx)

Return to All Sections
back to top
RSS Feeds

Growth processes and surface properties of diamondlike carbon films

Dongping Liu, Jialiang Zhang, Yanhong Liu, Jun Xu, and Günther Benstetter

J. Appl. Phys. 97, 104901 (2005); http://dx.doi.org/10.1063/1.1890446 (10 pages) | Cited 5 times

Online Publication Date: 28 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this study, we compare the deposition processes and surface properties of tetrahedral amorphous carbon (ta-C) films from filtered pulsed cathodic arc discharge (PCAD) and hydrogenated amorphous carbon (a-C:H) films from electron cyclotron resonance (ECR)-plasma source ion implantation. The ion energy distributions (IEDs) of filtered-PCAD at various filter inductances and Ar gas pressures were measured using an ion energy analyzer. The IEDs of the carbon species in the absence of background gas and at low gas pressures are well fitted by shifted Maxwellian distributions. Film hardness and surface properties show a clear dependence on the IEDs. ta-C films with surface roughness at an atomic level and thin (0.3–0.9 nm) graphitelike layers at the film surfaces were deposited at various filter inductances in the highly ionized plasmas with the full width at half maximum ion energy distributions of 9–16 eV. The a-C:H films deposited at higher H/C ratios of reactive gases were covered with hydrogen and sp3 bonded carbon-enriched layers due to the simultaneous interaction of hydrocarbon species and atomic hydrogen. The effects of deposited species and ion energies on film surface properties were analyzed. Some carbon species have insufficient energies to break the delocalized π(nC) bonds at the graphitelike film surface, and they can govern film formation via surface diffusion and coalescence of nuclei. Dangling bonds created by atomic hydrogen lead to uniform chemisorption of hydrocarbon species from the ECR plasmas. The deposition processes of ta-C and a-C:H films are discussed on the basis of the experimental results.
Show PACS
81.05.U- Carbon/carbon-based materials
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.35.B- Structure of clean surfaces (and surface reconstruction)
52.77.Dq Plasma-based ion implantation and deposition
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
61.72.up Other materials
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.60.Bs Mechanical and acoustical properties
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.Qp Friction, tribology, and hardness
71.55.Jv Disordered structures; amorphous and glassy solids
68.35.Fx Diffusion; interface formation
61.43.Er Other amorphous solids
68.43.Mn Adsorption kinetics

Scanning magnetron-sputtered TiN coating as diffusion barrier for silicon devices

Vijendra Lingwal and N. S. Panwar

J. Appl. Phys. 97, 104902 (2005); http://dx.doi.org/10.1063/1.1896433 (8 pages) | Cited 9 times

Online Publication Date: 28 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Scanning magnetron-sputtered titanium nitride (TiN) films were deposited onto silicon substrates under varying nitrogen and argon pressures. Golden TiN films with (220) orientation were deposited at different substrate bias voltages (0 to −120 V). Auger electron spectroscopy measurements show N/Ti ratio between 1.18 and 1.07, and oxygen content between 11% and 5% in the as-deposited TiN film samples. Dependence of the stress and grain size on substrate bias voltage and dependence of resistivity on bias voltage and annealing temperature have been studied for the deposited TiN films. Resistivity was found minimum for the TiN samples deposited at −40 V bias, which decreases from 320 to 132 μΩ cm on annealing, up to 750 °C. Copper was sputter deposited on the as-grown TiN films deposited at −40 V bias. The Cu/TiN/Si samples were annealed at different temperatures. Resistivity, x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray analysis results of the Cu/TiN/Si structure are consistent with each other, and show that scanning magnetron sputtering deposited TiN film is a good diffusion barrier for copper metallization of the silicon devices, up to 750 °C.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
73.61.At Metal and metallic alloys
85.40.Ls Metallization, contacts, interconnects; device isolation

Growth and hydrogen uptake of Mg–Y thin films

C. Chacon, E. Johansson, B. Hjörvarsson, C. Zlotea, and Y. Andersson

J. Appl. Phys. 97, 104903 (2005); http://dx.doi.org/10.1063/1.1896440 (7 pages) | Cited 7 times

Online Publication Date: 28 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Wedged Mg–Y films with compositions ranging from pure Mg to Mg0.83Y0.17 were grown by dc-magnetron sputtering and hydrogenated. Mg1−xYx forms a substitutional alloy, ranging from 0 to at least 17 at. % in thin films. The c lattice parameter of the film containing 17 at. % of yttrium is determined to be approximatively 1% larger than in pure Mg. Upon exposure to 1 bar of hydrogen at 300 K, the samples switch from shiny metals to colorless semiconductor. Different characteristic hydrogen depth distributions are found for different Y concentrations. At low yttrium contents, a large concentration gradient is observed, with the highest hydrogen concentration close to the Pd/Mg1−xYx interface. For yttrium concentrations larger than 7 at. %, the obtained hydrogen distribution is almost independent of depth. The optical band gap is determined to be 3.6 eV, for all the Y concentrations. The optical transmission is found to decrease for increasing Y content, which is associated with an incomplete hydride formation in the films.
Show PACS
81.05.Bx Metals, semimetals, and alloys
81.05.Hd Other semiconductors
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
81.65.-b Surface treatments
78.66.Bz Metals and metallic alloys
78.66.Li Other semiconductors
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
72.60.+g Mixed conductivity and conductivity transitions
68.43.-h Chemisorption/physisorption: adsorbates on surfaces

Effect of reactive ion etching-induced defects on the surface band bending of heavily Mg-doped p-type GaN

Yow-Jon Lin and Yow-Lin Chu

J. Appl. Phys. 97, 104904 (2005); http://dx.doi.org/10.1063/1.1894580 (4 pages) | Cited 9 times

Online Publication Date: 29 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of reactive ion etching-induced defects on the surface band bending of heavily Mg-doped p-type GaN (p‐GaN) was investigated in this study. According to the observed results from x-ray photoelectron spectroscopy and secondary-ion-mass spectroscopy (SIMS) measurements, we found that the formation of more nitrogen-vacancy-related defects created near the surface by reactive ion etching technique would lead to an increase in the surface band bending, a shift of the surface Fermi level toward the conduction-band edge, the reduction of the current flow at the metal∕etched p‐GaN interface, and an increase in the barrier height at the metal∕etched p‐GaN interface. In addition, from the SIMS measurements, it is suggested that the depth of the nitrogen-deficient near-surface region resulting from the dry-etch process is about 60 nm.
Show PACS
81.05.Ea III-V semiconductors
81.65.Cf Surface cleaning, etching, patterning
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
73.40.Ns Metal-nonmetal contacts
73.61.Ey III-V semiconductors
79.60.Dp Adsorbed layers and thin films
61.72.J- Point defects and defect clusters
73.30.+y Surface double layers, Schottky barriers, and work functions
79.60.Bm Clean metal, semiconductor, and insulator surfaces
79.60.Jv Interfaces; heterostructures; nanostructures
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
61.72.Yx Interaction between different crystal defects; gettering effect

Hydrostatic pressure response of polymer-dispersed liquid crystal gratings

Michael L. Ermold, Kashma Rai, and Adam K. Fontecchio

J. Appl. Phys. 97, 104905 (2005); http://dx.doi.org/10.1063/1.1896093 (4 pages) | Cited 1 time

Online Publication Date: 2 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Experimental analysis showed shifts in Bragg wavelength when examining the effects of applied hydrostatic pressure (0–10 psi above ambient) on the reflection spectrum of holographic polymer-dispersed liquid-crystal Bragg gratings. With increased pressure, a spectral blueshift was observed, suggesting applications in optical pressure sensing. To analyze and quantify the observations, a Gaussian curve was fitted to the reflection spectrum of the gratings at each pressure interval. The spectral dependence on applied pressure is explained by elastic compression of the polymer sections of the Bragg planes in the reflection grating. The presented theory shows that the response of the gratings to the applied pressure is independent of the probe light incidence angle, but is linearly dependent on the ambient pressure reflection wavelength of the gratings.
Show PACS
42.40.Eq Holographic optical elements; holographic gratings
62.50.-p High-pressure effects in solids and liquids
42.70.Df Liquid crystals

Measurement of source profile of proton beams generated by ultraintense laser pulses using a Thomson mass spectrometer

Y. Oishi, T. Nayuki, T. Fujii, Y. Takizawa, X. Wang, T. Yamazaki, K. Nemoto, T. Sekiya, K. Horioka, and A. A. Andreev

J. Appl. Phys. 97, 104906 (2005); http://dx.doi.org/10.1063/1.1896442 (4 pages) | Cited 5 times

Online Publication Date: 2 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
For measuring the source profile of proton beams, a method using a Thomson mass spectrometer, which has precise energy resolution and enables the discrimination of ion species, was proposed and applied in an experiment with irradiation of 55-fs, 6.6×1018-W/cm2-laser pulses on a 5-μm-thick copper tape target. The typical measured source size was 150 μm at E = 400 keV and 44 μm at E = 980 keV in full width at half maximum.
Show PACS
07.75.+h Mass spectrometers
07.77.Ka Charged-particle beam sources and detectors
06.60.Jn High-speed techniques (microsecond to femtosecond)
79.20.Ds Laser-beam impact phenomena

Microstructure of epitaxial Ba0.7Sr0.3TiO3/SrRuO3 bilayer films on SrTiO3 substrates

J. Q. He, E. Vasco, C. L. Jia, R. Dittmann, and R. H. Wang

J. Appl. Phys. 97, 104907 (2005); http://dx.doi.org/10.1063/1.1897067 (5 pages) | Cited 5 times

Online Publication Date: 3 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The thickness evolution of the microstructure of epitaxial Ba0.7Sr0.3TiO3 thin films grown on SrRuO3/SrTiO3 was investigated by means of transmission electron microscopy. Within the Ba0.7Sr0.3TiO3 layer, a layered structure (three sublayers) is distinguished as for the configuration of lattice strain and defects. The first sublayer extends for 3 nm from the lattice-coherent Ba0.7Sr0.3TiO3/SrRuO3 interface. The second 13-nm-thick sublayer forms a semicoherent interface with the first sublayer due to the creation of a misfit dislocation network. The third sublayer extends beyond the second sublayer exhibiting a structure characterized by compact columnar features. Planar defects are formed at the boundaries between such features. The formation of a layered structure within the Ba0.7Sr0.3TiO3 films is discussed in the light of the growth modes of films on lattice-mismatched substrates.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Orientation distribution of sheared isotactic polypropylene plates through thickness in the presence of sodium benzoate

Peng-wei Zhu, Andrew Phillips, Jason Tung, and Graham Edward

J. Appl. Phys. 97, 104908 (2005); http://dx.doi.org/10.1063/1.1897072 (6 pages) | Cited 9 times

Online Publication Date: 3 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The orientation distribution of sheared isotactic polypropylene (iPP) containing different amount of sodium benzoate (SB) has been investigated through the gradient of shear flow field using microbeam of synchrotron wide-angle x-ray techniques. The degree of the overall orientation of α-phase crystal is found to increase with increasing concentration of SB. Compared with the sheared iPP in the absence of SB, the orientation of α-phase crystal is found to distribute over a broader range of shear flow field in the presence of SB. The overall orientation of α-phase crystal is explained in terms of a parent-daughter model or lamella-branched shish-kebab structure. As the concentration of SB increases, the contribution from the c-axis orientation of parent lamellae decreases in the flow direction. The contribution from the a*-axis orientation of daughter lamellae is developed to be dominant in the flow direction when the concentration of SB exceeds a critical value.
Show PACS
61.41.+e Polymers, elastomers, and plastics
61.50.-f Structure of bulk crystals
78.70.Ck X-ray scattering

Microbridge testing of plasma-enhanced chemical-vapor deposited silicon oxide films on silicon wafers

Zhiqiang Cao, Tong-Yi Zhang, and Xin Zhang

J. Appl. Phys. 97, 104909 (2005); http://dx.doi.org/10.1063/1.1898449 (9 pages) | Cited 7 times

Online Publication Date: 3 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Plasma-enhanced chemical-vapor deposited (PECVD) silane-based oxides (SiOx) have been widely used in both microelectronics and microelectromechanical systems (MEMS) to form electrical and/or mechanical components. In this paper, a nanoindentation-based microbridge testing method is developed to measure both the residual stresses and Young’s modulus of PECVD SiOx films on silicon wafers. Theoretically, we considered both the substrate deformation and residual stress in the thin film and derived a closed formula of deflection versus load. The formula fitted the experimental curves almost perfectly, from which the residual stresses and Young’s modulus of the film were determined. Experimentally, freestanding microbridges made of PECVD SiOx films were fabricated using the silicon undercut bulk micromachining technique. Some microbridges were subjected to rapid thermal annealing (RTA) at a temperature of 400 °C, 600 °C, or 800 °C to simulate the thermal process in the device fabrication. The results showed that the as-deposited PECVD SiOx films had a residual stress of −155±17 MPa and a Young’s modulus of 74.8±3.3 GPa. After the RTA, Young’s modulus remained relatively unchanged at around 75 GPa, however, significant residual stress hysteresis was found in all the films. A microstructure-based mechanism was then applied to explain the experimental results of the residual stress changes in the PECVD SiOx films after the thermal annealing.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.-g Dielectric thin films
81.70.Bt Mechanical testing, impact tests, static and dynamic loads
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
81.40.Lm Deformation, plasticity, and creep
62.20.D- Elasticity
62.20.M- Structural failure of materials
62.20.F- Deformation and plasticity
68.60.Bs Mechanical and acoustical properties
61.72.Cc Kinetics of defect formation and annealing
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Single-defect Bragg stacks for high-power narrow-band thermal emission

Philippe Ben-Abdallah and Bo Ni

J. Appl. Phys. 97, 104910 (2005); http://dx.doi.org/10.1063/1.1898450 (5 pages) | Cited 14 times

Online Publication Date: 4 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The radiative properties of single-defect Bragg stacks are investigated in the midinfrared region with the transfer-matrix theory. For a sufficiently small number of layers we find a regime where the structure emits radiation within a narrow range of wavelengths (δλ/λ ⩽ 0.01) and with an emissivity close to 1 in all directions. A description of the electric-field distribution inside the structure allows us to interpret this behavior in terms of coupling between the localized defect states and surface waves. This result should find broad applications in infrared spectroscopy, chemical sensing, and thermophotovoltaic conversion.
Show PACS
44.40.+a Thermal radiation
73.20.At Surface states, band structure, electron density of states
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Dependence of microwave emissions from hypervelocity impacts on the target material

K. Maki, E. Soma, T. Takano, A. Fujiwara, and A. Yamori

J. Appl. Phys. 97, 104911 (2005); http://dx.doi.org/10.1063/1.1896092 (6 pages) | Cited 3 times

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Microwave emissions due to hypervelocity impacts and their dependence on the target material are described. Microwave signals were measured for four kinds of target materials: aluminum, alumina ceramic, red brick, and polyurethane rubber. The signals were composed of two kinds of wave form: intermittent sharp pulses and white noise. The pulse signals were emitted strongly, especially with the aluminum target. The energy emitted from each target was estimated from the signal detected after calibrating the measuring system. The energy of the pulses was greater for conductors than for insulators. We hypothesized that the microwaves were emitted from a discharge along a microcrack in the target. The signals detected in the experiment agreed well with theoretical results.
Show PACS
62.50.-p High-pressure effects in solids and liquids
46.55.+d Tribology and mechanical contacts

Two-dimensional model for melting and vaporization during optical trepanning

D. Zeng, W. P. Latham, and A. Kar

J. Appl. Phys. 97, 104912 (2005); http://dx.doi.org/10.1063/1.1897835 (7 pages) | Cited 2 times

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Annular laser beams provide a drilling mechanism that can be referred to as optical trepanning. In this paper an analytical two-dimensional model is developed for optical trepanning. The analysis accounts for conduction in the solid, vaporization, and convection due to the melt flow caused by an assist gas. Based on the model, the influences of pulse duration, laser-pulse length, pulse repetition rate, intensity profiles, and beam radius are investigated to examine their effects on the recast layer thickness, hole depth, and taper. Deeper cavity depth, thicker recast layer, and larger taper are obtained with the increase in the laser intensity. By using different types of intensity profiles, the nature of the hole taper can be modified, i.e., convergent or divergent holes can be produced. The effects of the inner radius of annular beams are more significant than other laser parameters. An increase in the inner radius reduces the hole taper and produces thinner recast layer and deeper cavity depth.
Show PACS
42.62.-b Laser applications

A time-dependent potential flow theory for the aerodynamics of vertical axis wind turbines

O. Ågren, M. Berg, and M. Leijon

J. Appl. Phys. 97, 104913 (2005); http://dx.doi.org/10.1063/1.1896091 (12 pages) | Cited 1 time

Online Publication Date: 6 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Betz factor, i.e., the value 16/27 for the power coefficient, is widely expected to give an upper limit for the performance of any wind turbine. In the present study, an analytical model of a vertical-axis wind turbine with straight vertical wings is developed. A goal of the work is to study if the one-dimensional Betz theory gives an upper limit of the performance of wind turbines when two-dimensional effects are included. The two-dimensional and time-dependent potential flow is solved by a conformal map of the wing sections to circles. The stagnation points are determined by the Kutta condition. The calculated power coefficient exceeds the Betz limit by a large factor. This is due to a completely different flow pattern compared to the one-dimensional Betz theory. In aerodynamic potential flow, the expanding flux tube of Betz is replaced by an asymptotic flow consisting of a superposition of homogeneous flow and a circulation around the wings. Moreover, the total torque on a turbine with three or more blades is found to be constant. The Betz theory does not take into account the two-dimensional flow effects and the velocity of the rotating wind turbine. By including these effects, far more optimistic theoretical results for the performance of vertical-axis wind turbines are obtained.
Show PACS
47.85.Gj Aerodynamics
88.60.-m Hydroelectric power
88.10.-g Geothermal energy
88.50.-k Wind energy
47.54.-r Pattern selection; pattern formation
47.40.-x Compressible flows; shock waves

Control of the Mg doping profile in III-N light-emitting diodes and its effect on the electroluminescence efficiency

K. Köhler, T. Stephan, A. Perona, J. Wiegert, M. Maier, M. Kunzer, and J. Wagner

J. Appl. Phys. 97, 104914 (2005); http://dx.doi.org/10.1063/1.1901836 (4 pages) | Cited 19 times

Online Publication Date: 10 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of the Mg doping profile on the electroluminescence (EL) efficiency of (AlGaIn)N quantum well (QW) light-emitting diodes, grown by low-pressure metal-organic vapor-phase epitaxy on sapphire, has been investigated. The actual Mg profile close to the active region was found to be influenced by segregation as well as by diffusion during growth. In a first experiment, diffusion of the Mg dopants towards the QW region through a not intentionally doped narrow GaN spacer layer, separating the topmost GaInN quantum well from the AlGaN:Mg electron-blocking barrier, was controlled by the growth temperature of the AlGaN:Mg barrier and GaN:Mg contact layer. Starting from low growth temperatures, an increase in Mg concentration close to the active region results in an improved hole injection and thus increased EL efficiency. However, for a too high growth temperature, an excessive spread of the Mg atoms into the active region leads to nonradiative recombination in the QW active region and thus a reduction in EL output. In a second experiment, identical structures were prepared with the Mg-doped (Al)GaN layers grown at lower temperature to minimize Mg diffusion. Instead, the nominal Mg doping level in the GaN spacer layer was varied systematically. Secondary-ion-mass spectrometry revealed that almost identical Mg doping profiles close the QW active region, and in turn very similar EL efficiencies, can be achieved by both approaches when appropriate growth parameters are used.
Show PACS
85.60.Jb Light-emitting devices
61.72.uj III-V and II-VI semiconductors
78.60.Fi Electroluminescence

Compact superradiant Čerenkov source

I. J. Owens and J. H. Brownell

J. Appl. Phys. 97, 104915 (2005); http://dx.doi.org/10.1063/1.1901840 (6 pages) | Cited 11 times

Online Publication Date: 11 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An economical, coherent, and widely tunable source does not exist spanning the far-infrared electromagnetic spectral range of 50–1000 μm in wavelength. The Čerenkov free-electron laser (CFEL) is a promising candidate. This report describes an experimental investigation of a compact CFEL driven by a high-quality low-energy electron beam. Čerenkov emission and strong gain but remarkably low output coupling were observed.
Show PACS
41.60.Cr Free-electron lasers
41.60.Bq Cherenkov radiation
42.60.Fc Modulation, tuning, and mode locking
42.72.Ai Infrared sources

High-energy x-ray production with pyroelectric crystals

Jeffrey A. Geuther and Yaron Danon

J. Appl. Phys. 97, 104916 (2005); http://dx.doi.org/10.1063/1.1915536 (5 pages) | Cited 16 times

Online Publication Date: 11 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The invention of pyroelectric x-ray generator technology has enabled researchers to develop ultraportable, low-power x-ray sources for use in imaging, materials analysis, and other applications. For many applications, the usefulness of an x-ray source is determined by its yield and endpoint energy. In x-ray fluorescence, for example, high-energy sources enable the excitation of the K-shell x-ray peaks for high-Z materials as well as the lower-energy L-shell peaks, allowing more positive sample identification. This report shows how a paired-crystal pyroelectric source can be used to approximately double the endpoint x-ray energy, in addition to doubling the x-ray yield, versus a single-crystal source. As an example of the advantage of a paired-crystal system, we present a spectrum showing the fluorescence of the K shell of thorium using a pyroelectric source, as well as a spectrum showing the fluorescence of the K shell of lead. Also shown is an x-ray spectrum with an endpoint energy of 215 keV.
Show PACS
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
77.70.+a Pyroelectric and electrocaloric effects
78.70.En X-ray emission spectra and fluorescence

Highly oriented Ni(Pd)SiGe formation at 400 °C

L. J. Jin, K. L. Pey, W. K. Choi, E. A. Fitzgerald, D. A. Antoniadis, A. J. Pitera, M. L. Lee, and C. H. Tung

J. Appl. Phys. 97, 104917 (2005); http://dx.doi.org/10.1063/1.1899759 (5 pages) | Cited 3 times

Online Publication Date: 12 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A germanosilicide technology employing Ni0.95Pd0.05 alloy to improve the germanosilicide film texture strucutre on relaxed Si1−xGex substrate has been developed. Highly oriented (Ni0.95Pd0.05)y(Si1−xGex)1−y films where x = 0.2, 0.25, 0.3, and y ≈ 0.5 are obtained at 400 °C annealing with (200) as the preferred orientation, as was revealed by cross-sectional transmission electron microscopy and x-ray diffraction results. The formation of the highly oriented (Ni0.95Pd0.05)y(Si1−xGex)1−y film can be explained by interface and surface energies minimization due to the addition of Pd.
Show PACS
81.05.Hd Other semiconductors
68.55.-a Thin film structure and morphology
68.35.Md Surface thermodynamics, surface energies
61.72.Cc Kinetics of defect formation and annealing

Three-dimensional lattice Boltzmann model for gaseous flow in rectangular microducts and microscale porous media

G. H. Tang, W. Q. Tao, and Y. L. He

J. Appl. Phys. 97, 104918 (2005); http://dx.doi.org/10.1063/1.1901839 (8 pages) | Cited 13 times

Online Publication Date: 12 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Microscale fluid dynamics has received intensive interest due to the rapid advances in microelectromechanical systems. In this work, the lattice Boltzmann method is applied to simulate isothermal gaseous slip flow in three-dimensional (3D) rectangular microducts and microscale porous structures. The flow characteristics in 3D microducts—including velocity profile, nonlinear pressure distribution, friction factor, and mass flow rate—are compared with analytical solutions, and the agreement is good. The flow-rate results show that due to the slip-velocity emergence at the walls, the lateral wall influence on the flow rate in 3D rectangular microducts is decreased. The predicted transport characteristics in 3D microscale porous media show that the rarefaction influence increases the gas permeability. The Klinkenberg effect is confirmed and the predicted gas permeability is qualitatively consistent with the experimental results. Furthermore, the nonlinear behavior of the porous flow at relatively higher Reynolds number is also observed. This study demonstrates that the lattice Boltzmann method can be employed to efficiently predict transport characteristics in microducts and microscale porous media.
Show PACS
47.45.Gx Slip flows and accommodation
47.60.-i Flow phenomena in quasi-one-dimensional systems
47.56.+r Flows through porous media
47.85.Np Fluidics
47.11.-j Computational methods in fluid dynamics
05.50.+q Lattice theory and statistics (Ising, Potts, etc.)
05.60.-k Transport processes

Step control of vicinal 6H–SiC(0001) surface by H2 etching

A. Nakajima, H. Yokoya, Y. Furukawa, and H. Yonezu

J. Appl. Phys. 97, 104919 (2005); http://dx.doi.org/10.1063/1.1901838 (5 pages) | Cited 17 times

Online Publication Date: 13 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Anisotropic step bunching on vicinal 6H–SiC(0001) surface induced by H2 etching was investigated. Step structures were observed using atomic force microscopy and high-resolution transmission electron microscopy at off angle <2°. The etched surfaces exhibited three types of step bunching: (1) straight six-bilayer steps, (2) straight six-bilayer steps and nanofacets, and (3) zigzag three-bilayer steps. The step height and density can be controlled by a tilt angle and direction of a vicinal surface. Mechanisms of the step bunching processes are discussed at points of an anisotropy of lateral-etching rates and surface-free energies.
Show PACS
68.47.Fg Semiconductor surfaces
81.05.Hd Other semiconductors
81.65.Cf Surface cleaning, etching, patterning
68.35.Md Surface thermodynamics, surface energies
68.37.Ps Atomic force microscopy (AFM)
68.37.Lp Transmission electron microscopy (TEM)
65.40.G- Other thermodynamical quantities

High-resolution elemental profiles of the silicon dioxide∕4H-silicon carbide interface

K.-C. Chang, Y. Cao, L. M. Porter, J. Bentley, S. Dhar, L. C. Feldman, and J. R. Williams

J. Appl. Phys. 97, 104920 (2005); http://dx.doi.org/10.1063/1.1904728 (6 pages) | Cited 20 times

Online Publication Date: 16 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-resolution elemental profiles were obtained from SiO2(N)/4H‐SiC structures by spatially resolved electron energy-loss spectroscopy (EELS) performed in the scanning transmission electron microscopy mode. The results show that following annealing in NO, N was exclusively incorporated within ∼ 1 nm of the SiO2(N)/4H‐SiC interface. Mean interfacial nitrogen areal densities measured by EELS were ∼ (1.0±0.2)×1015 cm−2 in carbon-face samples and (0.35±0.13)×1015 cm−2 in Si-face samples; these results are consistent with nuclear reaction analysis measurements. Some of the interface regions in the C-face samples also showed excess carbon that was not removed by the NO annealing process, in contrast with previous results on Si-face samples.
Show PACS
82.80.-d Chemical analysis and related physical methods of analysis
79.20.Uv Electron energy loss spectroscopy
68.35.Ct Interface structure and roughness
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Interfacial reaction in the growth of epitaxial SrTiO3 thin films on (001) Si substrates

J. Q. He, C. L. Jia, V. Vaithyanathan, D. G. Schlom, J. Schubert, A. Gerber, H. H. Kohlstedt, and R. H. Wang

J. Appl. Phys. 97, 104921 (2005); http://dx.doi.org/10.1063/1.1915519 (6 pages) | Cited 12 times

Online Publication Date: 16 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The SrTiO3/Si interface was investigated by transmission electron microscopy for SrTiO3 films grown on (001) Si by molecular-beam epitaxy with different native oxide (SiO2) removal treatments, and Sr/Ti flux ratios. The interface and film microstructure were independent of the process used to remove the native oxide, but the interface reactivity was dependent on the Sr/Ti flux ratio. A low Sr/Ti flux ratio ( ∼ 0.8) resulted not only in a layer of amorphous material at the film∕substrate interface but also in the formation of crystalline C49 TiSi2 precipitates at that interface. These results are consistent with thermodynamic expectations in which it is paramount to maintain separation between TiO2 and the underlying silicon.
Show PACS
77.55.-g Dielectric thin films
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.A- Nucleation and growth
68.35.Ct Interface structure and roughness
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close