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1 Aug 1985

Volume 58, Issue 3, pp. R1-1422

Page 1 of 3 Pages Next Page | Jump to Page

GaAs, AlAs, and AlxGa1−xAs@B: Material parameters for use in research and device applications

Sadao Adachi

J. Appl. Phys. 58, R1 (1985); http://dx.doi.org/10.1063/1.336070 (29 pages) | Cited 1506 times

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The AlxGa1−xAs/GaAs heterostructure system is potentially useful material for high‐speed digital, high‐frequency microwave, and electro‐optic device applications. Even though the basic AlxGa1−xAs/GaAs heterostructure concepts are understood at this time, some practical device parameters in this system have been hampered by a lack of definite knowledge of many material parameters. Recently, Blakemore has presented numerical and graphical information about many of the physical and electronic properties of GaAs [J. S. Blakemore, J. Appl. Phys. 53, R123 (1982)]. The purpose of this review is (i) to obtain and clarify all the various material parameters of AlxGa1−xAs alloy from a systematic point of view, and (ii) to present key properties of the material parameters for a variety of research works and device applications. A complete set of material parameters are considered in this review for GaAs, AlAs, and AlxGa1−xAs alloys. The model used is based on an interpolation scheme and, therefore, necessitates known values of the parameters for the related binaries (GaAs and AlAs). The material parameters and properties considered in the present review can be classified into sixteen groups: (1) lattice constant and crystal density, (2) melting point, (3) thermal expansion coefficient, (4) lattice dynamic properties, (5) lattice thermal properties, (6) electronic‐band structure, (7) external perturbation effects on the band‐gap energy, (8) effective mass, (9) deformation potential, (10) static and high‐frequency dielectric constants, (11) magnetic susceptibility, (12) piezoelectric constant, (13) Fröhlich coupling parameter, (14) electron transport properties, (15) optical properties, and (16) photoelastic properties.
Of particular interest is the deviation of material parameters from linearity with respect to the AlAs mole fraction x. Some material parameters, such as lattice constant, crystal density, thermal expansion coefficient, dielectric constant, and elastic constant, obey Vegard’s rule well. Other parameters, e.g., electronic‐band energy, lattice vibration (phonon) energy, Debye temperature, and impurity ionization energy, exhibit quadratic dependence upon the AlAs mole fraction. However, some kinds of the material parameters, e.g., lattice thermal conductivity, exhibit very strong nonlinearity with respect to x, which arises from the effects of alloy disorder. It is found that the present model provides generally acceptable parameters in good agreement with the existing experimental data. A detailed discussion is also given of the acceptability of such interpolated parameters from an aspect of solid‐state physics. Key properties of the material parameters for use in research work and a variety of AlxGa1−xAs/GaAs device applications are also discussed in detail.
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71.20.-b Electron density of states and band structure of crystalline solids
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
75.30.Cr Saturation moments and magnetic susceptibilities
65.90.+i Other topics in thermal properties of condensed matter (restricted to new topics in section 65)

A method of rapidly obtaining concentration‐depth profiles from x‐ray diffraction

K. E. Wiedemann and J. Unnam

J. Appl. Phys. 58, 1095 (1985); http://dx.doi.org/10.1063/1.336121 (7 pages) | Cited 9 times

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The construction of composition profiles from x‐ray diffraction peaks is an important and reliable technique, but it has not been widely adopted because it required hours of computer time and/or complicated optimization routines. The method proposed here utilizes an easily evaluated analysis of the diffraction peak. It is applicable to thin films and thick specimens for which the variation with composition of lattice parameters, linear absorption coefficient, and reflectivity are known. A deconvolution scheme is outlined that includes corrections for the instrumental broadening and singlet or doublet radiation.
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61.05.C- X-ray diffraction and scattering
61.05.cc Theories of x-ray diffraction and scattering
68.60.-p Physical properties of thin films, nonelectronic
82.80.-d Chemical analysis and related physical methods of analysis

Theory of elastic wave scattering: Applications of the method of optimal truncation

Jon L. Opsal and William M. Visscher

J. Appl. Phys. 58, 1102 (1985); http://dx.doi.org/10.1063/1.336122 (14 pages) | Cited 4 times

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The method of optimal truncation is developed and applied to a variety of rotationally symmetric defects in elastic materials. Results are presented for oblate and prolate spheroidal voids, cracks, irregularly shaped voids, and compound inclusions. Most of the examples are in the frequency domain, but samples of time‐domain calculations are included. Physical interpretations of some features of the calculated amplitudes are given. Checks on accuracy of the results are emphasized and implemented.
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41.20.Jb Electromagnetic wave propagation; radiowave propagation
62.30.+d Mechanical and elastic waves; vibrations
43.35.Cg Ultrasonic velocity, dispersion, scattering, diffraction, and attenuation in solids; elastic constants
43.20.Px Transient radiation and scattering

Determination of the external magnetic field of systems containing two‐dimensional semi‐infinite plates and one finite cross‐sectional plate

D. Owen and A. J. Parris

J. Appl. Phys. 58, 1116 (1985); http://dx.doi.org/10.1063/1.336123 (4 pages)

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Certain two‐dimensional symmetrical systems of magnetic conductors, consisting of semi‐infinite and finite plates are examined using a mapping method. Four examples are studied.
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41.20.Cv Electrostatics; Poisson and Laplace equations, boundary-value problems
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems

Short‐pulse, multiline energy extraction from a transversely excited atmospheric CO2 laser amplifier

R. A. Rooth and W. J. Witteman

J. Appl. Phys. 58, 1120 (1985); http://dx.doi.org/10.1063/1.336124 (4 pages) | Cited 3 times

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Data are presented on the energy extraction from a transversely excited atmospheric CO2 laser amplifier by a 1.1‐ns pulse consisting of an adjustable number of lines which are generated by a multiline oscillator of a new design. An increase in energy extraction of 95% with respect to single‐line extraction was achieved with a pulse consisting of up to six lines in the 10.6‐μm branch. Energy extraction at a fixed number of lines was not very sensitive to their spectral distribution. We observed a maximum increase of about 8% when the lines were spread over the 00°1–10°0 vibrational band. This indicates a slight preference for small Δj values in the rotational relaxation processes.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
33.20.Sn Rotational analysis

Temperature distribution along the striped active region in high‐power GaAlAs visible lasers

Satoru Todoroki, Masaaki Sawai, and Kunio Aiki

J. Appl. Phys. 58, 1124 (1985); http://dx.doi.org/10.1063/1.336125 (5 pages) | Cited 49 times

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Catastrophic degradation related to local heating in GaAlAs visible lasers occasionally occurs under relatively low optical output power. To develop highly reliable lasers, we used laser Raman spectroscope with an argon ion laser focused at about 1 μm≂ to evaluate the local operating temperature rise not only at the facet surface, but also along the striped active region. The local operating temperature rise in the vicinity of the facet’s active region increased exponentially up to 200 °C when the optical output power was 30 mW/facet. This high temperature causes the rapid formation of a dark region and final catastrophic degradation. The calculated temperature rise along the striped active region is about one‐half of that of the facet. The internal operating temperature is far higher than the average temperature measured by the thermal resistance method, which is considered to be a large influence on the lifetime and activation energy of lasers in practical applications.
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42.60.By Design of specific laser systems
42.79.Sz Optical communication systems, multiplexers, and demultiplexers
78.30.Hv Other nonmetallic inorganics
05.70.Ce Thermodynamic functions and equations of state

Properties of a KrF laser with atmospheric‐pressure Kr‐rich mixture pumped by an electron beam

Akira Suda, Minoru Obara, and Akira Noguchi

J. Appl. Phys. 58, 1129 (1985); http://dx.doi.org/10.1063/1.336126 (6 pages) | Cited 5 times

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Atmospheric pressure operation of a KrF laser is suitable for large‐aperture laser modules in which several technical limitations on the ICF driver design are overcome by the use of aerodynamic windows instead of the conventional solid optical windows. We experimentally studied atmospheric‐pressure operation of the KrF laser pumped by 50‐ns electron beams. For a 1‐atm mixture of Kr and F2 without diluent, a specific output energy of 4.2 J/1 was obtained with an intrinsic efficiency of 5%, which was comparable to that from normal 10% Kr mixture. According to the results of fluorescence measurements, a large amount of Kr2F∗ is formed via three‐body collisional quenching by high‐concentration Kr even in the atmospheric‐pressure mixture. Code calculations indicate that a higher excitation rate improves the intrinsic efficiency by reducing three‐body quenching especially in Kr‐rich mixtures, and that a specific energy in excess of 10 J/1 is realizable.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.62.-b Laser applications
52.38.-r Laser-plasma interactions
28.52.-s Fusion reactors

Asymmetry factors for randomly oriented infinite cylinders

Ariel Cohen, Richard D. Haracz, and Leonard D. Cohen

J. Appl. Phys. 58, 1135 (1985); http://dx.doi.org/10.1063/1.336127 (6 pages) | Cited 2 times

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A method is presented for obtaining optical parameters that are relevant to problems of radiative transfer in such fields as polyester fiber insulation and the passage of radiation through aerosol clouds. The concept of the asymmetry factor is generalized to include nonspherical particles in order to calculate the ratio of the power of radiated light into the forward direction to the power of backscattering light. The geometry for scattering from an infinite cylinder randomly oriented is discussed and related to the problem of identifying the forward and backward directions. This geometry is used to calculate the asymmetry factor versus the angle which the cylinder axis makes with the direction of incidence. The asymmetry factor is also plotted as a function of the size parameter of the cylinder for random orientations of the cylinder.
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42.25.Dd Wave propagation in random media
42.68.Ay Propagation, transmission, attenuation, and radiative transfer
42.68.Bz Atmospheric turbulence effects
42.68.Ge Effects of clouds and water; ice crystal phenomena
42.68.Kh Effects of air pollution
42.68.Wt Remote sensing; LIDAR and adaptive systems

Influence of the dynamic Stark effect on the small‐signal gain of optically pumped 4.3‐μm CO2 lasers

R.K. Brimacombe and J. Reid

J. Appl. Phys. 58, 1141 (1985); http://dx.doi.org/10.1063/1.336128 (5 pages) | Cited 1 time

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Experimental results are presented which show that the dynamic Stark effect significantly reduces the small‐signal gain (in discharge‐excited CO2) and absorption (in unexcited CO2) at the line center of 4.3‐μm laser lines directly coupled to 10.4‐μm sequence‐band pump transitions. In unexcited CO2, population transfer by the pump radiation is negligible and the influence of coherent effects can be observed unambiguously. The results of comparing experiment and theory in this simple case are used to modify a rate‐equation model of the 4.3‐μm gain dynamics, and the modified calculations are shown to be in good agreement with measured 4.3‐μm gain coefficients.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems

Radii of gyration of single‐oriented microparticles from small‐angle light scattering

F. A. Fischbach

J. Appl. Phys. 58, 1146 (1985); http://dx.doi.org/10.1063/1.336129 (2 pages) | Cited 1 time

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Gaussian functions characterized by a radius of gyration are shown to approximate the intensity of light diffracted at small angles by opaque single‐oriented microparticles. Procedures are presented for obtaining the radii of gyration.
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42.25.Fx Diffraction and scattering

Time‐Fourier transform by a focusing array of phased surface acoustic wave transducers

Jaroslava Z. Wilcox and Robert E. Brooks

J. Appl. Phys. 58, 1148 (1985); http://dx.doi.org/10.1063/1.336130 (12 pages) | Cited 7 times

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The generation of Fourier transforms of a time varying signal by frequency‐dependent beam steering of focused surface acoustic waves (SAWs) is described. This transform is accomplished by using a focusing array of phased SAW interdigital transducers (IDT) to generate, focus, and angularly disperse the acoustic waves according to the input signal frequencies. The spectrum is retrieved at the output by an array of independent SAW IDTs placed along the focal arc. Substrate anisotropy affects SAW diffraction, but need not present a problem when properly accounted for. This paper discusses the rationale for the design of the input transducer and its effect on the acoustic diffraction pattern, frequency response, and sidelobe suppression on an anisotropic substrate.
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43.38.Hz Transducer arrays, acoustic interaction effects in arrays
43.60.Gk Space-time signal processing, other than matched field processing
43.25.Jh Reflection, refraction, interference, scattering, and diffraction of intense sound waves
43.35.Pt Surface waves in solids and liquids

Frequency‐dependent beam steering by a focusing array of surface acoustic wave transducers: Experiment

Jaroslava Z. Wilcox and Robert E. Brooks

J. Appl. Phys. 58, 1160 (1985); http://dx.doi.org/10.1063/1.336131 (9 pages) | Cited 4 times

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Experimental results that verify focusing and dispersion with frequency of surface acoustic waves (SAW) by wide‐band phased array of SAW interdigital transducers (IDTs) are presented. The diffraction sidelobes are suppressed by weighting the drive to each IDT using capacitive taps.
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43.38.Hz Transducer arrays, acoustic interaction effects in arrays
43.35.Pt Surface waves in solids and liquids
43.60.Gk Space-time signal processing, other than matched field processing
43.25.Jh Reflection, refraction, interference, scattering, and diffraction of intense sound waves

Spatial characteristics of the optogalvanic effect in striated rare‐gas discharges

Randy D. May

J. Appl. Phys. 58, 1169 (1985); http://dx.doi.org/10.1063/1.336132 (8 pages) | Cited 5 times

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The spatial variation of the optogalvanic (OG) signal resulting from visible laser irradiation of rare‐gas positive column discharges has been investigated for the case of standing striations. The OG signal was observed to periodically change polarity as the laser was scanned transversly across the bright and (relatively) dark regions of the column. Transitions involving the 3P2,0 metastable levels were found to be everywhere opposite in polarity to those originating on freely radiating levels. The effects of trapped resonance level emission, and collisions of the second kind involving metastables are proposed to be important in determining the OG signal polarity for excitation in certain discharge regions.
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52.80.Hc Glow; corona
51.60.+a Magnetic properties
51.70.+f Optical and dielectric properties

Reaction of atomic fluorine with silicon

Ken Ninomiya, Keizo Suzuki, Shigeru Nishimatsu, and Osami Okada

J. Appl. Phys. 58, 1177 (1985); http://dx.doi.org/10.1063/1.336133 (6 pages) | Cited 35 times

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The etch rate of Si with F atoms was measured by the use of F2 microwave plasma over a range of discharge pressures between 2.7×10−2 and 17 Pa. Fluorine atom concentration in the plasma was determined over the same pressure range by means of both gas‐phase titration and actinometry using Ar gas. A Si surface etched at 1.0×10−1, 5.3×10−1, 1.3, and 5.3 Pa was analyzed with XPS without exposing the surface to room air. A linear relation was obtained between the Si etch rate and the F atom concentration at discharge pressures between 2.7×10−2 and 2.7 Pa. The reaction probability of F atoms with Si to yield SiF4 was determined from the linear relation to be 0.1 for a Si surface at about 300 K. When the discharge pressure was higher than 1.3 Pa, the surface became rather strongly oxidized by O atoms resulting from residual gases. This surface oxidation results in a slight saturation of the Si etch rate at about 10 Pa.
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81.65.-b Surface treatments
52.40.Hf Plasma-material interactions; boundary layer effects
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Depth profile of bulk stacking fault radius in Czochralski silicon

Kazumi Wada and Naohisa Inoue

J. Appl. Phys. 58, 1183 (1985); http://dx.doi.org/10.1063/1.336134 (4 pages) | Cited 3 times

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The depth profiles of bulk stacking fault radius formed under the annealed specimen surface of Czochralski silicon wafers have been obtained. It is clearly shown that the depth profiles have been well predicted by the theoretical result. The curve fitting gives the diffusion coefficient of the responsible point defects expressed by D=257 exp[−(2.84±0.66)eV/kT] in the temperature range between 1080 and 1270 °C. It is strongly suggested that vacancies, not self‐interstitials, dominate the growth of the bulk stacking faults.
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61.72.Nn Stacking faults and other planar or extended defects
61.72.jd Vacancies
61.72.jj Interstitials

Formation of pyrene crystalline thin films assisted by helium ion bombardment

Masahito Migita, Yoshio Taniguchi, Heigo Ishihara, Motoo Akagi, Tsutomu Ishiba, and Hifumi Tamura

J. Appl. Phys. 58, 1187 (1985); http://dx.doi.org/10.1063/1.336135 (5 pages) | Cited 1 time

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This paper reports on the effect of low energy He+ ion‐beam bombardment upon the structure of pyrene thin films formed on quartz substrates. Films are prepared by vacuum evaporation during ion bombardment at room temperature. The structure of the film is controlled by the kinetic energy and current density of the ions. The colorless and transparent crystalline films preferentially oriented with their {001} plane parallel to the substrates are obtained by bombardment of 350 to 500 eV, 60 nA/cm2 He+ ions. Ion‐beam irradiation of the higher ion current density enhances intermolecular chemical reactions and, as a result, a crystalline polymer with its {001} plane parallel to the substrate is produced.
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68.55.-a Thin film structure and morphology
81.15.Jj Ion and electron beam-assisted deposition; ion plating
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Crystallization characteristics of Co‐Zr metallic glasses from Co52Zr48 to Co20Zr80

Z. Altounian, R. J. Shank, and J. O. Strom‐Olsen

J. Appl. Phys. 58, 1192 (1985); http://dx.doi.org/10.1063/1.336136 (4 pages) | Cited 30 times

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We present a crystallization study of melt‐spun Co‐Zr metallic glasses. The primary crystallization products are all metastable or unstable except around the equiatomic composition where the stable phase CoZr is produced. Alloys at the composition Co25Zr75 show a crystallization characteristic that is dependent on heating rate.
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64.70.K- Solid-solid transitions
81.05.Kf Glasses (including metallic glasses)
64.60.My Metastable phases
72.15.Cz Electrical and thermal conduction in amorphous and liquid metals and alloys

Characterization of silicon implanted GaAs buffer layers grown by metalorganic chemical vapor deposition

T. F. Kuech, R. Potemski, and T. I. Chappell

J. Appl. Phys. 58, 1196 (1985); http://dx.doi.org/10.1063/1.336137 (8 pages) | Cited 4 times

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The uniform and reproducible activation of silicon, ion‐implanted directly into GaAs substrates, is often difficult to achieve. Epitaxial GaAs buffer layers have been used as an alternative implantation media which offers improved electrical characteristics. The characteristics of Si implanted GaAs buffer layers grown by the metalorganic chemical vapor deposition technique are presented here. The influence of the gas phase stoichiometry, a key determinant in the electrical properties of the layer, on the characteristics of the Si implanted and capless annealed layers was studied over the implantation dose range of 3×1012 to 1×1014 cm−2 at an implant energy of 150 keV. The electrical activation, mobility, deep‐level concentration, and impurity distribution both prior to and after the implant and anneal were determined through optical and electrical characterization techniques. Undoped GaAs grown by this technique provides reproducible high levels of implant activation. Implantation into thick buffer layers allows the study of the implant and anneal processes free from the complicating influence of the GaAs substrate.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.U- Doping and impurity implantation
68.55.-a Thin film structure and morphology
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors

Nonalloyed ohmic contacts to Si‐implanted GaAs activated using SiOxNy capped infrared rapid thermal annealing

M. Kuzuhara, T. Nozaki, and H. Kohzu

J. Appl. Phys. 58, 1204 (1985); http://dx.doi.org/10.1063/1.336138 (6 pages) | Cited 6 times

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SiOxNy capped infrared rapid thermal annealing was investigated for activating high dose (>7×1013 cm−2) Si implants in GaAs. The SiOxNy encapsulation resulted in enhancement in electrical activation. An electron concentration as high as 9×1018 cm−3 was obtained by 1120 °C, 5‐sec annealing using an SiOxNy encapsulant with 1.75 refractive index. Nonalloyed ohmic contacts were formed by depositing AuGe‐Ni on a heavily doped n‐type layer activated by this technique, where a 9×10−5 Ω cm2 specific contact resistance was obtained. Furthermore, low‐temperature (300 °C) alloying significantly improved a specific contact resistance to as low as 6×10−6 Ω cm2 while keeping a smooth morphology. These techniques, including low‐temperature alloying, are promising for GaAs and its heterostructure device applications.
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61.72.U- Doping and impurity implantation
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
73.40.Cg Contact resistance, contact potential
73.40.Ns Metal-nonmetal contacts

Geometric statistics and dynamic fragmentation

D. E. Grady and M. E. Kipp

J. Appl. Phys. 58, 1210 (1985); http://dx.doi.org/10.1063/1.336139 (13 pages) | Cited 74 times

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The present study is focused on the distributions in particle size produced in dynamic fragmentation processes. Previous work on this subject is reviewed. We then examine the one‐dimensional fragmentation problem as a random Poisson process and provide comparisons with expanding ring fragmentation data. Next we explore the two‐dimensional (area) and, less extensively, the three‐dimensional (volume) fragmentation problem. Mott’s theory of random area fragmentation is developed, and we propose an alternative application of Poisson statistics which leads to an exponential distribution in fragment size. Both theoretical distributions are compared with analytic and computer studies of random area geometric fragmentation problems, including those suggested by Mott, the Voronoi construction, a variation of the Johnson–Mehl construction, and several methods of our own. We find that size distributions from random geometric fragmentation are construction dependent, and that a conclusive choice between the two distributions cannot be made. A tentative application of the maximum entropy principle to fragmentation is discussed. The statistical theory is extended to include a concept of statistical heterogeneity in the fragmentation process. Finally, comparisons are made with various, dynamic fragmentation data.
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62.20.M- Structural failure of materials
46.50.+a Fracture mechanics, fatigue and cracks

Computation of fragment mass distributions for HF‐1 steel explosive‐filled cylinders

Willis Mock and William H. Holt

J. Appl. Phys. 58, 1223 (1985); http://dx.doi.org/10.1063/1.336140 (6 pages) | Cited 1 time

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Computations using a one‐dimensional computer program have been performed to determine fragment mass distributions for exploding cylinders of HF‐1 steel. Experiments were performed to guide the computations. Nucleation and growth models were used to simulate the brittle fracture and shear band damage that occurred in the metal cylinders prior to complete fragmentation. Material input parameters for these models have been previously determined. Computations were performed for two heat treatments of HF‐1 steel. The calculated brittle crack and shear band distributions were converted to fragment mass distributions using one of the experimental fragment shapes. Based upon the experimental results, suggestions are made for future refinements in the area of fragmentation modeling.
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62.20.M- Structural failure of materials

Interdiffusion and chemical ordering in composition‐modulated Fe70Si30/Si amorphous thin films

A. Bruson, M. Piecuch, and G. Marchal

J. Appl. Phys. 58, 1229 (1985); http://dx.doi.org/10.1063/1.336141 (5 pages) | Cited 14 times

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The interdiffusivity and chemical ordering in compositionally modulated (Λ=20 to 40 Å) amorphous Fe70Si30/Si thin films have been measured from the decay of the satellite intensities of the (000) x‐ray scattering peak during isothermal anneals in the temperature range 373–473 K. Diffusivities as low as 10−26 to 10−25 m2 s−1 have been measured. A linear dependence of mathΛ on 1/Λ2 has been observed, providing the evidence of chemical ordering in Fe‐Si alloy and leading to the determination of a critical wavelength.
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66.30.Ny Chemical interdiffusion; diffusion barriers
68.60.-p Physical properties of thin films, nonelectronic
78.70.Ck X-ray scattering

Transient annealing as a tool for the investigation of thin‐film–substrate solid‐phase reactions

G. G. Bentini, R. Nipoti, M. Berti, A. V. Drigo, and C. Cohen

J. Appl. Phys. 58, 1234 (1985); http://dx.doi.org/10.1063/1.336142 (6 pages) | Cited 7 times

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The solid‐phase reaction of a thin film and a substrate induced by a transient annealing in the solid phase is analyzed in detail. The technique is based on the scanning of a line‐shaped energy beam. At a given point on the sample the transient process can be considered equivalent to an isothermal one at an effective temperature for an effective time. Whatever the assumed reaction process is, it has an exponential dependence on the temperature; moreover, the real annealing time of the transient treatment is quite short so that the effective temperature can be chosen equal to the maximum value reached and the effective time can be computed by solving the heat equation numerically. The beam scanning induces a temperature gradient on the sample along the scanning direction so that each irradiated point is annealed at slightly different effective temperatures. In the present work the annealing temperatures range from 600 °C up to 1100 °C and the effective times from 0.7 to 1.5 sec, owing to the different experimental conditions. Such ranges make the transient annealing a powerful tool for the investigation of reaction processes on a time scale which is not accessible in a furnace treatment. As an application, the early stages of the reaction between a clean titanium film and a silicon substrate are described in the temperature range 700–900 °C. In this temperature range, the kinetics are first dominated by diffusion through the Ti‐rich silicides which are formed. This process, with presumably high activation energy and large preexponential factor, cannot be observed in standard furnace annealing where a continuous TiSi2 layer is formed at the interface during the temperature rise time and the silicon supply is limited by the diffusion through this layer.
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81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
66.30.J- Diffusion of impurities
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Dielectric isolation of silicon by anodic bonding

Thomas R. Anthony

J. Appl. Phys. 58, 1240 (1985); http://dx.doi.org/10.1063/1.336143 (8 pages) | Cited 29 times

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Dielectrically isolated silicon was produced by anodically bonding together a pair of silicon wafers whose surfaces were covered with an electrically nonconductive micron layer of thermally grown oxide. Although anodic bonding normally requires a conductive oxide, anodic bonding works with nonconductive silicon oxide if the total layer of silicon oxide is less than ten microns thick. The time needed for the anodic bonding process decreases monotonically with temperature because the increase in the deformability of silicon oxide overcomes the decrease in the maximum permissible anodic bonding voltage with temperature. However, factors such as silicon degradation and electrode reactions at very high temperatures indicate that a compromise temperature range of 850–950 °C is best for the anodic bonding of silicon oxide. Bonding voltages of 30–50 V for times of about an hour produced the best bonding yields at these temperatures. Anodically bonded silicon wafers were examined with infrared and ultrasonic transmission microscopy for bond quality. Small scattered nonbonded zones comprising on the average 5% of the total wafer area were found in all wafers. These nonbonded zones were the result of dust particles, entrapped gas, and dimensional mismatches between multiple bonding fronts.
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68.55.-a Thin film structure and morphology
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
73.20.-r Electron states at surfaces and interfaces

The structure of plasma‐deposited silicon nitride films determined by infrared spectroscopy

W. R. Knolle and J. W. Osenbach

J. Appl. Phys. 58, 1248 (1985); http://dx.doi.org/10.1063/1.336116 (7 pages) | Cited 38 times

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Plasma‐deposited silicon nitride, a‐SiN:H, has been deposited at low ammonia‐to‐silane gas ratios. The nitrogen‐to‐silicon ratio in the film is proportional to the NH3/SiH4 flow ratio in the reactor. The Si‐H peak in the infrared spectrum of the a‐SiN:H shifts to lower frequency as the N/Si of the film decreases. We use the random bonding model to calculate the average electronegativity that a Si‐H bond experiences for a particular N/Si ratio in the film. The measured Si‐H frequency correlates with the calculated electronegativities and agrees with a similar correlation of Si‐H obtained for molecules. For N/Si less than 0.27 we observe an additional peak at 650 cm−1 that also appears in the spectrum of plasma‐deposited amorphous Si and is the Si‐H wagging vibration. The random bonding model predicts amorphous Si to be the predominant constituent for N/Si less than 0.27, in agreement with the infrared data.
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68.60.-p Physical properties of thin films, nonelectronic
68.55.-a Thin film structure and morphology
78.30.Hv Other nonmetallic inorganics
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