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1 Jun 1993

Volume 73, Issue 11, pp. 7025-7994

Page 2 of 7 Pages Previous Page Next Page | Jump to Page

Ion drag on an isolated particulate in a low‐pressure discharge

M. D. Kilgore, J. E. Daugherty, R. K. Porteous, and D. B. Graves

J. Appl. Phys. 73, 7195 (1993); http://dx.doi.org/10.1063/1.352392 (8 pages) | Cited 87 times

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Classical scattering theory is used to calculate momentum‐transfer cross sections between positive ions and isolated particulates in glow discharges for several model particle sheath potentials. Cross sections calculated from a potential profile obtained using self‐consistent orbit (Poisson–Vlasov) theory, an attractive screened Coulomb potential, and an attractive cutoff Coulomb potential are compared. At high ion energies, all model potentials result in the same cross‐section dependence on ion energy. At low ion energies, however, the cutoff Coulomb potential gives a cross section too low by about a factor of 10. The screened Coulomb potential and Poisson–Vlasov theory potential result in momentum‐transfer cross sections equal to within 30% over the entire range of ion energies. An approximate analytic expression for the momentum transfer rate coefficient is given for order of magnitude estimation of the ion drag force.
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52.25.Vy Impurities in plasmas
51.50.+v Electrical properties (ionization, breakdown, electron and ion mobility, etc.)

Optical emissions from electron‐impact‐excited tetra‐ethoxysilane

M. Ducrepin, J. Dike, R. B. Siegel, V. Tarnovsky, and K. Becker

J. Appl. Phys. 73, 7203 (1993); http://dx.doi.org/10.1063/1.352393 (4 pages) | Cited 6 times

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The optical emission spectrum in the spectral region 200–800 nm produced by electron impact on tetra‐ethoxysilane (TEOS) under controlled single‐collision conditions is analyzed. Absolute emission cross sections (at an impact energy of 100 eV) of 0.7±0.2×10−20 cm2 for the Si (3p4s 1P0→3p2 1S) line at 390.6 nm, 2.4±0.5×10−20 cm2 for the CH(A 2Δ→X 2Π) band centered around 430 nm, and cross sections below 0.5×10−20 cm2 for the hydrogen Balmer‐α, ‐β, and ‐γ lines at, respectively, 656.4, 486.1, and 434.0 nm are measured. Comparatively high onset energies of 56.2±2.0 eV (Si) and 30.7±2.0 eV (CH) were found which when combined with the small cross sections indicate that the single‐step dissociative excitation of TEOS by electron impact cannot be expected to play a major role in the collision processes that dominate the plasma chemistry of TEOS‐containing processing plasmas.
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52.25.Os Emission, absorption, and scattering of electromagnetic radiation
33.20.Kf Visible spectra
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)

A study of Si outdiffusion from predoped GaAs

Horng‐Ming You, Ulrich M. Gösele, and Teh Y. Tan

J. Appl. Phys. 73, 7207 (1993); http://dx.doi.org/10.1063/1.352394 (10 pages) | Cited 5 times

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Experiments have been conducted to study the Si outdiffusion behavior in GaAs using predoped samples. The results showed that the Si diffusivity values are dependent on the As4 vapor‐phase pressure in the ambient, and on the electron concentration in the crystal. It is concluded from these results that, in GaAs, diffusion of the Si donor species occupying Ga sites SiGa+ is governed by the triply negatively charged Ga vacancies, VGa3−. The present VGa3−‐dominated SiGa+ outdiffusion diffusivity values are, however, larger than those obtained under Si indiffusion conditions by many orders of magnitude. A tentative explanation of this large difference is given in terms of an undersaturation of VGa3− in intrinsic GaAs during indiffusion experiments and of a supersaturation of VGa3− developed during the outdiffusion of Si from n‐type, Si‐doped GaAs.
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61.72.uj III-V and II-VI semiconductors
66.30.J- Diffusion of impurities

Solid‐state amorphization reaction in polycrystalline Ni and amorphous Si multilayer

W. H. Wang, H. Y. Bai, Y. Zhang, H. Chen, and W. K. Wang

J. Appl. Phys. 73, 7217 (1993); http://dx.doi.org/10.1063/1.352395 (5 pages) | Cited 3 times

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Interdiffusion‐induced solid‐state amorphization reaction (SSAR) in polycrystalline Ni/amorphous Si multilayers has been studied using an in situ x‐ray diffraction technique together with transmission electron microscope observations. The amorphization reaction was found to occur both on the Ni/Si interfaces in terms of a planar‐layer growth model and along the grain boundaries in the Ni sublayers. Thermodynamic and kinetic interpretations for the SSAR at grain boundaries are presented and an amorphous growth model is also suggested for elucidating the SSAR in polycrystalline Ni/amorphous Si multilayers.
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61.43.Dq Amorphous semiconductors, metals, and alloys
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
66.30.Ny Chemical interdiffusion; diffusion barriers

Investigation of lateral straggling of Xe ions in potassium titanyl phosphate

Ke‐Ming Wang, Bo‐Rong Shi, Bao‐Dong Qu, Zhong‐Lie Wang, Xiang‐Dong Liu, Yao‐Gang Liu, and Qing‐Tai Zhao

J. Appl. Phys. 73, 7222 (1993); http://dx.doi.org/10.1063/1.352396 (3 pages)

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150 keV Xe ions were implanted in potassium titanyl phosphate (KTP) at different angles of 0°, 45°, 60°, and 75°. The lateral straggling of Xe ions in KTP was investigated by normal and oblique incidence Rutherford backscattering of 2.1 MeV He ions. The result extracted is compared with the Monte Carlo code TRIM’89. The lateral straggling is seemed to be in a good agreement with TRIM’89 simulation within experimental error.
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61.72.up Other materials
61.85.+p Channeling phenomena (blocking, energy loss, etc.)

Stabilization of Li acceptors in ZnSe by above‐band‐gap photoirradiation

Masaya Ichimura, Takao Wada, Shizuo Fujita, and Shigeo Fujita

J. Appl. Phys. 73, 7225 (1993); http://dx.doi.org/10.1063/1.354034 (4 pages)

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We predict by theoretical calculation that the concentration of interstitial Li (Liint) in ZnSe can be decreased, i.e., the Li acceptor (LiZn) can be stabilized by above‐band‐gap photoirradiation. Creation of excess electrons by the irradiation increases the occupation probability of the Liint donor level and thus the concentration of neutral Liint (Liint0). Consequently, the LiZn concentration increases because of the reaction Liint0+VZn0→LiZn0, where VZn0 and LiZn0 are a neutral Zn vacancy and a neutral Li acceptor, respectively. The carrier injection through an electrical junction will have similar effects as the photoirradiation, and thus our results indicate that the Li acceptors tend to be stable in active regions of light‐emitting diodes and laser diodes.
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71.55.Gs II-VI semiconductors
61.72.uj III-V and II-VI semiconductors

Defects in electron irradiated GaInP

M. A. Zaidi, M. Zazoui, and J. C. Bourgoin

J. Appl. Phys. 73, 7229 (1993); http://dx.doi.org/10.1063/1.354009 (3 pages) | Cited 14 times

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We present a characterization of the defects created by electron irradiation at room temperature in n‐type GaInP. Four electron traps, labeled E1–E4, and no hole traps have been detected using deep level transient spectroscopy in the temperature range 4–400 K. The corresponding energy levels and barriers associated with electron capture have been measured. The introduction rates, ranging from 4×10−3 to 0.4 cm−1, indicate that these defects are probably not primary defects but complexes resulting from the interaction of these primary defects between themselves or with impurities. This is not surprising, owing to the fact that defect annealing takes place below 300 K in InP.
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71.55.Eq III-V semiconductors
61.80.Fe Electron and positron radiation effects

Enhanced imaging of biomolecules with electron beam deposited tips for scanning force microscopy

F. Zenhausern, M. Adrian, B. ten Heggeler‐Bordier, F. Ardizzoni, and P. Descouts

J. Appl. Phys. 73, 7232 (1993); http://dx.doi.org/10.1063/1.354010 (6 pages) | Cited 10 times

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Tip/sample interaction on the scanning force microscope (SFM) is a particularly difficult problem with biological materials. One major factor affecting image quality is the tip shape. Improved electron beam induced deposition technique with a scanning electron microscope (SEM) was used for the reproducible fabrication of carbon sharp tips on the end of commercially available silicon nitride cantilevers for scanning force microscopy. By aligning a fine focused beam of 20 nm diameter directly down the axis of the pyramidal tip at electron energy of 20 kV, carbon deposits grow with full cone angle of about 25°, cone length of 2 μm, and radii of curvature down to 10 nm, making these e‐beam tips suitable for biomolecules imaging. The tip dimensions also were controlled by adjusting the beam parameters. Three different types of SFM tips were used to image tobacco mosaic virus (TMV). Conventional pyramidal tips appeared generally worse for imaging helical particles of TMV than SEM‐deposited tips which were found more robust than commercially available conical tips. The use of sharper tips for SFM imaging of protein DNA revealed a 25% improvement in lateral resolution.
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68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
87.15.B- Structure of biomolecules

Thermally stable, buried high‐resistance layers in p‐type InP obtained by MeV energy Ti implantation

Jaime M. Martin, Ravi K. Nadella, Jayadev Vellanki, Mulpuri V. Rao, and O. W. Holland

J. Appl. Phys. 73, 7238 (1993); http://dx.doi.org/10.1063/1.354011 (6 pages) | Cited 5 times

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High‐energy Ti+ ions ranging from 1 to 5 MeV were implanted into p‐type InP:Zn (for two different zinc concentrations) at both room temperature and 200 °C. The range statistics for Ti implanted at various energies were calculated by analyzing the as‐implanted profiles determined by secondary‐ion mass spectrometry. Ti did not redistribute during post‐implantation annealing except for a slight indiffusion, irrespective of the implant or annealing temperatures used. This behavior is different from the behavior of other implanted transition metals (Fe and Co) in InP, which redistributed highly when the implants were performed at room temperature. In the MeV Ti‐implanted InP:Zn the background Zn showed a small degree of redistribution. Rutherford backscattering measurements showed a near virgin lattice perfection for 200 °C implants after annealing. Buried layers with intrinsic resistivity were obtained by MeV Ti implantation in InP:Zn (p=5×1016 cm−3).
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61.72.uj III-V and II-VI semiconductors
72.80.Ey III-V and II-VI semiconductors

Radiation‐induced reverse dark currents in In0.53Ga0.47As photodiodes

G. J. Shaw, S. R. Messenger, R. J. Walters, and G. P. Summers

J. Appl. Phys. 73, 7244 (1993); http://dx.doi.org/10.1063/1.354012 (6 pages) | Cited 9 times

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The reverse dark current‐voltage (dark I‐V) curves of InGaAs photodiodes have been measured as a function of temperature following irradiation with 1‐MeV electrons. Prior to irradiation, the I‐V curves are well described by a diffusion term alone indicating that the junctions are of good quality. Irradiation produces a large increase in the generation current which can be modelled as resulting from a single defect center with an energy Ec−0.29 eV. Such a defect center called E2 has been detected using deep level transient spectroscopy.
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85.60.Dw Photodiodes; phototransistors; photoresistors
61.80.Fe Electron and positron radiation effects
73.61.Ey III-V semiconductors

Study of Co silicide formation by multiple implantation

A. Witzmann, S. Schippel, A. Zentgraf, and P. I. Gajduk

J. Appl. Phys. 73, 7250 (1993); http://dx.doi.org/10.1063/1.354013 (11 pages) | Cited 6 times

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The annealing behavior of 〈111〉 Si implanted with cobalt to doses between 2.5×1016 and 2×1017 cm−2 at energies between 30 and 250 keV has been investigated. The silicide formation during postannealing has been found to proceed in two phases characterized by activation energies of 0.8±0.3 and 2.9±0.3 eV. During the first phase a fast Co redistribution and pronounced nucleation and growth of the CoSi2 precipitates at defects has been observed. The investigation of the dose dependence proved that the amount of Co redistributed during this phase depends on the initial Co and defect concentration. However, the processes contributing to this fast Co redistribution require further investigation. The second step is well characterized by Ostwald ripening. Multiple implantations of Co at different energies have been applied to modify the Co concentration profile. In this way, it is possible to form Si/CoSi2/Si/CoSi2‐layer systems on Si substrate with different layer thicknesses. All Si layers and the deeper lying CoSi2 layer are A type, whereas the crystalline orientation of the near surface layer depends on the procedure of formation. If the dose of the second implantation is too high CoSi nucleates during implantation. The CoSi precipitates are dissolved during annealing and a CoSi2 surface layer of type A is formed. Additional Si implantations offer the possibility to modify the defect profile without changing the Co distribution. During the subsequent annealing a redistribution of Co into the region of the additional defects was observed. Thus, implantation defects act as sinks for the metal atoms and play an important role during the first phase of the annealing process.  
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68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.uf Ge and Si

Hierarchical domain structures and in situ domain migration in the antiferroelectric ceramic PLSnZT

J. S. Speck, M. De Graef, A. P. Wilkinson, A. K. Cheetham, and D. R. Clarke

J. Appl. Phys. 73, 7261 (1993); http://dx.doi.org/10.1063/1.354014 (7 pages) | Cited 10 times

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The crystallography and microstructure of an antiferroelectric ceramic of approximate composition Pb0.97La0.02(Zr0.65Sn0.25Ti0.10)O3 have been examined. Transmission electron microscopy (TEM), x‐ray, and neutron powder studies were carried out. The cell is metrically tetragonal with a c/a ratio of 0.993 when indexed to the parent cubic perovskite cell. The structure exhibits both a commensurate supercell, believed to be associated with oxygen octahedra distortions, and an incommensurate modulation. The different crystallographic variants of the tetragonal antiferroelectric phase gave rise to a hierarchy of domain structures. Charging of TEM specimens having an incomplete conductive coating caused domain migration.
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77.80.Dj Domain structure; hysteresis
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
61.66.Fn Inorganic compounds

Behavior of elastic constants, refractive index, and lattice parameter of cubic zirconia at high temperatures

P. J. Botha, J. C. H. Chiang, J. D. Comins, P. M. Mjwara, and P. E. Ngoepe

J. Appl. Phys. 73, 7268 (1993); http://dx.doi.org/10.1063/1.354015 (7 pages) | Cited 19 times

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Acoustic mode frequency, lattice parameter, and refractive index measurements have been carried out on single crystals of cubic stabilized zirconia, ZrO2(xY2O3), in the temperature range 300 to 1450 K, using Brillouin scattering, x‐ray diffraction, and interferometric methods, respectively. Elastic constants Cij and associated quantities such as the bulk modulus B=(C11+2C12)/3, the anisotropy ratio A=2C44/(C11−C12), and the Cauchy relation failure Δ=(C12−C44) have been determined from these measurements. The results show a linear reduction in C11 , C12 , and C44 until a characteristic transition temperature Tc, which depends on the dopant concentration x. The linear decrease is understood in terms of normal thermal expansion. Above Tc (1300 K for x=9.4 mol % and 1050 K for x=24 mol %) there are elastic anomalies; significant reductions in C11, (C11‐C12)/2 and C44 occur, with an increase in C12 . These effects are considered to result from thermally generated disorder. Detailed examination of the temperature dependence of the Cij as well as B, A, and Δ show some similarities, but also significant differences in comparison with the anomalous elastic behavior corresponding to the high‐temperature superionic state of fluorites. The thermally created defect structures formed at high temperatures in cubic zirconia are thus considered to be different from the anion Frenkel disorder formed in fluorites; this is in accord with recent results from computational simulations and high‐temperature neutron scattering.
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62.20.D- Elasticity
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
64.70.K- Solid-solid transitions
78.35.+c Brillouin and Rayleigh scattering; other light scattering

Relation between photoacoustic signal and sample thickness

Guifen Wang, Yongmao Chang, Genyuan Ma, Qiang Guo, Xueqian Li, and Guangyin Zhang

J. Appl. Phys. 73, 7275 (1993); http://dx.doi.org/10.1063/1.354016 (5 pages)

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The object of this work is to study the relation between the amplitude of photoacoustic signals and the sample thickness when the sample wafer is perpendicular to the piezoelectric ceramics, to which is attached by an edge. Treating the sample as an infinite elastic layer, a three‐dimensional temperature function is introduced. Using the Green’s function for the thermal stress, we solve the thermoelectric equation obtaining an expression for the dependence of the photoacoustic signal on the thermal, mechanical, geometric, and optical properties of the sample. The relation between the photoacoustic signal and the sample thickness is applied for a silicon single crystal. The calculated results are in good agreement with the experimental data.
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43.35.Sx Acoustooptical effects, optoacoustics, acoustical visualization, acoustical microscopy, and acoustical holography
82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects

A method for the determination of the elastic constant ratio K33/K11 in nematic liquid crystals

A. Scharkowski, G. P. Crawford, S. Zumer, and J. W. Doane

J. Appl. Phys. 73, 7280 (1993); http://dx.doi.org/10.1063/1.354017 (8 pages) | Cited 9 times

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A detailed analysis of the recently proposed [Appl. Phys. Lett. 60, 3226 (1992)] method for the direct determination of the bend‐to‐splay bulk elastic constant ratio (K33/K11) in nematic liquid crystals is presented. K33/K11 is directly measured from the optical birefringence pattern of an escaped‐radial nematic director field using the Frank elastic free‐energy approach to determine the stable structure in supramicrometer capillary tubes with strong homeotropic anchoring conditions. No external field or a priori knowledge of the anisotropy in magnetic or electric susceptibility is required. The simple experimental setup used is available in most laboratories, making this an attractive and convenient technique to probe the elastic character of nematic materials. The results for 5CB and PCH‐5 are in good agreement with data obtained from conventional electo‐optic and magneto‐optic techniques.
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62.20.D- Elasticity
83.80.Xz Liquid crystals: nematic, cholesteric, smectic, discotic, etc.

The effect of void growth on Taylor cylinder impact experiments

F. L. Addessio, J. N. Johnson, and P. J. Maudlin

J. Appl. Phys. 73, 7288 (1993); http://dx.doi.org/10.1063/1.354018 (10 pages) | Cited 14 times

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Taylor cylinder impact experiments have provided useful information concerning the dynamic response of materials. In an effort to obtain data at elevated strain rates, Taylor experiments have been conducted at high velocities. Sections of the recovered specimens reveal a region of porosity located near the base of the cylinders. Computational simulations have been performed to explore the effect of porosity growth on the experimentally observable parameters for Taylor impact tests. The constitutive model used to simulate the growth of voids is based on the Gurson yield surface. A robust and efficient numerical algorithm was developed and implemented into an explicit, two‐dimensional, finite‐element computer code. The calculations provided good qualitative comparison with experimental data.
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62.20.M- Structural failure of materials
62.50.-p High-pressure effects in solids and liquids
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure

High‐temperature elastic constants of yttrium aluminum garnet

P. R. Stoddart, P. E. Ngoepe, P. M. Mjwara, J. D. Comins, and G. A. Saunders

J. Appl. Phys. 73, 7298 (1993); http://dx.doi.org/10.1063/1.354019 (4 pages) | Cited 18 times

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Elastic constants of yttrium aluminum garnet have been measured in the temperature range 300–1450 K using a combination of Brillouin scattering and refractive index measurements. Associated quantities such as the bulk modulus, anisotropy ratio, and thermo‐optic coefficient have been determined.
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62.20.D- Elasticity
78.35.+c Brillouin and Rayleigh scattering; other light scattering

Calorimetric and photoacoustic investigation of KNO3 phase transitions

M. J. Westphal, J. W. Wood, R. D. Redin, and T. Ashworth

J. Appl. Phys. 73, 7302 (1993); http://dx.doi.org/10.1063/1.354020 (9 pages) | Cited 11 times

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Results of a thermodynamic study of the phase transitions of powdered KNO3 at two impurity concentrations (99.999% pure and 99.9% pure) are reported. Transition onset and peak temperatures have been measured between 350 and 420 K using both heat flow and photoacoustic calorimetry. The transition temperatures and characteristics observed with both techniques show excellent agreement. Specific‐heat values calculated from scanning and stepped temperature heat‐flow data, utilizing both positive and negative temperature increments, compare well with previously reported values. Enthalpies for the II‐I, I‐III, and III‐II phase transitions were measured as 5.065, 2.603, and 2.084 kJ/mol, respectively, for 99.999% pure KNO3 powder using heat‐flow calorimetry. The transition enthalpies and temperatures measured for 99.9% pure powder were slightly lower for all three transitions. Entropy changes for the II‐I, I‐III, and III‐II transitions were 12.53, 6.61, and 5.30 J/mol K, respectively. Enthalpy, entropy, and Gibbs free‐energy curves are presented with emphasis on the temperature range over which the ferroelectric phase transition occurs. The experimental data and calculated thermodynamic functions indicate that the ferroelectric phase III in bulk KNO3 is a metastable state at atmospheric pressure, which was not observed to exist below 350 K contrary to previous reports.
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64.70.K- Solid-solid transitions
77.80.B- Phase transitions and Curie point
65.20.-w Thermal properties of liquids
65.40.gd Entropy

Phosphorus diffusion gettering of gold in silicon: The reversibility of the gettering process

Einar Ö. Sveinbjörnsson, Olof Engström, and Ulf Södervall

J. Appl. Phys. 73, 7311 (1993); http://dx.doi.org/10.1063/1.354021 (11 pages) | Cited 23 times

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Phosphorus diffusion gettering of gold in silicon is a reversible process with strong temperature and phosphorus concentration dependence. We show explicitly that gold diffuses back and forth between the highly doped phosphorus layer and the bulk of the material when the annealing temperature is varied. This was investigated using secondary‐ion mass spectroscopy to study the gold within the gettering layer and using deep level transient spectroscopy to estimate the gold content in the bulk. We observed no internal gettering or outdiffusion of gold as long as the gold concentration is below the solubility limit. The concentration profile of gold after successful gettering follows the phosphorus profile but virtually all the gold atoms are found in the region where the phosphorus concentration exceeds ∼3×1019 cm−3. This is related to a large solubility enhancement of gold when the phosphorus concentration is above 3×1019 cm−3. The simplest explanation for the observed gettering mechanism is formation of gold‐phosphorus pairs within the highly doped phosphorus layer. However, quantitative agreement cannot be obtained between our results and a simple segregation model based on gold solubilities in lightly doped material and highly phosphorus doped silicon. If the gold solubility in the bulk is modified by taking into account, proposed supersaturation of silicon self‐interstitials agreement between the model and the experimental data can be obtained.
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66.30.J- Diffusion of impurities
61.72.Yx Interaction between different crystal defects; gettering effect
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Modeling inactive boron during predeposition processes

Eric Vandenbossche and Bruno Baccus

J. Appl. Phys. 73, 7322 (1993); http://dx.doi.org/10.1063/1.354022 (9 pages) | Cited 12 times

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A new type of boron cluster is presented through the study of boron diffusion at high concentrations under predeposition conditions. Recent experimental results of boron predeposition give the opportunity to analyze, with the simulations, the behavior of the inactive part of the boron profile, found to increase dramatically with surface concentrations. After a rapid thermal annealing, the electrical activation appears to be extremely high due to the dissolution of the inactive part of the profile. The only way to reproduce the experimental observations has been to consider an inactive and mobile 2‐atom boron cluster. A complete kinetic model, including the reactions between boron cluster, boron‐interstitial pair, substitutional boron and point defects, is used in order to determine all the parameters characterizing this cluster. The diffusivity of the cluster is much less than the one of the boron‐interstitial pair (about 40 times). It is suggested that the nature of this cluster may depend on the exact predeposition conditions. Finally, from a general point of view, the behavior of supersaturations of interstitials during predeposition as a function of surface concentration is presented, in order to understand the implication of each basic reaction involved in the kinetic model.
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66.30.J- Diffusion of impurities
61.72.S- Impurities in crystals
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Fundamentals of epitaxial silicon film thickness measurements using emission and reflection Fourier transform infrared spectroscopy

Zhen‐Hong Zhou, Isabel Yang, Fuzhong Yu, and Rafael Reif

J. Appl. Phys. 73, 7331 (1993); http://dx.doi.org/10.1063/1.354023 (7 pages) | Cited 3 times

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A theoretical analysis of the principles and results of film thickness measurements using a reflection and an emission Fourier transform infrared spectrometer (FT‐IR) is presented. Epitaxial film thickness measurements by emission FT‐IR (E/FT‐IR) have been recently demonstrated and the study reported here was conducted to understand further the underlying physical principles. The theoretical basis for spatial Fourier transformation using the Michelson interferometer is introduced. Moreover, a transfer function for a linear system model of the Michelson interferometer is derived. The transfer function and the model are subsequently used to calculate interferograms, which agree well with our experimentally measured interferograms. The difference in the interferograms obtained by IR reflection and IR emission is explained theoretically. The limitation of the FT‐IR techniques is discussed. Furthermore, a comparison of the reflection FT‐IR and emission FT‐IR for epitaxial film thickness measurement will be given. Finally, an application of E/FT‐IR for real‐time in situ monitoring of epitaxial silicon film thickness is demonstrated.
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68.55.-a Thin film structure and morphology
78.30.Hv Other nonmetallic inorganics
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques

Structural evaluation of epitaxially grown organic evaporated films by total reflection x‐ray diffractometer

Kenji Ishida, Kouichi Hayashi, Yuji Yoshida, Toshihisa Horiuchi, and Kazumi Matsushige

J. Appl. Phys. 73, 7338 (1993); http://dx.doi.org/10.1063/1.354024 (6 pages) | Cited 17 times

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An in‐plane‐type total reflection x‐ray diffractometer was newly constructed, and the epitaxial growth of paraffin molecules (n‐C33H68) vacuum‐evaporated onto a KCl (001) surface was investigated. The molecular chains in as‐evaporated films were shown to arrange themselves parallel to the 〈110〉 direction of the KCl substrate. After the evaporation, moreover, some molecules were revealed to reorient and tend to deviate their c axis by about ±5° from the 〈110〉 direction of the KCl crystal, probably because of the lattice mismatchings between the paraffin and substrate crystals.
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81.15.Kk Vapor phase epitaxy; growth from vapor phase
61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Determination of the plane stress elastic constants of thin films from substrate curvature measurements: Applications to amorphous metals

Ann Witvrouw and Frans Spaepen

J. Appl. Phys. 73, 7344 (1993); http://dx.doi.org/10.1063/1.354025 (7 pages) | Cited 16 times

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A new method for measuring the static plane stress elastic constants of thin films on a substrate is described. It is based on measurements of the principal curvatures of two identical samples deposited on substrates with different preset curvatures. It is accurate if the deposition stress is no larger than the stress due to the bending of the substrates. Young’s modulus and Poisson’s ratio of amorphous Pd78Si22 were found to be the same as those of melt‐spun material. The biaxial modulus of amorphous PdSi/PdSiFe multilayers was found to be independent of the bilayer repeat length.  
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68.60.Bs Mechanical and acoustical properties
61.43.Dq Amorphous semiconductors, metals, and alloys
62.20.D- Elasticity

Terrace width evolution during step‐flow growth with multiterrace adatom migration

S. A. Chalmers, J. Y. Tsao, and A. C. Gossard

J. Appl. Phys. 73, 7351 (1993); http://dx.doi.org/10.1063/1.354026 (7 pages) | Cited 10 times

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We have developed a computer‐solvable model of step‐flow growth that includes both anisotropic multiterrace adatom migration and asymmetric step edge attachment. We find that terrace widths equalize not only when each adatom preferentially attaches to the ascending step edge of the terrace that it lands on, but also when adatoms preferentially migrate over ascending step edges. This latter process can equalize long‐range terrace width nonuniformities much more rapidly than can the former process. We also find that a slow lateral movement of terrace width distributions occurs when each adatom adheres to the step edges of the terrace that it lands on. More significantly, we find that a rapid lateral movement of terrace width distributions occurs when adatoms cross multiple step edges. This motion is especially fast when adatoms migrate distances that are comparable to or greater than the terrace width distribution period. We simulated the evolution of an experimentally observed (Al,Ga)Sb lateral superlattice (LSL) terrace width distribution, which led to quantitative estimates of the adatom migration characteristics present during the LSLs growth. At least one type of adatom, probably Ga, migrates nearly isotropically over many terraces. This method of determining adatom migration characteristics can be extended to any material system that allows LSL layers to be grown as terrace width markers.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Modeling of molecular‐beam epitaxy and metalorganic vapor‐phase epitaxy on nonplanar surfaces

Mitsuru Ohtsuka and Akira Suzuki

J. Appl. Phys. 73, 7358 (1993); http://dx.doi.org/10.1063/1.354027 (12 pages) | Cited 7 times

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A model allowing a consistent description of growth evolution on nonplanar surface by molecular‐beam epitaxy and metalorganic vapor‐phase epitaxy is presented. It is shown that the elemental kinetic processes (surface migration, incorporation, and desorption) are reduced to an equation of continuity for an atomic flow on a growing surface. In metalorganic vapor‐phase epitaxy this continuity equation is coupled with the diffusion equation in vapor phase, permitting to calculate self‐consistently the density distribution of reactant species in vapor and of the adatoms in the surface layer. In the model, anisotropic properties of growth are introduced by taking into account the surface diffusion around the atomic steps. The formulation of the model is based on the discrete form of the continuity equation (rather than the differential form) and therefore allows description of the growth behavior including the development of sharp facet edges. The method of simulation for nonplanar growth is illustrated in detail.  
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.15.Kk Vapor phase epitaxy; growth from vapor phase
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