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15 Dec 1998

Volume 84, Issue 12, pp. 6485-6945

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Near-field diffraction by a slit in a thick perfectly conducting screen flying above a magneto-optical disk

O. W. Shih

J. Appl. Phys. 84, 6485 (1998); http://dx.doi.org/10.1063/1.369017 (14 pages) | Cited 2 times

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A two-dimensional analysis is presented for the near-field diffraction of a plane wave incident upon a slit in a thick perfectly conducting screen flying above a magneto-optical disk. The angle and polarization of the incident wave are arbitrary. The screen thickness, slit width, and fly height are all on the order of a wavelength or less. The disk is treated as a thin-film multilayer stack on a semi-infinite substrate. Any combination of the thin-film layers can be magneto-optically active. Thus, polarization is not necessarily preserved. The fields and their polarizations within and around the slit are determined by rigorously solving Maxwell’s equations with the appropriate boundary conditions imposed by both the slit and the disk. The solution, which involves Fourier transforms and mode expansions, is based upon a method developed previously by other researchers to investigate scattering systems composed of slits in thick conductors only. In this article, their method is extended to include systems that also have thin-film multilayer media which can change polarization. The extended theory, numerical issues, and example calculations are presented and discussed. © 1998 American Institute of Physics.
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85.70.Sq Magnetooptical devices
85.70.Li Other magnetic recording and storage devices (including tapes, disks, and drums)
42.79.Vb Optical storage systems, optical disks
42.25.Fx Diffraction and scattering
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
03.50.De Classical electromagnetism, Maxwell equations

Fast loading of a magneto-optical trap from a pulsed thermal source

J. Fortagh, A. Grossmann, T. W. Hänsch, and C. Zimmermann

J. Appl. Phys. 84, 6499 (1998); http://dx.doi.org/10.1063/1.369018 (3 pages) | Cited 28 times

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We report an efficient method to load atoms into a magneto-optical trap. A resistively heated alkali metal dispenser, which is mounted close to the trapping region, serves as a compact, pulsed source for Rb atoms. The atoms are captured by the magneto-optical trap within less than 3 s at a loading rate of more than 107 atoms per second. The lifetime of the trapped atoms exceeds the filling time by about 30 s. © 1998 American Institute of Physics.
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37.10.De Atom cooling methods
37.10.Gh Atom traps and guides
07.77.-n Atomic, molecular, and charged-particle sources and detectors
32.50.+d Fluorescence, phosphorescence (including quenching)
85.70.Sq Magnetooptical devices
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Artificial dielectrics: Nonlinear properties of Si nanoclusters formed by ion implantation in SiO2 glassy matrix

S. Vijayalakshmi, H. Grebel, Z. Iqbal, and C. W. White

J. Appl. Phys. 84, 6502 (1998); http://dx.doi.org/10.1063/1.369019 (5 pages) | Cited 20 times

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The nonlinear optical properties of Si nanoclusters formed by ion implantation into an SiO2 glassy matrix and followed by annealing have been studied at λ = 532 nm and λ = 355 nm by use of Z-scan and pump-probe techniques. These have been compared to the nonlinear properties of laser-ablated Si films. At relatively large intensities (>1 MW/cm2), the absolute nonlinear values for these isolated nanoclusters were comparable to those obtained for laser-ablated samples although opposite in sign. Laser-ablated samples showed a much larger effect at relatively low intensities (<1 MW/cm2), while the ion-implanted films showed almost none. Lifetime constants were in the range of 3–5 ns for all samples. © 1998 American Institute of Physics.
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42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
61.72.up Other materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
78.66.Jg Amorphous semiconductors; glasses
81.05.Cy Elemental semiconductors
61.72.Cc Kinetics of defect formation and annealing
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.40.Fy Semiconductors
78.30.Am Elemental semiconductors and insulators

Macroscopic and microscopic second-harmonic response from subphthalocyanine thin films

G. Rojo, F. Agulló-López, B. del Rey, and T. Torres

J. Appl. Phys. 84, 6507 (1998); http://dx.doi.org/10.1063/1.369020 (6 pages) | Cited 8 times

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The second-harmonic generation (SHG) yield of both evaporated and spin-coated films of some tri-substituted subphthalocyanines has been measured for three linear polarizations of the fundamental beam. Partial molecular ordering in the spin-coated films was achieved by the corona poling technique. For the evaporated films the ordering is obtained through the evaporation process itself. By proper fitting of the SHG yield data and assuming C∞v symmetry the three nonzero independent components, χ31(2), χ15(2) and χ33(2), of the susceptibility tensor have been determined for the two types of films. Kleinman symmetry condition (χ31(2) = χ15(2)) is not obeyed. Values close to 10−9 esu have been obtained for the highest χ31(2) component of the spin-coated films containing trioctylsulfonylsubphthalocyanine molecules. For the evaporated films the susceptibility values are somewhat higher, indicating a significant degree of molecular ordering. For both types of films χ33(2)≪χ31(2), χ15(2), at variance with the case of linear molecules. From a statistical analysis of the macroscopic SHG emission the nonzero components of the microscopic (molecular) hyperpolarizability tensor, β15, β31 and β33, have also been estimated. The results indicate that β33 ≈ 0, and that β31 and β15 are dominant in accordance with the pyramid-shaped molecular geometry. The additional inplane components βyxx = −βyyy = βxxy = −β22 appearing in the C3v molecular symmetry cannot be determined from the macroscopic data. © 1998 American Institute of Physics.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.An Optical susceptibility, hyperpolarizability
68.55.-a Thin film structure and morphology
78.66.Qn Polymers; organic compounds

Effects of annealing on modal properties and second-harmonic generation in periodically poled LiTaO3 channel waveguides

Victor Wong and Mool C. Gupta

J. Appl. Phys. 84, 6513 (1998); http://dx.doi.org/10.1063/1.369021 (6 pages) | Cited 1 time

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We provide a systematic investigation of the effects of annealing on modal properties and second-harmonic generation in periodically domain-reversed LiTaO3 channel waveguides. Prism-coupling studies show complex spatial mode distributions and strong dependence of waveguide modal properties on index profiles. Second-harmonic measurements observe the recovery of the optical nonlinear coefficient by annealing. The optimum conversion efficiency is obtained in a very narrow window of annealing time. A considerably large shift in quasi-phase-matching wavelength is also documented. Measurement results are correlated with theoretical modeling. © 1998 American Institute of Physics.
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42.65.Wi Nonlinear waveguides
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.82.Et Waveguides, couplers, and arrays
81.40.Tv Optical and dielectric properties related to treatment conditions
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

Computational model of Q-switch Nd:YAlO3 dual-wavelength laser

H. Su, H. Y. Shen, W. X. Lin, R. R. Zeng, C. H. Huang, and G. Zhang

J. Appl. Phys. 84, 6519 (1998); http://dx.doi.org/10.1063/1.369022 (4 pages) | Cited 9 times

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A rate equation model with spatial hole-burning effect is built to calculate the Q-switch Nd:YAlO3(Nd:YAP) simultaneous dual wavelength laser. We find that 1341.4 and 1079.5 nm lasers can be simultaneously generated in a linear cavity by controlling the output coupling rates of the two coherent radiations. In contrast, a Y cavity and devices to control relative Q-switch delay were necessary for the dual wavelength Nd:YAG laser in previous work. Also with this model, some optimum parameters’ relationships to pump energy are investigated. © 1998 American Institute of Physics.
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42.55.Rz Doped-insulator lasers and other solid state lasers
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency

Parametric interaction of the electric and acoustic fields in a sapphire monocrystal transducer with a microwave readout

C. R. Locke, M. E. Tobar, E. N. Ivanov, and D. G. Blair

J. Appl. Phys. 84, 6523 (1998); http://dx.doi.org/10.1063/1.369023 (5 pages) | Cited 4 times

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A sapphire monocrystal configured with a parametric microwave readout can potentially monitor the motion of its internal acoustic resonances at the precision governed by quantum mechanical fluctuations. The mechanism of transductance is due to parametric interaction between the electric and acoustic field within the crystal. This mechanism has been tested for the first time, and the theory has been verified by observing the pump frequency dependence of the acoustic quality factor. Because of the extremely low acoustic losses (Q>107) and electrical losses (Q>104), measurements were sensitive enough to attain positive verification at room temperature. © 1998 American Institute of Physics.
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43.38.-p Transduction; acoustical devices for the generation and reproduction of sound
84.40.-x Radiowave and microwave (including millimeter wave) technology
85.50.-n Dielectric, ferroelectric, and piezoelectric devices

Theoretical study of a diode with dielectric-gridded cathode

L. Schächter, D. Fletchner, C. Golkowski, J. D. Ivers, and J. A. Nation

J. Appl. Phys. 84, 6528 (1998); http://dx.doi.org/10.1063/1.369024 (8 pages) | Cited 7 times

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We investigate the I–V characteristics of a vacuum diode with a gridded cathode. The grid is located on top of a dielectric material that on its back side is covered by a uniform electrode. Ignoring space-charge effects, the current density extracted from the grid is proportional to the dielectric coefficient and it is quadratic with the back electrode voltage. Considering only space-charge associated with the back electrode voltage, it is found that the anode current is proportional to the anode voltage. When all space-charge effects are considered, it is shown that the electrostatic energy coupled into the diode gap through the grid is responsible to the excess of current beyond the Child–Langmuir limit. © 1998 American Institute of Physics.
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84.47.+w Vacuum tubes

Plasma-sheath resonances and energy absorption phenomena in capacitively coupled radio frequency plasmas. Part I

Victor P. T. Ku, Beatrice M. Annaratone, and John E. Allen

J. Appl. Phys. 84, 6536 (1998); http://dx.doi.org/10.1063/1.369025 (10 pages) | Cited 26 times

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A plasma-sheath resonance has been observed at low pressures in argon plasmas. This phenomenon was known in a different context, that of the plasma resonance probe, but was hitherto unknown in parallel-plate plasma reactors. Two different models have been used to resolve the plasma-sheath resonances. A simple linear model is used to represent the plasma system as a series circuit of two capacitors (sheaths) and an inductor (plasma region). The plasma-sheath resonance occurs at a frequency where the cold plasma behaves inductively and resonates together with the two sheaths. The second model treats the plasma bulk as a series combination of an infinite number of elementary cells each one constituted by an inductor and a capacitor in parallel. By assuming an electron density profile the total impedance of the plasma can be obtained. Furthermore, the calculations show that the resonant energy is absorbed at an infinitely thin resonance plane. This causes the impedance of the system, filled with a lossless inhomogeneous plasma, to have a real part. This resonance can be used as a diagnostic, to measure the electron density. It could perhaps be exploited as the basis of a new plasma reactor. © 1998 American Institute of Physics.
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52.40.Hf Plasma-material interactions; boundary layer effects
52.50.Gj Plasma heating by particle beams
52.25.-b Plasma properties

Plasma-sheath resonances and energy absorption phenomena in capacitively coupled radio frequency plasmas. Part II. The Herlofson paradox

Victor P. T. Ku, Beatrice M. Annaratone, and John E. Allen

J. Appl. Phys. 84, 6546 (1998); http://dx.doi.org/10.1063/1.369026 (6 pages) | Cited 15 times

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The existence of plasma-sheath resonances in a capacitively coupled plasma reactor, which contains a fairly low pressure discharge, has been demonstrated. Under this kind of pressure the plasma is approximately collisionless and inhomogeneous. Two different models have been used to resolve the resonances successfully, a uniform and a nonuniform plasma model. It is shown that the uniform plasma model can explain well the experimental observations; the transmission of rf current circulating in the plasma system is maximum at the plasma-sheath resonance at a frequency below the electron plasma frequency. It was found during further analysis using the nonuniform plasma model, with experimental values for the plasma width and sheath thickness, that the plasma-sheath resonance coincides with the local plasma frequency at two planes within the discharge. At these two resonance planes, the plasma impedance function has a pole. The model predicts a resonant energy absorption in this region and, furthermore, the amount of absorbed energy is essentially determined by the steepness of the electron density profile within the resonance plane. This result is in good agreement with Crawford and Harker [J. Plasma Phys. 8, 261 (1972)]. © 1998 American Institute of Physics.
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52.50.Gj Plasma heating by particle beams
52.40.Hf Plasma-material interactions; boundary layer effects
52.25.-b Plasma properties
52.20.-j Elementary processes in plasmas
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Raman spectroscopic studies on well-defined carbonaceous materials of strong two-dimensional character

H. Wilhelm, M. Lelaurain, E. McRae, and B. Humbert

J. Appl. Phys. 84, 6552 (1998); http://dx.doi.org/10.1063/1.369027 (7 pages) | Cited 61 times

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Using 514 nm radiation and a careful experimental protocol allowing us to make quantitative intensity analyses, we have examined the first- and second-order Raman spectra of five varieties of graphite. These include single-crystal graphite and highly oriented pyrolytic graphite as references, then two with a significant content of c-axis translation faults introduced through grinding and exfoliation, and a last sample which is purely turbostratic. We show that full c-axis stacking disorder results in a strong increase of the scattered E2g-mode intensity. We have further shown that even in those strongly disordered stacking sequences, but in which the AB sequence persists over only a few layers, the doublet around 2700 cm−1 is resolved. We argue against assigning the peak around 1355 cm−1 to “disorder,” as is so often done, but to the finite in-plane domain size as proposed a number of years ago; moreover, we suggest that this peak is a more sensitive probe of such small domains than is x-ray diffraction. © 1998 American Institute of Physics.
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78.30.Hv Other nonmetallic inorganics
78.35.+c Brillouin and Rayleigh scattering; other light scattering

Positron annihilation investigation of porous silicon heat treated to 1000 °C

S. Dannefaer, C. Wiebe, and D. Kerr

J. Appl. Phys. 84, 6559 (1998); http://dx.doi.org/10.1063/1.369028 (6 pages) | Cited 6 times

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Positron lifetime and Doppler broadening spectroscopies were applied to investigate a porous silicon film subjected to heat treatment in an argon atmosphere. Heating between 300 and 500 °C increased the mass of the film by 17% due to oxygen uptake and the concentration of open volume defects associated with the formation of an oxide layer on the silicon nanocrystallites increased by a factor of 3. Between 600 and 1000 °C their concentration decreased gradually to 1/2 the original concentration. Doppler broadening results indicate two distinct electron momentum distributions, one arising from open volume defects and one from pickoff annihilation of positronium at the pore walls caused by electrons with an unexpectedly narrow momentum distribution. © 1998 American Institute of Physics.
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78.70.Bj Positron annihilation
61.43.Gt Powders, porous materials
61.46.-w Structure of nanoscale materials
61.72.Cc Kinetics of defect formation and annealing
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Neutron diffraction analysis on FINEMET alloys

J. Zhu, N. Clavaguera, M. T. Clavaguera-Mora, and W. S. Howells

J. Appl. Phys. 84, 6565 (1998); http://dx.doi.org/10.1063/1.369029 (5 pages) | Cited 7 times

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Neutron diffraction has been used to study in situ the nanocrystallization process of Fe73.5Cu1Nb3Si22.5−xBx (x = 5, 9, and 12) amorphous alloys. Nanocrystallization results in a decrease of both the silicon content and the grain size of the Fe(Si) phase with increasing value of x. By comparing the radial distribution function peak areas with those predicted for ideal bcc and DO3 structure, it can be concluded that the ordering in DO3 Fe(Si) crystals increases with the silicon content. © 1998 American Institute of Physics.
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81.07.-b Nanoscale materials and structures: fabrication and characterization
61.43.Fs Glasses
81.05.Kf Glasses (including metallic glasses)
64.70.K- Solid-solid transitions
61.46.-w Structure of nanoscale materials
61.72.-y Defects and impurities in crystals; microstructure

Depth analysis of phase formation in α-Fe after high-dose Al ion implantation

S. Kruijer, O. Nikolov, W. Keune, H. Reuther, S. Weber, and S. Scherrer

J. Appl. Phys. 84, 6570 (1998); http://dx.doi.org/10.1063/1.369030 (12 pages) | Cited 3 times

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α-Fe surfaces were implanted at room temperature (RT) and at 300 °C with 50 keV Al+ ions with a nominal dose of 5×1017 cm−2. The samples were studied in the as-implanted state and after annealing at 300 °C. The depth distribution of the Fe–Al phases formed was investigated nondestructively at RT and at 40 K by depth-selective 57Fe-conversion–electron Mössbauer spectroscopy (DCEMS) in the energy range of K- as well as L-conversion electrons. Integral conversion–electron Mössbauer spectroscopy (CEMS) was performed between 30 K and RT. In addition, secondary neutral mass spectroscopy and depth-profiling Auger-electron spectroscopy were employed for investigating the element–concentration depth profiles which were observed to extend deeper than Monte Carlo simulations predict. We found an atomically disordered magnetic and an atomically disordered nonmagnetic bcc phase in the as-implanted state the composition of which can be explained by the Al-concentration dependence of bulk disordered Fe–Al alloys. After annealing the nonmagnetic phase becomes atomically ordered (B2 structure) whereas the magnetic phase stays in the atomically disordered state. The layer-like structure of the two phases observed after annealing can be described by the magnetic phase diagram of ordered Fe–Al alloys. © 1998 American Institute of Physics.
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61.72.up Other materials
76.80.+y Mössbauer effect; other γ-ray spectroscopy
81.70.Jb Chemical composition analysis, chemical depth and dopant profiling
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
61.72.S- Impurities in crystals
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Bb Fe and its alloys

A Monte–Carlo approach to domain boundary precipitation in binary alloys

J.-M. Liu

J. Appl. Phys. 84, 6582 (1998); http://dx.doi.org/10.1063/1.368976 (6 pages) | Cited 3 times

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A Monte–Carlo approach on the second phase precipitation in polycrystalline binary alloys is developed. The approach starts from the kinetic spin-exchange Ising model and the Q-state Potts model, and a coupling algorithm for simulation of both phase precipitation and domain growth is developed. The simulation on a simplified system with slow domain boundary migration reveals precipitation phenomena on the domain boundaries. The effect of domain boundaries on the morphology and kinetics of the second phase precipitates is investigated. It is shown that the scaling concept and the Lifshitz–Slyozov–Wagner law are broken in the present system. © 1998 American Institute of Physics.  
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81.30.Mh Solid-phase precipitation
64.75.-g Phase equilibria
05.50.+q Lattice theory and statistics (Ising, Potts, etc.)
02.70.Rr General statistical methods

Raman probing of thermal damage depth profile in annealed GaAs

P. S. Pizani and C. E. M. Campos

J. Appl. Phys. 84, 6588 (1998); http://dx.doi.org/10.1063/1.369031 (4 pages) | Cited 9 times

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Raman scattering has been used to get information on the depth profile of both lattice damage and solid arsenic formation in gallium arsenide annealed at different temperatures. Measurements of Raman peak intensity ratio of GaAs transverse to longitudinal optical phonons as a function of exciting wavelength with a different penetration depth of the light gave information on the depth profile of the chemical and structural disorder in the gallium arsenide lattice. Moreover, measurements of the arsenic A1g and Eg phonon mode frequencies as a function of temperature showed that the arsenic formed in the vicinity of the surface is crystalline and submitted to very high temperature-dependent tensile stresses, with values ranging from 1.5 GPa at 300 K until 2.8 GPa at 10 K. On the other hand, the analysis of selection rules, phonon frequency, and linewidth indicates a strain-free and misoriented GaAs matrix. © 1998 American Institute of Physics.
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61.72.Cc Kinetics of defect formation and annealing
78.30.Fs III-V and II-VI semiconductors
78.35.+c Brillouin and Rayleigh scattering; other light scattering
63.20.D- Phonon states and bands, normal modes, and phonon dispersion

Thermal nonequilibrium of the shock-compressed state of polymers realized by 1 GPa shock waves

Kunihito Nagayama and Yasuhito Mori

J. Appl. Phys. 84, 6592 (1998); http://dx.doi.org/10.1063/1.369032 (8 pages) | Cited 4 times

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A thermodynamic theory has been developed to calculate the shock temperature of polymers in the 1 GPa pressure region. For this purpose, the Grüneisen parameter has been calculated based on the available nonlinear shock velocity–particle velocity Hugoniot function for polymers. The calculated large values of the parameter correspond to that of phonon frequencies in the collective motion of polymer molecules, and not to that of the intramolecular vibration frequencies. Then, the equilibrium shock temperature as well as the cold potential energy function is calculated using the calculated Grüneisen parameter and the available nonlinear shock velocity–particle velocity Hugoniot function. Shock temperature and cold potential function have also been calculated using the equilibrium thermodynamic values of the Grüneisen parameter and the specific heat. From these calculations, the following unphysical result has been derived; that is, the cold potential function for these polymers has no minimum value at zero-temperature volume, but monotonically decreases with compression. It is demonstrated that this kind of anomaly can be resolved only when large values of the Grüneisen parameter and the corresponding small values of the specific heat are assumed. These results strongly suggest that the state of the shocked polymers observed in the experiment of μs duration may be the thermodynamic state, which is very different from the thermal equilibrium state in that phonon temperature is sufficiently high but not in equilibrium with molecular vibrational temperature. © 1998 American Institute of Physics.
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62.50.-p High-pressure effects in solids and liquids
05.70.Ln Nonequilibrium and irreversible thermodynamics
61.41.+e Polymers, elastomers, and plastics
65.40.-b Thermal properties of crystalline solids
65.60.+a Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.
65.80.-g Thermal properties of small particles, nanocrystals, nanotubes, and other related systems
63.70.+h Statistical mechanics of lattice vibrations and displacive phase transitions
62.20.F- Deformation and plasticity
05.70.Ce Thermodynamic functions and equations of state
63.20.-e Phonons in crystal lattices
63.50.-x Vibrational states in disordered systems
65.20.-w Thermal properties of liquids
65.40.gd Entropy

Detonation wave velocity and curvature of a plastic-bonded, nonideal explosive PBXN-111 as a function of diameter and confinement

J. W. Forbes and E. R. Lemar

J. Appl. Phys. 84, 6600 (1998); http://dx.doi.org/10.1063/1.369033 (6 pages) | Cited 3 times

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Detonation velocities and wave front curvatures are measured on various diameter cylinders of PBXN-111 (RDX/AP/Al/HTPB binder with 20/43/25/12 weight percent). The cylinders are either unconfined or encased in 5-mm-thick brass tubes. In all experiments with brass tubes (diameters from 19 to 100 mm) the detonation velocity of PBXN-111 was affected by the confinement. Steady detonation waves propagated in brass encased charges with diameters as small as 19 mm, which is about half of the 37.1 mm failure diameter for unconfined PBXN-111. The radii of curvature at the center of the detonation wave fronts ranged from 52 to 480 mm for charge diameters from 25 to 100 mm, respectively. Detonation velocity as a function of radius of curvature at the wave’s center is represented by a single curve for both cased and uncased cylindrical charges. The difference in the axial position of the detonation wave at the center of the charge and at the edge of the charge (i.e., lag distance) are between 1.6 and 6.7 mm. The angles between the detonation wave fronts and the brass/charge interfaces are between 73° and 82° while the angles at the cylindrical free surface for the uncased charges are between 61° and 64°. Calculation of this angle for brass encased charges using oblique shock equations and assuming no reaction in the shock front resulted in angles 8° higher than measured except for the 100-mm-diam charge which was in agreement. The calculated angles for the uncased charge are in agreement with the measured values.
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47.40.Nm Shock wave interactions and shock effects
82.33.Vx Reactions in flames, combustion, and explosions

Shock jump equations for unsteady wave fronts of finite rise time

Yukio Sano and Isamu Miyamoto

J. Appl. Phys. 84, 6606 (1998); http://dx.doi.org/10.1063/1.369034 (8 pages) | Cited 5 times

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First, generalized Rankine–Hugoniot equations for unsteady wave fronts of finite width are derived. It is clarified from these jump equations for particle velocity, stress, and specific internal energy that shock jump conditions involve the effects of rise time of the front or the change in its velocity with time, in addition to that of strain rate and acceleration, and that the treatment in the previous study [Sano, J. Appl. Phys. 82, 5382 (1997)] where the rise time is reduced to an infinitesimal eliminates the terms of this change in the jump equations. Furthermore, the jump equations of the general form derived here support this elimination. Next, the influence of the rise time on the three jumps at the impacted surface of a lithium fluoride single crystal is calculated based on its experimental data and shown to be negligibly small. However, its influence, calculated for sandstone in a similar manner, is great. Finally, a parametric investigation of the influence is carried out for specific strain waves. © 1998 American Institute of Physics.
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62.50.-p High-pressure effects in solids and liquids

Index of refraction and mechanical behavior of soda lime glass under shock and release wave propagations

Dattatraya P. Dandekar

J. Appl. Phys. 84, 6614 (1998); http://dx.doi.org/10.1063/1.369035 (9 pages) | Cited 6 times

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This article reports a set of experiments designed to measure change in the refractive index of transparent material under both planar shock and release wave propagations. Information about both mechanical and optical properties of transparent material were obtained simultaneously through the measurement of particle velocity at or near the impact surface and the free surface velocity. Data thus obtained is used to determine shock and release wave velocities and the Hugoniot elastic limit (HEL) of the material. Shock wave velocity in soda lime glass remains unchanged at 5.83±0.04 km/s, i.e., equal to the measured ultrasonic longitudinal wave velocity, when it is shock compressed to less than or equal to 4.3 GPa. The value of shock wave velocity begins to decline when the impact stress in the glass exceeds this value. The release wave velocity, however, remains equal to the measured ultrasonic longitudinal wave velocity to only 3 GPa, it begins to decline at higher stresses. The variation in the refractive index of the glass shows a cusp at 3.04–3.14 GPa. Additionally, up to and including the impact stress of 3.14 GPa, the refractive index after shock compression and release is within 1% of its ambient value, but at higher stresses it differs by larger percentage points. The HEL of the glass is determined to be 3.10±0.06 GPa although it lacks the classic well defined cusp in all the recorded wave profiles of soda lime glass. © 1998 American Institute of Physics.
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62.50.-p High-pressure effects in solids and liquids
81.05.Kf Glasses (including metallic glasses)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
62.20.F- Deformation and plasticity
81.40.Lm Deformation, plasticity, and creep
62.65.+k Acoustical properties of solids

Low thermal diffusivity measurements of thin films using mirage technique

P. K. Wong, P. C. W. Fung, and H. L. Tam

J. Appl. Phys. 84, 6623 (1998); http://dx.doi.org/10.1063/1.369036 (5 pages) | Cited 12 times

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Mirage technique is proved to be powerful in measurements of thermal diffusivity. Its contactless nature makes it suitable for delicate samples such as thin films and single crystals. However, as the damping of the thermal wave profile increases progressively upon the decrease in thermal diffusivity of the medium, mirage technique becomes more difficult to be applied to low thermal diffusivity measurements. Moreover influences from substrate signals make analysis difficult when the samples are thermally thin. Recently a thermal-wave-coupling method for mirage signal analysis [P. K. Wong, P. C. W. Fung, H. L. Tam, and J. Gao, Phys. Rev. B 51, 523 (1995)] was reported for thermal diffusivity measurements of thin film down to 60 nm thick. In this article we apply the thermal-wave-coupling method to thin films of low thermal diffusivity, especially polymer films. A new lower limit of thermal diffusivity measurable by mirage technique has been reached. © 1998 American Institute of Physics.
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68.60.Dv Thermal stability; thermal effects
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves
07.20.-n Thermal instruments and apparatus

Plasma processing of the silicon surface: A novel method to reduce transient enhanced diffusion of boron

Giovanni Mannino, Francesco Priolo, Vittorio Privitera, Vito Raineri, Corrado Spinella, Enrico Napolitani, Alberto Carnera, Giuseppe Arena, Alberto Messina, and Cirino Rapisarda

J. Appl. Phys. 84, 6628 (1998); http://dx.doi.org/10.1063/1.369037 (8 pages) | Cited 1 time

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We investigate in detail the effect of plasma processing on the transient enhanced diffusion of implanted boron in silicon. Thermally oxidized silicon wafers were first processed with CHF3/CF4 plasma and subsequently implanted with boron, with energies ranging from 3 to 20 keV and a dose of 1×1013/cm2. Chemical profiles were measured by secondary ion mass spectrometry while lattice extended defects induced in silicon by plasma processing were characterized by transmission electron microscopy. Secondary ion mass spectrometry measurements reveal that the transient enhanced diffusion of boron after rapid thermal annealing is strongly reduced in plasma processed samples with respect to unprocessed samples. Defects induced by plasma processing are responsible for the reduction by acting as very efficient traps for the interstitial atoms generated during the implant. We note that the trapping efficiency is critically dependent on the projected range of the boron implant, being extremely evident at low energies and less marked as the energy is increased (i.e., when the interstitials generated by the B implant are far away from the trapping sites). By varying the plasma conditions (an argon plasma is used instead of a CHF3/CF4 plasma), we are able to establish a general correlation between trapping defect centers and transient enhanced diffusion reduction. Finally, spreading resistance measurements reveal that the amount of electrically active boron in plasma processed pure epitaxial Si is almost equal to that obtained in samples not exposed to plasma bombardment, thus demonstrating that the plasma processing has no detrimental effect on the boron electrical activation. © 1998 American Institute of Physics.
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81.05.Cy Elemental semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning
66.30.J- Diffusion of impurities
61.72.uf Ge and Si
61.80.Jh Ion radiation effects
61.72.S- Impurities in crystals
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
61.72.Cc Kinetics of defect formation and annealing
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.72.J- Point defects and defect clusters
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
72.80.Cw Elemental semiconductors
61.82.Fk Semiconductors
72.20.Fr Low-field transport and mobility; piezoresistance

Ultimate resolution electron energy loss spectroscopy at H/Si(100) surfaces

F. S. Tautz and J. A. Schaefer

J. Appl. Phys. 84, 6636 (1998); http://dx.doi.org/10.1063/1.369038 (8 pages) | Cited 31 times

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We have re-investigated the well-studied hydrogen covered Si(100) surface using high resolution electron energy loss spectroscopy (HREELS) with a spectral resolution down to 13 cm1, representing an improvement by a factor of 3–4 compared to earlier work. For the first time in HREELS, it has been possible to clearly distinguish between the stretching vibrations of H-Si-Si-H units on monohydride surfaces with a 2×1 low energy electron diffraction pattern, on the one hand, and SiH2 units on dihydride surfaces with 1×1 symmetry on the other hand, the two being shifted by 5 cm-1 with respect to each other, in good agreement with results from infrared spectroscopy. Furthermore, we find trihydride units even for relatively low exposures beyond monohydride saturation coverage from their distinct stretching frequencies, and this points towards early etching stages. The question of the scattering mechanism applicable in our experiments is discussed. Since there are no spectral limitations in HREELS, we can analyze the bending and scissor vibrations with similar accuracy as the stretching vibration. Again, we observe fine structure in our loss peaks, the umbrella mode, for example, giving once more evidence for trihydride species at the surface. The complicated line shape of all vibrational modes can thus be used to deduce detailed structural information about the surface atomic structure, opening up entirely new possibilities by employing HREELS for the structural characterization of (silicon) surfaces with atomic hydrogen as a local probe. © 1998 American Institute of Physics.
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79.20.Kz Other electron-impact emission phenomena
68.35.Ja Surface and interface dynamics and vibrations
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.43.Pq Adsorbate vibrations

Nickel distribution in crystalline and amorphous silicon during solid phase epitaxy of amorphous silicon

A. Yu. Kuznetsov, B. G. Svensson, O. Nur, and L. Hultman

J. Appl. Phys. 84, 6644 (1998); http://dx.doi.org/10.1063/1.369039 (6 pages) | Cited 8 times

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Solid phase epitaxy of nickel-doped amorphous silicon (a-Si) films on crystalline silicon (c-Si) substrates has been investigated. The crystallization mode of the a-Si films depends strongly on the nickel concentration. Below ∼ 5×1018 Ni/cm3, redistribution of nickel into the c-Si substrate occurs and the regrowth process is controlled by an “ordinary” thermally activated solid phase epitaxial crystallization (SPEC) process. In contrast, above 5×1018 Ni/cm3 segregation of Ni in the a-Si films is observed and the silicon crystallization is driven by impurity enhanced SPEC and/or silicide mediated crystallization in the bulk of the amorphous film. The redistribution of Ni during crystallization can be described in terms of an effective distribution coefficient accounting for the actual crystallization rate of a-Si and the Ni diffusivity in a-Si. Further, dissolution of implantation-induced (311) defects is observed in the samples exhibiting Ni diffusion into the crystalline phase during ordinary SPEC. This indicates annealing and /or suppression of the (311) defects due to nickel accumulating in the region of end-of-range defects. © 1998 American Institute of Physics.
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81.05.Cy Elemental semiconductors
68.55.-a Thin film structure and morphology
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Np Solid phase epitaxy; growth from solid phases
81.05.Gc Amorphous semiconductors
61.43.Dq Amorphous semiconductors, metals, and alloys
61.72.Cc Kinetics of defect formation and annealing
66.30.J- Diffusion of impurities
61.72.S- Impurities in crystals

Model for the recombination velocity of silicon interstitials at nonoxidizing interfaces

C. Tsamis and D. Tsoukalas

J. Appl. Phys. 84, 6650 (1998); http://dx.doi.org/10.1063/1.369040 (9 pages) | Cited 3 times

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In this work we propose a model for the time dependence of the surface recombination velocity of silicon interstitials at nonoxidizing (inert) Si/SiO2 interfaces. The model takes into account the experimentally observed diffusion of silicon interstitials through a thermal oxide. Comparison with previously published experimental results from various sources as well as from new experiments, which we present here, demonstrate that the proposed model can accurately simulate one-dimensional as well as two-dimensional experiments. Analysis of the experimental data permits the estimation of the segregation coefficient of silicon interstitials at the silicon–oxide interface. © 1998 American Institute of Physics.
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61.72.J- Point defects and defect clusters
68.35.Fx Diffusion; interface formation
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
66.30.Lw Diffusion of other defects
67.80.-s Quantum solids
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