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15 Dec 1990

Volume 68, Issue 12, pp. 5963-6540

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Canonical aberration theory in electron optics

Jiye Ximen

J. Appl. Phys. 68, 5963 (1990); http://dx.doi.org/10.1063/1.346928 (5 pages) | Cited 9 times

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By defining the Hamiltonian function in an electron optical system the canonical aberration theory has been developed in the up to fifth‐order approximation. Therefore, the canonical position and momentum aberrations can be expressed by eikonal functions and equivalently by Poisson brackets. Consequently, all fifth‐order canonical aberration coefficients for rotationally symmetrical electron optical systems have been derived at any arbitrary observation planes.
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41.75.Fr Electron and positron beams
84.47.+w Vacuum tubes
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.75.+h Mass spectrometers

Canonical aberration theory in electromagnetic multipoles

Jiye Ximen

J. Appl. Phys. 68, 5968 (1990); http://dx.doi.org/10.1063/1.346929 (8 pages) | Cited 2 times

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In a 2N‐pole electromagnetic system, defining the electron optical Hamiltonian function, we have derived both general algebraic expressions (arbitrary N) and special numerical formulas (N=3,4,5,6,7) for different aberrations from lower to higher order (i.e., the order of N−1, N+1, 2N−3, 2N−1, 3N−5). The so‐called canonical aberration theory in electromagnetic multipoles has thus been developed, which allows us to deduce angular dependencies of different aberrations and to examine the possibility for spherical correction of a round lens by using multipoles.
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41.75.Fr Electron and positron beams
84.47.+w Vacuum tubes
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.75.+h Mass spectrometers

Dependence of luminescence in five membered heterocyclic conducting polymers on molecular structure and temperature

Katsumi Yoshino, Yasuhisa Manda, Hiroyuki Takahashi, Yoshinori Nishioka, Tsuyoshi Kawai, Yutaka Ohmori, and Mitsuyoshi Onoda

J. Appl. Phys. 68, 5976 (1990); http://dx.doi.org/10.1063/1.346930 (5 pages) | Cited 6 times

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Dependencies of photoluminescence in five membered heterocyclic conducting polymers on heteroatoms and temperature are studied. Luminescence intensity of poly(3‐alkylthiophene)s increases with temperature and luminescence intensity of poly(3‐alkylfuran)s is slightly enhanced with increasing temperature. However, luminescence intensity of poly(3‐hexylselenophene) is even suppressed with temperature. These difference of properties among heterocyclic conducting polymers with different heteroatoms can be interpreted in terms of the difference of steric hindrance effect between heteroatoms and alkyl side chain and the interchain interaction which influence on the dynamics of excited species and recombination.
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78.55.Kz Solid organic materials
61.41.+e Polymers, elastomers, and plastics
81.40.Tv Optical and dielectric properties related to treatment conditions
78.40.Ha Other nonmetallic inorganics

Collision‐induced resonant amplification of electromagnetic waves by electrons in circular orbits

J. Felsteiner and A. Rosenberg

J. Appl. Phys. 68, 5981 (1990); http://dx.doi.org/10.1063/1.346931 (4 pages)

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Electrons moving in circular orbits and colliding with gas atoms interact with a circular electromagnetic mode. Applying the linearized Boltzmann equation, the known nonresonant‐stimulated bremsstrahlung and the near‐resonance Landau effect are obtained. We predict that resonant electrons moving with angular velocity equal to the azimuthal phase velocity of the electromagnetic wave can exchange energy with the wave if the momentum transfer cross section for an electron‐atom collision is velocity dependent. Amplification is obtained if the momentum transfer cross section has a positive slope.
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03.50.De Classical electromagnetism, Maxwell equations
41.20.Jb Electromagnetic wave propagation; radiowave propagation
52.40.Mj Particle beam interactions in plasmas
52.80.Hc Glow; corona

Foil focusing of electron beams

R. F. Fernsler, R. F. Hubbard, and S. P. Slinker

J. Appl. Phys. 68, 5985 (1990); http://dx.doi.org/10.1063/1.346932 (10 pages) | Cited 7 times

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Thin conducting foils focus charged particle beams through image charges induced on the foils. Such focusing has led to the suggestion that foils be used to transport intense, relativistic electron beams in high‐energy accelerators. This paper examines some of the limitations of foil focusing including sensitivity to the beam parameters, emittance growth from anharmonic focusing, and beam stability in multifoil transport. The analysis is based on a thin‐lens electrostatic treatment of paraxial beams.
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41.75.Ht Relativistic electron and positron beams
41.20.Cv Electrostatics; Poisson and Laplace equations, boundary-value problems
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems

Electromagnetic induction (eddy currents) in a conducting half‐space in the absence and presence of inhomogeneities: A new formalism

Satish M. Nair and James H. Rose

J. Appl. Phys. 68, 5995 (1990); http://dx.doi.org/10.1063/1.346933 (15 pages) | Cited 8 times

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Two problems are studied. First, a new method is presented for calculating the electromagnetic field in two conjoined conducting half‐spaces in the presence of current sources in either or both half‐spaces. The method allows the two half‐spaces to differ in the conductivity, permeability, and permittivity. The full Maxwell’s equations are used; the quasistatic results may be derived as a particular limit. The method is unique in that it depends only on the solution of two variables; the components of the magnetic field Bz, and the current Jz, normal to the interface between the half‐spaces. The second problem involves the determination of the fields induced by a current source in one half‐space with an arbitrary 3D inhomogeneity in the other. New, coupled integral equations for the fields are written down strictly in terms of Bz, Jz, and the external current source. The same formalism, used to generate the new integral equations, is also shown to yield the standard dyadic volume integral representations. Finally, it is shown that the formalism is a useful way of deriving various asymptotic results. The weak scattering limit (the Born approximation) is derived as an example.
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41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems
03.50.De Classical electromagnetism, Maxwell equations
81.70.-q Methods of materials testing and analysis

Radiation from a disk and loop of charge in a cylindrical pipe with multiple step changes in wall radius

Tan Pham and Robert A. Schill

J. Appl. Phys. 68, 6010 (1990); http://dx.doi.org/10.1063/1.346934 (14 pages) | Cited 1 time

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A theory is developed to model diffraction and Bremsstrahlung radiation from a loop and a disk of charge in a cylindrical pipe with multiple step changes in wall radius supporting all azimuthally symmetric transverse magnetic modes. The beam kinetics are assumed a priori. A correction in phase due to the abrupt change in beam velocity is incorporated at each step change in wall radius. A longitudinal coupling impedance based on energy and power considerations is employed. Loop charge radiation from cavity and collimator geometries is examined. By suitably choosing the loop charge radius, the energy backscattered in the beam tunnel problem can be minimized. The loading effects of the cavity onto the beam is sensitive to its length.
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29.27.-a Beams in particle accelerators

Second‐order nonlinearity of a novel diazo‐dye‐attached polymer

Michiyuki Amano and Toshikuni Kaino

J. Appl. Phys. 68, 6024 (1990); http://dx.doi.org/10.1063/1.346935 (5 pages) | Cited 22 times

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Second‐order nonlinear optical properties of a newly synthesized dye‐attached polymer (3R) were investigated. The dye has a conjugated diazo structure, and the βμg (β: second‐order molecular hyperpolarizability, μg: dipole moment in the ground state) is larger than five times that of a monoazo dye (2R). The second‐order nonlinear coefficient (χ(2)) of a 3R polymer is also greater than that of a 2R polymer throughout the fundamental wavelength of 1.06 μm and between from 1.50 to 1.70 μm when the polymers are electrically poled. For both polymers, the χ(2) dependence on the fundamental wavelength corresponds to the absorption spectrum, which is explained by two‐photon resonance near the absorption maxima. The attainable χ(2) of the polymers deviates from the theoretical linear relationship with the dye content when it is high. This indicates that the dipolar interaction increases as the dye content rises.
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61.41.+e Polymers, elastomers, and plastics
42.65.-k Nonlinear optics

First design and characterization of HgZnTe optical waveguides

A. Azema, P. Gaucherel, J. C. Roustan, R. Granger, and R. Triboulet

J. Appl. Phys. 68, 6029 (1990); http://dx.doi.org/10.1063/1.347189 (4 pages) | Cited 1 time

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Infrared waveguides have been made by isothermal evaporation diffusion of HgTe on a ZnTe substrate and characterized at 10.6 μm by m‐lines analysis. Refractive index profiles deduced from this analysis are correlated to the composition ones measured with a microprobe. As a result, we obtain the refractive index of the alloy as a function of the zinc concentration ranging from 0.2 to 1. Direct measurement of the substrate refractive index gives a value 2.60 to 2.65, results in slight disagreement with the previous data.
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42.79.Gn Optical waveguides and couplers
42.82.-m Integrated optics
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Field analysis of the Cerenkov doubling of infrared coherent radiation utilizing an organic crystal core bounded by a glass capillary

K. Hayata, K. Yanagawa, and M. Koshiba

J. Appl. Phys. 68, 6033 (1990); http://dx.doi.org/10.1063/1.346915 (11 pages) | Cited 2 times

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We present a mode field analysis of the second‐harmonic electromagnetic wave that radiates from a nonlinear core bounded by a dielectric cladding. With this analysis the ultimate performance of the organic crystal‐cored single‐mode optical fiber waveguide as a guided‐wave frequency doubler is evaluated through the solution of nonlinear parametric equations derived from Maxwell’s equations under some assumptions. As a phase‐matching scheme we consider a Cerenkov approach because of advantages in actual device applications, in which the phase matching is achievable between the fundamental guided LP01 mode and the second‐harmonic radiation (leaky) mode. Calculated results for organic cores made of benzil, 4‐(N, N‐dimethyl‐amino)‐3‐acetamidonitrobenzen, 2‐methyl‐4‐nitroaniline, and 4′‐nitrobenzilidene‐3‐acetoamino‐4‐metxianiline provide useful data for designing an efficient fiber‐optic wavelength converter utilizing nonlinear parametric processes. A detailed comparison is made between results for infinite and finite cladding thicknesses.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
03.50.De Classical electromagnetism, Maxwell equations
41.20.Jb Electromagnetic wave propagation; radiowave propagation

On the saturation of Tb phosphors under cathode‐ray excitation. I. Excited‐state absorption in Tb‐activated phosphor powders

K. J. B. M. Nieuwesteeg, R. Raue, and W. Busselt

J. Appl. Phys. 68, 6044 (1990); http://dx.doi.org/10.1063/1.346916 (14 pages) | Cited 9 times

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Optical transitions between the 5D4 excited state of the Tb3+ (4f)8 configuration and the crystal‐field split components of the (4f)7(5d) configuration are observed using high‐resolution laser excitation of Tb‐doped powder samples at room temperature. Excited‐state absorption spectra of Tb3+ in YAG, YAGaG, Y2SiO5, and LaOBr are presented. Superimposed on the broadband excitation spectrum of these transitions we find the relatively narrow 4f→4f lines. We present a theoretical model for interpreting the 4f→5d transitions, which predicts a strict proportionality between the (4f)8 5D4→(4f)7(5d) and the (4f)8 7F6→(4f)7(5d) transitions. This model is used to estimate the optical‐absorption cross section for the former transitions. Although the terminating 4f levels lie at the same energy as the 5d bands, the 4f→4f transitions can be interpreted on the basis of the Judd‐Ofelt theory. We derived a method for calibration of the Tb3+ 4f→5d fluorescence‐excitation spectra from powder samples. For YAG:Tb, the resulting optical cross sections were confirmed by direct‐absorption measurements on a Tb3+ ‐doped epitaxial YAG layer. To our knowledge, this is the first time that the probabilities for excited‐state absorption to highly excited 5d and 4f states in Tb3+ have been obtained theoretically and experimentally from Tb‐doped powder materials.
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78.30.Hv Other nonmetallic inorganics
78.40.Ha Other nonmetallic inorganics
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
78.55.Hx Other solid inorganic materials

On the saturation of Tb phosphors under cathode‐ray excitation. II. Upconversion processes in the excited‐activator bath

K. J. B. M. Nieuwesteeg and R. Raue

J. Appl. Phys. 68, 6058 (1990); http://dx.doi.org/10.1063/1.346892 (8 pages) | Cited 4 times

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A physical model based on resonant electric dipole interaction between excited activators is presented that may be used for gaining insight into the second‐order energy‐loss process in cathode‐ray‐irradiated Tb phosphors. It is shown that resonant up‐conversion of the 5DJ excitons (J=3,4) to highly excited 4f and 5d states may be of equal importance. The derivation of the rate constants for this second‐order energy‐loss process is given and experimental values for the 5D4 ‐5D4 and 5D3 ‐5D4 interaction are presented for Tb‐doped YAG, YAGaG, LaOBr, and Y2SiO5. The values depend on previously determined optical cross sections for excited‐state absorption. Based on this model we explain well‐known differences in saturation behavior between these Tb‐doped phosphors under cathode‐ray excitation.
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78.30.Hv Other nonmetallic inorganics
78.40.Ha Other nonmetallic inorganics
78.55.Hx Other solid inorganic materials
71.35.-y Excitons and related phenomena

Effect of magnetostatic field on the second‐order optical susceptibility of III‐V semiconductors

P. Sen and P. K. Sen

J. Appl. Phys. 68, 6066 (1990); http://dx.doi.org/10.1063/1.346893 (6 pages)

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An analytical investigation of the application of a large magnetostatic field on the second‐order optical susceptibility χ(2) in III‐V semiconductors like GaAs and InSb is reported. The model is based upon the parity indefiniteness of the electron wave functions in crystals lacking inversion symmetry. The generalized force and the electronic dipole moment operators are accordingly taken to be 2×2 matrices with all elements being finite. We have followed perturbation technique for the density matrix. The magnetostatic field renormalizes the transition frequency and sharpens the density of states. Both the resonant as well as nonresonant three‐wave parametric interactions have been discussed. Numerical estimates made for InSb crystal under resonant regime reveal considerable enhancement in the real part of χ(2) even at moderately low magnetic field while the imaginary part exhibits a near saturation behavior. Under nonresonant laser excitation, both χ(2)r and χ(2)i rise very sharply with magnetic field for effective cyclotron frequency ωc≤ω0−ωg, ω0 and ωg being the pump and crystal band‐gap frequencies, respectively. Quite interestingly, χ(2)r and χ(2)i decay almost exponentially to very low values at ωc>2(ω0−ωg).
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63.10.+a General theory
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Evaluation of friction‐welded aluminum‐steel bonds using dispersive guided modes of a layered substrate

Laszlo Adler, Michel de Billy, Gerard Quentin, Maryline Talmant, and Peter B. Nagy

J. Appl. Phys. 68, 6072 (1990); http://dx.doi.org/10.1063/1.346894 (5 pages) | Cited 7 times

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In nondestructive evaluation the inspection of bond quality is a very important problem. In this paper we suggest an experimental method based on dispersion curve measurements for evaluating the quality of the bond between a layer and a substrate bonded by the inertia‐friction welding process. The experimental results are in good agreement with theoretical calculations which show that the behavior of the lowest velocity modes is very sensitive to the interface conditions and to the quality of the bond.
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43.35.Zc Use of ultrasonics in nondestructive testing, industrial processes, and industrial products
43.35.Cg Ultrasonic velocity, dispersion, scattering, diffraction, and attenuation in solids; elastic constants
43.35.Pt Surface waves in solids and liquids

Laser ultrasonic monitoring of ceramic sintering

K. L. Telschow, J. B. Walter, and G. V. Garcia

J. Appl. Phys. 68, 6077 (1990); http://dx.doi.org/10.1063/1.346895 (6 pages) | Cited 12 times

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Noncontacting laser‐ultrasonic measurements of the sintering of ceramics in real‐time are described. Lasers are used for both generation and detection of ultrasonic waves propagating through the material. A pulsed laser generates the ultrasonic wave from thermoelastic absorption at the material surface. Detection is accomplished by a confocal Fabry–Perot interferometer, which is insensitive to the speckle nature of the scattered light from the sample surface and can obtain measurements from samples with rough or diffusely reflecting surfaces. The densification of the ceramic sample is determined by changes in the bulk longitudinal wave velocity and the sample shrinkage.
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81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
43.35.Zc Use of ultrasonics in nondestructive testing, industrial processes, and industrial products
62.20.D- Elasticity
79.20.Ds Laser-beam impact phenomena

Verification of the localized‐wave transmission effect

Richard W. Ziolkowski and D. Kent Lewis

J. Appl. Phys. 68, 6083 (1990); http://dx.doi.org/10.1063/1.346896 (4 pages) | Cited 27 times

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An acoustic array driven with a designed set of localized‐wave (LW) solutions of the scalar‐wave equation generates a robust, well‐behaved, transient pencil beam of ultrasound in water. The performance of the LW‐pulse‐driven array theoretically and experimentally exceeds a tenfold improvement over related continuous‐wave excitations of the same array.
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43.35.-c Ultrasonics, quantum acoustics, and physical effects of sound
41.20.Jb Electromagnetic wave propagation; radiowave propagation
43.20.+g General linear acoustics

Analysis of characteristic thermal transit times for time‐resolved infrared radiometry studies of multilayered coatings

L. C. Aamodt, J. W. Maclachlan Spicer, and J. C. Murphy

J. Appl. Phys. 68, 6087 (1990); http://dx.doi.org/10.1063/1.346897 (12 pages) | Cited 23 times

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Time‐resolved infrared radiometry (TRIR) has been shown to be a valuable thermal characterization technique for the nondestructive evaluation of layered coatings. In this method an external step heating pulse is applied to the coating system and the resulting change in surface temperature is monitored as a function of time. Characteristic times and amplitudes can be ascribed to internal thermal reflections that return heat to the coating surface. A full description of the time dependence of the coating surface temperature can be obtained from these quantities. This paper describes a method for determining these characteristic times and amplitudes and shows their relationship to internal heat‐flow patterns. Uses and limitations of the method are discussed, and comparison of the theory with experimental TRIR results is presented.
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44.30.+v Heat flow in porous media
44.10.+i Heat conduction
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.55.-a Thin film structure and morphology

Particle size statistics in dynamic fragmentation

Dennis E. Grady

J. Appl. Phys. 68, 6099 (1990); http://dx.doi.org/10.1063/1.347188 (7 pages) | Cited 17 times

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Condensed matter, when subjected to intense disrupting forces through impact or radiation deposition, will break up into a randomly distributed array of fragments. An earlier analysis of random fragmentation is extended to account for fragmentation in bodies which are finite in extent and for bodies within which the minimum fragment size is bounded. The statistical fragment size relations are compared with molecular dynamic simulations of dynamic fragmentation, with fragmentation caused by the high‐energy collision of nuclear particles, and with the distribution of galaxies in the universe which are assumed to be fragment debris from the primordial Big Bang.
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45.05.+x General theory of classical mechanics of discrete systems
83.10.Ff Continuum mechanics
05.20.-y Classical statistical mechanics

Boundary‐condition refinement of the Child–Langmuir law for collisionless dc plasma sheaths

Rida T. Farouki, Manoj Dalvie, and Luca F. Pavarino

J. Appl. Phys. 68, 6106 (1990); http://dx.doi.org/10.1063/1.346898 (11 pages) | Cited 16 times

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An exact solution to the problem of collisionless, space‐charge‐limited flow of cold ions across a one‐dimensional (planar) dc plasma sheath of negligible electron density is derived for general values of the presheath ion velocity v0 and electric field E0. For a given ion current density J and sheath thickness d, the exact solution reduces to the classical Child–Langmuir model in the case that v0=0 and E0=0. When either v0 or E0 is sufficiently large, however, the exact solution may differ appreciably from the Child–Langmuir law. The existence of a closed‐form expression for the spatial variation of the sheath potential is shown to be contingent upon the satisfaction of a simple inequality relating v0 and E0 to J. When v0 obeys the Bohm criterion and the magnitude of E0 suggests that the Bohm energy is acquired over a distance not less than one Debye length, this inequality is indeed satisfied.
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52.40.Hf Plasma-material interactions; boundary layer effects
52.25.Fi Transport properties

Electron‐beam probe measurements of electric fields in rf discharges

A. H. Sato and M. A. Lieberman

J. Appl. Phys. 68, 6117 (1990); http://dx.doi.org/10.1063/1.346899 (8 pages) | Cited 27 times

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An electron‐beam probe has been used to make time‐ and space‐resolved measurements of the electric field in a parallel plate rf discharge. Measurements were taken at a time resolution of 5 ns and a field resolution ±1 V/cm at increments of 0.32 cm from the powered electrode. The detection method provides the weighted average of the electric field along the beam trajectory. Measurements of fields less than 20 V/cm were made throughout the entire discharge. Data were obtained for 13.6‐MHz argon discharges at 2.3 and 20 mTorr, and at rf voltage amplitudes of 100 and 600 V at each pressure. The data for the 2.3‐mTorr, 600‐V case show (1) that a propagating double layer forms during the collapse of the sheath, (2) that the field near the electrode points in toward the plasma at the extreme collapse of the sheath, (3) that the collapse and expansion of the sheath proceeds asymmetrically for measurable field values, and (4) that the trajectory averaged electric field in the plasma has an anomalous phase shift and magnitude. Similar phenomena are observed for the remaining three discharge cases.
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52.70.Ds Electric and magnetic measurements
52.40.Hf Plasma-material interactions; boundary layer effects
52.80.Pi High-frequency and RF discharges
51.50.+v Electrical properties (ionization, breakdown, electron and ion mobility, etc.)

Pressure and frequency dependence of ion bombardment energy distributions from rf discharges

M. F. Toups and D. W. Ernie

J. Appl. Phys. 68, 6125 (1990); http://dx.doi.org/10.1063/1.346900 (8 pages) | Cited 13 times

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Experimental measurements of the energy distribution and flux of ions bombarding an electrode of a parallel‐plate rf reactor were performed in argon, neon, and a 95% helium‐5% argon mixture using a hemispherical retarding grid energy analyzer. Quadrupole mass analysis was performed to identify the ions which were bombarding the electrode. Frequencies from 2.5 to 20 MHz and pressures from 0.025 to 1.6 Torr were studied. For a given amplitude of the applied rf potential, the ratio of the frequency of the applied rf potential to the reactor gas pressure was found to be the critical parameter in determining the shape of the measured ion bombardment energy distributions. The total ion flux to the electrode surface was found to be proportional to the square of the frequency and insensitive to the reactor gas pressure, for a fixed amplitude of the applied rf potential. These results are discussed with reference to the physics of rf gas discharges.
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52.80.Pi High-frequency and RF discharges
52.70.Nc Particle measurements
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions

Grazing x‐ray reflection analysis of nanometric scale structures

Pierre Boher, Philippe Houdy, and Claude Schiller

J. Appl. Phys. 68, 6133 (1990); http://dx.doi.org/10.1063/1.346901 (10 pages) | Cited 17 times

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Grazing x‐ray reflection (GXR) has been performed on thick WN layers and on C/W multilayer mirrors deposited in a diode rf‐sputtering system. In the first case, we show that GXR can provide not only the layer thickness but also precise information on the occurrence of intermediate layers (native oxide superlayer, reactionlike sublayer). The relative thickness of each layer is determined very precisely. The GXR analysis of C/W multilayers can be perfectly interpreted using a physical model which includes a thickness drift during the deposit, an interface layer between W and C layers due to the interdiffusion, and interface roughness. In each case, the GXR simulation models are confirmed by in situ kinetic ellipsometry and ex situ transmission electron microscopy. Moreover, in the W/C multilayer case the soft x‐ray reflectivity calculated at the CKα line assuming the same model agree very well with the experimental value.
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07.85.-m X- and γ-ray instruments
61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
78.66.-w Optical properties of specific thin films
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures

Radiation‐induced charge trapping in implanted buried oxides

Frederick T. Brady, Sheng S. Li, and Wade A. Krull

J. Appl. Phys. 68, 6143 (1990); http://dx.doi.org/10.1063/1.346902 (6 pages) | Cited 9 times

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We investigate the response of buried oxide layers formed by oxygen implantation to total dose x‐ray irradiation. The characterization is based on C‐V measurements of the buried oxide capacitor and on back‐channel transistor measurements. Reduced charge trapping is found for material implanted with a lower oxygen dose, annealed at higher temperatures, and annealed for longer times. Also, total‐dose irradiation was found to generate few interface traps. A particularly interesting result is that an increase in the concentration of shallow donors with x‐ray dose was observed for certain samples. This increase in the donor concentration was observed only in the top Si film.
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61.80.Cb X-ray effects
61.72.Bb Theories and models of crystal defects
73.40.Ty Semiconductor-insulator-semiconductor structures

Experimental study of the effect of the ion‐implanted dose on the resistance‐area product of Hg0.8Cd0.2Te n+p photodiodes

J. M. Centeno, C. Gonzalez, J. Sangrador, and T. Rodriguez

J. Appl. Phys. 68, 6149 (1990); http://dx.doi.org/10.1063/1.346903 (4 pages)

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The temperature dependence of the differential resistance by area product at zero bias (R0 A) of boron‐implanted n‐on‐p infrared photodiodes made in x≊0.20 Hg1−xCdxTe has been measured and characterized as a function of the implanted dose assuming a simple model of the junction. The R0 A product and its functional dependence in the different temperature ranges are found to be dependent on the implanted dose in n+p as‐implanted abrupt junctions. The best performance diodes are found at the lowest implanted dose. The results indicate that there is an upper limit of the R0 A, in the range where the current is controlled by a minority‐carrier diffusion mechanism, that is determined in n+p junctions by the p‐side contribution. However, the indicated behavior of R0 A and its functional dependence at low temperatures supports the hypothesis defended by some workers in the literature indicating that the n‐side contribution to the current‐voltage characteristics may be important under some conditions, such as is the case when the current is controlled by conduction mechanisms through traps in the depletion region which are related to the heavily damaged n+ layer caused by the implantation process in this material.
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85.30.Kk Junction diodes
85.60.Gz Photodetectors (including infrared and CCD detectors)
61.72.U- Doping and impurity implantation
81.40.Rs Electrical and magnetic properties related to treatment conditions

Native defects in the AlxGa1−xSb alloy semiconductor

M. Ichimura, K. Higuchi, Y. Hattori, T. Wada, and N. Kitamura

J. Appl. Phys. 68, 6153 (1990); http://dx.doi.org/10.1063/1.346904 (6 pages) | Cited 27 times

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Defect concentrations in AlxGa1−xSb which is in equilibrium with a liquid phase are calculated. When the liquid phase is Ga rich, a Ga antisite (Ga2−Sb) or an Al antisite (Al2−Sb) is dominant, and the concentrations of vacancies are much smaller than the antisite concentrations. Ga2−Sb is dominant in GaSb equilibrated with a Sb‐rich solution, but the concentration of Sb antisites comes close to that of Ga2−Sb as temperature is lowered. For x larger than 0.6, a group‐III vacancy is the predominant defect in the case of Sb‐rich solutions. Calculated net acceptor concentrations agree well with those determined experimentally. A complex defect composed of GaSb and a Ga vacancy, which have been taken as the dominant residual acceptor, is expected to be negligible.
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61.72.Bb Theories and models of crystal defects
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
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