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22 Jan 1990

Volume 56, Issue 4, pp. 307-405

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Polymorphism and crystal‐crystal transformations of the highly optically nonlinear organic compound α‐[(4′‐methoxyphenyl)methylene]‐4‐nitro‐benzeneacetonitrile

S. N. Oliver, P. Pantelis, and P. L. Dunn

Appl. Phys. Lett. 56, 307 (1990); http://dx.doi.org/10.1063/1.103288 (3 pages) | Cited 12 times

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Crystals of α‐[(4′‐methoxyphenyl)methylene]‐4‐nitro‐benzeneacetonitrile exhibit powder second‐harmonic generation (SHG) efficiencies under 1.06 μm irradiation several times that of 2‐methyl‐4‐nitroaniline. We have identified three distinct, solution‐grown polymorphs which show marked variation in SHG efficiency. Controlled transformation between these polymorphs can be made either solvent assisted or thermally. One polymorph shows a 25‐fold increase in SHG efficiency when the irradiation wavelength is changed to 1.32 μm while the others show a small or no increase.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
78.20.-e Optical properties of bulk materials and thin films
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
64.70.K- Solid-solid transitions

108 GHz passive mode locking of a multiple quantum well semiconductor laser with an intracavity absorber

Steve Sanders, Lars Eng, Joel Paslaski, and Amnon Yariv

Appl. Phys. Lett. 56, 310 (1990); http://dx.doi.org/10.1063/1.103187 (2 pages) | Cited 27 times

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A two‐section multiple quantum well laser is passively mode locked without an external cavity at ∼108 GHz. The pulse widths average 2.4 ps and have a time‐bandwidth product of 1.1. Self‐pulsations at frequencies up to 8 GHz are also observed.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Rz Doped-insulator lasers and other solid state lasers

GaInP mass transport and GaInP/GaAs buried‐heterostructure lasers

S. H. Groves, Z. L. Liau, S. C. Palmateer, and J. N. Walpole

Appl. Phys. Lett. 56, 312 (1990); http://dx.doi.org/10.1063/1.102813 (3 pages) | Cited 19 times

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Mass transport of a semiconductor alloy has been demonstrated using Ga0.51In0.49P which is lattice matched to GaAs. Buried‐heterostructure diode lasers with Ga0.51In0.49P as cladding and GaAs as the active layer have been made using this fabrication technique. Initial attempts produce devices with room‐temperature lasing thresholds of ∼33 mA and 15% differential power efficiency per facet.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
68.35.Fx Diffusion; interface formation
81.05.Bx Metals, semimetals, and alloys

Quarter‐wave Bragg reflector stack of InP‐In0.53Ga0.47As for 1.65 μm wavelength

D. G. Deppe, N. D. Gerrard, C. J. Pinzone, R. D. Dupuis, and E. F. Schubert

Appl. Phys. Lett. 56, 315 (1990); http://dx.doi.org/10.1063/1.102814 (3 pages) | Cited 11 times

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Quarter‐wave semiconductor mirrors of InP‐In0.53Ga0.47As for high reflectivity at 1.65 μm wavelength are epitaxially grown using metalorganic chemical vapor deposition. Doping of the In0.53Ga0.47As layers is found to be critical for high reflectivity at wavelengths corresponding to the In0.53Ga0.47As band gap. n‐type doping reduces the band‐to‐band absorption resulting in high reflectivity while p‐type doped mirrors show reduced reflectivity.
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78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
42.15.Eq Optical system design
42.79.Bh Lenses, prisms and mirrors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Improving the performance of strained InGaAs/AlGaAs single quantum well lasers

D. P. Bour, Ramon U. Martinelli, F. Z. Hawrylo, G. A. Evans, N. W. Carlson, and D. B. Gilbert

Appl. Phys. Lett. 56, 318 (1990); http://dx.doi.org/10.1063/1.102815 (3 pages) | Cited 7 times

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By adjusting the carrier confining structure and the optical confining structure of strained InGaAs/AlGaAs single quantum well (QW) lasers, an improvement in performance has been obtained. First, the influence of optical confinement was examined by comparing two graded‐index confining structures. For InxGa1−xAs QWs with either x=0.20 or x=0.25, lasers with greater optical confinement factor had improved performance, with both lower threshold (180 A/cm2 for x=0.20) and higher characteristic temperature (250 K for x=0.20), despite their reduced carrier confining potentials. Second, experiments on graded‐composition quantum wells show that thin step‐grading layers result in improved performance. In this structure, where the QW has x=0.35, and the step layers have x=0.15, the optimum step thickness is 30–40 Å. Thicker step layers appear to create too much strain, degrading the laser operation. These results indicate that step grading of strained QWs produces active region interfaces with lower defect density, and that step grading is especially useful in improving the performance of long‐wavelength, highly strained InGaAs/AlGaAs QW lasers.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
85.60.Jb Light-emitting devices
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Growth of regularly coiled carbon filaments by Ni catalyzed pyrolysis of acetylene, and their morphology and extension characteristics

Seiji Motojima, Masayuki Kawaguchi, Koji Nozaki, and Hiroshi Iwanaga

Appl. Phys. Lett. 56, 321 (1990); http://dx.doi.org/10.1063/1.102816 (3 pages) | Cited 71 times

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Regularly coiled carbon filaments have been obtained by the catalytic pyrolysis of acetylene at 350–750 °C using Ni plate and powder as a catalyst. Morphology and extension characteristics of the obtained coiled filaments were examined in some detail. The regularly coiled filaments have generally a 0.1–0.3 μm thickness, a 2–8 μm coil diameter, and a 0.1–5 mm coil length. The coiled filaments were always formed by the entwistness of two pair coils which grew in the same direction simultaneously from a diamond‐shaped Ni seed. We have found that the coiled filaments could be elastically extended up to about three times versus the original coil length.
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68.70.+w Whiskers and dendrites (growth, structure, and nonelectronic properties)
68.35.B- Structure of clean surfaces (and surface reconstruction)
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.50.Bc Processes caused by infrared radiation
82.50.Hp Processes caused by visible and UV light

Grain refinement induced by a critical crystal growth velocity in undercooled melts

R. Willnecker, D. M. Herlach, and B. Feuerbacher

Appl. Phys. Lett. 56, 324 (1990); http://dx.doi.org/10.1063/1.103289 (3 pages) | Cited 54 times

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Containerless undercooling by electromagnetic levitation has been used to measure both growth velocity and grain size as a function of undercooling in Cu70Ni30 and Cu69Ni30B1 alloys. At a critical undercooling ΔT∗ the temperature dependence of the growth velocity changes discontinuously. This is accompanied by a sudden drop of grain size in the solidified product by more than two orders of magnitude. The comparative investigations show that it is not a critical undercooling that initiates the grain refinement process, but rather a critical crystal growth velocity, which approximately equals the diffusive speed.
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81.10.Aj Theory and models of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation
61.72.Mm Grain and twin boundaries
68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces

Heteroepitaxial growth of layered transition metal dichalcogenides on sulfur‐terminated GaAs{111} surfaces

Keiji Ueno, Toshihiro Shimada, Koichiro Saiki, and Atsushi Koma

Appl. Phys. Lett. 56, 327 (1990); http://dx.doi.org/10.1063/1.102817 (3 pages) | Cited 29 times

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Layered transition metal dichalcogenides (MoSe2, NbSe2) have been heteroepitaxially grown on (NH4)2 Sx (x≂2) treated GaAs(111)Ga, GaAs(∼(111))As surfaces in spite of the large difference in their crystal structures. The in situ observation of reflection high‐energy electron diffraction has shown that the grown film has its own lattice constant even from the first layer. The lattice matching condition, which is severely restricting in the usual heteroepitaxial growth case, is greatly relaxed in the present system because only weak van der Waals forces exist between the grown film and the substrate. This results from the fact that sulfur atoms regularly terminate dangling bonds on the GaAs surface after the (NH4)2Sx treatment.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Photoinduced structural defect levels in amorphous selenium films

M. N. Kamalasanan and Suresh Chand

Appl. Phys. Lett. 56, 330 (1990); http://dx.doi.org/10.1063/1.102799 (3 pages) | Cited 10 times

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Thermally stimulated discharge (TSD) behavior of native (dark rested) and irradiated amorphous selenium films (∼100 μm) has been studied. The TSD spectrum of nonirradiated films shows electron trapping levels at ∼0.99 eV and no detectable hole trapping levels. On the other hand, the irradiated films show both electron as well as hole trapping levels at 0.99 and 1.05 eV, respectively. These results have been explained in terms of trapping of charge carriers at intrinsic defect states and the photoinduced defect levels created during irradiation.
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71.55.Ht Other nonmetals
81.40.Rs Electrical and magnetic properties related to treatment conditions
72.40.+w Photoconduction and photovoltaic effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Measured brightness of electron beams photoemitted from multicrystalline LaB6

P. E. Oettinger

Appl. Phys. Lett. 56, 333 (1990); http://dx.doi.org/10.1063/1.103290 (2 pages) | Cited 16 times

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Laser‐driven semiconductor photoemitters can provide the very bright beams of electrons needed in advanced accelerators. However, these semiconductors are easily degraded in operation. Photoemissive testing of the compound LaB6, which is expected to be a more environmentally rugged material, has shown that under excimer laser irradiation normalized electron beam brightnesses of 6.7×106 , 2.6×106 , and 1.5×105 A/cm2  rad2 can be achieved at photon wavelengths, respectively, of 193, 248, and 308 nm.
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81.65.-b Surface treatments
41.75.Fr Electron and positron beams
29.25.Bx Electron sources
81.40.Rs Electrical and magnetic properties related to treatment conditions

Influence of slip direction on the photoplastic effect in cadmium sulfide

T. J. Garosshen, C. S. Kim, and J. M. Galligan

Appl. Phys. Lett. 56, 335 (1990); http://dx.doi.org/10.1063/1.102800 (2 pages) | Cited 2 times

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Studies of the photoplastic behavior of CdS single crystals show that when slip occurs on the basal plane, a large increase in flow stress is observed in the presence of incident light. However, when the crystal is oriented for slip on the prismatic planes, a very small photoplastic effect is observed. Measurements of the current associated with dislocation motion on the active slip systems indicate that the photoplastic effect is proportional to the charge on the dislocations in the respective slip planes.
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62.20.F- Deformation and plasticity
61.72.Lk Linear defects: dislocations, disclinations
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors

X‐ray observation of compositional modulation caused by phase decomposition in GaInP ternary alloys

Hiroshi Okuda, Makoto Kondo, Kiyoko Kato, and Kazuo Nakajima

Appl. Phys. Lett. 56, 337 (1990); http://dx.doi.org/10.1063/1.102801 (3 pages) | Cited 3 times

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The phase decomposition of GaInP ternary alloys grown by low‐pressure metalorganic vapor phase epitaxy has been investigated using x‐ray diffraction. Diffuse scattering around the Bragg peaks due to compositional modulation was observed clearly for the first time, for samples containing high dislocation densities. Thermodynamically, the present growth temperature lies between the chemical and coherent spinodal lines. It is suggested that phase decomposition of the alloys occurs clearly only when the strain relaxation during crystal growth is possible under the present growth conditions.
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68.55.Nq Composition and phase identification
81.15.Kk Vapor phase epitaxy; growth from vapor phase
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
61.05.C- X-ray diffraction and scattering

Photoluminescence from Si/Ge superlattices

E. A. Montie, G. F. A. van de Walle, D. J. Gravesteijn, A. A. van Gorkum, and C. W. T. Bulle‐Lieuwma

Appl. Phys. Lett. 56, 340 (1990); http://dx.doi.org/10.1063/1.102802 (3 pages) | Cited 19 times

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We have studied the luminescence of short‐period Si/Ge superlattices of varying composition grown on a Si1−xGex alloy buffer layer. X‐ray diffraction and Rutherford backscattering were used to analyze the composition of the samples. Luminescence bands at 1.5 and 1.6 μm originate from the superlattice, as is indicated by etching experiments. A strong change in luminescence intensity is observed as the composition and strain of the superlattice vary.
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78.55.Hx Other solid inorganic materials
78.66.-w Optical properties of specific thin films
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Microstrain and macrostrain profiles in ZnSe epitaxial layers

A. Krost, W. Richter, and O. Brafman

Appl. Phys. Lett. 56, 343 (1990); http://dx.doi.org/10.1063/1.102803 (3 pages) | Cited 16 times

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We present a microprobe Raman scattering study of the strain in a ZnSe heterostructure with GaAs, Ge, and Si. Measurements taken at adjacent sites of different distances from the interface prove Raman scattering to be a very powerful tool for detecting the strain and distinguishing between local high strains and macroscopic low strains.
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68.60.Bs Mechanical and acoustical properties
68.35.Gy Mechanical properties; surface strains
78.30.Fs III-V and II-VI semiconductors
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors

Electron transport properties of strained InxGa1−xAs

J. L. Thobel, L. Baudry, A. Cappy, P. Bourel, and R. Fauquembergue

Appl. Phys. Lett. 56, 346 (1990); http://dx.doi.org/10.1063/1.102780 (3 pages) | Cited 39 times

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As a first approach to the study of strained pseudomorphic materials, we have used a Monte Carlo method to calculate the effect of strain on electron transport properties of bulk InGaAs. Strain‐induced velocity reduction is found to be much more pronounced for InGaAs grown on GaAs substrate than for InGaAs grown on InP substrate.
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72.20.Dp General theory, scattering mechanisms
73.50.Bk General theory, scattering mechanisms
73.61.Ey III-V semiconductors
72.80.Ey III-V and II-VI semiconductors

Excited‐state spectroscopy of identified Mg acceptor in InP

A. C. Beye, A. Yamada, T. Kamijoh, H. Tanoue, K. M. Mayer, N. Ohnishi, H. Shibata, and Y. Makita

Appl. Phys. Lett. 56, 349 (1990); http://dx.doi.org/10.1063/1.102781 (3 pages) | Cited 4 times

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Photoluminescence experiments under resonant excitation have been performed at low temperature in Mg+‐implanted bulk InP. The energy difference between the ground 1S3/2 and excited 2S3/2 states of the Mg acceptor is accurately measured by two‐hole spectroscopy of Mg‐acceptor bound exciton. Selective excitation of donor‐acceptor pairs luminescence allows the identification of a set of 2P3/2 and 2P5/2 excited states. The measured values to be compared with similar published data obtained for Zn and C represent an additional step in the process of accurate identification of acceptors in InP.
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71.55.Eq III-V semiconductors
78.55.Cr III-V semiconductors
61.72.U- Doping and impurity implantation
71.35.-y Excitons and related phenomena

X‐ray moiré pattern in dislocation‐free silicon‐on‐insulator wafers prepared by oxygen ion implantation

B. L. Jiang, F. Shimura, and G. A. Rozgonyi

Appl. Phys. Lett. 56, 352 (1990); http://dx.doi.org/10.1063/1.102782 (3 pages) | Cited 2 times

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A moiré pattern formed by the two superimposed lattices of a host silicon substrate and the top ‘‘superficial’’ silicon layer formed in a separation by implanted oxygen (SIMOX) process has been observed with Lang transmission x‐ray topography. The moiré patterns clearly show a characteristic fingerprint related to a nonuniformity in the ion implantation apparatus. It is shown that moiré patterns obtained with x‐ray topography are a uniquely powerful tool for the characterization of highly ordered SIMOX wafers which have essentially no extended dislocations. Moiré patterns not only image the dilatational strain or lattice rotation between the two superimposed lattices, but also indicate the level of crystallographic perfection of the entire width and depth of the substrate/superficial layer system.
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61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
68.35.Dv Composition, segregation; defects and impurities
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.72.uf Ge and Si

Nonresonant electron and hole tunneling times in GaAs/Al0.35Ga0.65As asymmetric double quantum wells

M. Nido, M. G. W. Alexander, W. W. Rühle, T. Schweizer, and K. Köhler

Appl. Phys. Lett. 56, 355 (1990); http://dx.doi.org/10.1063/1.102783 (3 pages) | Cited 58 times

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Nonresonant carrier tunneling is investigated by time‐resolved and time‐averaged optical methods for a series of samples with various barrier thicknesses. The electron tunneling times decrease exponentially with the decrease of barrier thickness from 8 to 3 nm, and the trend is well described by a semiclassical model. Additional efficient hole tunneling is observed in the 3 nm barrier sample, and the time constant is of the order of 50 ps.
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73.40.Gk Tunneling
78.47.-p Spectroscopy of solid state dynamics
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Ellipsometric study of GaAs/GaP superlattices

G. Armelles, J. M. Rodríguez, and F. Briones

Appl. Phys. Lett. 56, 358 (1990); http://dx.doi.org/10.1063/1.102784 (3 pages) | Cited 4 times

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Ellipsometric measurements were performed to study the E1 and E1+Δ1 transitions on a set of GaAs/GaP strained‐layer superlattices. The experimental results show the existence of small quantum confinement effects.
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78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
07.60.Fs Polarimeters and ellipsometers

Carbon‐doped base GaAs/AlGaAs heterojunction bipolar transistor grown by metalorganic chemical vapor deposition using carbon tetrachloride as a dopant source

B. T. Cunningham, G. E. Stillman, and G. S. Jackson

Appl. Phys. Lett. 56, 361 (1990); http://dx.doi.org/10.1063/1.102785 (3 pages) | Cited 19 times

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Carbon tetrachloride (CCl4) has been used as a carbon doping source for the base region of a GaAs/AlGaAs Npn heterojunction bipolar transistor (HBT) grown by low‐pressure metalorganic chemical vapor deposition (MOCVD). Transistors were fabricated and characterized for dc current gain, emitter‐base junction ideality factor, base contact resistance, and external base resistance. Microwave characterization by S‐parameter measurement was performed to determine the common emitter current gain and maximum available gain as a function of frequency. Transistors with the base contact area self‐aligned to a 3×10 μm emitter finger had a dc current gain as high as 50, an emitter‐base junction ideality factor of n=1.2, and a current gain cutoff frequency of ft=26 GHz. Transistors of equal emitter area without self‐alignment exhibited dc current gain as high as 86, n=1.2, and ft=20 GHz. A base contact resistance of Rc=2.85×10−6 Ω cm2 and an external base sheet resistance of Rs=533.4 Ω/☒ were measured. These preliminary results indicate that carbon doping from CCl4 may be an attractive substitute for Zn or Mg in GaAs/AlGaAs HBT structures grown by MOCVD.
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85.30.Pq Bipolar transistors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Mobility‐lifetime product of photoexcited electrons in GaAs

George C. Valley, H. Rajbenbach, and H. J. von Bardeleben

Appl. Phys. Lett. 56, 364 (1990); http://dx.doi.org/10.1063/1.102786 (3 pages) | Cited 9 times

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We show that photorefractive beam coupling gain as a function of grating period measured in semi‐insulating GaAs with an external ac electric field or with a dc field and moving fringes can be explained theoretically by a mobility‐lifetime product about four orders of magnitude smaller than that obtained in low‐field conditions. This reduction is caused by enhanced occupation of the L band at high fields coupled with the low L band mobility and by the increase in recombination due to the cascade capture process that occurs for electric fields above a few kV/cm.
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72.20.Ht High-field and nonlinear effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.20.Jq Electro-optical effects
42.70.-a Optical materials

Evidence of segregation in (100) strained Si1−xGex alloys grown at low temperature by molecular beam epitaxy

E. T. Croke, T. C. McGill, R. J. Hauenstein, and R. H. Miles

Appl. Phys. Lett. 56, 367 (1990); http://dx.doi.org/10.1063/1.102787 (3 pages) | Cited 6 times

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High quality, coherently strained Si1−xGex alloy layers are studied using high‐resolution x‐ray diffraction (HRXRD) and ex situ transmission electron diffraction. Several samples were grown at extremely low temperatures (310–330 °C) by molecular beam epitaxy. Sample thicknesses and alloy concentrations were chosen to span a range beginning just below to significantly above critical thicknesses previously reported for this system. HRXRD observations demonstrate a high degree of coherency in the as‐grown structures since measurements of the lattice constant parallel to the sample surface (a∥) consistently yield the value for the (100)Si substrate. HRXRD from (004) planes used to measure a⊥ typically yield a spectrum with several peaks for growths in excess of the critical thickness and single peaks for those below the critical thickness. The high degree of coherency observed in these samples suggests that chemical segregation is responsible for the observed x‐ray peaks.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.05.C- X-ray diffraction and scattering
68.35.Fx Diffusion; interface formation

Thermodynamic explanation to the enhanced diffusion of base dopant in AlGaAs‐GaAs npn bipolar transistors

D. G. Deppe

Appl. Phys. Lett. 56, 370 (1990); http://dx.doi.org/10.1063/1.102788 (3 pages) | Cited 41 times

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A model is presented which accounts for the anomalous diffusion of the p‐type base dopant during the growth of AlGaAs‐GaAs npn bipolar transistors. The model is based upon Fermi level pinning at the crystal surface during epitaxial growth which leads to an increased concentration of column III interstitial defects in heavily n‐type AlGaAs or GaAs. The excess column III interstitials generated in the n‐type crystal flow into the p+ base region causing a transfer of the p‐type impurity atoms from column III lattice sites to interstitial positions through a ‘‘kick‐out’’ mechanism. Once in interstitial positions the impurity atoms are known to diffuse rapidly. The model is consistent with previously proposed mechanisms for both impurity diffusion and column III self‐diffusion.
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66.30.J- Diffusion of impurities
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
85.30.Pq Bipolar transistors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

A Si0.7Ge0.3 strained‐layer etch stop for the generation of thin layer undoped silicon

D. Godbey, H. Hughes, F. Kub, M. Twigg, L. Palkuti, P. Leonov, and J. Wang

Appl. Phys. Lett. 56, 373 (1990); http://dx.doi.org/10.1063/1.102789 (3 pages) | Cited 10 times

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The use of a Si0.7Ge0.3 strained layer as an etch stop in silicon‐based materials is reported. The etch rates were characterized through silicon and a 60 nm Si0.7Ge0.3 strained layer. The etch rate through undoped silicon was 17–20 nm/min, while the etch rate through the Si0.7Ge0.3 layer was 1 nm/min. After annealing the wafer to 850 °C for 30 min, transmission electron microscopy was used to show that strain in the alloy layer was only partially relieved, and that generated misfit dislocations were confined to the strained Si0.7Ge0.3 layer. The etch rate through the strained layer increased to 1.7 nm/min after this treatment, and was still perfectly functional as an etch stop.
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81.65.-b Surface treatments
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.35.Dv Composition, segregation; defects and impurities

Electron beam induced current and cathodoluminescence imaging of the antiphase domain boundaries in GaAs grown on Si

K. Nauka, G. A. Reid, and Z. Liliental‐Weber

Appl. Phys. Lett. 56, 376 (1990); http://dx.doi.org/10.1063/1.102790 (3 pages) | Cited 3 times

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Electrical and optical properties of antiphase domain boundaries (APBs) in GaAs epitaxial layers grown on Si substrates have been investigated using cathodoluminescence, electron beam induced current, and scanning deep level transient spectroscopy. It was found that APBs reduce near‐band‐gap luminescence and minority‐carrier lifetime. In contrast to recombination at threading dislocations in GaAs films, the nonradiative recombination processes at APBs are not due to deep traps but rather to a continuum of band‐gap states introduced by APBs.
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68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
78.60.Hk Cathodoluminescence, ionoluminescence
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