bluuebunny/crossref_metadata_2025 huggingface dataset:
Lattice images of defect-free silicon on sapphire prepared by ion implantation
Authors: Parker M. A. , Sinclair R. , Sigmon T. W.
Published: July 2002

We report for the first time high resolution cross section transmission electron microscopy (HRXTEM) of defect-free silicon on sapphire (SOS) films. These films are prepared from as-grown SOS films by use of multiple ion implantation and annealing sequences. HRXTEM lattice images for both as-grown and processed films are obtained, and correlation with previous ion channeling experiments on this material is discussed.
Elimination of dark line defects in lattice-mismatched epilayers through use of strained-layer superlattices
Authors: Gourley P. L. , Biefeld R. M. , Dawson L. R.
Published: July 2002

The microscopic optical quality of thick (∼1 μm) III-V semiconductor epitaxial layers, mismatched to their substrates, is examined by photoluminescence microimaging. The layers include several kinds of strained-layer superlattices (GaP/GaAsxP1−x, GaAs/GaAs1−xPx, and GaAs/InxGa1−xAs) and associated alloys. Microscopic images of epilayer luminescence directly reveal the presence of misfit dislocations which appear as dark line defects. These defects can be completely eliminated in the strained-layer superlattices if these structures have thin layers, less than the critical thickness for elastic accommodation, and sufficient numbers of interfaces of block threading dislocations.
Metal-oxide-semiconductor field-effect transistors fabricated using self-aligned silicide technology
Authors: Tsaur B-Y. , Anderson C. H.
Published: July 2002

N- and p-channel metal-oxide-semiconductor field-effect transistors have been fabricated with self-aligned WSi2 source, WSi2 drain, and WSi2/polycrystalline-silicon gate. Ion beam mixing and rapid thermal annealing techniques were employed to form smooth WSi2 films selectively on the device area and to simultaneously form shallow source and drain p-n junctions. Good electrical characteristics were obtained for both n- and p-channel devices, which have a gate length of 1.5 μm.
Amplification by a voltage locked array of Josephson junctions
Authors: McDonald D. G. , Frederick N. V.
Published: July 2002

We have studied a new type of Josephson junction amplifier which is based on a two-junction array; the junctions are mutually phase locked at the Josephson self-oscillation frequency. With this frequency at 82 GHz, the voltages of the junctions remain equal (locked) for a bias current range as large as 60% of the critical current. Over a much smaller bias range, with an applied signal frequency of 1 kHz, a small-signal power gain of 19 dB was measured, accompanied by a negative resistance input impedance. This performance is consistent with a quasistatic theory of the amplifier.
Theory of the effect of traps on the spectral characteristics of diode lasers
Authors: Zeiger H. J.
Published: July 2002

The effect of traps on the spectral characteristics of diode lasers has been calculated by solving a set of coupled linearized equations of motion for fluctuating system variables under the influence of Langevin forces. The results have been used to compute the FM and AM noise spectra, current noise spectrum, and laser line shape. Trap effects are capable of explaining the 1/ f  contributions to the spectra, as well as the excess power-independent linewidth observed in GaAs diode laser emission.
Calculation of the effects of a focused laser beam on the dynamic Josephson tunneling states
Authors: Chang Jhy-Jiun
Published: July 2002

Perturbative calculations of the voltage response of constant-current biased Josephson tunnel junctions to a focused laser beam have been performed. The dependence of the voltage modification as a function of the laser beam position was calculated. The results were found to be qualitatively different for junctions biased on the first zero-field current step but with either vortex-mode or cavity-mode excitations. Therefore, the recently developed scanning focused laser beam technique operated in this mode can be a simple and effective method for probing the nature of the dynamic Josephson tunneling state.
Conversion of optical path length to frequency by an interferometer using photorefractive oscillation
Authors: Kwong Sze-Keung , Yariv Amnon , Cronin-Golomb Mark , Ury Israel
Published: July 2002

Frequency detuning effects in photorefractive oscillators are used in a new type of (passive) interferometry which converts optical path length changes to frequency shifts. Such an interferometer is potentially more accurate than conventional interferometers which convert optical path length changes to phase or intensity changes.
Recoil ion confinement in a radio frequency quadrupole ion trap
Authors: Church D. A. , Holzscheiter H. M. , Kenefick R. A. , O C. S. , Short R. T. , Berry S. D. , Elston S. B. , Breinig M. , DeSerio R. , Sellin I. A. , Thomas B.
Published: July 2002

Multicharged Ne q+ recoil ions (3≤q≤8) arising from impact of 1 MeV/u Cl beam ions (mean charge near 11e) on Ne target gas have been produced and observed with good resolution in an axially symmetric radio frequency quadrupole ion trap. Investigations of the stability properties are in agreement with theory, while measurements of ion storage time constants, in comparison with those in other trap types, indicated that ion loss arose from electron capture collisions.
Canceling beam deflection in an acousto-optic frequency shifter using a self-pumped phase conjugating mirror
Authors: Cronin-Golomb Mark , Anderson Dana Z.
Published: July 2002

A self-pumped phase conjugating mirror in conjunction with a traveling-wave acousto-optic modulator can be used to derive a spatially undisplaced frequency translatable optical beam. One can also obtain a beam consisting of multiple optical frequencies spaced by twice the modulator drive frequency. We find that the appropriate measure of the phase conjugating mirror’s ability to retroreflect a moving optical beam can be its response (writing) time, its memory time, or the ratio of the two, depending on how the beam is moving.
Power-dependent attenuation of nonlinear waves guided by thin films
Authors: Ariyasu J. , Seaton C. T. , Stegeman G. I.
Published: July 2002

We show that if one or both of the media bounding a thin film has an intensity-dependent refractive index, and is also lossy, then the attenuation coefficient for nonlinear waves guided by the film can be very strongly power dependent.
Highly doped GaAs:Si by molecular beam epitaxy
Authors: Sacks Robert , Shen H.
Published: July 2002

Highly doped (N++) GaAs:Si with n up to 1.8×1019 cm−3 has been grown by molecular beam epitaxy at a ‘‘normal’’ growth rate of ∼0.8 m/h−1. These layers have been studied by Raman spectroscopy, van der Pauw–Hall measurements, and capacitance-voltage plotting. They show no appreciable surface accumulation or diffusion of donors into low-doped layers grown on top of them, and thus should be suitable as buffer layers for n/N+ devices as well as aiding in the production of low resistivity ohmic contacts. Resistivity of these layers has a lower limit of 4.75×10−4 Ω cm occurring at about 1.2×1019 cm−3. The possibility of this being an intrinsic lower limit to the resistivity of GaAs is discussed.
Uniformity in the electrical characteristics of GaAs/AlAs tunnel structures grown by metalorganic chemical vapor deposition
Authors: Bonnefoi A. R. , McGill T. C. , Burnham R. D.
Published: July 2002

Uniformity of current-voltage characteristics in GaAs/AlAs tunnel structures grown by metalorganic chemical vapor deposition has been investigated by studying electronic transport perpendicular to GaAs layers separated by one or two AlAs barriers. For each sample, measurements of the current-voltage curves and their first and second derivatives, for series of 10 to 80 identical devices taken randomly across the sample, gave reproducible and uniform results. These showed evidence that the doping concentrations and layer thicknesses were uniform across the wafers. In single barrier structures, they further suggested that the average fluctuations in the thicknesses of ultrathin layers should be within one atomic layer.
Infrared properties and band gaps of HgTe/CdTe superlattices
Authors: Jones C. E. , Casselman T. N. , Faurie J. P. , Perkowitz S. , Schulman J. N.
Published: July 2002

Measurement of the optical transmission spectra of four HgTe/CdTe superlattices grown by molecular beam epitaxy has been carried out at 300 and 30 K to determine the absorption coefficients, refractive indexes, and band-gap energies. In all cases the optical absorption coefficients reached high values (near 104 cm−1) at energies above the band gap. The absorption coefficients had an energy dependence of α≊(E−Eg)1/2 which confirms theoretical predictions of a superlattice band structure with a direct gap. Three of the superlattices measured showed little or no temperature dependence for their band gaps while the third, which may be anomalous, showed a temperature-dependent band gap.
Si-on-insulator films of high crystal perfection by zone melting under a SiO2 cap provided with vent openings
Authors: Pfeiffer Loren , Kovacs T. , West K. W.
Published: July 2002

We observe a marked improvement in the crystal perfection of zone melted thick Si-on-insulator films that were prepared for melt processing by etching an array of openings in the SiO2 capping layer. Chemical defect etching and Rutherford backscattering measurements reflect this improvement, which we believe is due to the creation of new venting paths that reduce the level of excess dissolved SiO2 in the molten Si before recrystallization.
Large-signal dynamics of an ultrafast semiconductor laser at digital modulation rates approaching 10 Gbit/s
Authors: Lau K. Y. , Yariv A.
Published: July 2002

High-fidelity pseudorandom digital modulation at 8.2 Gbit/s of an ultrahigh speed semiconductor laser is demonstrated. Studies using simple but representative pulse patterns at 10 Gbit/s give insights into the maximum digital modulation rate attainable from a given laser, as well as relations between large-signal digital performance and small-signal analog response.
Influence of implantation induced damage in sapphire upon improvement of crystalline quality of silicon on sapphire
Authors: Yamamoto Y. , Kobayashi H. , Takahashi T. , Inada T.
Published: July 2002

Crystalline quality improvement of silicon on sapphire (SOS) was carried out using thermal regrowth following Si implantation at energies of 130 and 150 keV, where the projected range of Si corresponded to and exceeded the SOS film thickness, respectively. Under the latter implant condition, it has been shown from Rutherford backscattering spectrometry (RBS) measurements that damage in sapphire does not anneal out after annealing at 1000 °C. RBS and Hall measurements have revealed that the damage introduced into the sapphire during implantation limits the degree of improvement in crystallographic and electrical properties of SOS.
Single-channel injection locking of a diode-laser array with a cw dye laser
Authors: Hohimer J. P. , Owyoung A. , Hadley G. R.
Published: July 2002

We report injection-locking studies on a gain-guided diode-laser array using a single-frequency cw tunable dye laser master oscillator. By injecting a single end element, both the spatial and spectral emission characteristics of the entire ten-element array could be controlled. The injection-locked array produced over 100 mW output in a single-lobed far-field beam (<0.5° angular width) with a bandwidth of less than 2 MHz. With 3 mW injection, locking occurred over a number of discrete frequency intervals (∼6 GHz wide). At higher power levels (12 mW), these intervals merged to form one continuous locking range >60 GHz wide. Furthermore, by varying the injection frequency, the far-field emission angle of the array could be continuously scanned over several degrees at a rate of 2.3×10−2 deg/GHz.
Thermionic electron emission of the barium tungsten bronzes Ba0.15WO3 and Ba0.21WO3
Authors: Zocchi F.
Published: July 2002

The values of the work function and thermionic constant were determined for orthorhombic Ba 0.15WO3 (φ=2.04 eV, A=100 A/cm2 K2) and tetragonal Ba 0.21WO3 (φ=2.27 eV, A=88 A/cm2 K2). The different thermionic behavior of the two bronzes, shown even in the activation processes, cannot be explained in terms of their known structures, and therefore a more detailed structural analysis is suggested.
Thermal and chemical stability of Schottky metallization on GaAs
Authors: Lau S. S. , Chen W. X. , Marshall E. D. , Pai C. S. , Tseng W. F. , Kuech T. F.
Published: July 2002

The high-temperature stability of Schottky barriers on GaAs has been correlated with the thermodynamic driving force for chemical reaction between the metallic contacts and the substrate. The chemical stability of a gate metallurgy can result in the stability of the electrical characteristics of the contact after high-temperature anneal. Since single element metal contacts on GaAs are chemically unstable, thermally stable Schottky barriers are not expected from these systems. Alternatively, most of the common metal silicides are chemically stable on GaAs and hence are more likely to form Schottky barriers which are stable against high-temperature annealing. The chemically stable silicides of Ni and Co, which exhibit low electrical resistivities, are suggested as improved gate metallurgies in self-aligned metal-semiconductor field-effect transistor technologies.
Electrical property improvements in In-doped dislocation-free GaAs by bulk annealing
Authors: Osaka Jiro , Hyuga Fumiaki , Watanabe Kazuo
Published: July 2002

The effects of bulk annealing on the electrical properties of an In-doped dislocation-free semi-insulating GaAs are investigated. The crystal is grown by a fully encapsulated Czochralski method using the vertical magnetic field. It was found that the EL2 concentration increases after isochronal bulk annealing for 5 h from 800 to 1100 °C. In addition, the activation efficiency of implanted Si was found to correlate to the annealing behavior of the defect.
Growth and characterization of Hg1−xMnxTe grown by molecular beam epitaxy
Authors: Reno J. , Sou I. K. , Wijewarnasuriya P. S. , Faurie J. P.
Published: July 2002

Growth of Hg1−xMnxTe epilayers by molecular beam epitaxy is reported here for the first time. The layers were grown on both CdTe(111) and GaAs(100) substrates. Hall measurements and electron diffraction experiments confirm their high quality. Both n-type and p-type layers were grown. The layers exhibited cut-off wavelengths in the infrared range, thus making them interesting for infrared detector device applications.
Lateral dopant diffusion in implanted buried-oxide structures
Authors: Kamins T. I. , Chiang S. Y.
Published: July 2002

During fabrication of short-channel transistors in silicon films above implanted buried oxides, the possibility of rapid lateral dopant diffusion in the damaged region near the bottom of the silicon layer is of concern. To investigate the possibility of such enhanced lateral diffusion, arsenic, phosphorus, and boron were diffused into silicon films on buried oxides. No excess lateral diffusion was observed even for the phosphorus diffusion, which penetrated through the thickness of the film in a fraction of the diffusion time.
Dependence of Si-SiO2 interface state density on oxide thickness in structures with ultrathin (79–227 Å) oxides
Authors: Kar S. , Shanker D. , Chari K. S.
Published: July 2002

Admittance voltage characteristics of Si/79–227 Å SiO2/metal structures were measured in dark and under optical illumination in the frequency range of 30 Hz–100 kHz. For fabricating the structures, thermal oxidation was carried out in dry oxygen at 900 °C at 1 atm. The interface state versus band-gap energy profiles of the unannealed samples exhibited peaked distributions near the valence and conductance-band edges, overlying a concave background. The interface state density versus oxide thickness profile was observed to go through a minimum and a maximum instead of decreasing in a monotonic fashion.
Narrow single stabilized mode operation of coupled-stripe diode lasers
Authors: Berger J. , Fekete D.
Published: July 2002

In order to investigate the possibility to force an array of coupled lasers to emit a single longitudinal mode under current pulse modulation, a new hybrid device was constructed from two twin coupled-stripe lasers with external mirrors. A single narrow longitudinal mode has been obtained from the two coupled lasers. The spectrum was stabilized to less than 0.15 Å through a wide range of current pulse amplitudes.
Axial x-ray preionized XeCl laser and direct comparison with UV preionization mode
Authors: Bishop G. J. , Dyer P. E. , Raouf D. N. , Tait B. L.
Published: July 2002

Axial x-ray preionization of a compact XeCl laser is demonstrated; significant improvements (∼1.5) in laser performance compared with an optimized UV preionization array are obtained. This simple and compact technique can readily be incorporated into existing lasers.
Detection of optical emission from InSb induced by pulsed laser evaporation
Authors: Bhat P. K. , Dubowski J. J. , Williams D. F.
Published: July 2002

The results of in situ measurements of the optical emissions which occur during the deposition of InSb films by pulsed laser evaporation are reported. Evaporation was induced by a Q-switched neodymium : yttrium aluminum garnet laser with 90 ns pulse width and powers less than 1.5 mJ per pulse at a wavelength of 1.06 μm impinging on the surface of a rotating single crystal InSb target. At low laser powers, emission lines characteristic of In and Sb species were detected which decayed in 800 ns. At higher laser powers, emissions from excited atoms and/or ions were observed. Surface contamination of the target reduced the power threshold to produce ions.
Growth of high quality GaInAs on InP buffer layers by metalorganic chemical vapor deposition
Authors: Chan K. T. , Zhu L. D. , Ballantyne J. M.
Published: July 2002

The uninterrupted growth of high quality GaInAs layers on InP buffers by atmospheric pressure metalorganic chemical vapor deposition using trimethylindium is reported. A lattice mismatch smaller than 4.3×10−4 and low-temperature photoluminescence exciton linewidth of 2.6 meV have been obtained, along with best 300-K, 77-K, and 4.2-K Hall mobilities of 11 200, 64 000, and 80 000 cm2/Vs, respectively. Such high mobility values at 4.2 K are explained by the existence of a two-dimensional electron gas and demonstrate the superior quality of the GaInAs epilayers grown in our laboratory.
Transverse modes of gain-guided coupled-stripe lasers: External cavity control of the emitter spacing
Authors: Epler J. E. , Holonyak N. , Burnham R. D. , Paoli T. L. , Thornton R. L. , Blouke M. M.
Published: July 2002

By means of an external grating cavity, the dispersion relation of the transverse modes of gain-guided coupled-stripe laser diodes is determined. The parabolic relation obtained indicates (despite the stripes) a relatively flat gain profile similar to a broad area laser. Accordingly, higher order transverse modes are possible and are demonstrated with near and far fields exhibiting one and two emitters per stripe.
Tilted-mirror semiconductor lasers
Authors: Salzman J. , Lang R. , Margalit S. , Yariv A.
Published: July 2002

Broad-area GaAs heterostructure lasers with a tilted mirror were demonstrated for the first time, with the tilted mirror fabricated by etching. These lasers operate in a smooth and stable single lateral mode with a high degree of spatial coherence. The suppression of filamentation manifests itself in a high degree of reproducibility in the near-field pattern.
Power characteristics of unstable resonator cavity semiconductor stripe lasers
Authors: Wilcox Jaroslava Z.
Published: July 2002

Approximate formulas for the power output from unstable resonator cavity high-gain semiconductor stripe lasers are derived using the geometrical optics theory. The formulas for the outcoupling efficiency are related to measurable quantities, and shown to be in good agreement with the available experimental data.
Grating enhanced quantum well detector
Authors: Goossen K. W. , Lyon S. A.
Published: July 2002

An infrared detector based on the excitation of carriers out of a modulation-doped quantum well is theoretically investigated. The efficiency of the detector is increased by using a grating to enhance the fields in the well. Scattering effects are taken into account by designing the quantum well so that upon excitation carriers will escape in a short time compared to the time it takes to scatter back into the well. Despite this constraint, a quantum efficiency of 90% is shown to be possible for a GaAs-AlGaAs quantum well with a carrier density of 1012 cm−2.
Structural characterization of GaInAs(P)/InP quantum well structures grown by gas source molecular beam epitaxy
Authors: Vandenberg J. M. , Hamm R. A. , Macrander A. T. , Panish M. B. , Temkin H.
Published: July 2002

We have carried out an x-ray study of 20-well quaternary InGaAsP/InP and ternary InGaAs/InP structures grown on [100]InP by gas source molecular beam epitaxy (GSMBE). The multilayers were found to grow laterally coherent and very closely lattice matched in the [100] growth direction. The presence of well-defined higher order harmonics in the high-resolution x-ray diffraction confirms the excellent quality of InGaAs(P)/InP superlattices grown by the GSMBE technique.
Synthesis of Nb3Ga and Nb3Al superconducting composites by laser beam irradiation
Authors: Kumakura H. , Togano K. , Tachikawa K. , Yamada Y. , Murase S. , Nakamura E. , Sasaki M.
Published: July 2002

Nb3Ga and Nb3Al superconductors were successfully fabricated by continuous CO2 laser beam irradiation of a moving material. Transition temperatures after the irradiation are 17.0 and 16.5 K, respectively. These temperatures are increased by ∼2 K by the subsequent annealings. Critical current density Jc (for the reacted area) of 3×104 A/cm2 at 15 T and 4.2 K is obtained for Nb3Al tape with small magnetic field dependence up to 23 T. The results indicate that the continuous laser beam irradiation is a very attractive method for fabricating advanced superconductors, such as Nb3Ga, Nb3Al, Nb3(Al,Ge), etc.
UV laser deposition of metal films by photogenerated free radicals
Authors: Montgomery R. K. , Mantei T. D.
Published: July 2002

Silver, copper, and palladium films have been deposited by UV laser-induced reduction of metal ions in solution. Metal lines have been written and metal pattern generation by projection imaging has been demonstrated.
Single mode magneto-optic waveguide films
Authors: Wolfe R. , Hegarty J. , Luther L. C. , Wood D. L.
Published: July 2002

A novel triple layer film is described which provides single mode propagation in a magneto-optically active waveguide of convenient thickness. All three layers are modified yttrium iron garnet (YIG) films grown by liquid phase epitaxy on a gadolinium gallium garnet substrate. The top film is the active layer, several microns thick. The middle layer is similar but it has a slightly smaller refractive index to assure single mode operation of the top layer. The bottom layer has high optical absorption to eliminate all of the higher order modes which are propagated in the triple layer and a slightly higher refractive index to prevent the confinement of any modes to the top two low loss layers. Using a praseodymium YIG film as the absorbing layer, 17 TE modes were propagated at 1.51 μm where the Pr absorption is low but only the TE0 mode was observed at 1.48 and 1.54 μm where the Pr absorption is high. Such triple layer garnet films will be useful in all magneto-optic waveguide devices.
Molecular beam epitaxial growth of high quality ZnSe on (100) Si
Authors: Park R. M. , Mar H. A.
Published: July 2002

ZnSe films have been grown by molecular beam epitaxy for the first time on argon ion sputtered and annealed (100) Si substrates, the simultaneous sputtering and annealing process being performed at a substrate temperature of 400 °C. The sputtered and annealed Si substrates were atomically clean as determined by Auger electron spectroscopy analysis, and exhibited a streaky, reconstructed (2×1) reflection high-energy electron diffraction (RHEED) pattern. Films grown with both the constituent element (Zn and Se) fluxes set to provide a growth rate of ∼0.6 μm/h at initiation of growth were polycrystalline, the crystallites being strongly oriented in the [111] direction as determined by RHEED observations. Parallel epitaxy, i.e., (100) ZnSe∥(100) Si was achieved when the growth rate at initiation of growth was close to zero. Epitaxial ZnSe films exhibited dominant bound excitonic 4.2 K photoluminescence (PL) emission at 2.788 eV (Iz1). The Iz1 peak was also detected in the PL spectra of polycrystalline films; however, its absolute intensity was reduced by over two orders of magnitude.
One-way, real time wave front converters
Authors: Kwong Sze-Keung , Yariv Amnon
Published: July 2002

Optical one-way, real time wave front cleanup by means of photorefractively pumped oscillators is reported. A factor of 4000 increase in beam brightness has been achieved.
Ion channeling effect of In dopant in semi-insulating GaAs
Authors: Kuriyama K. , Satoh M. , Kim C.
Published: July 2002

The channeling phenomena of undoped and In-doped semi-insulating GaAs grown by the liquid encapsulated Czochralski method have been analyzed by 1.5 MeV 4He+beam. It is suggested that the minimum yield of backscattering particles is affected by the local lattice distortion due to the addition of large amounts of In atoms rather than the difference in dislocation density. It is also indicated that the In atoms of ∼1020/cm3 doped in GaAs occupy substitutional sites within the statistical errors.
High performance HgCdTe photoconductive devices grown by metalorganic chemical vapor deposition
Authors: Specht L. T. , Hoke W. E. , Oguz S. , Lemonias P. J. , Kreismanis V. G. , Korenstein R.
Published: July 2002

Photoconductive detector arrays fabricated from metalorganic chemical vapor deposited epitaxial films of Hg0.8Cd0.2Te on both CdTe and Al2O3 substrates are reported for the first time. These devices operate in the 8–12-μm spectral region and have detectivities of 3.6×1010 and 2.6×1010 cm Hz1/2/W for CdTe and Al2O3 substrates, respectively. These results approach background limited performance, and as such establish the feasibility of metalorganic chemical vapor deposited HgCdTe for use in advanced infrared detection systems.
Optically pumped laser oscillation at 3.9 μm from Al0.5Ga0.5Sb/InAs0.91Sb0.09/Al0.5Ga0.5Sb double heterostructures grown by molecular beam epitaxy on GaSb
Authors: van der Ziel J. P. , Chiu T. H. , Tsang W. T.
Published: July 2002

Double heterostructures consisting of InAs0.91 Sb0.09 active layers with Al0.5 Ga0.5Sb cladding layers were grown by molecular beam epitaxy on GaSb substrates. Optically pumped laser emission at 3.9 μm was observed from 80 to 135 K with an exponentially dependent threshold with T0=17  K. At 80 K the threshold corresponds to an effective current of 4 kA/cm2. This value represents a significant reduction when compared with previous results. For a 1-μm-thick active layer the full angular width of the far field at the half intensity point normal to the junction is 40° and is in reasonable agreement with the width calculated from the guide and cladding refractive indices.
Localized epitaxial growth of MnSi1.7 on silicon
Authors: Lian Y. C. , Chen L. J.
Published: July 2002

Epitaxial MnSi1.7 was grown locally on both (111) and (001)Si. The orientation relationships were found to be [11̄0]MnSi1.7//[111]Si, (220)MnSi1.7//(22̄0)Si and [001]MnSi1.7//[001]Si, (100)MnSi1.7//(400)Si for epitaxy grown on (111) and (001)Si samples, respectively. Three variants of epitaxy, required by the symmetry consideration, were also observed to form on (111)Si. Interfacial dislocations were identified to be of edge type with (1)/(6) 〈112〉 and 1/2 〈110〉 Burgers vectors for epitaxial MnSi1.7 grown on (111) and (001)Si, respectively. The presence of different forms of MnSi1.7 is suggested in view of the important difference in details of diffraction patterns of MnSi1.7 along the [001] direction. The growth of epitaxial MnSi1.7 on silicon has filled the ‘‘gap’’ of the growth of stable phases of silicides of the fourth period transition elements in the periodic table epitaxially on silicon.
Universal expressions of projected range and damage distributions
Authors: Kido Yoshiaki , Kawamoto Junichi
Published: July 2002

Depth distributions of implanted ions and induced defects have been determined by backscattering (including channeling) and nuclear resonance reaction measurements followed by computer-simulated spectrum analyses. The reduced energies cover the range from 0.1 to 5. We demonstrate that the average projected range and average damage depth can be expressed universally as functions of an average reduced energy by introducing a new scaling coefficient. Simple, unified relations of relative range and damage stragglings versus average reduced energy have also been found to hold.
Nonlinear optical coupling to planar GaAs/AlGaAs waveguides
Authors: Chen Y. J. , Carter G. M. , Sonek G. J. , Ballantyne J. M.
Published: July 2002

Nonlinear optical coupling to planar GaAs/AlGaAs waveguides has been observed at 1.06 μm using a grating coupling technique. At an input intensity of 100 MW/cm2, intensity dependent nonlinear switching to the waveguide mode occurs. The results indicate a fast nonlinear response time.
Effects of buffer layers in GaAs-In0.2Al0.8As strained-layer superlattices
Authors: Nakayama M. , Kubota K. , Kato H. , Chika S. , Sano N.
Published: July 2002

Raman spectroscopy has been used to study strains in GaAs-In0.2Al0.8As strained-layer superlattices with a fixed layer thickness (100–100 Å) and various InxAl1−xAs buffer layers [x=0 (GaAs in place of AlAs), 0.1, and 0.2]. Strain-induced frequency shifts of the longitudinal optic phonon modes depend on the alloy composition (lattice constant) of the buffer layer. For the GaAs buffer layer (x=0) the mismatch between the superlattice and the buffer layer is accommodated by dislocations near the interface region, while for the In0.2Al0.8As buffer layer the mismatch is accommodated by the tensile strain in the GaAs layers.
Observation of giant induced voltages in high mobility GaAs-AlxGa1−xAs heterostructures in the quantized Hall regime
Authors: Syphers D. A. , Martin K. P. , Higgins R. J.
Published: July 2002

We report studies on the use of the very low resistivity ( ρxx∼0) of GaAs-AlxGa1−xAs heterostructures in the quantized Hall regime (QHR). It is shown that low-frequency inductive coupling to this system can result in radial charge transport, and is perhaps the first use of the QHR lossless properties free of losses from the Hall resistance ρxy. We show that this effect provides an easy way to measure the value of ρxx throughout a quantized Hall plateau, and the effect of capacitance between contacts is discussed.
Growth of a ZnSe-ZnTe strained-layer superlattice on an InP substrate by molecular beam epitaxy
Authors: Kobayashi Masakazu , Mino Naoki , Katagiri Hironori , Kimura Ryuhei , Konagai Makoto , Takahashi Kiyoshi
Published: July 2002

A ZnSe-ZnTe strained-layer superlattice (SLS) was grown on an InP substrate by molecular beam epitaxy for the first time. The x-ray diffraction measurement technique was used to confirm the existence of the high quality SLS structure. Overall quality may also be inferred from the observed quantum size effects of the photoluminescence data.
Temperature dependence of electron mobility in (InAs)3(GaAs)1 superlattices
Authors: Matsui Y. , Hayashi H. , Yoshida K.
Published: July 2002

(InAs)3(GaAs)1 superlattices have been obtained successfully by the beam separation method of molecular beam epitaxy. The superlattice structure has been confirmed by lattice images and satellite spots of transmission electron microscopy. The electron mobilities of the superlattices are higher than those of InxGa1−xAs alloys at high temperature. The electron mobility of superlattices with the carrier density of 3.3×1017 cm−3 is 6000 cm2/V s at 400 K, which is about 20% higher than that of InxGa1−xAs ternary alloys with higher In mole fraction (x=0.9).
Demonstration of an all-optical associative holographic memory
Authors: Yariv Amnon , Kwong Sze-Keung , Kyuma Kazuo
Published: July 2002

We describe a new type of associative holographic memory and some related results. The memory can retrieve overlapping images which are stored in a volume hologram. The storage and retrieval of more than one image is demonstrated for the first time. The important role of thresholding in assuring ‘‘clean’’ retrieval is demonstrated.
Pump intensity dependent cavity mode frequency shifting in a 12.08 μm NH3 laser
Authors: Mehendale S. C. , Harrison R. G. , Vass A.
Published: July 2002

Experimental and theoretical results are presented for a CO2 laser pumped 12.08 μm NH3 laser which show evidence of pump intensity dependent unidirectional cavity mode frequency shifting rather than conventional frequency pulling. The frequency shifting arises due to the near-resonant nature of lasing in this system and hence should be a common feature of optically pumped lasers involving off-resonant pumping.
Resonance frequencies of a ring fluxon oscillator
Authors: Marchesoni Fabio
Published: July 2002

The behavior of a long ring Josephson transmission line (fluxon oscillator) is analyzed in the presence of a bias dc current. The conditions of stability for fluxon oscillations and the dependence of their frequnecy on both the intensity of the bias current and the radius of the line are determined analytically. A splitting of the fundamental resonance band is predicted to take place in ring fluxon oscillators with finite radius.
Microstructure of high-temperature annealed buried oxide silicon-on-insulator
Authors: Mao B.-Y , Chang P.-H. , Lam H. W. , Shen B. W. , Keenan J. A.
Published: July 2002

The microstructure of buried oxide silicon-on-insulator (SOI) annealed in the temperature range of 1150–1300 °C was examined. The microstructure of the buried oxide SOI was improved by increasing the annealing temperature. The minimum channeling yield of the top silicon layer in 1250 °C annealed SOI measured by Rutherford backscattering and channeling analysis is 5% which is comparable to unprocessed bulk single crystal material. This is further verified by the cross-sectional transmission electron microscopy observation of the precipitate-free top silicon layer with low dislocation density. The improvement in the microstructure is attributed to the dissolution of oxygen precipitates and oxygen outdiffusion during high-temperature annealing.
Variably spaced superlattice energy filter, a new device design concept for high-energy electron injection
Authors: Summers C. J. , Brennan K. F.
Published: July 2002

A new variably spaced superlattice energy filter is proposed which provides high-energy injection of electrons into a bulk semiconductor layer based on resonant tunneling between adjacent quantum well levels which are brought into alignment by an applied bias. Applications of this concept to a variety of optoelectronic devices and to thin-film electroluminescent devices and photodetectors are discussed.
Detection of Ga vacancies in electron irradiated GaAs by positrons
Authors: Hautojärvi P. , Moser P. , Stucky M. , Corbel C. , Plazaola F.
Published: July 2002

Positron lifetime measurements have been used to study the recovery of electron irradiated GaAs between 77 and 800 K. Below room temperature positrons are trapped by vacancies in Ga sublattices. The Ga vacancies recover between 200 and 350 K.
Optimum overlap of electric and optical fields in semiconductor waveguide devices
Authors: Adams M. J. , Ritchie S. , Robertson M. J.
Published: July 2002

The effect of an applied field on the propagation constant of a mode in a semiconductor slab waveguide is examined theoretically. A figure of merit defined as the change of propagation constant with voltage is related to the relative widths of the electrical and optical fields. It is shown that the figure of merit is maximized when the region over which the electric field is applied is minimized, rather than when the two fields have similar profiles. The constraint of electrical breakdown is also discussed with respect to the maximum change in propagation constant.
Selectively buried epitaxial growth of GaAs by metalorganic chemical vapor deposition
Authors: Okamoto Kotaro , Yamaguchi Ko-ichi
Published: July 2002

Selectively buried epitaxial growth of GaAs was attempted by metalorganic chemical vapor deposition using SiO2 films and W/SiO2 films as mask materials. Lateral supply of reactant species from mask areas to grooves occurred, which brought about the dependences of growth rate upon the width and the depth of grooves and produced swells near the groove edges. By use of W/SiO2 masks patterned narrower than 40 μm, grooves were selectively buried by epitaxial layers without accompanying polycrystal deposition on the masks.
First observation of the quantum Hall effect in a Ga0.47In0.53As-InP heterostructure with three electric subbands
Authors: Razeghi M. , Duchemin J. P. , Portal J. C. , Dmowski L. , Remeni G. , Nicholas R. J. , Briggs A.
Published: July 2002

Shubnikov–de Haas and quantum Hall effects have been studied in GaInAs-InP heterojunctions grown by modified low pressure metalorganic chemical vapor deposition. In contrast to the results reported up till now on GaInAs-InP heterojunctions with nearly the same channel electron density, not one but three electric subbands, E0, E1, and E2, are occupied in zero magnetic field. Two electric subbands E0 and E1 contribute to the quantum Hall effect. Magnetic depopulation of the higher (E1 and E2) subbands is observed in both perpendicular and tilted magnetic field orientations. This enables a demonstration of the importance of intersubband scattering in resistivity and cyclotron resonance.
Dry-etched-cavity pair-groove-substrate GaAs/AlGaAs multiquantum well lasers
Authors: Yuasa Tonao , Mannoh Masaya , Asakawa Kiyoshi , Shinozaki Keisuke , Ishii Makoto
Published: July 2002

A fabrication technique based on reactive ion beam etching is presented for the formation of the facet mirrors on GaAs/AlGaAs lasers called pair-groove-substrate (PGS) multiquantum well lasers. Laser cavities with vertical and smooth walls are achieved with this etching technique by using a high-temperature baked photoresist mask. PGS lasers with 200-μm-long etched cavities show a low pulsed threshold current of 29 mA and a high external differential quantum efficiency of 43%. The threshold current is comparable to those of cleaved lasers. Room-temperature cw operation is easily realized in junction-up mounting.
Streak-camera observation of 200-ps recovery of an optical gate in a windowless GaAs étalon array
Authors: Lee Y. H. , Warren M. , Olbright G. R. , Gibbs H. M. , Peyghambarian N. , Venkatesan T. , Smith J. S. , Yariv A.
Published: July 2002

Fast recovery (<200 ps) of an optical gate at room temperature in a GaAs étalon is observed by eliminating the top AlGaAs window and defining 9×9 μm2 pixels. This recovery time is at least an order of magnitude shorter than that for previous étalons consisting of AlGaAs/GaAs/AlGaAs heterostructures. The fast recovery is attributed to faster surface recombination of carriers at the GaAs-dielectric mirror interface as compared to that at a GaAs-AlGaAs interface.
Lateral solid phase epitaxy of amorphous Si films onto nonplanar SiO2 patterns on Si substrates
Authors: Ishiwara Hiroshi , Tamba Akihiro , Furukawa Seijiro
Published: July 2002

Lateral solid phase epitaxy (L-SPE) of amorphous Si (a-Si) films onto nonplanar SiO2 patterns on Si(100) substrates was investigated. The patterns were formed by local oxidation of silicon (LOCOS) and the thickness of the SiO2 films ranged from 60 to 470 nm. The L-SPE characteristics similar to those for planar patterns were observed in dense a-Si films prepared by high-temperature vacuum deposition and subsequent ion implantation. The maximum L-SPE lengths onto the LOCOS patterns were 4.5, 6.5, and 44 μm in undoped, B-doped, and P-doped samples, respectively.
Silicon surface roughness—Structural observation by reflection electron microscopy
Authors: Honda Kouichirou , Ohsawa Akira , Toyokura Nobuo
Published: July 2002

Surface roughness of polished silicon wafers was observed by reflection electron microscopy. Small steps were clearly resolved as fringe pattern, and rather rough steps of 1.2–1.6 nm in height and 200–500 nm in interval were observed as dark and bright bands. This is the first direct visualization of polished wafer surface roughness.
High resolution infrared diode laser spectroscopy for isotope analysis—Measurement of isotopic carbon monoxide
Authors: Lee Peter S. , Majkowski Richard F.
Published: July 2002

A tunable infrared diode laser spectroscopic system for stable isotope analysis has been developed. The system uses (1) a tunable single mode PbTe/PbEuSeTe diode laser and (2) a sample cell with dual path length matched to the expected order of relative isotopic spectral intensities. Because of the unique features of such a system, isotopic molecules with similar mass and vastly different concentrations can readily be detected and measured. The principle and operation of the system are described, and the relative abundance of isotopic carbon monoxide 12C16O, 12C17O, 12C18O has been measured for the first time by a tunable diode laser system.
Point defect kinetics and dopant diffusion during silicon oxidation
Authors: Mathiot D. , Pfister J. C.
Published: July 2002

Using a full calculation including all the couplings between the dopants and the point defects, we show that the transient effect observed at short times for the influence of oxidation on dopant diffusion in Si cannot be explained by the existence of an energy barrier to the recombination of interstitials and vacancies. We suggest that this transient is due to a transient in the self-interstitial injection, due to high strains at the early stage of the oxidation, which can relax later through the viscoelastic flow of the oxide.
Reversible neutralization of boron acceptors by hydrogen in Pd-SiO2-Si capacitors
Authors: Fare T. L. , Lundstrom I. , Zemel J. N. , Feygenson A.
Published: July 2002

A palladium metal-silicon dioxide-silicon (Pd-MOS) capacitor is used to study the reversible injection and extraction of atomic hydrogen from a p-type implanted boron layer on an n-type (1016 phosphorus/cm3) substrate. 0.70±0.03 of the boron acceptors are deactivated by the hydrogen atoms diffusing from the Pd-SiO2 interface, on through the SiO2 and on into the silicon surface region. It is established that the atomic hydrogen can diffuse through a 10-nm-thick thermal SiO2 film. The isothermal uptake and release of atomic hydrogen in the silicon surface are demonstrated. The hydrogen data offer evidence that the boron acceptors and the phosphorus donors form a neutral complex during the processing of the ion implanted boron layer.
Fast imaging of tokamak plasmas with integrated photodiode arrays
Authors: Castracane J. , Demers Y.
Published: July 2002

Images with high temporal and spatial resolution of the resurrector tokamak plasma were obtained. The plasma cross section was focused onto a commercially available 128 pixel photodiode array (active area: 2.5×3.2 mm2). Specially designed data acquisition electronics allowed rapid readout for the observation of the spatial profile of visible emissions with 150 μs time resolution. The breakdown and subsequent evolution of the discharge was monitored to allow improvement of the plasma parameters.
Characterization of beam-recrystallized Si films and their Si/SiO2 interfaces in silicon-on-insulator structures
Authors: Vu D. P. , Pfister J. C.
Published: July 2002

A technique equivalent to the conventional C(V) measurement is developed for silicon-on-insulator technology. A depletion mode transistor is used. The ID(VG) characteristic and its derivative, i.e., the transconductance, allow the determination of the doping of the Si film, the oxide thickness, the fixed oxide charge at both Si/SiO2 interfaces. The device can be used in process control without any extra process steps.
Reformulation of atom location by channeling enhanced microanalysis
Authors: Goo E.
Published: July 2002

The current formulation for atom location by channeling enhanced microanalysis requires three characteristic x-ray spectra and is overdefined [J. C. H. Spence and J. Tafto, J. Microscopy 130, 147 (1983)]. A formulation is presented where only two characteristic x-ray spectra are needed to determine the distribution of substitutional impurity atoms in a layered compound.
Electrical transport of holes in GaAs/InGaAs/GaAs single strained quantum wells
Authors: Fritz I. J. , Drummond T. J. , Osbourn G. C. , Schirber J. E. , Jones E. D.
Published: July 2002

We report electrical transport data for holes in single strained quantum well structures of the type GaAs/InxGa1−xAs/GaAs with x≊0.2. With modulation doping, 4 K mobilities of ∼3×104 cm2/V s have been achieved. This value is near that attained for electrons in comparable structures, illustrating the enhanced transport possible due to the strain-induced light-hole planar mass.
HgTe-CdTe double barrier tunneling structures
Authors: Schulman J. N. , Anderson C. L.
Published: July 2002

Double barrier heterostructures consisting of HgTe-CdTe-HgTe-CdTe-HgTe layers are proposed as providing improved negative differential resistance current-voltage characteristics as compared with similar devices based on the GaAs-GaAlAs system. The small HgTe-CdTe valence-band offset and the inverted light holelike conduction band of HgTe produce intrinsic interface states with long decay lengths in the CdTe barrier layers. This enhances the transmission coefficient and thus the tunneling current. Also, the small offset causes the CdTe barriers to present more blockage to unwanted thermal electron currents than do typical GaAlAs barriers. The high mobility of HgTe reduces the series resistance of the contacting layers, thus reducing the bias voltage required to achieve resonance and increasing the speed of the device. The effectiveness of the structure will depend on the value of the valence-band offset and material quality.
High power coupled CO2 waveguide laser array
Authors: Newman L. A. , Hart R. A. , Kennedy J. T. , Cantor A. J. , DeMaria A. J. , Bridges W. B.
Published: July 2002

A hollow-bore ridge waveguide technique for phase locking arrays of coupled CO2 rf excited waveguide lasers was demonstrated. Stable phase-locked operation of two- and three-channel arrays has been demonstrated at the 50 W output level. Preliminary experiments with a five-element array generated an output power of 95 W but phase-locked operation was not conclusively demonstrated.
Low threshold, optically pumped, room-temperature laser oscillation at 0.88 μm from AlGaAs/GaAs double heterostructures grown by metalorganic chemical vapor deposition on Ge-coated Si substrates
Authors: van der Ziel J. P. , Dupuis R. D. , Bean J. C.
Published: July 2002

Low threshold, optically pumped laser oscillation has been obtained using AlGaAs/GaAs double heterostructures grown on Ge-coated Si substrates. The optical pump power for threshold is comparable to similar heterostructures grown on GaAs substrates. Between 20 and 85 °C the threshold temperature dependence is exponential with T0=160 °C. The laser wavelength and the peak of the spontaneous emission of lasers grown on Si substrates are shifted to longer wavelengths relative to bulk GaAs. This results largely from the strain in the plane of the epilayer produced by the difference in the thermal contraction of the layers and the Si substrate on cooling from the growth temperature.