bluuebunny/crossref_metadata_2025 huggingface dataset:
Propagation loss of the acoustic pseudosurface wave on (ZXt)45° GaAs
Authors: Melloch M. R. , Wagers R. S.
Published: February 2003

Measurements of propagation loss for the leaky surface acoustic wave on (100)-cut GaAs with 〈110〉 propagation direction are reported. The measurements were made in the frequency range 200–900 MHz. The propagation loss was determined with a novel technique using a delay line with four interdigital transducers. The effect of a hydrogen implant of dose 1014 cm−2 and energy 120 keV (technique for producing high resistivity isolation regions in GaAs) on propagation loss and macroscopic piezoelecticity are reported.
Al-Si contacts formed by ion irradiation and post-annealing
Authors: Hung L. S. , Mayer J. W. , Zhang M. , Wolf E. D.
Published: February 2003

Al-Si contacts have been formed by implantation of As ions through Al-Si interfaces followed by heat treatment at 400–500 °C for 10 min. The erosion of Si proceeds uniformly in contact areas at the sintering temperatures. Diodes using Al-Si contacts produced by this technique have been fabricated on thin n+ layers in p-type Si substrates with junction depths of 0.35 μm and contact areas of 5 μm2. The average leakage current per diode (with an approximate junction area of 14×26 μm2) is about 10−8 A, as compared to the leakage current of 10−5 A for diodes with Al-Si contacts prepared by sintering of Al on Si at 420 °C. We attribute the improvement to the uniformity of Si erosion after the interfacial oxide has been dispersed by ion irradiation.
Occupation fluctuation noise: A fundamental source of linewidth broadening in semiconductor lasers
Authors: Vahala Kerry , Yariv Amnon
Published: February 2003

In this letter we consider the effect of fast thermal fluctuations of electronic state occupancy on the field spectrum of semiconductor lasers and derive for the first time an expression for the resulting power independent linewidth contribution. The magnitude and temperature dependence of this linewidth component agree reasonably well with measurements of a power independent linewidth made by Welford and Mooradian.
InP surface states and reduced surface recombination velocity
Authors: Brillson L. J. , Shapira Y. , Heller A.
Published: February 2003

Surface photovoltage and Auger electron spectroscopy studies of ultrahigh vacuum cleaved (110) and chemically treated (110) InP reveal direct optical transitions to and from surface states in the band gap for a wide variety of surface conditions. These states correlate with reported Fermi level pinning behavior but cannot account for the unique reduction in surface recombination velocity at KAg(CN)−2 treated surfaces. This reduction is identified instead with formation of a surface layer which excludes ambient-induced recombination states.
Inversion layers at PbTe interfaces
Authors: Cerrina F. , Daniels R. R. , Fano V.
Published: February 2003

Synchrotron-radiation photoemission experiments directly demonstrate that the creation of an inversion layer is a common feature of the PbTe-Al, PbTe-In, and PbTe-Ge interface formation processes. This phenomenon is interpreted in terms of the experimentally observed adatom-Pb exchange reactions.
New thermal-neutron solid-state electronic detector based on HgI2 single crystals
Authors: Melamud M. , Burshtein Z. , Levi A. , Schieber M. M.
Published: February 2003

The use of HgI2 as a thermal-neutron solid-state electronic detector, in particular its application for neutron diffractometry, is demonstrated for the first time. A single crystal HgI2 detector is used to count prompt gamma emissions (0.2–5 MeV) from (n,γ) nuclear reactions in Gd or Cd foils. The neutron counting efficiency depends on the HgI2 detector thickness. For a 1-mm thickness of HgI2 the efficiency is about 10% compared to the efficiency of a 10BF3 gas detector.
Monolithic integration of a double heterostructure light-emitting diode and a field-effect transistor amplifier using molecular beam grown AlGaAs/GaAs
Authors: Wada O. , Sanada T. , Hamaguchi H. , Fujii T. , Sakurai T.
Published: February 2003

A surface emitting AlGaAs/GaAs double heterostructure light-emitting diode (LED) and an amplifier composed of three GaAs field-effect transistors have been first integrated on a single GaAs substrate. Molecular beam epitaxy has been extensively used to grow a six-layer heterostructure involving a high resistivity AlGaAs layer for electronic isolation. Input voltage to output optical power transfer characteristics are presented. It has also been shown that this integrated device successfully operates at the speed limited by the LED rise time, 7 ns in the present case.
Thermoelastic wave generation by resistive heating in silicon
Authors: Deggendorf Steven E. , White Richard M.
Published: February 2003

We report the piezoelectric detection and thermoelastic signals resulting from resistive heating within a diffused resistor and commercial packaged transistor. cw and pulse experiments at 5 V and 300 kHz, as well as 5-V 10-MHz mixing experiments, result in transducer outputs in the 25 μV–1 mV range. Theoretical values are in good agreement with experimental findings.
Influence of doping on the liquid-amorphous transition induced by picosecond laser irradiation of Si
Authors: Campisano S. U. , Baeri P. , Zhang Jing-Ping , Rimini E. , Malvezzi A. M.
Published: February 2003

The effect of Bi doping on the quench of amorphous Si directly from the melt during 30-ps, 0.53-μm laser irradiation has been studied. The amorphous thickness (45 nm) in Bi implanted samples was observed to increase 50% over the corresponding undoped samples (25 nm). No change in the Bi profile was detected upon amorphization.
Optical loss increase of phosphor-doped silica fiber at high temperature in the long wavelength region
Authors: Uesugi Naoshi , Kuwabara Tsuneo , Koyamada Yahei , Ishida Yukinori , Uchida Naoya
Published: February 2003

The wavelength-dependent loss increase in the long wavelength region is revealed for phosphor-doped silica fiber at a high temperature around 200 °C. The loss increases around 1.3 μm and becomes larger for longer wavelength regions. The loss increase is suppressed by reducing P2O5 dopant concentration. The overtone absorption of Ge–OH at 1.41 μm as well as that of Si–OH at 1.39 μm also increases markedly. The possible origin of the loss increase is discussed.
Rapid thermal annealing of Se and Be implanted InP using an ultrahigh power argon arc lamp
Authors: Masum Choudhury A. N. M. , Tabatabaie-Alavi K. , Fonstad C. G. , Gelpey J. C.
Published: February 2003

A 100-kW water-walled dc argon arc lamp has been used for the first time to post anneal ion-implanted InP samples. Temperatures as high as 925 °C and short cycle times (3 and 10 s) are used for the process. Se and Be were ion implanted into room temperature and hot substrate InP samples. A sputter deposited SiO2 layer, 120 mm thick, covering all wafer surfaces was used as an encapsulant during the lamp anneal. Hot substrate Se implants (400 keV, 1.8×1014 cm−2, 200 °C) show an average mobility of 1415 cm2/Vs and an activation of ∼63%, and room-temperature Be implants (50 keV, 3.35×1013 cm−2 and 150 keV, 5.74×1013 cm−2) an average mobility of 88 cm2/Vs and activation of ∼45%. This annealing technique is straightforward and gives activations and mobilities comparable to, or better than, the best furnace anneals with sharp profiles and simplified surface encapsulation.
Rapid thermal annealing of Be, Si, and Zn implanted GaAs using an ultrahigh power argon arc lamp
Authors: Tabatabaie-Alavi K. , Masum Choudhury A. N. M. , Fonstad C. G. , Gelpey J. C.
Published: February 2003

The use of a 100-kW water-walled dc argon lamp to anneal ion-implanted GaAs is reported. Annealing cycles of 3 and 10 s and peak temperatures from 950 to 1200 °C have been used to anneal Be, Si, and Zn implanted following representative implant schedules of technological importance. It is demonstrated that this technique is superior to conventional furnace anneal techniques in terms of the doping profiles, peak carrier concentrations, activation efficiencies (particularly at high doses), and mobilities achieved. The annealing technique should be applicable to large volume GaAs integrated circuit production and 100-mm-diam wafers can be annealed in a single exposure with better than 2% temperature uniformity (Si data).
Control of mutual phase locking of monolithically integrated semiconductor lasers
Authors: Kapon E. , Katz J. , Lindsey C. , Margalit S. , Yariv A.
Published: February 2003

The mutual coherence of two coupled semiconductor lasers is investigated experimentally. It is demonstrated that by varying the gain in the overlap region, the degree of phase coherence can be continuously controlled. The quantitative characterization of the degree of phase coherence by fringe visibility is demonstrated.
Twisted double-heterostructure GaAs-(AlGa)As laser
Authors: Sugino Takashi , Wang Shyh
Published: February 2003

A novel laser structure in which a terraced substrate laser and a channeled substrate laser are connected is fabricated. The active layer of the composite cavity is twisted in the junction area between the two laser cavities. Internal reflection and polarization change occur in the twisted region. A built-in refractive index variation is formed by the terraced substrate and the channeled substrate structures. Remarkable characteristics of the laser are a low threshold current of 40 mA, a stable fundamental transverse-mode and single longitudinal-mode oscillation, and a wavelength locking over a temperature range of more than 6 °C.
Transverse second-order mode oscillations in a twin-stripe laser with asymmetric injection currents
Authors: Mukai S. , Yajima H. , Uekusa S. , Sone A.
Published: February 2003

Transverse second-order mode oscillations in asymmetrically pumped twin-stripe lasers are described. Both far-field patterns and near-field patterns have two peaks, and a stronger peak appears on the weakly pumped side. The dependence of light intensity in one peak of the far-field pattern on the current into one stripe shows threshold characteristics. On application of rectangular pulse to one stripe, switching from one peak to the other occurs within 5 ns.
Influence of helium I layer formation on the copper-helium-4 Kapitza resistance at helium II bath temperatures
Authors: Kim Y. I. , Lin Li-He , Chuang C. , Frederking T. H. K.
Published: February 2003

The transient Kapitza resistance between copper and helium II caused by a step input in power has been studied near 2 K. The resistance is affected by formation of a helium I layer whose thickness, of the order 10−4–10−5 cm, is evaluated as a function of the heat flux density.
High-efficiency (21.4%) Ga0.75In0.25As/GaAs (E
g=1.15 eV) concentrator solar cells and the influence of lattice mismatch on performance
Authors: Ludowise M. J. , Dietze W. T. , Boettcher R. , Kaminar N.
Published: February 2003

High-efficiency Ga0.75In0.25As/GaAs concentrator solar cells (Eg=1.15 eV, area=0.32 cm2) have been fabricated and tested at 21.4% efficiency under 380 AM2.4 sun. The cell performance parameters of open-circuit voltage, fill factor, and efficiency are presented as functions of concentration up to 987 sun. The spectral response, and current-voltage characteristics under concentration, of cells grown by organometallic vapor phase epitaxy on graded and ungraded lattice-constant buffer layers are compared. It is shown that a graded lattice-constant buffer layer is necessary for high-efficiency performance. In general, Ga0.75In0.25As cells have higher efficiencies and open circuit voltages than Si cells (Eg=1.11 eV) for concentrations in excess of about 200 sun.
Selective low-temperature mass transport in InGaAsP/InP lasers
Authors: Hasson A. , Chiu L. C. , Chen T. R. , Koren U. , Rav-Noy Z. , Yu K. L. , Margalit S. , Yariv A.
Published: February 2003

A low-temperature mass transport process in InP was investigated. Mass transport of InP was achieved at 570–600 °C in a closed ampoule using iodine or InI as a catalytic transporting agent. Accomplishing the mass transport process at lower temperature has eliminated the problem of thermal etching and resulted in lasers with higher T0.
Influence of an external cavity on semiconductor laser phase noise
Authors: Tamburrini M. , Spano P. , Piazzolla S.
Published: February 2003

Investigation of phase noise in semiconductor lasers allows one to understand the physical processes that influence both the width and the shape of the emission line. Furthermore, the limitations associated with phase noise have to be taken into account when semiconductor lasers are employed in coherent optical communication systems. In this letter we report phase-noise measurements on single-mode semiconductor lasers in the presence of optical feedback. We are able to observe, besides the expected linewidth reduction, a peculiar behavior in the high-frequency region not yet reported in the literature, strongly dependent on the external cavity length.
Nb3Al/oxide/Pb Josephson tunnel junctions fabricated using a CF4 cleaning process
Authors: Tanabe K. , Katoh Y. , Michikami O.
Published: February 2003

Nb3Al/oxide/Pb Josephson tunnel junctions have been fabricated using a new surface cleaning technique, the CF4 cleaning process (CFCP), in which the base electrode is cleaned prior to oxide barrier formation in an Ar and CF4, rf plasma mixture. Adopting lower cleaning voltages than for Nb/oxide/Pb junctions, makes it possible to obtain high-quality junctions with very low leakage (Vm=30 mV) and uniform Josephson current distribution. Such good junction characteristics indicate the formation of damage-free cleaned electrode surfaces and highly insulating mixed oxide barriers.
Stable field electron emission from a tungsten tip under the ultrahigh vacuum of 10−10 Pa
Authors: Oshima C. , Souda R. , Aono M. , Ishizawa Y.
Published: February 2003

A stable field emission from the tungsten tip with axis in the (110) direction has been found under ultrahigh vacuum of 10−10 Pa. The noise of 0.3% under the condition is attributed to the surface migration of impurity atoms and/or tungsten atoms.
High-efficiency Si solar cells by beam processing
Authors: Young R. T. , van der Leeden G. A. , Sandstrom R. L. , Wood R. F. , Westbrook R. D.
Published: February 2003

Utilizing two recently developed beam processing techniques, i.e., gas discharge implantation and XeCl excimer laser annealing, p-n junction silicon solar cells with total area (∼2 cm2) AM1 efficiencies as high as 16.5% have been made. These cells are of a particularly simple structure, fabricated without any sophisticated processing steps, and subjected to no high-temperature treatment.
Effects of doping on transport and deep trapping in hydrogenated amorphous silicon
Authors: Street R. A. , Zesch J. , Thompson M. J.
Published: February 2003

We report a quantitative comparison of the trapping rates of carriers at charged and neutral dangling bonds in hydrogenated amorphous silicon (a-Si:H). The data are obtained from time-of-flight photoconductivity studies of doped and undoped samples. The temperature dependence of the trapping rates, as well as the effect of boron doping on the hole drift mobility, is also reported.
Pressure dependence of the electron capture cross section of the B hole trap in liquid phase epitaxial gallium arsenide
Authors: Barnes C. E. , Samara G. A.
Published: February 2003

A study of the hydrostatic pressure dependence of the electron capture cross section of the B hole trap in liquid phase epitaxial gallium arsenide has revealed that this cross section is strongly affected by pressure. The results are consistent with, and provide support for, the multiphonon emission model for the capture process at this trap.
Electrochromism for organic materials in polymeric all-solid-state systems
Authors: Hirai Yoshihiko , Tani Chizuka
Published: February 2003

This letter reports a new electrochromic polymeric film system consisting of a polymer, an electrochromic (EC) dye which is pyrazoline or tetrathiafulvalene (TTF), and lithium perchlorate (LiClO4). The electrochromic cell structure is glass/ITO/polymeric EC film/Au film. The cell using pyrazoline as an EC dye exhibited yellow coloration at 1.0 V and the cell with TTF exhibited red coloration at 3.5 V. These cells exhibited memory.
Electrical characteristics of Be-implanted GaAs diodes annealed with an ultrahigh power argon arc lamp
Authors: Tabatabaie-Alavi K. , Masum Choudhury A. N. M. , Kanbe H. , Fonstad C. G. , Gelpey J. C.
Published: February 2003

The potential of arc lamp annealing techniques in GaAs device processing is demonstrated by the fabrication of Be-implanted mesa pin diodes. Implants were done at 50 and 120 keV with doses of 4.4×1014 and 5.1×1014 cm−2, respectively (total dose =9.5×1014 cm−2) into a 14-μm-thick undoped (ND−NA≊7.5×1014 cm−3) GaAs epitaxial layer grown by vapor phase epitaxy. Ten-second annealing cycles with peak temperatures of 950° and 1050 °C have been studied. The electrical characteristics of these diodes are superior to published furnace-annealed, Be-implanted GaAs diodes.
Observation of rapid field aided diffusion of silver in metal-oxide-semiconductor structures
Authors: McBrayer J. D. , Swanson R. M. , Sigmon T. W. , Bravman J.
Published: February 2003

Fast electric field aided diffusion of silver in SiO2 has been observed for fields of 104 V/cm and temperatures as low as 275 °C. The diffusion coefficient of silver in SiO2 is estimated to be 10−13 cm2/s at 300 °C, with an activation energy of 1.24 eV. The consequences of Ag contamination in very large scale integrated metallization systems are discussed.
Heterojunction formation in (CdZn)S/CuInSe2 ternary solar cells
Authors: Ahrenkiel Richard K. , Kazmerski L. L. , Matson R. J. , Osterwald C. , Massopust T. P. , Mickelsen R. A. , Chen W. S.
Published: February 2003

The electrical properties of (CdZn)S/CuInSe2 solar cells have been investigated by combining electron beam induced current measurements and capacitance-voltage measurements on the same device. In the as-grown device, the CuInSe2 is lightly doped n type. After baking to about 225 °C in vacuum, the CuInSe2 converts to p type forming the heterojunction. Oxygen does not appear to be necessary for type conversion to occur.
1.0-GHz thin-film bulk acoustic wave resonators on GaAs
Authors: Kline G. R. , Lakin K. M.
Published: February 2003

This letter reports on a new fabrication technique and experimental results obtained on bulk acoustic wave resonators using thin piezoelectric composite films of A1N on GaAs insulating substrates. The fabrication involves only a wafer top side planar processing compatible with integrated circuit technology. Resonators have been made in the frequency range UHF to 1 GHz in order to demonstrate the fabrication technique and evaluate material performance in resonator devices. Both longitudinal and shear wave resonators have been measured with temperature coefficients of −24 and −26.5 ppm/°C, respectively. Shear wave results were obtained from tilted c-axis films grown in a dc planar magnetron sputtering system.
Single mode operation of 1.5-μm cleaved-coupled-cavity InGaAsP lasers
Authors: Temkin H. , van der Ziel J. P. , Linke R. A. , Logan R. A.
Published: February 2003

Single longitudinal mode operation of cleaved-coupled-cavity lasers formed by recleaving of 1.5-μm InGaAsP buried crescent lasers is investigated as a function of bias current, temperature, and modulation frequency. The two-cavity lasers are made to operate in a stable single mode by adjusting the bias levels of the electrically isolated and optically coupled sections. The wavelength stability with temperature results in a change of only 0.48 Å/°C over a range of 14 °C. Single mode operation is preserved under direct modulation at rates as high as 1 Gb/s. The reduction in linewidth and the absence of partition noise makes these lasers useful for optical transmission through highly dispersive single mode fibers.
Crystalline correlation of epitaxial Si films with underlying spinel films in Si/(MgO Al2O3) spinel/Si structure
Authors: Egami Koji , Mikami Masao , Tsuya Hideki
Published: February 2003

Using epitaxial magnesia spinel (MgO Al2O3) films on (100) Si, heteroepitaxial Si films (0.6–3 μm) on these substrates are obtained by a conventional chemical vapor deposition method. The crystallinity of both epitaxial Si and spinel films was investigated by x-ray diffraction techniques. Silicon film quality becomes more perfect on thinner spinel films with smoother surfaces in the range of more than ∼0.1 μm, in spite of the spinel crystal perfection becoming inferior with decreasing film thickness. These results are discussed in terms of the spinel surface roughness effect on Si nuclei coalescence.
Photochemical vapor deposition of undoped and n-type amorphous silicon films produced from disilane
Authors: Inoue Takeshi , Konagai Makoto , Takahashi Kiyoshi
Published: February 2003

Hydrogenated amorphous silicon films have been deposited by mercury photosensitized decomposition (photochemical vapor deposition: photo-CVD) of disilane at a substrate temperature below 300 °C. The structural and optical properties of undoped films are very similar to those of films deposited by rf glow discharge decomposition. The electronic property measurement shows that the conductivity strongly depends on the substrate temperature during deposition. The photoconductivity reaches 5.7×10−3 (Ω cm)−1 (AM1,100 mW/cm2) at a substrate temperature of 200 °C. The dark conductivity is 10−6–10−8 (Ω cm)−1 and the Fermi level is located near the middle of the gap. n-type doping has been also achieved by adding phosphine as an impurity to disilane. Furthermore, a p-i-n a-Si solar cell was fabricated using photo-CVD undoped and P-doped films. The initial cell showed a conversion efficiency of 4.39% under AM1 insolation.
Spatial melt instabilities in radiatively melted crystalline silicon
Authors: Celler G. K. , Robinson McD. , Trimble L. E. , Lischner D. J.
Published: February 2003

Strongly nonplanar melting of polished and oxidized single crystalline silicon heated by intense incoherent light is reported. Although irradiation is uniform, the surface breaks up into an array of distinctly faceted molten segments separated by solid unmelted regions. The melt depth can have a sawtooth appearance and is always nonuniform. We show that initiation of melting at discrete sites must be caused by the presence of a nucleation barrier and that the phase coexistence is sustained because of the difference in light coupling to the solid and to the liquid Si. Faceting of the molten regions is then a simple, although rarely observed, consequence of melting from inside the crystal. We also show that phase coexistence at the irradiated surface assures steady-state heat flow in the samples over a wide range of input powers.
Relaxation time broadening on emission spectrum of a Zn-doped p-type GaAs injection laser
Authors: Yamada Minoru , Tanaka Akira , Moriya Kiyoshi , Kado Yuichi
Published: February 2003

Spontaneous emission and lasing gain profiles of semiconductor injection lasers which have Zn-doped GaAs active regions were experimentally determined, and the tailing phenomenon into the band gap of these profiles was theoretically explained as a result of relaxation time broadening due to scattering of electrons and holes. Especially, the tail of the gain profile was found to show a concave shape, which was better explained by the relaxation time broadening model than by the band tail state model.
Hydrogen content of thermally nitrided thin silicon dioxide films
Authors: Habraken F. H. P. M. , Evers E. J. , Kuiper A. E. T.
Published: February 2003

The hydrogen content of thermally nitrided silicon dioxide films (20–120 nm thick) was measured by means of the resonant nuclear reaction 1W(15N, αγ)12C. Although the hydrogen concentration in these films amounts to 1–3 at. %, no significant diffusion of hydrogen into the underlying silicon was observed. The hydrogen concentration is largest in the thinnest oxide films: nitridation at 1000 °C results in a higher hydrogen content than at 800 or 1160 °C. Although the exact shape of the in-depth hydrogen profile, especially in the surface and interface regions, could not be clearly resolved, the detected amount of incorporated hydrogen is such that only part of it can be bonded to nitrogen atoms. Hydrogen must also be incorporated as water, molecular hydrogen, Si–H or O–H groups, a fact which must play a role in the observed changes in electrical behaviour upon nitridation of thin silicon dioxide films.
Comment on ‘‘Lattice location of chromium in semi-insulating GaAs by ion channeling techniques’’ [Appl. Phys. Lett. 4
2, 599 (1983)]
Authors: Pronko P. P. , Bhattacharya R. S. , Holland O. W. , Appleton B. R.
Published: February 2003

A comment on lattice location of chromium by ion channeling and detection of x-ray signals of Cr-Kα excited by 1-MeV H+ from a Cr-doped GaAs is presented.
Monolithic optoelectronic integration of a GaAlAs laser, a field-effect transistor, and a photodiode
Authors: Bar-Chaim N. , Lau K. Y. , Ury I. , Yariv A.
Published: February 2003

A low threshold buried heterostructure laser, a metal-semiconductor field-effect transistor, and a p-i-n photodiode have been integrated on a semi-insulating GaAs substrate. The circuit was operated as a rudimentary optical repeater. The gain bandwidth product of the repeater was measured to be 178 MHz.
Triple ion implantation technique for formation of shallow n
p
n bipolar transistor structures in silicon
Authors: Tsaur B-Y. , Woodhouse J. D.
Published: February 2003

Shallow-emitter, narrow-base npn bipolar transistor structures have been obtained by implantation of B+ and As+ ions into amorphous Si layers formed by the prior implantation of Si+ ions. Thermal annealing results in recrystallization of the amorphous layers by solid phase epitaxy and activation of the implanted dopant atoms. Emitter-base junction depths and base widths of ∼0.10 μm, as determined by secondary ion mass spectroscopy analysis, have been achieved both for single-crystal Si samples and for samples with poly-Si emitter contacts. Transmission electron microscopy shows that the recrystallized layers are almost free of defects near the emitter-base and base-collector junctions. Discrete bipolar transistors with good electrical characteristics have been fabricated using this technique.
Intensity-dependent photobleaching in thin polymer films by excimer laser: Lithographic implications
Authors: Sheats James R.
Published: February 2003

Strongly intensity-dependent photobleaching was observed in polymethyl methacrylate films doped with acridine and irradiated by a KrF laser. The transmission of low intensity pulses (<2 MW/cm2) increased from <0.01% to 60% as the intensity of a single prior bleaching pulse increased from 3 to 4 MW/cm2. The implications of this result for image enhancement in excimer laser projection photolithography are discussed: features in the region of 0.2–0.3 μm may be printable by such techniques.
Effects of mercury and krypton on the glow discharge decomposition of disilane
Authors: Kenne Jean , Konagai Makoto , Takahashi Kiyoshi
Published: February 2003

The effects of mercury and krypton on the glow discharge decomposition of disilane have been studied. It is found that mercury-sensitized plasma decomposition of disilane yields higher deposition rate hydrogenated amorphous silicon (a-Si:H) films. At a deposition rate as high as 60 Å/s no change was observed on the dark and photoconductivities. A similar effect was obtained in krypton-sensitized plasma decomposition of disilane.
A novel technique to fabricate GaInAsP/InP buried heterostructure laser diodes
Authors: Imanaka K. , Horikawa H. , Kawai Y. , Sakuta M.
Published: February 2003

A chemical etching process to obtain a double heterostructure of InP-GaInAsP-InP with a very narrow active layer width is proposed in which three layers are etched preferentially. The quaternary layer works as the inner etching mask; the cladding layers above and below the active layer show reversed-mesa and normal-mesa shapes, respectively. The method is used to fabricate a buried heterostructure laser which lases at 1.3 μm on the p-type InP substrate. The fundamental lateral mode operation with threshold current as low as 15 mA is achieved with 0.8-μm active layer width.
High field performance of superconducting magnets using powder metallurgy processed Cu-Nb-Sn and Nb-Al
Authors: Zaleski A. J. , Foner S.
Published: February 2003

Small superconducting magnets were fabricated with powder metallurgy processed Nb-Al wire and with powder metallurgy processed multistrand Cu-Nb–Sn wire with 19 tin cores. Tests in a background field of up to 15 T showed that short sample characteristics were achieved for three coils. Upper limits of resistivity were established for both powder metallurgy processed wires. The reacted wires in the magnets gave upper limits of resistivity at 10 T of less than 1.4×10−14 Ω cm for the Nb3Sn wire, and less than 9×10−13 Ω cm for the Nb-Al wire.
Optical recording applications of reactive ion beam sputter deposited thin-film composites
Authors: Hebard A. F. , Blonder G. E. , Suh S. Y.
Published: February 2003

Metal/metal oxide and metal/metal nitride thin-film composites (metal=In,Cu) have been prepared by reactive ion beam sputter deposition (RIBSD) and incorporated into antireflection trilayer structures. The RIBSD technique produces thin, homogeneous films whose complex index of refraction can be reproducibly varied. We find the In/InOx composite to have extremely favorable characteristics for optical recording, such as an optimized 0.25-nJ threshold sensitivity, a reflection contrast ratio higher than 60, and good environmental stability. Repeated write-erase cycles have demonstrated a fast reversible phase change which occurs without noticeable degradation in reflection contrast.
Amorphous and metastable phases formation in Au-Ge bilayers by ion beam mixing
Authors: Chu Te-Chang , Cannavò S. , Rimini E. , Campisano S. U.
Published: February 2003

Amorphous alloys have been produced by Ar+ beam irradiation of Au-Ge thin-film bilayers. Two different average compositions have been detected for implantation at 80 or at 300 K, respectively. Each amorphous phase decomposes into a crystalline one after aging at room temperature for several hours. The composition and structure of such crystalline phases are also controlled by the irradiation temperature. Prolonged annealing at 45 °C produces precipitation of pure Au and Ge respectively. The metastable crystalline phase formed at LN2T irradiation is tetragonal and has a composition range close to the χ phase formed after splat cooling technique. The room temperature phase has instead an hexagonal structure.
Electrolytical diffusion of antimony in silicon
Authors: Ruiz J. C. , Martínez J. L. , Urías Jesús
Published: February 2003

Experimental results for the electrodiffusion of antimony into 〈111〉 p-type silicon through thin SiO2 films are reported. C-V plots of metal-oxide-semiconductor capacitors show that n-p junctions are formed by the electrochemical process. The electrolytical doping profile is determined from C-V data in the depletion regime and it shows that the amount of antimony impurity ions in silicon can be controlled by means of the current-time product of the electrodiffusion process.
Heat treatment induced redistribution of vanadium in semi-insulating GaAs:V
Authors: Kütt W. , Bimberg D. , Maier M. , Kräutle H. , Köhl F. , Bauser E.
Published: February 2003

The redistribution and diffusion of vanadium in V-doped high resistivity bulk as-grown GaAs, in V-doped GaAs ion implanted with V, and in high purity epitaxial layers grown on top of V-doped substrates upon various thermal annealing processes are compared to that of Cr using secondary ion mass spectrometry. The thermal processes studied are typical for GaAs IC technology. V diffuses by one order of magnitude less than Cr in all cases investigated. Thus, from thermal stability point of view V-doped GaAs substrates should be superior to Cr-doped ones and probably also to the present so-called ‘‘undoped’’ ones containing 1016 cm−3 EL2 compensators.
Power dependence of the linewidth enhancement term in semiconductor lasers
Authors: Elsässer W.
Published: February 2003

The theory of the spectral linewidth of a single longitudinal laser mode is re-examined on the basis of a phase diffusion model. The contribution to the linewidth resulting from the coupling of phase and amplitude (self-coupling term described by the enhancement factor α) is investigated exactly. In particular, the commonly used approximation of a small spontaneous emission rate and/or strongly damped relaxation resonance is not applied. The self-coupling then results no longer in a constant enhanced slope in the Schawlow-Townes formula. The enhancement linewidth itself is now no linear function of the inverse optical power and decreases to zero in the limit of high spontaneous emission rates and small optical power. Therefore, deviations from the linear dependence of the mode linewidth on mode power are predicted.
Further characterization of the 4.4-μm 13C 16O2 cascade laser
Authors: Johnson R. P.
Published: February 2003

Nine distinct rotational laser lines of the ([10° 1]I–[10° 0]I) vibrational band of 13C 16O2 near 4 μm have been observed and identified. Wavelength measurements of these lines are given as well as a simplified design for a CO2 cascade laser resonator.
Ultrahigh frequency operation of ion-implanted GaAs metal-semiconductor field-effect transistors
Authors: Feng M. , Kanber H. , Eu V. K. , Watkins E. , Hackett L. R.
Published: February 2003

High-performance, ion-implanted GaAs metal-semiconductor field-effect transistors for operation in the frequency range 10–60 GHz have demonstrated noise figures of 1.15 dB at 12 GHz and 1.63 dB at 18 GHz. A single-stage amplifier has demonstrated a noise figure of 2.8 dB with 8.3-dB associated gain at 30 GHz and a gain of 6 dB at 60 GHz.
Self-confined metallic interconnects for very large scale integration
Authors: Bartur M. , Nicolet M-A.
Published: February 2003

A novel method to produce narrow metallic lines is presented. Lines of NiSi2 lithographically formed on SiO2 substrates are oxidized. The formed SiO2 layer consumes most of the Si from the silicide, leaving a metallic Ni line fully confined by SiO2. The associated problems together with the potential utilization are discussed.
Resonance ionization spectroscopy measurement of vapor pressure of rubidium iodide
Authors: Capelle Gene A. , Jessup Donald A. , Borella Henry M. , Franks Larry A.
Published: February 2003

Resonance ionization spectroscopy has been used to measure vapor pressure data for a solid (RbI) to very low pressures. A pulsed UV laser was used to dissociate RbI molecules in the vapor phase established over a sample at known temperature. The rubidium atoms were then ionized by a two-step process using a dye laser tuned to either of two allowed transitions in the ground-state atomic Rb system. These measurements have extended the RbI vapor pressure versus temperature curve approximatelly 10 orders of magnitude below previously reported experimental data. Although this experiment is limited to RbI, the technique is applicable to a wide variety of solids, both atomic and molecular.
Current-voltage and capacitance-voltage characteristics of a metal/Al0.5Ga0.5As/GaAs capacitor
Authors: Drummond T. J. , Fischer R. , Arnold D. , Morkoç H. , Shur M. S.
Published: February 2003

The dependence of current and capacitance on gate voltage for a metal/Al0.5Ga0.5As/GaAs capacitor is reported as a function of temperature between 300 and 77 K. The capacitor has an Al Schottky gate, a 400-Å-thick layer of Al0.5Ga0.5As as an insulator, and a 1-μm-thick layer of n−-GaAs on an n+-GaAs substrate. I-V and C-V data were used to estimate the accumulation layer density under forward bias to be as high as 1×1012 cm−2. In a certain range of temperatures resonant Fowler–Nordheim tunneling was observed. The tunneling current was strongly temperature dependent due to the temperature dependence of the Fermi level at the Al0.5Ga0.5As/GaAs interface. The results obtained indicate that for an appropriate choice of parameters it should be possible to fabricate field-effect transistors based on such a structure suitable for high-speed operation at 77 K.
Distributed Bragg reflector lattice-matched Pb1−xSnxTe/PbSeyTe1−y diode lasers
Authors: Kapon Eli , Zussman A. , Katzir A.
Published: February 2003

Distributed Bragg reflector (DBR) lattice-matched Pb1−xSnxTe/PbSeyTe1−y diode lasers were fabricated using liquid phase epitaxy. These DBR lasers were operated within a limited range of heat-sink temperatures 8.5–38 K, and the threshold current density at 20 K was ∼3 kA/cm2. Single longitudinal-mode operation was obtained up to more than three times the threshold current. The DBR lasers exhibited continuous tuning over a relatively wide range of ∼6 cm−1 near 775 cm−1 (12.9 μm). The average tuning rate was 0.21 cm−1/K, and it was much smaller than the rate for corresponding Fabry–Perot lasers, which was 2.3 cm−1/K.
Low-loss GaInAsP buried-heterostructure optical waveguide branches and bends
Authors: Johnson L. M. , Liau Z. L. , Groves S. H.
Published: February 2003

Low-loss GaInAsP buried-heterostructure waveguide branches and bends have been demonstrated using a novel etch and liquid phase epitaxial regrowth technique. Branching losses as low as 0.4 dB at 1.3-μm wavelength for a 1° branch have been achieved. The measured waveguide propagation loss is ≤1.5 cm−1.
Minority-carrier injection annealing of electron irradiation-induced defects in InP solar cells
Authors: Yamaguchi M. , Ando K. , Yamamoto A. , Uemura C.
Published: February 2003

The first observation of minority-carrier injection annealing of radiation-induced defects in InP is reported. Minority-carrier injection due to both forward bias application and light illumination at room temperature after electron irradiation is shown to enhance defect annealing in p-InP and to result in the recovery of InP solar cell properties. These results suggest that most InP-based devices under minority-carrier injection mode operation conditions are more radiation resistant than any other material-based devices.
Temperature dependence of the threshold current of an InGaAsP laser under 130-ps electrical pulse pumping
Authors: Liu Pao-Lo , Heritage J. P. , Martinez O. E.
Published: February 2003

We have measured the temperature dependence of the threshold current of an InGaAsP injection laser pumped by 130-ps electrical pulses. By comparing the data with the empirical rule Ith=I0 exp(T/T0), we have observed a T0 of 148 K. The results indicate that we can partially separate carrier depletion processes, e.g., spontaneous radiative, Auger, or other nonradiative recombination, and carrier leakage from the fast stimulated emission process, hence, eliminate their effect on the temperature stability of the threshold current.
Operation of cleaved-coupled-cavity Pb-salt diode lasers in the 4–5-μm spectral region
Authors: Linden Kurt J. , Reeder Robert E.
Published: February 2003

We have demonstrated operation of a cleaved-coupled-cavity (C3) diode laser of PbS1−xSex in the 4–5-μm infrared spectral region. It was possible to obtain improved laser mode control by adjusting the modulator section current. Reproducible single mode operation with 1.5 mW of cw output power at 175 mA of laser current (power efficiency of 3.5%) was observed. A single mode tuning range of 2.16 cm−1 was obtained at a lower power value. Laser frequency tuning rates were found to be significantly reduced by use of modulator current tuning as opposed to laser current tuning. The observed results suggest that the C3 Pb-salt laser may provide a much greater degree of mode control than has been possible with single-cavity lasers.
Characterization of surface defects using a pulsed acoustic laser probe
Authors: Jungerman R. L. , Khuri-Yakub B. T. , Kino G. S.
Published: February 2003

A pulsed acoustic laser probe is used to measure vertical acoustic displacements in the near field of surface defects. A method of optically determining acoustic reflection coefficients in the time domain is presented. The spatial variation of acoustic displacements over a slot is modeled with a static theory. This theory estimates a depth of 230 μm for a 250-μm-deep slot. A near field image of a fatigue crack demonstrates an application of the technique.
Josephson tunnel junctions with chemically vapor deposited polycrystalline germanium barriers
Authors: Kroger H. , Jillie D. W. , Smith L. N. , Phaneuf L. E. , Potter C. N. , Shaw D. M. , Cukauskas E. J. , Nisenoff M.
Published: February 2003

High quality Josephson tunnel junctions have been fabricated whose tunneling barrier is polycrystalline germanium chemically vapor deposited on a NbN base electrode and covered by a Nb counterelectrode. These junctions have excellent characteristics for device applications: values of Vm (the product of the critical current and the subgap resistance measured at 2 mV and 4.2 K) ranging between 35–48 mV, ideal threshold curves, a steep current rise at the gap voltage, and Josephson current densities from 100 to 1100 A/cm2.
Location of Te in epitaxially regrown Si layers
Authors: Dézsi I. , Van Rossum M. , Langouche G. , Coussement R. , Schroyen D. , Wu M. F.
Published: February 2003

Single crystal of Si was implanted with 125mTe along (100) direction with a dose of 2×1015 atoms/cm2. The epitaxial regrowth was studied by Mössbauer spectroscopy. The symmetry around the Te atoms was found to be lower than cubic after oven annealing.
Plasma-assisted epitaxial growth of GaSb in hydrogen plasma
Authors: Sato Yasushi , Matsushita Koichi , Hariu Takashi , Shibata Yukio
Published: February 2003

Plasma-assisted epitaxy (PAE) has been applied to grow GaSb films at substrate temperatures as low as 340 °C. A hydrogen plasma can reduce the density of residual impurities and/or defects. The hole concentration and Hall mobility of an undoped GaSb layer deposited in a hydrogen plasma at a substrate temperature of 410 °C on a GaAs (100) substrate are about 6×1016 cm−3 and 750 cm2/Vs, respectively, which are comparable to those obtained by other methods like molecular beam epitaxy, metalorganic chemical vapor deposition etc., in spite of a lower substrate temperature in PAE.
Epitaxial regrowth of silicon implanted with argon and boron
Authors: Delfino M. , Milgram A. , Strathman M. D.
Published: February 2003

The epitaxial regrowth of silicon implanted with both argon and boron is performed by isochronal furnace and cw laser annealing. Argon is found to enhance the thermal anneal threshold for boron-silicon reordering, while itself exhibiting essentially no redistribution after annealing. Boron, by comparison, increases the solid-phase regrowth velocity and prevents the outdiffusion of argon. Based on these findings, a methodology for forming and preserving shallow boron junctions is suggested.
Surface-energy-driven secondary grain growth in ultrathin (<100 nm) films of silicon
Authors: Thompson C. V. , Smith Henry I.
Published: February 2003

Growth of grains with sizes many times (>50×) larger than the film thickness and with uniform (111) texture, has been achieved in ultrathin (<100 nm) films of Si on SiO2. Growth of these secondary grains is driven by minimization of anisotropic surface energy. As a result, the secondary grain growth rate increases with decreasing film thickness. The time required for growth of large secondary grains decreases with increasing temperature.
Low power transverse optical bistability near bound excitons in cadmium sulfide
Authors: Dagenais M. , Winful H. G.
Published: February 2003

We report the observation of cw transverse optical bistability without power hysteresis at 1-mW power levels in uncoated cadmium sulfide platelets. Optically induced refractive index changes as large as 0.15 are deduced from measurements of the transverse spatial ring profile.
Band-to-band luminescence of ion-implanted InP after rapid lamp annealing
Authors: Kirillov D. , Merz J. L. , Kalish R. , Ron A.
Published: February 2003

Room-temperature band-to-band luminescence is studied to evaluate the results of rapid lamp annealing of ion-implanted InP. Because of the high sensitivity of luminescence to the presence of low concentrations of deep level defects, this technique may be used successfully to characterize the quality of the annealed layers. Heat pulse annealing of SiO2-capped samples at 950 °C results in material that is better than that obtained by oven annealing, with no sign of surface decomposition.
Multiplexing the bistable boundary layer liquid crystal display
Authors: Senft Donna Cowell , Boyd Gary D. , Thurston R. N.
Published: February 2003

Shorter switching times in liquid crystal devices are traditionally achieved by raising the switching voltage. However, one of the limitations in multiplexing the boundary layer display is the necessity to keep the rms switching voltage Vs on the not-yet-selected pels below a critical threshold voltage Vth that would hold them in an asymmetric state and prevent switching. By using a periodic square wave to simulate a sequence of bipolar switching pulses, we show that their orienting effect in a ‘‘dual-frequency’’ liquid crystal can be prevented by simultaneously applying a voltage at a higher frequency where the dielectric anisotropy is negative. This permits Vs>Vth, and in principle allows faster multiplexing. The goal of increased speed was not achieved in our simulation experiment due to the inherently slow response of the dual-frequency material used. Nevertheless, the demonstrated scheme will be advantageous when faster dual-frequency materials are developed.
Extreme-ultraviolet and x-ray emission and amplification by nonrelativistic electron beams traversing a superlattice
Authors: Kaplan A. E. , Datta S.
Published: February 2003

High-energy electrons emit resonant electromagnetic radiation when passing through a spatially periodic medium. It is conventionally assumed that ultrarelativistic electron beams are required to obtain significant emission. We demonstrate theoretically the feasibility of exploiting solid-state superlattices with short spatial periods to obtain both spontaneous and stimulated emission in the extreme-ultraviolet and soft x-ray range using nonrelativistic beams.
Recrystallization of silicon film on insulating layers using a laser beam split by a birefringent plate
Authors: Aizaki Nao-aki
Published: February 2003

20-μm-wide, 1-mm-long, single-crystal Si films on SiO2 have been produced using a cw Ar laser beam split by a birefringent quartz plate. The single-scan recrystallized region width has been widened by multiple beam splitting. The resultant single-crystal region obtained by multiple scan from the seed is a 90-μm-wide and 100-μm-long area with rare grain boundaries. This split beam method uses the stable and highly efficient TEM00 mode and needs no prepatterned antireflection layers.
Ion beam oxidation for Josephson circuit applications
Authors: Pei S. S. , van Dover R. B.
Published: February 2003

Niobium-niobium oxide-lead Josephson tunnel junctions have been fabricated using reactive ion beam oxidation. High quality junctions were obtained using a low beam voltage without cooling the sample to 77 K during oxidation. A Vm∼20 mV was achieved routinely at a beam voltage of 100 V and Vm≳30 mV at 67 V. Furthermore, excellent critical current uniformity was demonstrated using a 10-cm Kaufman ion source with substrate motion implemented. A standard deviation in the critical current of 0.5% was obtained among three hundred and fifty 30×30 μm windowed junctions laid out over an area of 1.1×0.34 cm.
dc getter sputtered amorphous GdCo films: Magnetic anisotropy and in-depth chemical composition
Authors: Hong M. , Gyorgy E. M. , Bacon D. D.
Published: February 2003

dc getter sputtering was used to deposit amorphous GdCo films. No bias voltage was applied to the substrates during the deposition. A uniform chemical composition throughout the depth of the film was observed using Rutherford backscattering spectrometry. These GdCo films show perpendicular magnetic anisotropy. Furthermore, the magnetic anisotropy can be well described by a uniaxial film whose easy axes are distributed within a range of 15° around the film plane normal.