bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron-beam-induced current measurements in silicon-on-insulator films prepared by zone-melting recrystallization
Authors: Maby E. W. , Atwater H. A. , Keigler A. L. , Johnson N. M.
Published: February 2003

Enhanced diffusion of arsenic along grain boundaries and subboundaries in zone-recrystallized silicon-on-insulator films has been measured by electron-beam-induced current analysis of lateral pn junctions fabricated in the films. A four-hour diffusion at 1100 °C resulted in protrusions of arsenic at the junction edges which measured approximately 3–5 μm along the grain boundaries and only 1–2 μm along the subboundaries. The results suggest that under more ordinary thermal processing conditions, field-effect transistors with channel lengths greater than about 1.5 μm can be randomly positioned with respect to the more numerous subboundaries, but grain boundaries should be avoided.
Acoustic and optical-phonon-limited mobilities in  p-type silicon within the deformation-potential theory
Authors: Szmulowicz Frank
Published: February 2003

The deformation-potential theory of Bir and Pikus, for the hole-optical phonon scattering, has been extended for the treatment of nonparabolic bands and combined with the theory of Tiersten, for the hole-acoustic phonon scattering, to calculate phonon-limited mobilities in  p-type silicon. The mobilities were calculated without the relaxation-time approximation from solutions of the full Boltzmann equation, with accurate hole wave functions and valence-band dispersions. Only the hole-optical phonon deformation-potential parameter was adjusted to yield agreement with transport data at room temperature; other experimental input was fixed. This represents the first such calculation for silicon. The conductivity and Hall mobilities, and the Hall factor, are in very good agreement with most of the available experimental data. The agreement between experiment and theory is significantly better than that attained by earlier calculations.
Double ion exchanged chirp grating lens in lithium niobate waveguides
Authors: Warren Christopher , Forouhar Siamak , Chang William S. C. , Yao S. K.
Published: February 2003

An integrated optical chirped grating lens has been produced which exhibits high throughput efficiency (75%) and large angular field of view (3°). The waveguide substrate is x-cut lithium niobate, and ion exchange in benzoic acid is the method used for making the lens and the waveguide.
Ultrasonic modulation of persistent spectral holes in crystals
Authors: Lengfellner H. , Gosnell T. R. , Tkach R. W. , Sievers A. J.
Published: February 2003

Persistent IR spectral holes in KI:ReO−4 and in RbI:ReO−4 crystals have been both modulated and erased with 10-MHz ultrasound. This mechanical modulation of the hole depth leads to a new phase-insensitive optical detector for ultrasonic waves in solids.
Spatial resolution of thermal wave microscopes
Authors: Inglehart L. J. , Grice K. R. , Favro L. D. , Kuo P. K. , Thomas R. L.
Published: February 2003

It is demonstrated theoretically and confirmed experimentally that the intrinsic spatial resolution of a thermal wave microscope in the extreme near field limit is independent of thermal wavelength and is determined by the depth of the thermal scatterer beneath the surface of the specimen.
Photodeposition of aluminum oxide and aluminum thin films
Authors: Solanki R. , Ritchie W. H. , Collins G. J.
Published: February 2003

Uniform films of Al2O3 have been photodeposited using an excimer laser operating at 248 nm (KrF) or at 193 nm (ArF) and trimethylaluminum and N2O as the reactants. Deposition rates were typically 2000 Å/min and the physical, chemical, and electrical properties of the photodeposited Al2O3 films are comparable to films deposited using conventional techniques. Properties of photodeposited aluminum films are also presented.
Laterally seeded regrowth of silicon over SiO2 through strip electron beam irradiation
Authors: Hayafuji Y. , Yanada T. , Usui S. , Kawado S. , Shibata A. , Watanabe N. , Kikuchi M. , Williams K. E.
Published: February 2003

We have studied the laterally seeded regrowth of polycrystalline Si film over SiO2 islands through the use of a very narrow strip electron beam of a high-energy density. A 0.5-μm polycrystalline Si film was deposited over the entire surface of wafers on which SiO2 islands, 30–100 μm wide and 2 cm long, had been formed. A stationary electron beam 60 μm×3 cm was focused on the wafer surface with an average energy density of 0.7 MW/cm2 at 10 kV. The wafers were irradiated for 0.1–2 ms while moving at a speed of up to 500 cm/s past the beam. A transmission electron microscopic analysis showed that the laterally seeded regrowth of Si films over SiO2 islands were realized successfully and that the regrowth film which covered the SiO2 islands resulted in a quasi-single-crystal film with small-angle boundaries. The average speed of the front of the lateral regrowth over the SiO2 was estimated to be about 200 cm/s.
Wavelength multiplexing of 1.31-μm InGaAsP buried crescent laser arrays
Authors: van der Ziel J. P. , Temkin H. , Logan R. A.
Published: February 2003

A monolithic array of five noninteracting buried crescent lasers has been optically multiplexed using an external cavity with a grating as a dispersive element. The lasers have a center to center separation of 8 μm, and with an external cavity consisting of a 4-mm focal length lens and a 600-line/mm grating used in second order, the lasers emit at ≊1.31 μm in essentially single longitudinal modes separated by 19.6 Å. Single longitudinal mode operation has also been obtained using a cleaved coupled cavity (C3) laser array. In this case the dominant mode is determined by the coherent interference of the mode spectrum of the two subcavities.
Charge trapping instabilities in amorphous silicon-silicon nitride thin-film transistors
Authors: Powell M. J.
Published: February 2003

The most important instability mechanism in amorphous silicon-silicon nitride thin-film transistors is charge trapping in the silicon nitride layer, which leads to a threshold voltage shift (ΔVT). We have measured the time, temperature, and gate voltage dependence of ΔVT and conclude that the rate limiting process, in the charge transfer from semiconductor to insulator, is the conduction in the nitride by variable-range hopping. The threshold shift (under positive bias) is temperature dependent with an activation energy of 0.3 eV. This activation energy is identified with the mean hop energy required to inject charge deep into the silicon nitride at the low applied fields appropriate to transistor operation.
Nb3Sn-Pb Josephson tunnel junctions using patterned rf sputtered material and rf oxidation
Authors: Tsuge H. , Houck L. L. , Nordman J. E.
Published: February 2003

Josephson tunnel junctions have been fabricated using standard photolithography and rf plasma oxidation on rf sputtered Nb3Sn films. Good quality Nb3Sn surfaces have been obtained by evaporating a Sn layer of 50–70 nm on the Nb3Sn films and annealing at 800–850 °C in a high vacuum. The measured energy gap values for the Nb3Sn films are between 3.0 and 3.1 meV. The subgap resistance is more than six times the normal resistance. A significant improvement in tunnel characteristics can be achieved by using this surface treatment process on sputtered Nb3Sn films.
Electronic excitation in electron bombardment enhancement of chemical reactions
Authors: Ashby C. I. H.
Published: February 2003

The role of electronic excitation in the electron bombardment enhancement of surface reactivity of graphite with hydrogen has been identified. The correlation between the electron and photon enhanced reactivities of a graphite surface is consistent with electrons exciting the 4.8-eV Π-valence to Π-conduction transition responsible for photoenhanced reactivity. An electron impact study has shown that low-energy electrons excite the same low-energy transitions observed in optical studies. Secondary electrons produced by electron bombardment are of appropriate energies to excite these transitions. Similar processes are expected to be operative in other chemical systems exhibiting photoenhanced reactivity.
Shock wave pressure enhancement using short wavelength (0.35 μm) laser irradiation
Authors: Trainor R. J. , Holmes N. C. , Anderson R. A. , Campbell E. M. , Mead W. C. , Olness R. J. , Turner R. E. , Ze F.
Published: February 2003

Shock velocities in planar aluminum targets irradiated at 0.35- and 1.06-μm laser wavelengths have been measured. Absorbed intensities of ∼1.0×1014 W/cm2, produced by 700-ps full width at half-maximum Gaussian pulses, generated shock pressures of 1.0±0.2 and 0.6±0.2 TPa, respectively, demonstrating an enhancement of shock pressure at decreased laser wavelength.
Radical species in argon-silane discharges
Authors: Robertson R. , Hils D. , Chatham H. , Gallagher A.
Published: February 2003

SiHn radical densities at the surface of discharges in Ar-SiH4 mixtures have been measured by low-energy, electron-collisional ionization and mass spectrometer detection of SiH+n. The principal radical seen at the substrate surface of a dc proximity discharge is SiH3.
Correlation among secondary ion mass spectrometry, cross-section transmission electron microscopy, and Rutherford backscattering analyses for defect density and depth distribution determination
Authors: Wilson R. G. , Sadana D. K. , Sigmon T. W. , Evans C. A.
Published: February 2003

Correlation is found between the relative densities and depth distributions of defect clusters/disorder/damage measured by cross-section transmission electron microscopy and Rutherford backscattering and silver atom depth distributions measured by secondary ion mass spectrometry for (100) and (111) silicon implanted with silver ions and annealed at 550 °C.
Photoacoustic determination of thermal diffusivity of solids: Application to CdS
Authors: Cesar C. L. , Vargas H. , Filho J. Mendes , Miranda L. C. M.
Published: February 2003

A novel and simple approach, which uses a lateral heating source for the sample, is proposed as an alternative method for the photoacoustic determination of the thermal diffusivity of solids. The method is experimentally tested using a CdS sample.
Characteristics of Schottky diodes with microcluster interface
Authors: Schneider M. V. , Cho A. Y. , Kollberg E. , Zirath H.
Published: February 2003

We present experimental evidence that a single Schottky diode on GaAs is an agglomorate of paralleled microjunctions with different barrier heights and saturation currents. The current-voltage characteristic of the cluster breaks up into sections of exponentials with different slopes as one cools the diode from 300 to 10 K. Noise measurements performed on cooled diodes at 4 GHz also confirm that a single device is a cluster of paralleled diodes.
Wideband frequency conversion in the UV by nine orders of stimulated Raman scattering in a XeCl laser pumped multimode silica fiber
Authors: Pini Roberto , Salimbeni Renzo , Matera Manlio , Lin Chinlon
Published: February 2003

Efficient wideband frequency conversion of the UV XeCl excimer laser wavelength has been accomplished by stimulated Raman scattering in a multimode UV silica fiber. Nine Stokes orders have been generated in the 308–350-nm spectral region at 650-kW input power.
Low-loss integrated optical waveguides fabricated by nitrogen ion implantation
Authors: Naik I. K.
Published: February 2003

A technique for fabricating low-loss (on the order of 0.1 dB/cm) integrated optical waveguides in amorphous SiO2-based material by nitrogen ion implantation is reported. By comparing the results of nitrogen implantation and oxygen implantation in SiO2, the mechanism of waveguide formation in the nitrogen-implanted waveguides is shown to be chemical doping effect of the nitrogen dissolved in amorphous SiO2.
Optical recording media with thermal coloration
Authors: Morinaka Akira , Oikawa Shigeru , Yamazaki Hiroki
Published: February 2003

Laser recording on novel optical recording media with thermal coloration is reported. The basic recording mechanism is thermally induced chemical reaction between a coloring reagent and a coupling reagent that are deposited in vacuum, separated by a light absorbing layer. Transmittance changes on a 1-μm size recording pit have been observed by writing with a laser diode at 830 nm. This medium is colored blue, red, or black by selecting a coloring reagent layer. It is applied to multicolor recording by accumulating units of media.
Localized wet-chemical etching of InP induced by laser heating
Authors: Bjorkholm J. E. , Ballman A. A.
Published: February 2003

Light at 5145 Å is used to induce rapid localized etching of grooves and holes in InP samples (of all doping types) immersed in aqueous solutions of phosphoric acid. In the absence of light no etching takes place. The process is shown to be thermally activated.
Surface compensation of p-InP as observed by capacitance dispersion
Authors: Ahrenkiel R. K. , Sheldon P. , Dunlavy D. , Roybal L. , Hayes R. E.
Published: February 2003

Very strong capacitance-voltage dispersive effects are observed in mercury/indium phosphide Schottky diodes. These effects are related to a partially compensated region at the surface for which the Debye length is relatively large. The small-signal capacitance is indicative of a critical dielectric relaxation time exceeding the period of the ac probe. This effect may be used to characterize the majority-carrier profile in lightly doped or low mobility semiconductors.
Reduction in the localized band-gap states in amorphous silicon by annealing and hydrogen implantation
Authors: Neudeck G. W. , Lee T. C.
Published: February 2003

The effect of in situ thermal annealing prior to hydrogen implantation is reported on vacuum evaporated amorphous silicon. By performing a 400 °C anneal for 4 h immediately following film deposition the film porosity is greatly reduced. The film is then implanted with hydrogen to a dose of 5×1016/cm2. A field-effect conductance change of six orders of magnitude was observed which yielded a density of localized states near the Fermi level of 4×1017/cm3 eV.
Stable carbide field emitter
Authors: Adachi Hiroshi , Fujii Kiyoshi , Zaima Shigeaki , Shibata Yukio , Oshima Chuhei , Otani Shigeki , Ishizawa Yoshio
Published: February 2003

New experimental results of very stable field emitted electrons from TiC single crystal needles are presented. The optimum flashing temperature region for the stable field emission was found. The stability, which is defined by the ratio of current fluctuation to total current, was better than 0.5% at a vacuum of 10−7 Pa with total electron emission of 1 μA.
Simultaneous measurement of magnetic field direction and ion temperature in a plasma by collective scattering with a CO2 laser
Authors: Kasparek W. , Holzhauer E.
Published: February 2003

The effect of strongly magnetized electrons on the spectrum of collective electron density fluctuations was observed for the first time in a laboratory plasma. A single mode CO2 laser and coherent detection were used to scatter from a hydrogen plasma with the scattering wave vector perpendicular to the magnetic field. The results demonstrate that both the ion temperature and direction of the magnetic field can be measured simultaneously.
Analysis of laser annealed polycrystalline silicon thin-film transistors
Authors: Chen Inan
Published: February 2003

A one-dimensional theory of laser annealed polycrystalline silicon thin-film transistors operating in the inverted enhancement mode is described. The conductance versus gate voltage relations are characterized by two electronic parameters,namely, the charge transferred at zero-gate voltage and the interface state density. In addition to the determination of these parameter values for three actual devices of different doping levels, this analysis also reveals the roles of each parameter and suggests optimal values of these parameters for devices.
Chemical compositions at and near the grain boundaries in bronze-processed superconducting Nb3Sn
Authors: Suenaga M. , Jansen W.
Published: February 2003

The chemical composition of bronze-processed Nb3Sn at grain boundaries and its variation as a function of distance from the grain boundary were determined using Auger electron spectroscopy. The composition at the grain boundary was 44.1, 30.6, and 25.4 at. % for Nb, Sn, and Cu, respectively, and approached to the bulk value (∼75 at. % Nb and ∼25 at. % Sn) at ∼20 Å into the grain, as determined by a depth-profiling method.
New iron-rare-earth based permanent magnet materials
Authors: Hadjipanayis G. C. , Hazelton R. C. , Lawless K. R.
Published: February 2003

The magnetic and structural properties of rapidly quenched FePr(BSi) alloys are presented. The samples are usually magnetically soft in the as-quenched state. However, large coercive fields in the range of 5–20 kOe are developed upon heating the samples to a temperature around 700 °C. The best properties have been obtained on a Fe76Pr16B5Si3 sample with a maximum energy product (BH)m≂12 MGOe. This value is much better than that of AlNiCo and makes these materials outstanding as cobalt-free permanent magnets.
Fundamental linewidth in solitary, ultranarrow output PbS1−xSex diode lasers
Authors: Freed Charles , Bielinski Joseph W. , Lo Wayne
Published: February 2003

The fundamental, quantum phase noise limited Lorentzian linewidth was directly measured from the beat-note spectra generated by heterodyning PbS1−xSex diode lasers with a stable CO gas laser. The experimental results were matched by calculated theoretical line profiles. Linewidths as narrow as 22 kHz full width at half-maximum power were observed.
Generation and detection of millimeter waves by picosecond photoconductivity
Authors: Auston D. H. , Smith P. R.
Published: February 2003

Picosecond photoconductors in the form of dielectric resonators have been used to generate and detect extremely short bursts of millimeter wave radiation at 55 GHz with a repetition rate of 100 MHz. Both the generator and detector are tuned to a frequency which is determined by the length of the photoconducting dielectric resonators. The detector, which is phase coherent, has an estimated noise equivalent power of only 4×10−11 W for an integration bandwidth of 1 Hz, and is capable of resolving time intervals corresponding to a small fraction of one millimeter-wave cycle.
Optical remote monitoring of CH4 gas using low-loss optical fiber link and InGaAsP light-emitting diode in 1.33-μm region
Authors: Chan Kinpui , Ito Hiromasa , Inaba Humio
Published: February 2003

Purely optical remote monitoring of low-level CH4 gas is realized for the first time by the method employing a 2-km long-distance, low-loss silica optical fiber link and a compact absorption cell in conjunction with a high radiant InGaAsP light-emitting diode (LED) at 1.33 μm. Based on the present experiment, the detection limit of CH4 in air was confirmed to be approximately 2000 ppm, i.e., 4% of the lower explosion limit of CH4. This result supports the conclusion that the fully optical remote sensing system incorporating ultralow loss optical fiber networks and near infrared LEDs or laser diodes can be extensively used for the detection and surveillance of various inflammable and/or explosive gases in industrial and mining complexes as well as in residential areas.
Auger voltage contrast depth profiling of shallow p-n junctions
Authors: Pantel R.
Published: February 2003

A contactless measurement technique for electrical depth profiling of very shallow p-n junctions using a scanning Auger microscope is presented. The physical principle is the detection of variations in internal potential via shifts in the Auger peaks. Depth profiling of shallow junctions is realized by ion milling. Deep junctions are more rapidly analyzed via bevelling. For a p-n junction of classical depth (3500 Å), Auger voltage contrast depth profiling is compared with spreading resistance measurements and shown to be an accurate and sensitive means of detecting low concentrations of electrically active impurities (in the 1015 cm−3 range). The main advantage of the method is excellent depth resolution when using ion milling. This is demonstrated for a very shallow p-n junction (400 Å).
Subnanosecond pulsed laser annealing of Se-implanted InP
Authors: Tell B. , Bjorkholm J. E. , Beebe E. D.
Published: February 2003

Indium phosphide implanted with Se+ has been laser annealed with 70 ps pulses at both λ=0.53 and 1.06 μm. For doses of 1×1015 cm−2, activations of ∼70% with peak electron concentrations of 6×1019 cm−3 have been achieved, while for doses of 3×1015 cm−2, activations of 33% with peak electron concentrations of 1.2×1020 cm−3 were measured. The carrier depth profiles for the laser annealed samples are shallow while those for thermal annealing are broad compared to the as-implanted profiles. The morphology of the laser annealed spots is briefly discussed.
Fiber optic pulsed laser holography
Authors: Dudderar T. D. , Gilbert J. A.
Published: February 2003

This study demonstrates that pulsed laser illumination may be used to suppress the ambient motion related instabilities associated with the application of coherent multimode optical fiber image bundles to the recording of remote holograms.
Broadband tuning (ΔE∼100 meV) of Alx Ga1−xAs quantum well heterostructure lasers with an external grating
Authors: Epler J. E. , Holonyak N. , Burnham R. D. , Lindström C. , Streifer W. , Paoli T. L.
Published: February 2003

Alx Ga1−xAs-GaAs quantum well heterostructure laser diodes are shown to be tunable over a 100-meV range when operated continuously (cw) at room temperature in an external cavity with a grating to control feedback. The gain profile of the n=1 and n′=1′ (electron-to-heavy hole and electron-to-light hole, e→hh and e→lh) transitions and the n=2 electron-to-heavy hole transitions are clearly outlined by the intensity profile of the selected laser lines. The partial homogeneous broadening of the gain profile agrees with rapid carrier relaxation in the well. The diodes contain a single 60–90-Å GaAs well and are grown by metalorganic chemical vapor deposition.
Low power optical saturation of bound excitons with giant oscillator strength
Authors: Dagenais Mario
Published: February 2003

The optical saturation of the I2 bound exciton in cadmium sulfide, an exciton bound to a donor, is reported. This system, which decays radiatively in 500 ps, can be saturated with a cw power of only 3.6 μW, which is equivalent to a saturation intensity of 58 W/cm2. Good agreement is found with the predictions of an inhomogeneously broadened two-level system. Thermal effects appear to play a minimal role.
Demonstration of large electron-beam energy extraction by a tapered-wiggler free-electron laser
Authors: Grossman W. M. , Slater J. M. , Quimby D. C. , Churchill T. L. , Adamski J. , Kennedy R. C. , Shoffstall D. R.
Published: February 2003

Electron-beam energy spectral measurements were made on a tapered-wiggler free-electron laser amplifier. A 19-MeV electron beam from a traveling-wave linear accelerator interacted in a tapered wiggler with an intense 10.6-μm CO2 laser beam. The electron spectra show a 4% net energy loss and a 9% peak loss. Measurements of electron energy spectra, extraction efficiency as a function of electron-beam energy, and extraction efficiency as a function of optical power are presented and are consistent with theoretically predicted performance.
Measurement of periodic surface heating using surface acoustic waves
Authors: Stearns R. G. , Khuri-Yakub B. T. , Kino G. S.
Published: February 2003

A new technique is described to measure periodic heating at and near the surface of a material. The technique involves the phase perturbation of a surface acoustic wave propagating through the heated region. Temperature fluctuations can be measured at modulation frequencies of several hertz to hundreds of kilohertz with high sensitivity. A theory is given which predicts the acoustic phase perturbation as a function of thermal modulation frequency, and is shown to agree well with experiment.
A 30-W radio frequency excited waveguide CO2 laser
Authors: He D. , Hall D. R.
Published: February 2003

We describe the design and preliminary performance characteristics of a compact sealed, transverse rf discharge excited waveguide CO2 laser which is capable of output powers of 30 W and a peak efficiency of 13% from a 37-cm discharge length.
Simple mixture rule for the conductivity of a partially ionized gas
Authors: Simpson S. W. , Kovitya P.
Published: February 2003

A mixture rule for calculating the electrical conductivity of a partially ionized gas is described. Simple formulae, suitable for rapid computer evaluation of the conductivity for arbitrary species concentrations, are presented. Calculated conductivities are in good agreement with more sophisticated formulations. The average cross-section data needed to use the mixture rule are given for hydrogen, helium, and argon.
Donor-related microdefects at surface of denuded zone in Czochralski-grown silicon
Authors: Takizawa Ritsuo , Ohsawa Akira , Honda Kouichirou , Toyokura Nobuo
Published: February 2003

Microdefects related to donors in the denuded zone formed after (1200–700 °C) annealing were investigated using spreading resistance, etching, and transmission electron microscope methods. It is found that donors are generated about 1×1014 cm−3 even at the surface of the denuded zone and are closely related to small oxygen precipitates rather than dislocation dipoles corresponding to etch pits. Donor formation at 700 °C annealing is concluded to be concerned with small oxygen precipitates nucleated at embryo sites in addition to carbon sites.
Influence of hydrogen on the performance of magnetron-sputtered amorphous hydrogenated silicon field-effect transistors
Authors: Abdulrida Moafak C. , Allison John
Published: February 2003

The characteristics of amorphous hydrongenated silicon field-effect transistors (a-Si:H FET’s) depend strongly on the partial hydrogen pressure during rf magnetron sputtering of the active material. The density of states near midgap can be reduced to around 8×1016 cm−3 eV−1, and, as a consequence, the on-off drain current ratio increases by more than four orders of magnitude at a gate voltage lower than 15 V. The performance of such FET’s, in particular their output characteristics, is found to be comparable to that of glow-discharge produced devices.
Electron beam assisted chemical vapor deposition of SiO2
Authors: Thompson L. R. , Rocca J. J. , Emery K. , Boyer P. K. , Collins G. J.
Published: February 2003

We have demonstrated electron beam assisted chemical vapor deposition of silicon dioxide films on silicon substrates via electron impact dissociation of SiH4 and N2O gas. Dissociation of reactant gases occurs primarily in the confined planar region of the electron beam created plasma. Electron beam deposited SiO2 films have been categorized in terms of their electrical, physical, and chemical properties.
High-power transverse-discharge Ca+ recombination laser
Authors: Butler M. S. , Piper J. A.
Published: February 2003

Operation of a transverse-discharge-excited Ca+ recombination laser at high He buffer gas pressures (1200 Torr) and high discharge current densities (103 A/cm2) is reported. Single laser pulse energies at λ373.7 nm exceeding 0.7 mJ have been obtained corresponding to specific energy densities over 35 μJ/cm3. There appear to be no fundamental limitations to attainment of pulse repetition rates in the megahertz range.
Acoustic signals from laser-annealed amorphous silicon
Authors: Baltzer N. , von Allmen M. , Sigrist M. W.
Published: February 2003

Acoustic signals generated by Q-switch laser irradiation of amorphous Si have been investigated as a function of incident laser fluence. Marked discontinuities in the signal at the recrystallization threshold and at the damage threshold are found. The results indicate that the first effect is due to melting and the second is due to evaporation.
Extended x-ray absorption fine structure studies of diffused copper impurities in ZnSe
Authors: Goldman A. I. , Canova E. , Kao Y. H. , Fitzpatrick B. J. , Bhargava R. N. , Phillips James C.
Published: February 2003

We have performed the first extended x-ray absorption fine structure investigation of the local environment around dilute copper impurities diffused into the II-VI semiconductor ZnSe. An average first nearest neighbor distance of 2.32±0.06 Å is obtained. Our results indicate a rather large distortion of the local environment surrounding the copper impurities and/or displacement of these impurity atoms from simple substitutional sites (CuZn) and high symmetry interstitial sites (CuI).
Interferometric coupled-waveguide semiconductor laser: Structural optimization and its performance
Authors: Kitayama Ken-ichi , Fattah Ismail H. A. , Wang Shyh
Published: February 2003

Interferometric effect of coupled-waveguide semiconductor laser consisting of two active and passive waveguides is investigated theoretically and experimentally. The structural optimization is made to select and control the longitudinal mode. The test GaAlAs laser shows a single longitudinal operation and good temperature stability of lasing wavelength due to the optimized interferometric effect predicted by the theory.
Photoelectric probing of inhomogeneity in undoped, semi-insulating GaAs crystals
Authors: Mita Yoh , Sugata Sumio , Tsukada Noriaki
Published: February 2003

Photocurrent distribution profiles in undoped, semi-insulating GaAs crystals have been investigated under 1.06-μm laser light irradiation. Results were compared with distributions of leakage current, etch pit density, and optical absorption at the same wavelength. It has been shown that inhomogeneities in undoped GaAs crystals have been observed by this method, which are closely related with etch pit density distribution.
Effect of pH on the production of chalcopyrite CuInSe2 prepared by spray pyrolysis
Authors: Bates Clayton W. , Uekita Masakaza , Nelson Kim F. , Abernathy Cammy R. , Mooney John B.
Published: February 2003

Thin films (∼1 μm) of CuInSe2 were prepared by spray pyrolysis from solutions with various initial Cu:In:Se ratios and in which 75–90% of the acid was neutralized. The substrate temperature was varied between 225 and 300 °C. The chalcopyrite structure dominated the as-sprayed films with 90% of the acid neutralized and 300 °C substrate temperature. At 225 °C all films were sphalerite independent of the degree of acid neutralization. Unlike previous studies which only produced the sphalerite structure in films prepared from unneutralized solutions, the present study indicates that the chalcopyrite phase can be produced in as-sprayed films with a range of initial ratios.
Orientation effect reduction through capless annealing of self-aligned planar GaAs Schottky barrier field-effect transistors
Authors: Sadler R. A. , Eastman L. F.
Published: February 2003

A reduction in the orientation effect on self-aligned ion-implanted planar GaAs Schottky barrier field-effect transistors (FET’s) has been found. The FET’s were fabricated using capless annealing to avoid thermal stress that occurs at a dielectric/GaAs interface during capped annealing. Both mean and standard deviation in FET threshold voltage as a function of gate length are compared for FET’s oriented in the two perpendicular [110] directions. Very little orientation dependence is observed. Similar high-speed switching operation is also found for either orientation. These results indicate that stress-enhanced preferential lateral diffusion which appears to be a major factor in the orientation effect can be reduced through capless annealing.
Photothermal spectroscopy using a pyroelectric thin-film detector
Authors: Coufal H.
Published: February 2003

The application of pyroelectric thin-film transducers for photothermal studies is described. The sensitivity and versatility of pyroelectric detection are demonstrated by spectroscopic studies of neodymium oxide doped poly (methyl methacrylate) films. At energy fluences of less than 10 mJ/cm2, sensitivities of 1014 molecules/cm2 are achieved with a conventional amplitude modulated light source as well as with a pulsed laser. A detector response time of less than 100 ns is observed with pulsed excitation.
Interfacial electromigration of aluminum in thin-film polysilicon/silicide structures
Authors: Lloyd J. R. , Sullivan M. J. , Jozwiak J. L. , Murphy R. J.
Published: February 2003

Electromigration in thin-film polycides of Ta and W was studied. Extrusions formed after several weeks of powering at current densitites of 106 A/cm2 at a temperature of 400 °C. The extrusions were determined to be of aluminum, which had diffused from the wire bonds.
Periodically structured amorphous silicon detectors with improved picosecond responsivity
Authors: Glass A. M. , Liao P. F. , Johnson A. M. , Humphrey L. M. , Lemons R. , Olson D. H. , Stern M. B.
Published: February 2003

Enhanced optical absorption has been obtained in thin (∼30 nm) layers of hydrogenated amorphous silicon by depositing films on periodically structured substrates. At the appropriate angle of incidence, light is coupled to a surface wave in the abosrbing ‘‘artificial dielectric’’ region formed by the structured interface. This effect is used as the basis of high-speed metal a-Si:H metal detectors to overcome the conflicting requirements of high optical absorption and short transit times in thin layers. Peak response as high as 0.16 V is achieved for 50-pJ incident pulses of picosecond duration. This is comparable to that obtained with much higher mobility crystalline semi-insulators.
Variation of intervalence band absorption with hole concentration in p-type InP
Authors: Casey H. C. , Carter P. L.
Published: February 2003

The intervalence band absorption in p-type InP between wavelengths of 1.0 and 3.4 μm was measured at 297 K for hole concentrations from 3.1×1017 to 6.6×1018 cm−3. The absorption coefficient α was found to vary with hole concentration p as α=14(p/1018 cm−3)cm−1 at a wavelength of 1.3 μm and as α=20( p/1018 cm−3) cm−1 at a wavelength of 1.5 μm. For a temperature of 400 K, the absorption has a small increase.
Resonant Fowler–Nordheim tunneling in n−GaAs-undoped AlxGa1−xAs-n+GaAs capacitors
Authors: Hickmott T. W. , Solomon P. M. , Fischer R. , Morkoç H.
Published: February 2003

Periodic structure is observed in the current-voltage characteristics at 4.2 K of n−GaAs-AlxGa1−xAs-n+GaAs capacitors, grown by molecular beam epitaxy, which have AlxGa1−xAs thicknesses of 30–35 nm. The periodicities can be explained quantitatively by the theory of resonant Fowler–Nordheim tunneling.
Paramagnetic trivalent silicon centers in gamma irradiated metal-oxide-silicon structures
Authors: Lenahan P. M. , Dressendorfer P. V.
Published: February 2003

We find that two paramagnetic ‘‘trivalent silicon’’ centers appear to be primarily responsible for radiation damage in metal-oxide-silicon structures.
Pseudomorphic growth of GexSi1−x on silicon by molecular beam epitaxy
Authors: Bean J. C. , Sheng T. T. , Feldman L. C. , Fiory A. T. , Lynch R. T.
Published: February 2003

GexSi1−x layers are grown on Si substrates over the full range of alloy compositions at temperatures from 400–750 °C by means of molecular beam epitaxy. At a given growth temperature films grow in a smooth, two-dimensional manner up to a critical germanium fraction xc. Beyond xc growth is rough. xc increases from 0.1 at 750 °C to 1.0 at ∼550 °C. Rutherford ion backscattering measurements indicate good crystallinity over a wide range of growth conditions. Transmission electron microscopy reveals that in thin films, the lattice mismatch between the GexSi1−x and Si layers can be accommodated by lattice distortion rather than by misfit dislocation formation. This pseudomorphic growth condition can persist to alloy thicknesses as large as l/4 μm.
Transient enhanced diffusion in arsenic-implanted short time annealed silicon
Authors: Kalish R. , Sedgwick T. O. , Mader S. , Shatas S.
Published: February 2003

An anomalous enhanced diffusion is observed when As-implanted Si samples are exposed to rapid heating (∼ seconds) from room temperature to temperatures exceeding 1000 °C. This diffusion can be characterized by a low activation energy of ∼1.8 eV and is active during a very short time (≲ 1 s) probably during the rapid heating up of the sample.
Infrared photodetection in proton-bombarded InP
Authors: Miyoshi T. , Tien P. K. , Martin R. J. , Tennant D. M. , Johnson A. M. , Downey P. M.
Published: February 2003

We demonstrated photodetection in proton-bombarded InP at wavelengths well below the normal band edge of InP (hν<Eg). We used p-type substrates. The proton bombardment served two functions: (1) it converted the bombarded layer into n type, thus, forming p-n photodiodes reported in this letter, and (2) it produced a broad band of absorption extending below the band edge which made photodetection in the infrared possible. Responses up to wavelength of 1.52 μm, a dark current of 3 nA at a bias of −10 V, and a transient response of less than 100 ps (full width at half-maximum) at 1.06 μm have been observed.
Effects of a voltage-dependent light-generated current on solar cell measurements: CuInSe2/Cd(Zn)S
Authors: Eron M. , Rothwarf A.
Published: February 2003

Chopped beam measurements on CuInSe2/Cd(Zn)S solar cells have revealed a failure of the superposition principle, with the light-generated current showing a strong voltage dependence. The light I-V curve can be fully explained with no change in the diode current. The voltage-dependent light-generated current dominates the light I-V curve below Voc, requiring that the analysis of all the traditional solar cell characterization measurements be modified. We have derived the general expressions needed to obtain the diode factor from the light I-V and Voc versus intensity curves. We have also shown how the temperature variation of Voc is affected.
Meyer–Neldel rule in solar cells
Authors: Coutts T. J. , Pearsall N. M.
Published: February 2003

The temperature dependence of the reverse saturation current of a wide variety of solar cells has been examined and the results indicate an interdependence of the activation energy and the pre-exponential factor. This is, in fact, an example of the Meyer–Neldel or thermodynamic compensation law. The physical mechanism responsible for this effect is not understood.
Stimulated emission of GaAs-Al0.6Ga0.4As multiple quantum well structures grown by metalorganic chemical vapor deposition
Authors: Xu Z. Y. , Kreismanis V. G. , Tang C. L.
Published: February 2003

Well correlated stimulated and spontaneous emission peaks corresponding to electronic transitions from the n=1 and 2 subbands of the conduction band to the corresponding states in the valence band of GaAs-Al0.6Ga0.4As multiple quantum well structure grown by metalorganic chemical vapor deposition were observed. No evidence of phonon-assisted transitions was seen in any of our samples.
Iodine ion milling of indium-containing compound semiconductors
Authors: Chew N. G. , Cullis A. G.
Published: February 2003

The effects of reactive I+ ion beams, derived from a source of solid elemental I, on In-containing compound semiconductors have been investigated using transmission electron microscopy. The results are compared with the effects produced by beams of Ar+ and Xe+ inert gas ions. It is shown that the surface accumulation of metallic In due to the disproportionation normally associated with ion milling of these materials can be eliminated by the use of I+ ion beams. Transmission electron microscope specimens in cross-sectional configuration are used to demonstrate the excellent results which may be obtained by I+ ion milling of InP and InSb.
Urea optical parametric oscillator
Authors: Donaldson William R. , Tang C. L.
Published: February 2003

The operation of the first optical parametric oscillator using a urea crystal is reported. Tunable radiation in both the visible and IR was obtained with conversion efficiencies as high as 20%.
Pulsed laser melting of amorphous silicon layers
Authors: Narayan J. , White C. W.
Published: February 2003

We have investigated microstructural changes in self-implanted and arsenic-ion-implanted amorphous silicon layers as a function of energy density after pulsed ruby laser irradiation, using cross-section transmission electron microscopy and Rutherford backscattering. In specimens irradiated with energy densities less than that required to cause complete annealing, we have identified two distinct regions; the first one consisting of fine polycrystals and the second one consisting of large polycrystals. The changes in thickness of these two regions as a function of pulse energy density are described. Concomitant changes in arsenic concentration profiles are consistent with diffusion in liquid silicon. From the profile broadening in the large polycrystalline region, the crystal growth velocity was estimated to be 4–6 ms−1.
Device fabrication by nanolithography and electroplating for magnetic flux quantization measurements
Authors: Kratschmer E. , Erko A. , Petrashov V. T. , Beneking H.
Published: February 2003

100-keV e-beam lithography and electroplating of gold have been used to fabricate a device for the measurement of quantum changes in magnetic flux. The structure is defined in a 200-nm-thick layer of a copolymer of methyl methacrylate and methacrylic acid (PMMA/MAA) on top of a Si wafer covered by 150 nm of Si3N4. The device is a square frame of 2×2 μm2 and 100-nm linewidth. Gold was electroplated to a thickness of 100 nm. This technique allows the fabrication of high resolution, high aspect ratio gold structures.
Theory for cross coupling in ultrasonic transducer arrays
Authors: Baer R. L. , Kino G. S.
Published: February 2003

Ultrasonic transducer arrays suffer from the effects of acoustic cross coupling. The beam pattern and temporal response are degraded. The mechanism for acoustic cross coupling has been postulated to be surface wave propagation along the array. Our theory has shown that surface waves are indeed responsible, and that they may propagate in either the backing or load medium. The new theory is based on an extension to periodic systems of the theory for excitation of a uniform semi-infinite substrate by a single line source. It provides a quantitative model for cross coupling, as well as physical insight into its mechanism.
Crystallographic orientation control of silicon stripes in SiO2 grooves using a new double laser annealing technique
Authors: Egami Koji , Kimura Masakazu , Hamaguchi Tsuneo
Published: February 2003

Crystallographic orientation control using a new double laser annealing of silicon stripes in SiO2 grooves is presented. In the laser recrystallization of silicon stripes in the structure consisting of SiO2 grooves/polysilicon sublayer/quartz glass substrates, first, a part of the Si stripe is intentionally recrystallized by a cw Nd:yttrium aluminum garnet laser to obtain 〈100〉 texture with a small grain size. Next, using these 〈100〉 oriented Si grains as seed crystals, 〈100〉 oriented large Si stripes are obtained by scanning a cw Ar ion laser along the stripe direction. This double laser annealing technique for orientation control can potentially be used to fabricate three-dimensional devices.
X-ray photoelectron spectroscopy study of the chemical structure of thermally nitrided SiO2
Authors: Vasquez R. P. , Hecht M. H. , Grunthaner F. J. , Naiman M. L.
Published: February 2003

X-ray photoelectron spectroscopy has been used to study the composition of 100-Å thermally grown SiO2 films that have been thermally nitrided in ammonia. The SiOxNy/Si interface was studied both by chemical depth profiling of the oxynitride and by removal of the Si substrate with XeF2. It is found that N is distributed throughout the film, but with the concentration higher at the surface and in a region centered 25 Å from the film/substrate interface. The interface region itself is found to be oxygen-rich relative to the rest of the film. Possible models which can explain these results are discussed.
X-ray study on impurity diffusion in a GaAs-AlAs superlattice
Authors: Terauchi H. , Sekimoto S. , Sano N. , Kato H. , Nakayama M.
Published: February 2003

The mechanism of Zn diffusion in a GaAs-AlAs superlattice has been studied by measuring the x-ray satellite intensity. The satellite intensity decreases and its width increases with increasng annealing time. The local structure around Zn atom is discussed.
Polymethyl methacrylate resist sensitivity enhancement in x-ray lithography by i
n s
i
t
u polymerization
Authors: Liu W.-T. , Corelli J. C. , Steckl A. J. , Moore J. A. , Silverman J.
Published: February 2003

X-ray-induced grafting of acrylic acid to poly (methyl methacrylate) (PMMA) increases the resist sensitivity by at least three orders of magnitude. Scanning electron microscopy of grafted PMMA revealed micron and submicron features for dose levels as small as 0.1–1 mJ/cm2, thus demonstrating the possibility of using this technique for x-ray lithography.
80-MW photoconductor power switch
Authors: Nunnally W. C. , Hammond R. B.
Published: February 2003

The application of photoconductors to fast rise time, high-power switching is discussed. We report the successful switching of a 100-kV system to generate a 1.8-kA, <5-ns rise time, 200-ns duration electrical pulse in a 25-Ω load using a single photoconductor switch excited by a Q-switched Nd: glass laser. The photoconductor was a 2.5-cm-long bar of single-crystal, high-resistivity silicon with a 0.5×0.5 cm cross section. Only a depth of about 1 mm of one side was used for conduction.
Preparation and properties of hydrogenated amorphous silicon films by glow discharge decomposition of silane in cascade reactors
Authors: Dixit P. N. , Bhattacharya R. , Panwar O. S. , Shah V. V.
Published: February 2003

A novel and economical method for the preparation of the hydrogenated amorphous silicon films by glow discharge composition of silane in two reactors connected in cascade is presented. Whereas the films obtained from the first reactor have nearly the same dark and photoconductivity as reported in literature, those from the second reactor exhibit four orders less dark conductivity and one order less photoconductivity for the same deposition conditions.
High performance hydrogenated amorphous Si solar cells with graded boron-doped intrinsic layers prepared from disilane at high deposition rates
Authors: Matsushita Tsutomu , Komori Koichiro , Konagai Makoto , Takahashi Kiyoshi
Published: February 2003

High speed preparation of A1/nip/SnO2/indium tin oxide/Glass type amorphous Si solar cells from disilane is presented with emphasis on the boron doping profile during the intrinsic layer deposition. It was found that the cell characteristics strongly depend on the doping level and the profile of B2H6, and 8.05% and 6.85% conversion efficiencies were obtained with a linear graded doping profile at the deposition rates of 15 and 30 Å/s, respectively.
Ultrahigh speed direct coupled logic gate fabricated with NbN/Pb Josephson junctions
Authors: Hatano Y. , Nishino T. , Tarutani Y. , Kawabe U.
Published: February 2003

A chain circuit of direct coupled logic gates consisting of niobium nitride (NbN)-lead (Pb) alloy electrodes has been fabricated. The junctions used were of 1.5 μm square and had a current density of 20 kA/cm2. A special sampling method with jitter of ±1.5 ps was used to precisely measure the short delay time. A minimum logic delay of 5.6 ps/gate has been obtained with a fan in=fan out=1 structure.
Room-temperature cw operation of InGaAsP/InGaP lasers at 727 nm grown on GaAs substrates by liquid phase epitaxy
Authors: Wakao K. , Nishi H. , Kusunoki T. , Isozumi S. , Ohsaka S.
Published: February 2003

InGaAsP/InGaP lasers emitting at 724–727 nm have been fabricated on GaAs substrates using liquid phase epitaxy. The threshold current is reduced to 8 kA/cm2 by thinning the active layer. Room-temperature cw operation is achieved for the first time in the lasing wavelength range below 760 nm in this quaternary system.