WAVEGUIDING IN A DIELECTRIC MEDIUM VARYING SLOWLY IN ONE TRANSVERSE DIRECTION

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Oxynitride films formed by low energy NO+ implantation into silicon

Oxynitride (SiOxNy) insulators have been obtained by low-energy nitric oxide ion (NO+) implantation in Si substrates prior to thermal oxidation. Characterization by Fourier transform infrared (FTIR) and secondary ion mass spectrometry (SIMS) analyses reveal the presence of Si-O, Si-N, and Si-N-O bonds in the high quality 37 nm silicon oxynitride films. The dielectric constant=5.5, effective charge density=7X10(10) cm(-2) and breakdown E-fields of 3 MV/cm were determined by capacitance-voltage (C-V) and current-voltage (I-V) measurements, respectively, indicating that the SiOxNy films formed are suitable gate insulators for metal-oxide-semiconductor (MOS) devices. (C) 1996 American Institute of Physics.69152214221

RAPID THERMAL-DIFFUSION OF SN FROM SPIN-ON-GLASS INTO GAAS

Diffusion of dopants into semiconductors from a spin-on-glass (SOG) source is of great interest because of its versatility, simplicity, and relatively low cost. SiO2 SOG films doped with Sn and/or Ga were used as a diffusion source on GaAs. Diffusion was studied during rapid thermal annealing with or without an As over-pressure ambient, which was produced by either the proximity over-pressure or the enhanced over-pressure proximity techniques. Diffusivity of Sn was observed to decrease as As over-pressure increases. Modifying the Sn doped SOG to contain 4 mole percent Ga slightly reduced the Sn diffusivity. An explanation of these results is proposed based on the chemical reactions between the SOG and GaAs. Highly doped layers (1-3 x 10(18) cm(-3)) with good electron mobility (>1000 cm(2)/V . s) resulting in abrupt shallow junctions (<0.5 mu m) were obtained.14282829283

Evidence of Be3P2 formation during growth of Be-doped phosphorus-based semiconductor compounds

In this work, we present evidence that Be3P2 microcrystals are formed in Be-doped phosphorus-based semiconductor compounds grown by chemical beam epitaxy. Our results suggest that microcrystal formation occurs when high Be concentrations (> 10(18) cm(-3)) and temperatures higher than 500 degrees C are used for crystal growth. The main consequence of Be3P2 formation is a high phosphorus consumption close to these microcrystals that causes a large density of P vacancies in the semiconductor layer. This results in reduced electrical mobility, lattice parameter reduction, and poor crystalinity of the film in general. (c) 1999 American Institute of Physics. [S0003-6951(99)01624-1].74243669367

EVIDENCE FOR HEAVY-ION CHANNELING IN ALGAAS AT LOW ENERGIES

We used a new molecular dynamics simulation program to model the scattering of low-energy ions into the relatively open axial channels of zinc-blende crystals. We also implanted 1-5 keV Si ions into GaAs/AlGaAs multiple-quantum well samples and used secondary ion mass spectrometry and photoluminescence to search for the deep ion penetration and optical damage which are characteristic of this ion channeling. Both the simulated and measured Si depth distributions have exponential tails extending at least 20 times further than the mean ion range. The photoluminescence efficiencies are severely degraded in the quantum wells which are overlapped by the observed Si profile tails. These results suggest that unintentional ion channeling is a major factor in the extensive degradation of optical and electrical properties of semiconductor surfaces which are exposed to low-energy ion bombardment during device fabrication.60131603160

BE INCORPORATION AND SURFACE MORPHOLOGIES IN HOMOEPITAXIAL INP FILMS

We have studied the mechanism of Be incorporation in InP homoepitaxial films grown by metalorganic molecular beam epitaxy. The actual Be concentration in the films reaches 1-2X10(19)cm(-3) while the hole concentration saturates at a lower value (similar to 2X10(18)cm(-3) in our case). The measured lattice mismatch between him and substrate depends both on growth temperature and Be flux. The resulting changes in morphology suggest that the excess Be forms microclusters in the films grown at higher temperatures-due to the higher surface mobility, leading to the growth of oval defects. Be rejection to the surface is also observed. The surfaces of samples with no cap layer present a granulation which may be related to the formation of a new phase like Be3P2. (C) 1995 American Institute of Physics.6781122112

Residual carbon and carrier concentration in InGaP layers grown by chemical beam epitaxy

In this work we present a study on the carbon incorporation in InGaP layers grown by Chemical Beam Epitaxy as a function of growth temperature. Hall measurements show that the electron concentration increased from 2.3 X 10(14) to 8.9 X 10(16) cm(-3) as the growth temperature increased from 500 degreesC to 560 degreesC. Lower growth temperature InGaP layers are more resistive. Using photoluminescence and a carbon-implanted sample, we identify an acceptor level at nearly 45 meV from the top of the valence band. Part of incorporated carbon acts as an acceptor and part as a donor. The electrical and photoluminescence measurements show that the ratio between acceptors and donors increase as the growth temperature decreases. Due to this compensation, samples grown at lower temperatures (500 degreesC) present a resistively 10(4) times higher than those grown at high temperature (560 degreesC). (C) 2003 Elsevier Science B.V. All rights reserved.42941671919