L. R. Thompson

Electron beam assisted chemical vapor deposition of SiO2

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.

X‐ray‐diffraction characterization of silicon‐on‐insulator films

Silicon‐on‐insulator layers produced by the processes of oxygen implantation into single‐crystal silicon substrates, zone melt recrystallization of deposited polysilicon films, and silicon epitaxy on sapphire substrates have been examined by an improved x‐ray‐diffraction technique. The technique incorporates a position‐sensitive x‐ray detector placed on the 2θ arm of a conventional double‐crystal diffractometer, thus allowing the measurement of scattered x‐ray intensity in both the incident and diffracted x‐ray beam angles simultaneously. X‐ray scattering intensity maps plotted in k space reveal the relative strain and mosaic spread of the silicon overlayers with respect to the (001) silicon substrates. Oxygen‐implanted films and graphite strip recrystallized films exhibit mosaic spreads (<±0.08° and ±0.05°, respectively) approaching that of bulk single‐crystal Si. The electron‐beam‐recrystallized films exhibit significantly larger mosaic spreads (≊±0.52°). These silicon overlayer films all exhibit simila...

Cold Cathode Electron Beam Recrystallization of Soi Films

A cold cathode line source electron beam system for forming SOI (Silicon-om-Insulator) films by zone melt recrystallization is described. Possible advantages gained from using a cold cathode electron beam include the controllability of the beam profile and power level, as well as straight-forward scaling to 6 or 8 inch wafers. A computer-based melt width control procedure incorporating feedback to the line intensity from optical observation of the molten zone is also described. This technique allows direct control and adjustment of the melt zone over widths typically from 1 to 3 mm. 5 figs.

Silicon nitride anti-reflection coatings for CdS/CuInSe2 thin film solar cells by electron beam assisted chemical vapor deposition

Abstract The electron beam assisted chemical vapor deposition of silicon nitride anti-reflection coatings onto thin film CdS/CuInSe2 solar cells and the resultant effects on their performance are reported. In some cases large increases in the short circuit current open circuit voltage and fill factor were observed. The present results are explained by the usual index matching anti-reflection mechanisms and either the passivation of undesirable shunts or improvement of intrinsic diode characteristics.

In-situ generated arsine radicals for gallium arsenide homoepitaxy

Removed from the deposition region, an upstream hydrogen microwave plasma generates arsenic hydrides by etching the surface of solid arsenic. The hydrides are transported to the deposition region and mixed with trimethylgallium to achieve low temperature (350°-400°C) and low pressure (750 mtorr) homoepitaxial GaAs films. Low precursor V:III ratios are used to achieve homoepitaxial films with high levels of carbon dopants (l019 to mid 1020 cm−3). No active or afterglow plasma exists in the growth region. The observed homo epitaxial growth activation energies of 54 kcal/mole and 66 kcal/mole for films deposited with V:III ratios of 1:1 and 1:4, respectively, are in the range of those reported for the heterogeneous decomposition of trimethylgallium in the absence of arsine. The films are found to be of good crystalline quality via double crystal x-ray rocking curves. The majority carriers are holes and have hole concentrations that correlate to the carbon doping, as determined by room temperature Hall effect measurements and secondary ion mass spectroscopy. Carrier mobility versus carbon concentration is also presented.

Low pressure and low temperature gallium arsenide homoepitaxy employing in-situ generated arsine

Removed from the deposition region, an upstream hydrogen microwave plasma etches a surface of solid arsenic located downstream to generate arsenic hydrides. The latter are used with trimethylgallium (TMGa) to achieve low temperature (400–490° C) and low pressure (750 mTorr) homoepitaxial GaAs films. No active or afterglow plasma exists in the growth region. The homoepitaxial growth activation energy of 62 kcal/mole is consistent with the heterogeneous decomposition of TMGa in the absence of arsine. Precursor V-III ratios as low as 0.25 are used to achieve homoepitaxial films, but with high levels of carbon impurities (1019 to mid 1020 cm−3). Carbon incorporation increases at low V-III ratios (0.25 to 0.5) for increasing temperatures with an activation energy of 23 kcal/mole. As the V-III ratios are increased above 1.0, the carbon incorporation activation energy decreases slightly to 15 kcal/mole.

Thin Film Deposition By UV Laser Photolysis

An ArF excimer laser was used to photochemically deposit thin films of silicon dioxide, silicon nitride, aluminum oxide and zinc oxide at low temperatures (100-500°C) for microelectronic applications. High depo-sition (>1000 A/Min) rates and conformal step coverage were obtained. The hydrogen bonding, pinhole density, index of refraction, etch rate, and breakdown voltage have been measured for the Si02 and silicon nitride films. The effect of substrate temperature and ArF (193 nm) surface photons on the physical, chemical and electrical properties of Si02 films have been investigated.

Low temperature homoepitaxial growth of GaAs by dissociating trimethylgallium and trimethylarsenic in a remote hydrogen plasma

Abstract A downstream near afterglow plasma was used to deposit epitaxial GaAs at substrate temperatures as low as 300 °C. Feedstock organometallics of trimethylgallium and trimethylarsenic were employed at a ratio of 1:2, respectively. The observed growth rate varies with the substrate temperature, but no growth occurs without the plasma. Scanning electron microscopy electron backscattering was used to probe the single crystal quality of the deposited layers.

Gallium arsenide homoepitaxy employing in‐situ generated arsine radicals

Removed from the deposition region, an upstream hydrogen microwave plasma generates arsenic hydrides by etching the surface of solid arsenic. The hydrides are transported to the deposition region and mixed with trimethylgallium to achieve low temperature (350–400 °C) and low pressure (750 mTorr) homoepitaxial GaAs films. Low precursor V/III ratios are used to achieve homoepitaxial films with high levels of carbon dopants (1019 to mid 1020 cm−3). No active or afterglow plasma exists in the growth region. The observed homoepitaxial growth activation energies of 54 kcal/mole and 66 kcal/mole for films deposited with V/III ratios of 1/1 and 1/4, respectively, are in the range of those reported for the heterogeneous decomposition of trimethylgallium in the absence of arsine. The majority carriers are holes and have hole concentrations which correlate to the carbon doping, as determined by room temperature Hall effect measurements and secondary ion mass spectroscopy. Carrier mobility versus carbon concentration...

Organometallic vapor‐phase homoepitaxy of gallium arsenide assisted by a downstream hydrogen afterglow plasma in the growth region

In situ generated arsenic hydrides are reacted downstream with trimethylgallium (TMGa), both in the presence of and in the absence of a downstream hydrogen afterglow plasma. The homoepitaxial activation energy dramatically changes from 62 kcal/mol for the pure thermal to 21 kcal/mol for the plasma‐assisted growth. The carbon incorporation mechanism for the plasma‐assisted growth at temperatures less than 400 °C has a distinct activation energy for carbon incorporation of 23 kcal/mol, independent of V‐III ratios. At temperatures above 400 °C, the level of carbon incorporated in the films reaches a level that appears to be dependent on the gas‐phase precursor V‐III ratio. The activation energy of the low‐temperature region is consistent with the surface decomposition of arsenic hydrides.