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

Abstract

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.