Low Temperature Plasma‐Enhanced Epitaxy of GaAs

Abstract

Low temperature (⩽450°C) deposition of single‐crystal using a new plasma‐enhanced MO‐CVD technique is reported. In this technique, plasma is created by a dc potential and the substrate is not directly exposed to the plasma. Deposition of was achieved at extremely low plasma power (0.3–0.5 W/cm2) using trimethylgallium (TMGa) and arsine (or trimethylarsenic) reactants. The resulting epitaxial films show excellent surface morphology and thickness uniformity over a large area substrate. A linear dependence of growth rate upon TMGa concentration was observed with a typical growth rate of 0.1 μm/min for a TMGa flow rate of 15 ml/min. Undoped films were found to be n‐type with a room temperature mobility in the range of 5200 cm2 V−1 · s−1. Measurements on Schottky barrier devices fabricated on n/n+ layers show uniform impurity doping profiles. Temperature dependence of the diode capacitance indicates a density of deep trapping centers as low as .