Effect of GaAs or Ga<i>x</i>Al1−<i>x</i>As oxide composition on Schottky-barrier behavior

Abstract

The electrical behavior of GaAs and other Schottky barriers is known to be affected by the presence of an oxide layer, but little is known of the effect of the oxide composition on the electrical characteristics (i.e., I-V and C-V). In this study, the surfaces of GaAs and AlxGa1−xAs were prepared in H2O, H2O2, and NH4OH, and electrical measurements were made of these Schottky barriers. The surface composition of these samples was studied with Auger electron spectroscopy and compared to the electrical behavior of the Schottky barriers. The presence of measurable amounts of As oxides in the oxide layer resulted in soft I-V characteristics. However, samples with predominantly Ga2O3 oxide layers (i.e., small amounts of As oxides) were found to exhibit more nearly ideal Schottky-barrier behavior, with conduction ideality values from 1.2 to 1.4.