Dependence on doping type (<i>p</i>/<i>n</i>) of the water vapor oxidation of high-gap Al<i>x</i>Ga1−<i>x</i>As

Abstract

The oxidation (H2O vapor+N2 carrier gas, 425–525 °C) of high-gap AlxGa1−xAs of different doping types (p and n) is characterized by oxide depth measurements utilizing scanning electron microscopy. The conductivity type is found to affect significantly the oxidation rate, with p-type samples oxidizing more rapidly than n-type samples. Classical oxidation theory is employed to explain these phenomena which are related to the position of the Fermi level in the samples.