Formation of amorphous native oxides by very-low-temperature molecular beam epitaxy and water vapor oxidation

Abstract

A method of preparing amorphous native aluminum oxide layers has been demonstrated. Using amorphous (Ga, As) and (Al, As) layers deposited by molecular beam epitaxy at very low temperatures (∼100°C), amorphous native oxides have been formed on various compound semiconductor substrates by wet oxidation at temperatures as low as 300°C. Extensive wet oxidation of the amorphous (Ga, As)/(Al, As) heterostructures at 400°C results in As loss near the surface of the underlying GaAs substrate. Interface degradation, however, is not observed near the surface of InP and GaP substrates under similar oxidation conditions.