Composition and Growth of Thermal and Anodic Oxides on InAlP

Abstract

This chapter presents data on insulating oxides formed on InAlP layers by thermal oxidation at 500º C in moist nitrogen (95º C) or by anodization in sodium tungstate solution. The composition and nature of the oxides are determined by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectroscopy (RBS), and transmission electron microscopy (TEM) and current voltage (IV) measurements on Al-gated capacitors are performed. Thermal oxidation of InAlP layers at 500° C in moist nitrogen produces amorphous, insulating oxide which is a mixture of indium phosphates and aluminum oxide. The oxidation kinetics are parabolic whereas the thickness of anodic oxides increases linearly with potential up to ∼120V. Indium hydroxide and adsorbed hydroxyl ions and adsorbed water are present at the outer surface of anodically grown oxide. Electrical measurements on oxidized capacitors indicate that the thermal oxides have low leakage currents and high breakdown fields, making them potentially useful for some device applications.