Characterization of GaSb anodic oxide grown in a solution of 3% tartaric acid and ethylene glycol using XPS and ellipsometry

A chemical depth profile of anodic oxide on GaSb, which was grown in a solution of 3% tartaric acid and ethylene glycol with pH approximate to 2, was investigated by using the XPS and ellipsometry. The constant current anodic oxidation was not able to control the oxide thickness by the terminating voltage at which the oxidation was finished. The oxidized gallium was distributed uniformly throughout the oxide layer, but showed an increase near the oxide-semiconductor interface. The oxide antimony in the oxide layer was less than the oxide gallium and showed a decrease near the interface. Small pile-up of elemental antimony was also detected at the interface.