A study for anodic oxide films of GaAs by radioactivation analysis

Gallium arsenide was anodically oxidized in a mixture of ethylene glycol an d tartaric acid as an electrolyte. The numbers of Ga and As atoms in the an odic oxide films and in the used electrolytes were measured by radioactivat ion analysis. During the anodic oxidation, GaAs dissolved into the electrol yte. The numbers of Ga and As atoms that dissolved into the electrolytes wa s proportional to the anodic voltage, and the number of Ga atoms in the ele ctrolyte was about five times more than that of As atoms. The composition o f the anodic oxide films varied with depth. However, the atomic profiles me asured by Auger electron spectroscopy displayed As atoms much less than Ga atoms throughout the anodic oxide films, because Ga oxides were lost from t he anodic oxide films into the vacuum during the Auger electron spectroscop y, accompanying sputtered thin film removal.