Auger electron spectroscopy analysis of the first stages of thermally stimulated oxidation of GaAs(100)

The first stages (exposures <104 L) of thermally stimulated oxidation of GaAs(100) have been studied using Auger electron spectroscopy and principal component analysis. We compare the GaAs oxidation processes taking place at high (700 K) and room temperatures, and during simultaneous electron bombardment and oxygen exposure. We found that while at room temperature, GaAs oxidizes via a one-phase process involving the simultaneous oxidation of Ga and As, the high temperature process is characterized by the presence of two different GaAs oxide phases. The first phase involves the simultaneous oxidation of Ga and As while in the second, only Ga oxides are formed. On the other hand, under simultaneous oxygen exposure and electron irradiation, two different oxide phases appear, both of them exhibiting the same features of the room temperature process, i.e., the simultaneous oxidation of Ga and As.