ANGER ELECTRON-SPECTROSCOPY ANALYSIS OF THE FIRST STAGES OF THERMALLYSTIMULATED OXIDATION OF GAAS(100)

The first stages (exposures < 10(4) L) of thermally stimulated oxidati on of GaAs(100) have been studied using Auger electron spectroscopy an d principal component analysis. We compare the GaAs oxidation processe s taking place at high (700 K) and room temperatures, and during simul taneous electron bombardment and oxygen exposure. We found that while at room temperature, GaAs oxidizes via a one-phase process involving t he simultaneous oxidation of Ga and As, the high temperature process i s characterized by the presence of two different GaAs oxide phases. Th e first phase involves the simultaneous oxidation of Ga and As while i n the second, only Ga oxides are formed. On the other hand, under simu ltaneous 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. (C ) 1998 Elsevier Science B.V. All rights reserved.