ROOM-TEMPERATURE OXIDATION OF A GAAS(001) SURFACE-INDUCED BY THE INTERACTION OF HYPERTHERMAL ATOMIC OXYGEN AND STUDIED BY X-RAY PHOTOELECTRON-SPECTROSCOPY AND ION-SCATTERING SPECTROSCOPY

In this study a hyperthermal oxygen atom source has been used to form an oxide layer on an Ar+-sputtered GaAs(001) surface at room temperatu re, and this layer has been examined using x-ray photoelectron spectro scopy (XPS) and ion scattering spectroscopy (ISS). XPS data indicate t hat the Ga in the near-surface region is oxidized predominantly to Ga2 O3 with a significant contribution from GaAsO4 while the As is oxidize d predominantly to an AsOx species with significant contributions from As2O3 and GaAsO4 and/or As2O5. The oxide layer thickness is estimated to be about 25 Angstrom, and the XPS Ga:As atom ratio increases from 1.1 to 1.6 during the oxidation. The ISS data indicate that the result ing oxide layer formed is more electrically insulating than a native o xide layer on this surface. (C) 1998 American Institute of Physics.