SEGREGATION OF AS ON GAAS(100) SURFACE DURING ABRASION PROCESS STUDIED BY X-RAY PHOTOELECTRON-SPECTROSCOPY AND AUGER-ELECTRON SPECTROSCOPY

When a GaAs(100) surface was mechanically scribed by a diamond tip in an ultrahigh vacuum (UHV), surface segregation of As was observed usin g X-ray photoelectron spectroscopy (XPS) and Auger electron spectrosco py (AES). The same phenomenon was also seen when the surface was abrad ed in air using emery paper. In the latter case, angle-resolved XPS an alysis of As3d and Ga3d spectra showed the formation of As-As bonds on the abraded surface. Ga-Ga bonds existed beneath the layer of As-As b onds isolated from Ga-As bonds. The mechanism of the surface segregati on of As is discussed.