Auger electron spectroscopy studies of nitridation of the GaAs(001) surface

Abstract

Auger electron spectroscopy has been used to investigate the processes taking place during the initial stages of nitridation of the As-stabilized GaAs(001)-2×4 surface by active nitrogen species generated by a radio-frequency plasma source. The results of analysis of the spectral shape of core-level Auger electron signals from Ga, As, and N, as well as dependencies of the intensities of those signals on the duration of nitridation combined with reflection high-energy electron diffraction results show that nitridation occurs in two distinct steps: the first step (with duration of only a few minutes) being the formation of 1 ML of nitrogen (partially mixed with arsenic) on the surface, and the second stage being the formation of the disordered GaAsN phase, which may be the GaAsxN1−x surface phase. The subsequent thermal annealing for several minutes at 600 °C leads to the desorption of arsenic and the resulting crystallization of the GaAsN phase into a cubic GaN layer of about 20 Å thickness.