AUGER-ELECTRON SPECTROSCOPY STUDIES OF NITRIDATION OF THE GAAS(001) SURFACE

Auger electron spectroscopy has been used to investigate the processes taking place during the initial stages of nitridation of the As-stabi lized GaAs(001)-2 x 4 surface by active nitrogen species generated by a radio-frequency plasma source. The results of analysis of the spectr al shape of core-level Auger electron signals from Ga, As, and N, as w ell as dependencies of the intensities of those signals on the duratio n of nitridation combined with reflection high-energy electron diffrac tion results show that nitridation occurs in two distinct steps: the f irst step (with duration of only a few minutes) being the formation of 1 ML of nitrogen (partially mixed with arsenic) on the surface, and t he second stage being the formation of the disordered GaAsN phase, whi ch may be the GaAsxN1-x surface phase. The subsequent thermal annealin g for several minutes at 600 degrees C leads to the desorption of arse nic and the resulting crystallization of the GaAsN phase into a cubic GaN layer of about 20 Angstrom thickness. (C) 1998 American Institute of Physics.