Auger electron spectroscopy and x-ray photoelectron spectroscopy analysis of angle of incidence effects of ion beam nitridation of GaAs

Abstract

Ion beam nitridation (IBN) of GaAs at room temperature was studied as a function of N2 + ion incident angle at ion energy of 10 keV. The ion beam bombardment surface area of GaAs was characterized in situ by both Auger electron spectroscopy (AES) and small spot-size x-ray photoelectron spectroscopy (XPS). Thin GaN reaction layers are formed at all N2 + ion incident angles, whereas the formation of As-N bonds has not been found. However, the degree of nitridation of Ga decreases with increasing incident angle. The observed angular dependence of the N incorporation can be explained in terms of sputtering yield, indicating that the growth kinetics can be described as a dynamic process comprising the accumulation of N and sputter removal of the surface layer. N2 + ion bombardment causes the depletion of As from the surface region because of the preferential sputtering of As from GaAs. The preferential sputtering of As reduces with increasing N2 + ion incident angle. The angular dependent behavior of preferential sputtering of As by 10 keV N2 + ions can be attributed to the angular dependence of GaN surface layer formation.