AUGER-ELECTRON SPECTROSCOPY AND X-RAY PHOTOELECTRON-SPECTROSCOPY ANALYSIS OF ANGLE OF INCIDENCE EFFECTS OF ION-BEAM NITRIDATION OF GAAS

Ion beam nitridation (IBN) of GaAs at room temperature was studied as a function of N-2(+) ion incident angle at ion energy of 10 keV. The i on beam bombardment surface area of GaAs was characterized in situ by both Auger electron spectroscopy (AES) and small spot-size x-ray photo electron spectroscopy (XPS), Thin GaN reaction layers are formed at al l N-2(+) ion incident angles, whereas the formation of As-N bonds has not been found. However, the degree of nitridation of Ga decreases wit h increasing incident angle. The observed angular dependence of the N incorporation can be explained in terms of sputtering yield, indicatin g that the growth kinetics can be described as a dynamic process compr ising the accumulation of N and sputter removal of the surface layer. N-2(+) ion bombardment causes the depletion of As from the surface reg ion because of the preferential sputtering of As from GaAs. The prefer ential sputtering of As reduces with increasing N-2(+) ion incident an gle. The angular dependent behavior of preferential sputtering of As b y 10 keV N-2(+) ions can be attributed to the angular dependence of Ga N surface layer formation.