XPS STUDIES ON NITRIDATION OF INP(100) SURFACE BY N-2(-BEAM BOMBARDMENT() ION)

ion beam nitridation (IBN) of InP at room temperature was studied as a function of both N-2(+) ion incident angle and energy. The InP surfac es were exposed to N-2(+) ion beam in an ultrahigh vacuum environment and the resulting surfaces were characterized in situ by small spot si ze x-ray photoelectron spectroscopy (XPS) for accurate determination o f the surface composition and chemical state. Thin InN reaction layers were formed at all N-2(+) ion incident angles and ion energies wherea s the formation of P-N bonds was no: observed. However, the degree of nitridation of In decreases with increasing incident angle and ion ene rgy, closely following the reduced incorporation of N at higher angles and ion energies. The variation in nitridation is smaller with ion en ergy in the 2-10 keV range than with ion incident angle. The observed angular and energy dependence of the N incorporation can be explained in terms of sputtering yields, indicating that the growth kinetics can be described as a dynamic process comprising the accumulation of N an d sputter removal of the surface layer.