ABSTRACTSilicon oxynitride films, fabricated by direct thermal growth and annealing in N2O or NO, were analyzed by Angle-Resolved X-ray Photoelectron Spectroscopy (ARXPS). It is seen that for the samples processed in N2O, N is bonded as Si3N4 only, irrespective of whether the fabrication was done on bare Si or on an oxide pre-grown in O2. But the films processed in NO depict additional bonding arrangements, namely, non-stoichiometric SiOxNy, (Si-)2-N-O, and Si-N(-O)2. These bonding states are found to be concentrated in a higher proportion above the oxynitride/substrate interface. Further, it is seen that annealing of a pre-grown oxide in NO for 30 min incorporates the same bonding states as by direct growth in NO for as long as 120 min. Also, a critical N concentration (between 1.9% and 2.3%) is required for the incorporation of the Si-N(-O)2 structure, observed at 400.7 eV. Besides enhancing the overall understanding of the progress of silicon oxynitridation process in N2O and NO, these findings can help significantly towards developing process-property relationships for incorporation of N with the desired bonding state(s) at specific positions within an oxynitride film.
X-ray Photoelectron Spectroscopic Study of Nitrogen Depth Profile in Radical Nitrided Silicon Oxynitride Film