Profiling nitrogen in ultrathin silicon oxynitrides with angle-resolved x-ray photoelectron spectroscopy

Angle-resolved x-ray photoelectron spectroscopy (AR-XPS) is utilized in thi s work to accurately and nondestructively determine the nitrogen concentrat ion and profile in ultrathin SiOxNy films. With furnace growth at 800-850 d egrees C using nitric oxide (NO) and oxygen, 10(13)-10(15) cm(-2) of nitrog en is incorporated in the ultrathin (less than or equal to 4 nm) oxide film s. Additional nitrogen can be incorporated by low energy ion (N-15(2)) impl antation. The nitrogen profile and nitrogen chemical bonding states are ana lyzed as a function of the depth to understand the distribution of nitrogen incorporation during the SiOxNy thermal growth process. AR-XPS is shown to yield accurate nitrogen profiles that agree well with both medium energy i on scattering and secondary ion mass spectrometry analysis. Preferential ni trogen accumulation near the SiOxNy/Si interface is observed with a NO anne aling, and nitrogen is shown to bond to both silicon and oxygen in multiple distinct chemical states, whose thermal stability bears implications on th e reliability of nitrogen containing SiO2. (C) 2000 American Institute of P hysics. [S0021-8979(00)02808-5].