Low Temperature Fourier Transform Infrared Spectroscopic Studies of Hydrogenated Amorphous Silicon Nitride Films

Abstract

Low-temperature IR absorptance measurements on thin films of hydrogenated amorphous silicon nitride have revealed the existence of different groups such as NH, SiH and SiH 2 . Although NH stretching vibration is not observed in the IR transmission-absorption measurements at ambient temperature in such thin films, it becomes quite intense in the temperature range of 230 K to 100 K, and its absorptance slowly reduces on further lowering of temperature. Absorptance-temperature curves revealed that the SiH wagging mode and SiH 2 bending mode undergo a large variation in absorptance on lowering of the temperature. Low-temperature Fourier transform infrared (FTIR) spectroscopic studies have been found to be very useful for characterisation of the hydrogenated amorphous silicon nitride films.