Reduced interface state densities for remote microwave plasma silicon nitride

The interface state density and fixed charge density of films of a-Si3N4:H deposited on silicon substrates by remote microwave plasma chemical vapour deposition have been studied as a function of deposition and annealing temperature. Interface state densities (D(it) as low as 9 X 10(10) cm-2 eV-1 have been obtained for films deposited at 215-degrees-C and annealed for 15 min at 500-degrees-C. The films exhibited positive fixed charge levels (Q(N)/q) > 10(13) cm-2, increasing slightly with deposition temperature and decreasing slightly with annealing at temperatures from 500 to 700-degrees-C. Fourier transform infrared spectroscopy and Auger depth profiling were used to study the impurities in the films and at the interface. Metal-insulator-silicon field effect transistors made with these films showed room temperature effective channel hole mobilities of 37 cm2 V-1 s-1.