Deposition Characteristics of SiNx Films by Atmospheric Pressure Plasma CVD

Silicon nitride (SiNx) films were fabricated with extremely high deposition rate using the atmospheric pressure plasma CVD technique. The films were prepared on Si(001) wafers at atmospheric pressure in a very high frequency (150MHz) plasma of gas mixtures containing He, H2, SiH4 and N2 or NH3. Film properties (structure and composition of SiNx) were studied as a function of each deposition parameter by Fourier transformation infrared (FTIR) absorption spectroscopy and Auger electron spectroscopy. The maximum deposition rate was 120nm/s, which was 40 times as fast as that achieved by the conventional plasma CVD technique. It was found that SiNx films with uniform structure could be deposited using NH3 as the N source gas. When N2 was used, however, the composition of the film changed in the normal direction of the surface.