PREPARATION OF PLASMA CHEMICAL VAPOR-DEPOSITION SILICON-NITRIDE FILMS FROM SIH2F2 AND NH3 SOURCE GASES

Fluorinated silicon nitride films are prepared by plasma chemical vapor deposition (PCVD) of the difluorosilane (SiH2F2)-ammonia (NH3) system. The films deposited with varied gas-phase composition were characterized by means of infrared spectroscopy (IR) and Auger-electron spectroscopy (AES). It is shown that the deposition rate, refractive index and density of silicon nitride films depend on the SiH2F2-NH3 ratio of the input gases. It is further shown that the stress, resistivity and dielectric breakdown strength do not depended on it. The resistivity and breakdown strength were observed to be as high as 10(16) OMEGA.cm and 5 MV/cm, respectively.