The feasibility of Si 3 N 4 films prepared by a catalytic chemical vapor deposition (Cat-CVD) method is studied with the idea of considering its applications to the ULSI process. In this study, SiN x films are prepared by Cat-CVD at various catalyzer temperatures, gas pressures and substrate temperatures. It was verified that the content of metal contamination is much lower than that permitted in a ULSI manufacture line. The maximum deposition rate reaches up to 132 nm/min, which is sufficiently higher than the deposition rate required for sidewall films near gate electrodes. The leakage current for SiN x films is lower than that for plasma enhanced CVD (PECVD) SiN x films. These features show that Cat-CVD SiN x films have the potential to be employed in the ULSI process.