Formation of highly moisture-resistive SiN x films on Si substrate by Cat-CVD at room temperature

Abstract

Silicon nitride (SiN x ) films were prepared with a gas mixture of SiH 4, NH 3 and H 2 on Si wafers at low temperatures using the catalytic chemical vapor deposition (Cat-CVD) method. For fixed flow-rates, properties for the SiN x films depending on substrate temperatures from 20 °C to 100 °C were investigated. The N/Si composition ratio depended little on the substrate temperature. When the substrate temperature was low, the refractive index decreased, the deposition rate increased slightly, the etch rate became large and the internal stress decreased. No variation appeared in the infrared absorption of the films before and after a pressure cooker test. It is found that highly moisture-resistant SiN x films without stress can be obtained at room temperature by using Cat-CVD.