Room-Temperature Deposition of Silicon Nitride Films with Very High Rates Using Atmospheric-Pressure Plasma Chemical Vapor Deposition

We have investigated the structure and stability of SiN$_{x}$ films deposited with very high rates ($>$50 nm/s) in atmospheric-pressure (AP) He-based plasma excited by a 150 MHz very high-frequency (VHF) power using a cylindrical rotary electrode at room temperature. The SiN$_{x}$ films are prepared on Si(001) substrates with varying VHF power density ($P_{VHF})$, H$_{2}$ concentration and source ratio (NH$_{3}$/SiH$_{4})$. The results show that increasing H$_{2}$ concentration under the supply of a moderately large $P_{VHF}$, together with the adjustment of NH$_{3}$/SiH$_{4}$ ratio, enables us to prepare SiN$_{x}$ showing reasonable stability against a buffered hydrofluoric acid solution in spite of the very high deposition rate of 130 nm/s. The achievement of such a high-rate deposition at room temperature is primarily due to the significant enhancement of both gas-phase and surface-phase reactions in AP-VHF plasma.