High Quality Plasma‐Enhanced Chemical Vapor Deposited Silicon Nitride Films

The qualities of plasma-enhanced hemical vapor deposited (PECVD) silicon itride films can be improved by increas-ing the deposition temperature. This report compares PECVD silicon itride films to low pressure chemical vapor deposited (LPCVD) films. The dependence of the film properties on process parameters, pecifically power and temperature, are investigated. The stress is shown to shift from tensile to compressive with increasing temperature and power. The deposi-tion rate, uniformity, wet etch rate, index of refraction, composition, stress, hydrogen content, and conformality are considered to evaluate the film properties. Temperature affects the hydrogen content in the films by causing decreased incorporation of N-H containing species whereas the dependence o power is due to changes in the gas-phase precursors. All PECVD film properties, with the exception of cenformality, are comparable to those of LPCVD films. Future technology requires high quality films while maintaining min ima l thermal budget. For this reason, in-terest in substituting PECVD films for LPCVD films is in-creasing. In silicon nitride, LPCVD films are highly stressed (approximately 10 I ~ dyne/cm 2 tensile). This stress limits their utility in fabrication of semiconductor devices.