THE MECHANICAL-PROPERTIES AND MICROSTRUCTURE OF PLASMA ENHANCED CHEMICAL VAPOR-DEPOSITED SILICON-NITRIDE THIN-FILMS

Plasma enhanced chemical vapor deposited silicon nitride thin films, possessing a wide range of mechanical and physical properties, were made by changing the flow rate ratios of the various processing gases, NH3/SiH4/N2, while basically keeping the other deposition parameters constant. A set of films with N/Si ratios of 1.0 to 1.5 were produced, all showing compressive stress. The intrinsic compressive stress was found to increase with increasing amounts of N-H bonding. The density and Young's modulus also increased with increasing amounts of N-H bonding. The values for Young's modulus, obtained by using a Nano indenter instrument, were mainly dependent upon the film density, and the hardness to modulus ratio was 0.09 for all of the silicon nitride thin films.