Mechanical properties of PECVD thin ceramic films

Silicon dioxide (thickness 350 nm and 969 nm) and silicon nitride (thickness 218 nm) films deposited on silicon substrate using plasma enhanced chemical vapor deposition process were investigated using a Berkovich nanoindenter. The load-depth measurements revealed that the oxide films have lower modulus and hardness compared to the silicon substrate, where as the nitride film has a higher hardness and slightly lower modulus than the substrate. To delineate the substrate effect, a phenomenological model, that captures most of the 'continuous stiffness measurement' data, was proposed and then extended on both sides to determine the film and substrate properties. The modulus and hardness of the oxide film were around 53 GPa and 4-8 GPa where as those of the nitride film were around 150 GPa and 19 GPa, respectively. These values compare well with the measurements reported elsewhere in the literature. (C) 2009 Elsevier Ltd. All rights reserved.