Nanomechanical properties of sputter-deposited HfO2 and HfxSi1-xO2 thin films

The mechanical properties of sputter-deposited HfO2 and HfxSi1-xO2 films were studied as a function of composition using nanoindentation. The elastic modulus and hardness were measured at room temperature for as-deposited films of varying Hf content and for films subjected to annealing at 1000 degrees C. The elastic modulus and hardness of as-deposited films were found to increase monotonically with increasing HfO2 content, with the hardness increasing from 5.0 +/- 0.3 GPa for pure SiO2 to 8.4 +/- 0.4 GPa for pure HfO2. All films were found to be harder after annealing at 1000 degrees C, with the increase for SiO2 films attributed to densification of the SiO2 network and that for the HfxSi1-xO2 films to a combination of phase separation, densification, and crystallization. (C) 2011 American Institute of Physics. [doi:10.1063/1.3627155]