Nanoindentation of GaN/SiC thin films on silicon substrate

Abstract

The indentation process of thin gallium nitride film grown on SiC buffer layer on silicon was studied. SiC was obtained by the new method of substitution of atoms directly in a silicon substrate. Indentation data, atomic force microscopy and Raman spectroscopy were used to characterize the indented system. Mechanical properties of the film and the substrate were derived using single-layer Oliver-Pharr and Doerner-Nix approaches. Micro-Raman confocal microscopy was used to construct 3-dimensional maps of mechanical stresses and crystalline quality both of GaN and silicon near the indenter impression for different indentation depths. The anisotropy of propagation of the elastic stresses during indentation was investigated and it was shown, that distribution of stress in the substrate has a shape of trefoil. This process has been modeled by means of molecular dynamics.