Mechanical properties of sputter deposited strontium bismuth titanate thin films by nanoindentation and nanoscratch techniques

Abstract

Substrate dependence of the mechanical properties of strontium bismuth titanate (SBTi) thin films were studied for MEMS based devices. Hence a comparative study was done for films deposited on amorphous substrates and crystalline substrates sputtered by rf sputtering were presented in this paper. Their crystal structure and surface morphology are characterized by X-ray diffraction and atomic force microscopy respectively. The substrate effect was observed on grain growth and crystal orientation of the films. The films deposited on Pt/Si substrates are having higher hardness and Young's modulus than the films deposited on fused silica with respect to crystal orientation and grain size. For example the range of the values obtained for hardness of the films deposited on Pt/Si and fused silica is 8.4-7.7 GPa and 6.1-5.4 GPa while their Young's modulus is 137-130 GPa and 100-91 GPa respectively. The tribological properties of these films are confirmed by performing scratch test on the same films. Copyright © 2012 American Scientific Publishers.