Effect of wafer bonding and layer splitting on nanomechanical properties of standard and strained SOI films

The response to mechanical deformation of bonded strained Si-on-Insulator (sSOI) wafers was investigated by nanoindentation. Both the hardness and elastic moduli were determined for the Si film on the surface of the bonded composite SOI wafers, the buried SiO2 and the bulk silicon using the continuous stiffness method (CSM) XP Nano Instruments Nanoindentation tester. The measured hardness values for biaxial tensile strained sSOI films were found to be 9.23 GPa and for standard non-strained SOI films 9.36 GPa. The moduli are 101.2 GPa and 105.6 GPa respectively. The thin bonded Si film values were measured to be considerably lower in comparison with single crystal Si bulk values of 12.5 GPa and 160.0 GPa for hardness and modulus.