Thermal Stress Induced Thin Film Transfer from Single-crystal Silicon Layer on Sapphire Substrate

Abstract

Silicon-on-sapphire (SOS) is a member of the silicon-on-insulator (SOI) family which uses a hetero-epitaxial process to generate thin films of semiconductor materials. SOS has become an attractive technology for low-power and radio-frequency integrated circuits. This study tends to apply SOS to thin film solar cell by thin film transfer technique. The nano-scale silicon thin film can be generated on the high quality sapphire substrate to form SOS. SOS is soaked in the special H+-chemical solution at first. The aluminum layer is bonded by thermal annealing treatment and the silicon thin film will transfer to the aluminum layer with cooling slowly due to the thermal stress induced. Through the special H+ chemical treatment and the annealing process, the SOS can be transferred to Si/Al layer and sapphire layer successfully. The Si/Al layer can be applied to thin film solar cell or other nano-size devices. The sapphire layer can be recycle for the SOS use.