Piezoresistive properties of heavily doped P-type polysilicon films

The different thickness polysilicon films were prepared by low pressure chemical vapor deposition. The microstructures of samples were observed by X-ray diffraction, scanning electron microscope and transmission electron microscope. The piezoresistive properties of samples were tested. The experimental results show that under high doping concentration, the gauge factor of polysilicon nanofilms is larger than that of common polysilicon films, which can not be explained reasonably by existing piezoresistive theories, but can be well explained by tunneling piezoresistive theory. The experimental results imply that the polysilicon nanofilms is a promising high temperature piezoresistive material.