A tunneling piezoresistive model for polysilicon

Based on the trap model, the band structure and the conductive mechanism of polysilicon were analyzed, and then an equivalent circuit used to interpret the tunneling piezoresistive effect was proposed. Synthesizing the piezoresistive effect of the grain boundary region and grain neutral zone, a new piezoresistive model-a tunneling piezoresistive model is established. The results show that when the doping concentration is above 1020 cm 3, the piezoresistive coefficient of the grain boundary is higher than that of the neutral zone, and it increases with an increase in doping concentration. This reveals the intrinsic mechanism of an important experimental phenomena that the gauge factor of heavily doped polysilicon nano-films increases with an increase in doping concentration.