Influence of current-induced recrystallization on piezoresistive properties of polysilicon nanosized thin films deposited at different temperatures

Abstract

To improve the accuracy and stability of piezoresistive sensors based on polysilicon nanosized thin films (PNTFs), 80nm-thick PNTFs were deposited on Si substrates by LPCVD at different temperatures and fabricated into cantilever beams. The electrical trimming characteristics and dependences of gauge factor, TCR and TCGF on resistor trim were measured. Based on interstitialvacancy model, the electrical trimming is due to the mobility increase caused by current-induced recrystallization of grain boundaries (GBs). The changes in GF, TCR and TCGF with resistor trim are due to the GB state variation (including scattering center, GB width, tunneling current, localized and extended state conductions).