Analysis for piezoresistive property of heavily-doped polysilicon with upper and lower bounds

作者：Matsuzuka Naoki^*; Toriyama Toshiyuki

来源：Journal of Applied Physics, 2010, 108(6): 064902.

DOI：10.1063/1.3481093

• doping profiles
• elasticity
• grain boundaries
• piezoresistance
• polymer structure
• silicon compounds

This paper proposed an analysis for the piezoresistive property of heavily-doped polycrystalline silicon (polysilicon) with upper and lower bounds derived using the fundamental piezoresistive coefficients of single-crystalline silicon (SCS). The analysis is applicable to the polysilicon that the piezoresistive effect in grain boundaries is negligible and the orientations of the SCS grains are completely random. For deriving the upper and lower bounds, the analysis employed two approximation models on the basis of two extreme assumptions of uniform stress and fractional change in resistivity in each SCS grain of polysilicon. The fundamental piezoresistive coefficients of polysilicon derived from these models were successfully defined as the upper and lower bounds, based on the elastic theories in the micromechanics filed. The applicability of the analysis was discussed by comparing the derived upper and lower bounds with the piezoresistive property of heavily-doped polysilicon measured in some previous works. The measured piezoresistive property of both p-type and n-type polysilicon lay within the theoretical possible range between the upper and lower bounds at the impurity concentration of 10(19) cm(-3) levels, which suggested the applicability of the proposed analysis for the piezoresistive property of heavily-doped polysilicon.

• 出版日期2010-9-15