Analysis of the piezoresistive properties of isotropic polysilicon based on a self-consistent micromechanics model

作者：Matsuzuka Naoki^*; Toriyama Toshiyuki

来源：Smart Materials and Structures, 2011, 20(8): 085018.

DOI：10.1088/0964-1726/20/8/085018

This paper presents the analysis method for the piezoresistive property of isotropic polycrystalline silicon (polysilicon) based on the self-consistent micromechanics model which enables us to reflect the effects of local strain and stress in the polysilicon. The analysis method is developed on the assumption that the polysilicon is composed of spherical single-crystalline silicon (SCS) grains with random orientations and the piezoresistive effect in grain boundaries is negligible. The fundamental piezoresistive coefficients of the polysilicon are derived from the elastic and piezoresistive properties of SCS and the resistivity ratio of SCS to polysilicon through this analysis. The fundamental piezoresistive coefficients of the p-type polysilicon are analyzed using the resistivity ratio from more than 0 to less than 1, which shows that the resistivity of polysilicon is higher than that of SCS. The analysis results are compared with the measurement ones reported in some previous works. The analysis results are in good agreement with the measurement ones of the polysilicon specimens which might have the isotropic piezoresistive property, giving the appropriate resistivity ratios. The resistivity ratios given are in the almost practical range. These results support the applicability of the proposed analysis method.

• 出版日期2011-8