Engineering piezoresistivity using biaxially strained silicon

We calculate the shear piezocoefficient of p-type silicon with grown-in biaxial strain using a 6x6 k center dot p method. We find a significant increase in the value of the shear piezocoefficient for compressive grown-in biaxial strain, while tensile strain decreases the piezocoefficient. The dependence of the piezocoefficient on temperature and dopant density is altered qualitatively for strained silicon. In particular, we find that a vanishing temperature coefficient may result for silicon with grown-in biaxial tensile strain. These results suggest that strained silicon may be used to engineer the piezoresistivity to enhance the performance of piezoresistive stress sensors.