Abstract
We have discussed the deformation of band structure due to stresses and the piezoresistivity in single-crystal bulk silicon based on the first-principles calculations. For n-type bulk silicon, the longitudinal and transverse piezoresistance coefficients originate from the energy gap between the valleys, whereas the shear piezoresistance coefficient arises from a distortion of the "ellipsoids" in the valleys. The distinction between the origins of piezoresistivity can be followed as a dependence on a surface concentration or temperature by our novel procedure to calculate the piezoresistance coefficients. Furthermore, for p-type bulk silicon, we have applied the perturbational approach to the band splitting in the valence bands due to the spin-orbit coupling, and then a more quantitative estimate of the piezoresistance coefficients can be expected.
