Scattering Mechanisms in Heavily Doped Semiconductors. II. Effect of Mass Anisotropy and Multiple Scattering

Abstract

Resistivities and Hall coefficients of unstressed and uniaxially saturation-stressed samples of heavily antimony-doped germanium in the metallic concentration range are investigated by the degenerate electron gas model with impurity scattering. The effect of anisotropic effective mass is investigated, firstly by the variational method, and secondly by solving the Boltzmann equation directly in a numerical method. The anisotropy of screened impurity potential is fully taken into account within the linear screening theory. The effect of finite electron life time is studied by a simplified coherent potential approximation. By these effects, in addition to the effect of the nonlinear screening and many-body interaction investigated in the authors’ previous paper, the agreement with experiments on the unstressed samples is much improved and a good agreement is obtained on the saturation-stressed samples.