Simple approximations for degenerate non-parabolic semiconductors

The authors propose simple, explicit expressions that describe properties of semiconductor devices with nonparabolic energy bands. The new model includes effects of carrier degeneracy and impurity freeze-out. The approach is based on a recently proposed approximation for the semiconductor statistics derived from Kane´s k· p model. The authors use that approximation to calculate intrinsic properties of semiconductors, n·p product, and the Einstein relation. They then solve a one-dimensional Poisson´s equation and obtain a relationship between the total semiconductor charge and the surface potential. This method can be applied to heterojunction and field effect devices with wide and narrow band gaps. They use the new approach to calculate the incremental capacitance of an MIS structure and compare the results with an accurate numerical model and experimental measurements of an HgCdTe capacitor