Transport equations in heavy doped silicon

The general transport equations in a heavy doped semiconductor are given, taking the position-dependent band structure into account. An intrinsic concentration depending on the doping levels is introduced. This quantity allows us to use the classical equations in a slightly modified form, if Maxwell-Boltzmann statistics can be applied for one or both kinds of the carrier. The total density of states in a heavy doped semiconductor is assumed to be the envelope of the density of states of the conduction (valence) band and impurity band. The effect of the skewness of the impurity band is included. The Fermi level and the effective intrinsic carrier concentration are calculated for this total density of states function. Experimental evidence for the calculated values is given.