Reformulation of macroscopic transport models based on the moments of the scattering integral [semiconductor device modeling applications]

We present a formulation of non-parabolic macroscopic transport models which avoids the commonly used relaxation time approximation by using an expansion of the scattering integral into the odd moments of the distribution function. The parameters of this expansion and the other closure relations are directly calculated via analytical models of the distribution function. We compare models of order four and six to demonstrate the substantially improved accuracy of the six moments description over the conventional four moments energy-transport formalism.