An implicit LU-SGS spectral volume method for moment models in device simulations II: Accuracy studies and performance enhancements using the penalty and BR2 formulations.

In this paper, the second in a series, the accuracy and performance of the high-order spectral volume (SV) method for moment models in device simulations is enhanced by employing the penalty and BR2 formulations for discretizing the second derivative diffusive fluxes. The potential equation is also discretized using the above formulations. The actual accuracy and the numerical orders are obtained by performing accuracy studies. An n -n-n diode was assumed for simulation purposes. The results obtained by solving steady-state hydrodynamic (HD) and energy transport (ET) models are compared with the existing local discontinuous Galerkin formulation (LDG) results. The newer formulations yield more accurate solutions than the ones which used the LDG formulation. In addition, the newer formulations converge to steady state much faster than the LDG formulation. The BR2 formulation is compact and hence can be easily parallelized. The penalty formulation is however not compact. In general, the numerical results are very promising and indicate that the newer diffusive flux formulations are more accurate, converge faster, have greater potential and hence are suited better than the LDG for higher dimensional device problems. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]