PERIODIC BOUNDARY CONDITIONS FOR THE NUMERICAL ANALYSIS OF SEMICONDUCTOR DEVICES

摘要

In the numerical analysis of semiconductor device equations we have to introduce the artifitial boundaries, which do not exit in the real devices. The artifitial boundaries, commonly described by the homogeneous Neumann conditions (reflecting boundary conditions) cause accuracy problems, when they intersect the p-n junction. We have analysed the numerical error introduced by the application of the artifitial, reflecting bouandry conditions in the cases of the intersection with heterojunctions. The unphysical fluctuations in the potential and carrier distributions have been shown in places, where the heterojunctions cross the artifitial boundaries. The application of periodic boundary conditions has been proposed to remove the error introduced by the reflecting boundaries. A simple implementation of the periodic boundary conditions to the limite element method has been presented and improvement in accuracy of the solution has been shown.