Energy conserving, self-force free Monte Carlo simulations of semiconductor devices on unstructured meshes

Unphysical self-forces resulting from the particle-mesh coupling occur when ensemble Monte Carlo simulations of semiconductor devices use an unstructured mesh to describe device geometry. We report on the development of a correction to the driving electric field on arbitrary meshes and show that self-forces can be virtually eliminated on a finite element mesh at a small additional computational cost. The developed methodology is included into a self-consistent 3D finite element Monte Carlo device simulator. We show the efficiency of the method simulating an isolated particle and obtaining kinetic energy conservation down to a magnitude of 10−10 meV. The methodology is later applied to a FinFET simulation to show what impact can be expected from the self-forces using traditional electric field interpolation strategies. We find that for a large enough ensemble of particles, the impact of self-forces on the final ID-V G is almost negligible.