Variance reduction for Monte Carlo simulation of semiconductor devices

Some techniques being effective for the variance reduction of ensemble Monte Carlo simulation(EMC) are proposed on the basis of the electron physics. They consist of expression of a particle with the gaussian cloud depending on the electron density, suppression of the local fluctuation of the electron density due to the dielectric relaxation, introduction of the displacement current and so on. They are applied to an EMC of the GaAs MESFET with a submicrometer gate length. Their effectiveness is confirmed through a calculation of the spatial distributions of the electron density and the electric field and the current responses. The present variance reduction technique causes an increase of the computational time. But the increase is not so much.