TIME STABILITY OF MONTE-CARLO DEVICE SIMULATION

An important numerical constraint on self consistent Monte Carlo devic e simulation is the stability limit on the time step imposed by plasma oscillations. The widely quoted stability limit for the time step bet ween Poisson field solutions, DELTAt < 2/omega(p) where omega(p) is th e plasma frequency, is specific to the leapfrog particle advance used in collisionless plasma simulation and does not apply to typical parti cle advance schemes used for device simulation. We derive a stability criterion applicable to several algorithms in use for solid state mode ling; this criterion is verified with numerical simulation. This work clarifies the time step limitation due to plasma oscillations and prov ides a useful guide for the efficient choice of time step size in Mont e Carlo simulation.