Monte Carlo modeling of electron transport in repeated overshoot structures

Repeated velocity overshoot has been proposed as a way of obtaining high average velocities over significant distances in semiconductor devices. The potential of this concept is examined using a fully-self-consistent particle-field Monte Carlo simulation. Numerical results are presented for realistic periodic overshoot structures for a range of bias conditions and operating temperatures of 77 and 300 K. Local velocity overshoot peaks are observed in the simulated structures, but the average carrier velocity and current at each bias point are in all cases less than those associated with transport in bulk material at the same bias point. The physical mechanisms underlying this result are analyzed. It is found that ensemble (diffusion) effects, which were neglected in the original proposal of the repeated overshoot concept, strongly influence the results that are achievable in practice