A HYBRID DEVICE SIMULATOR THAT COMBINES MONTE-CARLO AND DRIFT-DIFFUSION ANALYSIS

A hybrid simulator suitable for modeling small semiconductor devices h as been developed in which Monte Carlo and drift-diffusion models are combined. In critical device regions, the position-dependent coefficie nts of an extended drift-diffusion equation are extracted from a Monte Carlo simulation. Criteria for identifying these regions are describe d. Additional features which make the code more efficient are presente d. First, a free-flight time calculation method using a new self-scatt ering algorithm is described. It allows for an efficient reduction of self-scattering events. Second, a unique Monte Carlo Poisson coupling scheme has been developed which converges faster than all presently kn own schemes. It exploits the so-called Monte Carlo-drift diffusion cou pling technique, which also forms the basis of the hybrid method. The simulator has been used to model submicron MOSFET's with gate lengths down to 0.15 mu m. In addition to the non-local effects occurring in t hese devices, the performance of the hybrid simulation method is analy zed.