A hybrid device simulator that combines Monte Carlo and drift-diffusion analysis

A hybrid simulator suitable for modeling small semiconductor devices has been developed in which Monte Carlo and drift-diffusion models are combined. In critical device regions, the position-dependent coefficients of an extended drift-diffusion equation are extracted from a Monte Carlo simulation. Criteria for identifying these regions are described. Additional features which make the code more efficient are presented. First, a free-flight time calculation method using a new self-scattering 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 known schemes. It exploits the so-called Monte Carlo-drift diffusion coupling 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 /spl mu/m. In addition to the non-local effects occurring in these devices, the performance of the hybrid simulation method is analyzed.>