Hybrid fullband cellular automaton/Monte Carlo approach for fast simulation of charge transport in semiconductors

We present a fullband cellular automaton (CA) code for simulation of electron and hole transport in Si and GaAs. In this implementation, the entire Brillouin zone is discretized using a nonuniform mesh in k-space, and a transition table is generated between all initial and final states on the mesh, greatly simplifying the final state selection of the conventional Monte Carlo algorithm. This method allows for fully anisotropic scattering rates within the fullband scheme, at the cost of increased memory requirements for the transition table itself. Good agreement is obtained between the CA model and previously reported results for the velocity-field characteristics and high field distribution function, which illustrate the potential accuracy of the technique. A hybrid CA/Monte Carlo algorithm is introduced which helps alleviate the memory problems of the CA method while preserving the speed-up and accuracy.