Monte Carlo Impurity Diffusion Simulation Considering Charged Species

A Monte Carlo dopant diffusion simulation program has been developed which includes charged species, i.e. Fermi-level effects on drift-diffusion and reactions. In order to save computational time, an algorithm that determines variable time steps was improved to account for all the Fermi-level dependent quantities, such as different charge states of point-defects, pairs and complexes, and different diffusivities/reaction rates for them. Simulation of coupled arsenic and boron diffusion for a typical sub-100nm CMOS process has been demonstrated by using this MC program.