Two-dimensional process simulation using verified phenomenological models

Two-dimensional (2-D) effects are becoming increasingly important in the diffusion of impurities in submicrometer silicon devices. The authors describe a 2-D process simulator, PREDICT2, that handles implant damage effects, annealing, and lateral diffusion. PREDICT2 simulates the diffusion of impurities in silicon by using phenomenological diffusion coefficients. The phenomenological models are verified by comparing simulated and experimental results. This approach is compared with that of point-defect-based simulators. The experimental technique for measuring impurity profiles in two dimensions is outlined. The method for generating diffusion models is illustrated by examining 2-D phosphorous diffusion. Numerical simulations and experimental measurements are compared. The numerical methods used in the simulator are described, and directions for future work are suggested