Simulation of reverse breakdown in planar P- N junctions

Abstract

The two-dimensional numerical simulator BAMBI has been modified to simulate reverse biased P- N junction characteristics. Complete I–V characteristics of the reverse biased P- N junction is obtained to predict the breakdown voltage rather than the ionization integral. Simulations are then applied to the field limiting ring (FLR) structure and the reduced surface field (RESURF) structure. A quasi-three-dimensional approach is used to simulate cylindrically symmetric P- N junctions to model the three-dimensional effects due to lateral curvature at corners of mask patterns. A resistive contact to the FLR is used to stabilize the numerical solution of floating FLRs. Simulation results suggest that the breakdown voltage of devices with smaller radii at the rounded corner are much lower as compared to predictions from two-dimensional simulation. In the case of the FLR and RESURF structures, three-dimensional effects play an important role in determining optimal design parameters.