Blocking capability of planar devices with field limiting rings

Abstract The results of breakdown voltage investigations of planar devices with field limiting rings are described. The two-dimensional Poisson equation is solved using the finite difference method. The question of the optimal ring spacings for devices with more than one field ring and the influence of surface charges on the blocking capability are extensively studied. The influence of the following device parameters is discussed: ring spacing, ring width, doping gradient and surface charge density. An analytical model for simplified calculations showing the principal characteristics of field ring devices is presented. Furthermore some experimental results of EBIC measurements are shown.