Off-state avalanche-breakdown-induced on-resistance degradation in SGO–NLDMOS

Abstract

In this paper, on-resistance (Ron) degradation induced by off-state avalanche breakdown in a 40V LDMOS with step-shaped gate oxide (SGO–LDMOS) is investigated. Ron unexpectedly decreases at the beginning of stress, which is different from the phenomenon described in works on LDMOS with uniform gate oxide (UGO–LDMOS). Based on the experiment data and TCAD simulation results, two degradation mechanisms are proposed. That is the generation of positive oxide-trapped charges at the bird’s beak region near source and formation of interface state at the bird’s beak region near source and drain respectively.