Duty-cycle-accelerated hot-carrier degradation and lifetime evaluation for 700V lateral DMOS

Abstract

Due to serious self-heating effect, traditional DC stress is hard to be used for evaluating the hot-carrier degradation of the LDMOS above 600V. In this work, the hot-carrier degradation for a 724V-breakdown LDMOS is studied by adopting gate duty-cycle-accelerated AC stress. It demonstrates that hot-electrons injection and donor-like interface states generation happen near the drain when the gate pulse is high. No obvious degradation and recovery can be observed when the gate pulse is zero. Moreover, the short pulse edges enhance the decrease of on-resistance (Ron) due to transient hot-holes injection into bird's beak. The device lifetime is also calculated according to the proposed models related to duty-cycle.