Electrical overstress effect characterization on Power MOS Trenchfet and correlation with time dependent dielectric breakdown

Abstract In recent years, power electronics has played a fundamental role in the development of increasingly efficient circuits for energy conversion. The characterization of a Power MOSFET under a gate overstress and the correlation with the reliability performances represent a crucial point in the optimization of the trench technology where the oxidation processes of the gate oxide are critical in terms of uniformity and reproducibility of the thickness. This article explores these aspects with particular attention to the analysis of the electrical overstress effect on aging transistors parameters and the classical TDDB (time dependent dielectric breakdown) test for gate oxide integrity characterization and lifetime extrapolation. The latter actually trigger oxide breakdown which is not as relevant at operating conditions as parametric degradation which usually occurs much earlier. Moreover, a possible physical explanation to the adherence of both failure modes (breakdown and transistor aging) to the two typical failure model such as thermochemical model and anode hole injection has been subjected to analysis following fitting methods as did in the past including their reciprocal correlation.