A methodology for projecting SiO2 thick gate oxide reliability on trench power MOSFETs and its application on MOSFETs VGS rating

Abstract

In this work, a methodology based on the E-model for the reliability projection of a thick (>20nm) SiO2 gate oxide on a vertical trench power MOSFET, is presented. Experimental results suggest that a Logic Level (LL) trench MOSFET with 35nm of gate oxide can be rated at VGS=+12V if one assumes continuous DC Gate-Source bias of VGS=+12V at T=175°C for 10years at a defect level of 1 Part Per Million (PPM). We will demonstrate that if we take into account MOSFET device lifetime as dictated by the Automotive Electronics Council (AEC Q101) mission profile, then devices can be rated higher to VGS=+14.7V at T=175°C for the same PPM level (1PPM). The application of the methodology for establishing the oxide thickness, tox, for any required voltage rating, is discussed.