Avalanche Ratings in Trench Power MOSFETs

摘要

Trench power MOSFETs provide considerably lower on-resistance than the same size planar MOSFETs but until recently this lower on-resistance came at the expense of reduced avalanche capability. To use these designs in automotive applications, the avalanche capability must not be compromised and the test methodology needs to be understood - and predictable. Extensive testing has shown that the avalanche capability can be predicted for a given MOSFET family based on an equation that uses the intrinsic carrier concentration. This paper will describe a test method developed for planar MOSFETs that has been applied to the newest trench MOSFETs, review data on both older and newer designs and provide an analysis of avalanche failures based on the model.