Stress and Reliability of Power Devices: an Innovative Thermal Analysis Approach to Predict a Device’s Lifetime

摘要

Lifetime estimation of discrete power devices in an automotive market context plays a key role andrnimposes more and more accurate characterization strategies aimed at guaranteeing demanding customerrnrequirements. In this paper it will be shown how a correct lifetime estimation can not prescindrnfrom a correct junction temperature variation analysis during power cycling. The objective of this paperrnis to give a brief overview on common approaches adopted for estimating the temperature variationrninside the silicon and then focus on a new methodology aimed at accurately predicting real temperaturernbehavior on non-homogenous device layouts. The new proposed methodology is based on arncustom EDA flow able to retrieve very accurate thermal information during turn-on/turn-off switchingrntransient in whatever working condition discrete power device could have.rnA deep thermal investigation will also be performed on a STMicroelectronics power MOSFET devicernshowing how the layout influences on the current distribution inside the active area could make obsoleternwhatever average temperature estimation approach based only on models referring to currentsrnand voltages retrievable at the device terminals.