3-D analysis of the breakdown localised defects of ACS through a triac study

The reliability tests of triac and ACS^TM present similarities. In this paper, we propose to analyse the origin of the defects observed by using measurements and 3D simulation with the ISE tools. We are interested in the operation of the triac or ACS^TM in quadrant 2. The results presented here relate to the discrete triac only for reasons of confidentiality. Thermal simulation of the triac shows a strong thermal gradient (thermal shock) in the silicon at turn-on. Stresses and strains in the material created micro crackings that increase the temperature until the fusion of silicon (hot spot).