Improvement of PC ruggedness by AlN substrate in Easy power modules with Silicon Carbide technology

Abstract:
This article discusses the impact of AlN substrate insulation ceramic material on the power cycling performance of Infineon’s CoolSiCTM MOSFET with M1H technology. Using the high performance AlN instead of the standard Al2O3 as the substrate insulation ceramic material ensures lower thermal resistance. This is because, AlN has a higher thermal conductivity and, therefore, a higher load current is needed to achieve comparable temperature conditions as per Tvj,max and DTj.A series of tests conducted at different stress conditions confirmed the applicability of the known power laws for high temperature swings and pulse load duration. Additionally, after testing power cycling with high temperature swings, a 60% higher cycle count until end of life (EoL) was observed for the CoolSiCTM Easy power modules with AlN ceramic compared to those with Al2O3. This higher cyclic robustness could also be motivated by the reduced accumulated plastic strain shown in a thermo-mechanical simulation.