Reducing Migration of Sintered Ag for Power Devices Operating at High Temperature

Abstract

Wide-bandgap power devices are usually operated at a higher temperature or larger electrical bias and the harsh conditions often lead to early failure of the widely used Ag-based die-attach materials due to electrochemical migration (ECM). Common methods to mitigate ECM tend to be quite costly and can only enhance the performance slightly under high-temperature conditions. In this letter, novel nano-Ag-based die-attach materials are designed and prepared by doping with 0.1 wt% Si nanoparticles. The higher affinity of Si to oxygen reduces oxidation of silver and increases the median time to failure at 400 °C by 4.8 times. According to the life prediction model, the materials extend the lifetime for operation at 200 °C from 9.5 to 63 years, while the cost remains unchanged. The sintered nano-Ag-0.1%Si die attachment has long-term reliability rendering them desirable for power devices operating at a high temperature.