Novel SiC-Based Power Device Bonding Materials of Nano Foam Sheet and Its Characteristic and Properties

Abstract

Silicon carbide (SiC) has excellent characteristics such as high thermal and electrical conductivity. However, traditional bonding materials are difficult to serve lastingly at high temperature, which directly affects the performance of SiC-based devices. In this study, nano foam sheet was prepared by dealloying, and used to sinter chip and substrate at low temperature. Microstructure, interfacial composition, mechanical properties and fracture of the sintered joint were characterized and analyzed. The precursor was AgCu alloy, and the bicontinuous ligament/channel structure was formed on the precursor surface after dealloying. As the etching temperature increased from 80 °C to 90 °C, the ligament width of nano foam became large and channel diameter became small. With the extension of etching time from 2 h to 5 h, the etching depth gradually increased. The nano foam sheet could realize metallurgical reaction between substrate and chip at a sintering temperature of 300 °C. The joint had high shear strength, and could meet the strength requirement of standard.