Reliability of Ag-Sintering and Sn-Ag TLP-Bonding for Mounting of SiC and GaN Devices

Abstract:
This work focuses on the performance comparison of Ag-sintering and foil-based Sn-Ag Transient Liquid Phase (TLP) bonding as die-attachment techniques for novel SiC and GaN devices. State-of-the-art GaN high electron mobility transistors (HEMTs) and SiC Schottky diodes were mounted. These devices are aimed at their use in high-power and high-temperature applications. At the CIPS 2014 [1], we already have demonstrated the high-temperature stability of Ag-sintering and foil-based TLP bonding . In this work, the electrical and thermal performance of the assembled devices is presented. The influence of thermal effects on the electrical characteristics of SiC and GaN devices was studied. More-over, both GaN and SiC assemblies were subjected to passive temperature cycling and active power cycling. A comparative study of power cycling reliability of the novel foil-based TLP bonding is made with die-attachments such as Ag-sintering, soldering and adhesive bonding. Ag-sintering and foil-based TLP bonding exhibited the best reliabilities. The lifetime of TLP bonding can be modeled based on crack propagation using Paris’ law. The current studies show a great potential for both Ag-sintering and foil-based TLP bonding as industrial die-attach processes.