Control Technique of Solidus Temperature on Gold Base Solder for SiC Devices with High Temperature Operation

Abstract

  A high temperature soldering technique that enables to design the solidus temperature of the solder material has been developed by using Au-Ge-Ag system. By touching liquid phase Au-Ge to a solid phase Ag, Ag diffuses to the liquid and its solidus temperature rises up to the applied temperature. Authors have executed a series of sharing tests of die attached samples and confirmed solidus phase in 425°C which is much higher than 356°C, which is the solidus temperature of the eutectic alloy of Au-Ge. This technique will make possible to realize a high temperature operating power semiconductor module.