Ag/Au diffusion wafer bonding for thin-GaN LED fabrication

In this study we successfully demonstrate a method for Ag/Au diffusion wafer bonding. We were able to achieve a high-meltingpoint bonding interface at a relatively low bonding temperature of 150 C. The Ag/Au interdiffusion coefficient is defined against the Au content. Au atoms have a faster diffusion rate in the Ag matrix layer, which causes the Ag/Au interface to move toward the Au side over time. The use of this method of Ag/Au diffusion bonding makes the fabrication of high-power thin-GaN light-emitting diode chips on Si wafers a feasible possibility. (c) 2007 The Electrochemical Society. All rights reserved.