Grain Boundary Diffusion of Ni through Au-Doped Ni3Sn2 Intermetallic Compound for Technological Applications

In recent years Au-Sn solid–liquid interdiffusion (SLID) has become a widely known bonding method to deliver promising die attaching techniques for high-temperature operating electronic vehicles. Insulated-gate bipolar transistor (IGBT) chips were assembled on direct bonded copper substrates by utilizing a Ni/Au-20Sn/Ni system based on SLID. Our previous research investigated the intermetallic compounds formed after isothermal aging. Electron microscopic instrumentation was employed to determine the interfacial reactions between AuSn and nickel (Ni). After total consumption of AuSn at the rim sites of (Ni, Au)3Sn2 grains, an increased concentration of Ni was identified. Prolongation of aging time at 240°C helped in precipitation of Ni3Sn at the interface of (Ni, Au)3Sn2 and Ni. This current research has theorized the mechanism of the intermetallic compounds formed at the rim sites of the Au-Sn System. From the results, the Au-Sn eutectic system attained in this article is ideal to assemble an IGBT for high-temperature devices using SLID.