A new low-temperature bonding technology between large-area, high-power devices and Mo electrodes using Au-Al films

In order to realize large-area, high-power devices with high-performance, low-temperature diffusion, bonding technology between Al electrodes on both cathode and anode sides of Si devices and Mo electrode foils has been investigated, The 100 mm diameter power devices and the same size Mo foils could be joined by the formation of Au-Al intermetallic compounds below 573 K. The compounds were formed by solid state diffusion with activation energy of about 1.0 eV. Substantial reduction of the mounting force while keeping uniform contact was possible after low-temperature bonding. Reliability of the bonded large area, high-power device was predicted to be sufficient from a metallurgical viewpoint.