Room temperature bonding of aluminum nitride ceramic and semiconductor substrate

AlN and Si substrates were bonded at room temperature after sputtering the surfaces under ultra-high vacuum conditions. The bonding strength was insignificant when they were directly bonded. However, the strong bonding equivalent to the Si bulk strength (2.5 J/m(2)) was achieved by a process modification to form a 1.5-nm-thick Si adhesion layer on the AlN substrate. When the Au/Ti bonding layers were deposited on the surfaces before bonding, such strong bonding was also obtained. As the bonding layers were atomically thin, we expect that the thermal resistance between the substrates is limited compared with other integration techniques.