Laser bonding of dissimilar semiconductors

A laser bonding technique for joining dissimilar semiconductors is investigated. Acceptable mechanical strength, electrical conductance, and optical transparency of the bond region are demonstrated, together with the survivability of the device structure in the vicinity of the bond during the bonding operation. Also discussed are future applications of this bonding technique for more complicated semiconductor devices. The dissimilar semiconductors joined include GaAs, CdTe, InAs, Ge, GaSb, Al(x)Ga(1-x)As, and Si. To effect the bonding, the dissimilar semiconductor wafers are pressed together between two glass anvils inside a bonding fixture having an aperture that allows the laser irradiation to reach the samples. The bonding environment is laboratory air, with the sample initially at room temperature. Since the energy distribution of the laser beam is not spatially uniform, a glass diffuser is included in the optical path, and multiple pulses are employed to improve the uniformity of the bond.