Abstract

Wafer direct bonding is an attractive technique for the integration of different materials without any adhesives. The authors have applied this technique to bonding of a III-V compound semiconductor and a garnet crystal for the aim of integrating a laser diode and an optical isolator. In a previous study, we demonstrated the bonding between InP and several kinds of garnets [1], the latter of which are essential to an optical isolator. Figure 1 shows a laser diode integrated with an optical isolator by wafer direct bonding. A GaInAsP etch stop layer of the laser diode is prepared for vertical alignment between an active layer of the laser diode and a guiding layer of the optical isolator. The vertical alignment can be achieved by adjusting the thickness of cladding layers. The lateral alignment of a waveguide with the laser stripe can be accomplished by conventional lithography and etching techniques. In this paper, we report the direct bonding between GaInAsP and Gd₃Ga₅O₁₂ (GGG). GGG is used as a substrate for epitaxial growth of magnetic garnets.

© 1998 IEEE