Low Temperature Wafer Direct Bonding Between GaInAsP Etch Stop Layer and Gd/sub 3/Ga/sub 5/O/sub 12/

Abstract

gamer crystal for the aim of integrating a lher diode and an optical isolator In a precious study, we demonsrated the bonding between InP and several kinds ofgmetr [I] , the latter ofwhich are essential to an optical isolator. Figure 1 shows B laser diode iiitegrated with an uptical isolator by wafa direct banding A GalnAsP etch stop layer ofthe 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 accampliahed by mowntional lithography and etching techniques In this paper, we report the direct bonding between GalnAsP and GdiGasOu [GGG) GGG ss used BS a mbstrate for epitaxial growth of maget ic garnets. Ali wafers were chmically treated. and contacted at roam temperature. The contacted samplas were immediately haded into an anneaiig furnace for the heat treatment at tcmperatures between I10 and 3301'. since magnetic garnets were damaged by heat treatment in H2 ambient st 385'L. 121 A pressure of250 p l c d was applied to the wafers during the h a t t rmment The bonded samples w ~ r e subjected to V ~ O U B dewce fabbrication pracesses, such rn baking, thermal annealing. wet etching and exposure to the plasma discharge. for investigmng the bundine Jurabihty. The bonding betaeen GalnAsP and GCG was achieved d t h the heat treatmm at temperatures between 110 and 3307: The samples bonded by the heat treatment at 110 and 220C rcmvned banded against all the processes The bonding between a terraced l a w diode and GGG was also petiomcd. The GalnAsP etched surface was bonded with C i G by heat treatnient at temperatures between I I O and 22OT. We believe that the low temperature wafer direct bonding is a promising technique for the integration ofa semiconductor laser diode and an optical isolator