Fabrication of GaAs laser diodes on Si using low temperature bonding of MBE grown GaAs wafers with Si wafers

The conventional heteroepitaxial GaAs-on-Si growth suffers from poor III-V material quality (dislocation density of /spl sim/10/sup 8/ cm/sup -2/ and a residual thermal stress of /spl sim/10/sup 9/ dyn/cm/sup 2/) and some process incompatibilities between the CMOS and III-V technologies. For these reasons, we have developed a heterogeneous integration scheme, which has the wafer-scale characteristics of monolithic integration and at the same time is compatible with commercial fully processed CMOS or bipolar-CMOS (BiCMOS) technology. We report on the basic process flow the properties of the GaAs/Si material and the processed laser diodes. MBE was used to grow GaAs/AlGaAs heterostructures with an inversed epitaxial structure, on 3inch GaAs substrates, after the inclusion of an AlAs etch stop layer. The GaAs wafer was then bonded at room temperature face-to-face with a 4inch Si wafer covered by spin-on-glass. Backside thinning of the GaAs substrate was used to leave the active thin III-V heterostructure on Si. The optoelectronic quality and the residual stress in the bonded III-V layers were assessed by photoluminescence and photoreflectance spectroscopies.