Combining SiGe BiCMOS and InP Processing in an On-top of Chip Integration Approach

Applications such as radar imaging and wideband communications are driving the research on millimeter-wave circuits. For some applications SiGe hetero junction bipolar transistors (HBTs) are limited in output power. III-V technologies (like InP) can realize devices showing a high product of peak transit frequency multiplied with the open base breakdown voltage. Therefore, merging the qualities of both III-V and Si technology will enable a new class of high-performance ICs. Our approach combines an InP-DHBT transferred-substrate process with a Si-BiCMOS process. The key method is an aligned face-to-face wafer bonding with a subsequent removal of the InP substrate. Different integrated signal sources with an output frequency up to 246 GHz were designed and produced using different combinations of BiCMOS and InP circuit building blocks to demonstrate the capabilities of the hetero-integration routine. In this paper the influences of the wafer bonding and the finalization of the InP-DHBT process on SiGe devices were investigated. It was found that the influences on the BiCMOS devices were rather small