"On-glass" process option for BiCMOS technology

An industrial SiGe BiCMOS technology is presented, in which the silicon substrate has been removed and replaced by a lossless glass substrate. This will enable the integration of better passives, while the active devices remain fully library compatible. Specifically, ideal NPN characteristics with 111/94 GHz f/sub T//f/sub max/ are shown without significant degradation of the thermal characteristics. This substrate transfer technology requires almost no changes to the standard processing and gives access to high-performance inverse NPN and vertical PNP devices, in addition to the lossless substrate.