Why BiCMOS and SOI BiCMOS?

Silicon technology development is at a crossroads, following an exponential rate of progress for more than thirty years. While CMOS (complementary metal-oxidesemiconductor) will remain the backbone of digital logic, silicon technology will evolve in directions driven by system needs that are not met by CMOS alone. It is argued that BiCMOS (bipolar complementary metaloxide-semiconductor), particularly SOI (silicon-on-Insulator) BiCMOS, will emerge as an important technology platform for mixed-signal systems. The bipolar transistors will be used primarily for the rf (radio-frequency) and analog functions, while the CMOS will be used for most digital functions. The SOI substrate provides dc and ac isolation, as well as opportunities for further device and circuit innovation.