FD-SOI and RF-SOI technologies for 5G

This chapter presents silicon-on-insulator (SOI) technology for high-frequency applications. Major improvements at device- and substrate levels have enabled the commercial success of SOI technology. At transistor level, the development of SOI's low-parasitic architecture with excellent electrostatics has enabled high oscillation and cut-off frequencies in the range of 400 GHz. Such SOI architectures (partially depleted and fully depleted) are presented, along with their radio-frequency (RF) performance. Furthermore, the integration of several thick metal layers on the back end of line, coupled with the development of low-loss, highly linear silicon substrate, has boosted the quality factor of passives. Examples of low-loss integrated passives (spiral inductors, metal-on-metal capacitors, transmission lines) in an industrial SOI technology are presented. The existing SOI substrate flavors are reviewed and their impact on some passives is studied. Overall, SOI technology, presenting the best RF performance among all CMOS technologies, along with the powerful digital CMOS capabilities, is a prime candidate for high-performance millimeter-wave 5G applications.