Importance of V rm th and Substrate Resistance Control for RF Performance Improvement in MOSFETs

Transistor scaling with the CMOS technology advancement results in f sub(max) saturation in contrast to fT improvement. Effective improvement methods for such saturated f sub(max) are presented to the transistors fabricated by 45- and 65-nm low standby power CMOS technology. The primary parameters investigated are V sub(th) optimization through adjusting the channel implantation and R sub(sub) control through adjusting the active to substrate contact spacing. It is demonstrated that V sub(th) optimization and R sub(sub) control result in more than 20% and 10% improvements for f sub(max), respectively.