New insights on RF CMOS stability related to bias, scaling, and temperature

The stability issues of CMOS devices for RF applications were studied. The stability factor of MOS devices based on the small-signal model (SSM) parameters was derived, for the first time. The results reveal some new insights on the effects of biasing, and scaling parameters on the stability; and were subsequently confirmed by our experimental results. Our results also show that unconditional stability of RF CMOS devices can be obtained with proper biasing and device geometries. Finally, the effects of temperature on stability were also investigated. Our results suggest that careful attention needs to be paid for stable low temperature operation.