Accurate Extraction of Effective Gate Resistance in RF MOSFET

Abstract

This paper describes the gate electrode resistance of MOSFET and non-quasi-static (NQS) effect for RF operation. The vertical current paths between the silicide layer and poly-silicon are considered in the gate electrode. The vertical current paths are not effective in long-channel devices, but become more significant in short-channel devices. The gate resistance including vertical current paths can reproduce the practical RF characteristics well. By careful separation of the above gate electrode resistance and the NQS effect, the small-signal gate-source admittance can be analyzed with 130-nm CMOS process. Elmore constant (κ) of the NQS gate-source resistance is about five for long-channel devices, while it decreases down to about three for short-channel devices.