Simple S/D Series Resistance Extraction Method Optimized for Nanowire FETs

The conventional source/drain series resistance ( R sd ) extraction method is not applicable to nanowire field effect transistors (NWFETs), as NWFETs have fluctuating characteristics in Id and there is insufficient physical modeling. In this letter, we propose a modified R sd extraction method that uses an optimized Id equation and a threshold voltage ( V th ) extraction procedure for NWFETs. The Id equation is modified for the geometry of the NWFET, and V th is obtained from the linear Y-function that can be observed in NWFETs because of volume inversion. A necessary assumption for this procedure is experimentally confirmed using the Y-function, and equations that fit the measured data perform well; this justifies the validity of applying the modified Id equations to NWFETs. Therefore, R sd is perfectly extracted in all NWFETs and it is observed to be dependent on the channel diameter ( d NW ) when normalized by d NW , indicating that the extension resistance is the dominant component in the total R sd .