Extraction of Channel Length Independent Series Resistance for Deeply Scaled Metal-Oxide-Semiconductor Field-Effect Transistors

The recently developed four R_sd extraction methods from a single device, involving the constant-mobility method, the direct I_d–V_gs method, the conductance method and the Y-function method, are evaluated on 32 nm n-channel metal-oxide-semiconductor field-effect transistors (nMOSFETs). It is found that R_sd achieved from the constant-mobility method exhibits the channel length independent characteristics. The L-dependent R_sd extracted from the other three methods is proven to be associated with the gate-voltage-induced mobility degradation in the extraction procedures. Based on L-dependent behaviors of R_sd, a new method is proposed for accurate series resistance extraction on deeply scaled MOSFETs.