A New Series Resistance and Mobility Extraction Method by B SIM Model for Nano-Scale MOSFETs

摘要

As MOSFET gate length scales down to nano scale regime, parasitic source/drain series resistance (R{sub}(sd)) becomes one of the most critical parameters impacting device performance. Many studies have focused on developing an effective R{sub}(sd) extraction methodology. The "Channel-Resistance method" [1] provides a simple way to extract R{sub}(sd); however, this method is no longer adequate as pocket implants are introduced into the nano-scale MOSFET. In this case, pocket profiles overlap in the short channel region, causing higher effective bulk concentration and resulting in a total resistance which does not scale linearly with channel gate length (L{sub}G) [2]. Another famous method called "Shift & Ratio" (S&R) also suffers the similar issue because of its basic assumption that mobility (μ{sub}(eff)) does not change with L{sub}G [3]. Actually, pocket implant degrades μ{sub}(eff) in short channel region because of higher effective bulk concentration by the halo overlapping profile [4]. Therefore, the key point for extracting R{sub}(sd) in nano-scale MOSFETs is to take the impacts of L{sub}G dependency ofμ{sub}(eff) into account. In this work, a simplified BSIM-based model has been proposed to solve the above issues contributed by halo implants [5]. In this new methodology, R{sub}(sd) and μ{sub}(eff) can be uniquely extracted in nano-scale devices. Furthermore, the extracted L{sub}G dependency of μ{sub}(eff) may serve as a good indicator for monitoring the relationship between geometry and stress parameters.