Design Considerations and Capacitance Dependent Parametric Assessment of Gate Metal Engineered SiNW MOSFET for ULSI Switching Applications

Abstract

This work investigates design consideration of Gate Electrode Workfunction Engineered (GEWE) silicon nanowire MOSFET at room temperature. It is perceived from the results that the parasitic capacitances are higher in the deep inversion region, however; the coupling of parasitic capacitance is weak in GEWE-SiNW due to lower gate metal workfunction at the drain end. Moreover, the influence of drain voltage on Cgs is very less owing to constant depletion charges at the source side which results in almost constant value of Cgs with the change in Vds. With tuning of channel length (Lg) and oxide thickness (tox), the effect of capacitances in GEWE-SiNW further reduces significantly due to quantization effect at such scaled dimensions. Furthermore, Transconductance Frequency Product (TFP), Energy Delay Product (EDP) and Gain Bandwidth Product (GBP) have also been calculated with an aim to analyze the device DC and switching performance as they are directly or indirectly linked with parasitic capacitance. Calibrated 3D simulations validate that the GEWE-SiNW MOSFET exhibit 2.57, 34.5 and 2.75 times improvement in TFP, EDP and GBP respectively in comparison to SiNW in the linear region.