Analytical Threshold Model for Nanoscale Cylindrical Surrounding-Gate Metal--Oxide--Semiconductor Field Effect Transistor with High-$\kappa$ Gate Dielectric and Tri-Material Gate Stack

A novel cylindrical surrounding-gate metal--oxide--semiconductor field effect transistor with high-$\kappa$ gate dielectric and tri-material gate stack (TMGCSG MOSFET) is presented. The performance of the new structure is studied by developing physics-based analytical models for surface potential, electric field, and threshold voltage. It is found that TMGCSG MOSFET can effectively suppress short-channel effects and hot-carrier effects, and simultaneously improve carrier transport efficiency. It is also revealed that threshold voltage roll-off for TMGCSG MOSFET can be significantly reduced by adopting both a small effective stack-gate oxide thickness and a small radius silicon channel. The accuracy of the analytical models is verified by its good agreement with the three-dimensional numerical device simulator DESSIS.