A Charge-Based Model for Long-Channel Cylindrical Surrounding-Gate MOSFETs From Intrinsic Channel to Heavily Doped Body

Abstract

A charge-based model is presented for long-channel cylindrical surrounding-gate (SRG) MOSFETs from an intrinsic channel to a heavily doped body. The model derivation is based on an accurate inversion charge solution of Poisson's equation in a cylindrical coordinate system. The general drain-current equation is obtained from Pao-Sah's dual integral, which is expressed as a function of inversion charge at the source and drain terminals. The model is valid for all regions of operation without employing any smoothing function. The model has been extensively verified by numerical simulations with a wide range of SRG MOSFET geometry parameters and channel doping concentrations, including the undoped channel.