Current Model of Fully Depleted Nanoscale Surrounding-Gate Metal–Oxide–Semiconductor Field-Effect Transistors with Doped Channel in All Operation Regions

Abstract

The diffusion current of fully depleted (FD) nanoscale surrounding-gate (SG) metal–oxide–semiconductor field effect transistors (MOSFETs) with a doped channel was physically modeled with a simple closed form based on the surface potential. The potential distribution [\\varPhix(z)] of doped SG MOSFETs was derived using Young's simple approximation from a two-dimensional (2D) Poisson's equation. In the diffusion current model, to consider the dependence on gate bias (VGS) and drain bias (VDS), parameters (DG and DD) were introduced. In the saturation region, the drift current modeling of doped FD SG MOSFETs was easily performed from the derived current model in the linear region. The current of the devices in the transition region was also modeled with the simple closed form using the diffusion and drift current model. Our simple compact model accurately predicted the current behaviors of the devices with a channel length up to 20 nm and shown good agreement with three-dimensional (3D) simulation.