Compact modeling of non-classical MOSFETs for circuit simulation

Abstract

This thesis documents the compact models developed for SOI/FinFET/SiNW

MOSFETs as well as Schottky barrier and dopant-segregated Schottky MOSFETs.

The Unified Regional Modeling approach is extended from bulk MOSFETs to SOI

MOSFETs as well as the next generation FinFET/SiNW MOSFETs. SOI-specific

effects, such as floating-body and self-heating effects, are physically modeled using

both analytical and subcircuit approaches. The limitations of unipolar assumption are

explored through TCAD simulation and a novel symmetrical imref correction is

proposed to effectively remedy the unipolar assumption. A unified model for

FinFET/SiNW MOSFETs is formulated. The Gummel symmetry issue in three

terminal devices is essentially solved by the proposed effective drain-source voltage

expression. The unified model is validated extensively with experiment data and has

been coded in Verilog A for statistical and technology variation studies. A physicsbased

single piece compact model for undoped Schottky barrier SiNW MOSFETs is

formulated based on a quasi-2D surface potential solution and Miller-Good tunneling

model. Unique ambipolar behavior is excellently reproduced. A unique subcircuit

approach is proposed to physically model the dopant-segregation in Schottky SiNW

MOSFETs. The model can not only reproduce the unique convex curvature in Ids-Vds

characteristics, but also explain the process variations in particular the Schottky barrier

height variations. The research demonstrated the unique advantage of the Unified

Regional Modeling approach in modeling the next generation non-classical MOS

devices.