Overview

This chapter describes the fundamentals of metal oxide semiconductor (MOS) device physics. It discusses the physics of bulk metal oxide semiconductor field‐effect transistors (MOSFETs). The chapter introduces some important physics related to silicon‐on‐insulator metal oxide semiconductor field‐effect transistors (SOI MOSFETs) and explores the theoretical basis of tunnel field‐effect transistors (TFETs). It is obvious that we must minimize the subthreshold swing (SS) value of the MOS device in designing device parameters for low‐power applications. However, there is still some controversy regarding the issue of whether the subthreshold issue is the substantial problem in overcoming the stand‐by power issue. In many MOS devices, there is a simultaneous increase in the band‐to‐band tunneling (BTBT) current around the source and drain junctions because there must be shallow junctions in bulk devices or an extremely thin semiconductor layer in silicon‐on‐insulator (SOI) devices in order to suppress short‐channel effects.