Chapter 1 - Basic MOS Device Physics

Abstract

This chapter focuses on the fundamental aspects of metal-oxide semiconductor (MOS) device behavior that are of immediate relevance to practical integrated circuit (IC) design. It is intended as a review of basic principles. An MOS transistor is also referred to as a metal-oxide semiconductor field-effect transistor (MOSFET). There are two complementary MOS (CMOS) transistors: N-channel MOS (NMOS) and P-channel MOS (PMOS). Both NMOS and PMOS transistors can be incorporated onto the same monolithic chip, resulting in a CMOS circuit. There are three different types of CMOS processes: local-oxidation-of-silicon (LOCOS) process, shallow-trench-isolation (STI) process, and silicon-on-insulator (SOI) process. The chapter illustrates a conceptual cross-section diagram of a typical NMOS transistor implemented in a LOCOS-type CMOS process. It discusses the basic properties of MOS switches. The chapter also describes the behavior of the MOS device as a capacitor. A MOSFET capacitor can be divided into three different regions: accumulation, depletion, and inversion.