Compact MOSFET Models for VLSI Design

1

Semiconductor Physics Review for MOSFET Modeling

1.1 Introduction

The idea of controlling electric current through the field effect on a semiconductor surface dates back to as early as 1930. It was proposed in a patent claim by Lilienfeld which forms the conceptual framework of present day MOSFET operation [1]. From the account of the evolution f the MOS transistor, as outlined by Sah [2], it appears that MOS technology did not emerge primarily as a consequence of a focussed pursuit to realize Lilienfeld's field effect concept, but as a by-product of a series of revolutionary developments in the field of solid-state electronics. These developments include the invention of point contact and junction bipolar transistors by Bardeen [3], and Shockley [4], innovations in planar technology and selective diffusion through windows etched in oxide as demonstrated by Hoerni [5], integration of passive and active components by Kilby [6], to name only a few landmark milestones. These technological capabilities enabled the realization of the Metal–Oxide–Semiconductor Field Effect Transistor (MOSFET) structure by Kahng and Atalla [7–9], which was considered suitable for replacement of prevailing bipolar integrated transistor logic circuits. The complementary PMOS–NMOS inverter structure by Wanlass and Sah [10] provided a defining innovation which heralded the CMOS digital era. While the realization of MOSFET on silicon took about as long as thirty years, taking the initial patent as the reference ...