Chapter 3 - CMOS Scaling to Nanometer Lengths

Abstract

This chapter deals with the complementary metal oxide semiconductor (CMOS) scaling and its future. The idea of modulating the surface conductance of a semiconductor by the application of an electric field was first invented in 1930. However, early attempts to fabricate a surface field-controlled device were not successful because of the presence of large densities of surface states which effectively shielded the surface potential from the influence of an external field. The first MOSFET on a silicon substrate using SiO2 as the gate insulator was fabricated in 1960. The major breakthrough in the level of integration came in 1963 with the invention of CMOS (Wanlass and Sah 1963) in which both n- and p-channel MOSFETs are constructed simultaneously on the same substrate. The most basic building block of digital CMOS circuits is a CMOS inverter. A CMOS inverter consists of an n-MOSFET and a p-MOSFET.