Preface

The computer revolution (i.e., faster, smaller, and cheaper computers), and the technologies it has enabled (e.g., the Internet, laptops, smart phones), have been driven by continued size-scaling of the CMOS transistors in the constituent integrated circuits (ICs, e.g., the microprocessor) of the computer. This scaling, which has doubled the transistor density on the CMOS IC chip about every two years, has been achieved by simply ratioing the dimensions and related parameters of the basic, classical transistor structure (i.e., the planar single-gate MOSFET in bulk silicon or partially depleted SOI) (Taur and Ning, 2009) as improvements in lithography enabled reduced minimum feature size. The CMOS devices have now become so small (e.g., gate lengths are 30–40 nm) that this straightforward scaling is no longer possible, mainly because of fundamental limitations in reliable doping of the classical MOSFET. Thus, continued CMOS scaling will require a new, nonclassical transistor structure with ultra-thin body (UTB) that avoids these limitations. The first concrete evidence of the transition to a UTB transistor structure is Intel Corporation’s adoption of the “trigate transistor” (or FinFET) (Auth et al., 2012) for 22 nm CMOS technology and beyond.

This book details the fundamental physics of silicon-based UTB MOSFETs, overviews their designs, with links to the process integration, and projects potential nanoscale UTB-CMOS performance. The presentations are facilitated by the authors’ process/physics-based compact model for double-gate MOSFETs, UFDG (Appendix). This book is suitable as a textbook for a one-semester graduate or senior-undergraduate university course, as well as for a fundamental guide to optimal nonclassical device design and integration for professional engineers in the CMOS IC field. The prerequisites are good backgrounds in basic semiconductor device physics (e.g., as in Sze and Ng (2007)) and in fundamentals of classical bulk-Si MOSFETs (Taur and Ning, 2009). In fact, this book is intended to be a supplementary text for the latter book.