CHAPTER LIST

9.1. INTRODUCTION

Microelectronic devices have evolved rapidly in terms of size, cost and performance. Scaling of device dimensions has been the engine of the semiconductor industry1 allowing manufacturers to produce consecutive generations of integrated circuits of ever decreasing dimensions and increasing transistor densities. This trend has resulted in feature sizes with nanometer dimensions. Current physical gate lengths of transistors used in high performance integrated circuits are around 50 nm and will go down to 18 and 9 nm by 2010 and 2016, respectively, according to projections made in the 2003 International Technology Roadmap of Semiconductors (ITRS).2 Prototype transistors with gate lengths as small as 15 nm have already been fabricated in research labs around the world.3 ^,4 Clearly, the microelectronics industry has entered the nanotechnology era and is manufacturing millions of nanoscale transistors on a phenomenal scale.

The semiconductor industry has produced one of the most sophisticated manufacturing processes known to mankind. The key productivity drivers have been the scaling of the transistors, the device switching speed, and the reduced cost per function. To get an appreciation of the magnitude it is instructive to mention that the number of transistors produced in 2002 in DRAMs alone exceeds the number of grains of rice produced yearly. In addition, for each grain of rice one...