Introduction

Miniaturization of circuit elements has played an essential role in improving the performance, capacity, and functionality of semiconductor integrated circuits. Transistors with shorter channel lengths can switch faster. The capability to integrate a larger number of devices generally translates into enhanced capacity and functionality. For these reasons, the semiconductor industry is expected to continue its miniaturization efforts in the coming decades. Indeed, minimum feature sizes of integrated circuit components are projected to reach the sub-0.1 /un regime during the first decade of the 21st century. A recent study (Timp et al., 1997) demonstrated the operation of field-effect transistors with 61 nm gate width.