25nm Short and Narrow Strained FDSOI with TiN/HfO2 Gate Stack

Abstract

We investigate for the first time the experimental performance of strained silicon directly on insulator (sSOI) for short and narrow FDSOI NMOS transistors integrated with a TiN/HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gate stack. A +16% drive current improvement is reported for a 25nm gate length (among the best ever reported for short substrate-induced strained devices). Through in-depth electrical characterization and mechanical simulations, transition from bi-axial to uni-axial strain is evidenced in extremely narrow sSOI channels, with a 40% mobility enhancement for 35nm wide devices. This highlights that the strain is not lost at sub-40nm dimensions