On the Low-Frequency Noise of pMOSFETs With Embedded SiGe Source/Drain and Fully Silicided Metal Gate

Abstract

The low-frequency noise of silicon pMOSFETs with embedded SiGe source/drain (S/D) regions is studied. The gate stack consists of HfSiON/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> covered by a fully silicided gate electrode. S/D regions with different Ge content and thickness have been processed. It is shown that, while mobility and drive current are significantly enhanced by this strain-engineering approach, the 1/ <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> noise is little affected, irrespective of the germanium content or thickness of the epitaxial SiGe S/D layers, i.e., the amount of compressive strain in the channel. From this, it is derived that, first of all, the embedded (S/D) processing does not degrade the gate-stack quality and that, second, no evidence of an intrinsic strain effect on the 1/ <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> noise is observed here.