On the low-frequency noise of pMOSFETs with embedded SiGe source/drain and fully silicided metal gate

The low-frequency noise of silicon pMOSFETs with embedded SiGe source/drain (S/D) regions is studied. The gate stack consists of HfSiON/SiO2 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/f 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/f noise is observed here.