Observation of Mobility Enhancement in Strained Si and SiGe Tri-Gate MOSFETs with Multi-Nanowire Channels Trimmed by Hydrogen Thermal Etching

Strained Si and SiGe tri-gate nanowire (NW) MOSFETs with significantly reduced line-edge roughness and smooth sidewalls were fabricated by a novel anisotropic thermal etching technique in H
₂
atmosphere. Effective carrier mobility measurements revealed mobility enhancements for the strained-Si NW n-MOSFETs and the strained-SiGe NW p-MOSFETs by factors of 1.9 and 1.6 against unstrained Si NW n- and p-MOSFETs, respectively. It was also shown that the sidewall shapes of the NWs have a great impact on the mobility via the difference in the surface roughness scattering on the sidewalls.