Abstract
Suspended strained-Si nano-wires (NWs) were fabricated from a highly biaxially strained-Si substrate (with an initial stress of 2.16 GPa). Using e-beam lithography, ~25nm thick NWs with the widths in the range of 20 to 80 nm were fabricated and the stress was investigated by UV micro-Raman spectroscopy. Suspended NWs are strained to an average uniaxial tensile stress level of ~2.1 GPa which is almost independent of NW width, in the range studied in this work. Ultra-dense (25 NWs per micron) sub-20 nm suspended strained-Si NWs were fabricated using resolution-enhanced lithography to improve the Raman signal-to-noise ratio. A tensile in-plane stress level of 1.7GPa was measured for 18 nm-wide NWs at 40 nm pitch. Gate-all-around n-MOSFETs were fabricated based on these strained-Si NWs. Electrical measurements on these MOSFETs demonstrate near ideal subthreshold behavior, very high on-to-off ratio and current drive and transconductance enhancement of ~2X over unstrained NWs.