Hole Mobility Boosters of (110)-Oriented Extremely Thin Body SiGe-on- Insulator (SGOI) pMOSFETs

The effectiveness of (110)-oriented substrates and strain modulation by using starting substrates with thin SiGe and channel width narrowing on mobility enhancement in SiGe-on-insulator (SGOI) pMOSFETs is systematically investigated down to the body thickness (
${T}_{\text {body}}{)}$
of 3.2 nm. The initial strain of 1.6% is realized at a Ge fraction of 60% by using the optimized Ge condensation. We confirm the significant mobility enhancement by narrowing the channel width (
${W}_{\text {ch}}{)}$
of (110) SGOI channels, attributed to strong asymmetric strain. At
${T}_{\text {body}}$
of around 5 nm, (110) SGOI pMOSFETs provide higher hole mobility of 971 cm
²
/Vs than the ones fabricated on (100) GOI substrates, resulting in
$1.9\times $
mobility enhancement. The effective hole mobility of 291 cm
²
/Vs is also achieved on 3.2-nm-thick (110) SGOI pMOSFETs with asymmetric strain channels at
${W}_{\text {ch}}$
of 120 nm, leading to mobility enhancement of
$1.5\times $
against the mobility of quasi-uniaxial (100) GOI ones at the same
${T}_{\text {body}}$
despite the lower Ge fraction.