Ultrathin strained-ge channel P-MOSFETs with high-k/metal gate and Sub-1-nm equivalent oxide thickness

Surface-channel strained-Ge (s-Ge) p-MOSFETs with high-K/metal gate stack and ozone surface passivation are fabricated, for the first time. The channel is ultrathin (∼3-6 nm thick) s-Ge (∼2.2%, biaxial compression) epitaxially grown on a relaxed Si 0.56Ge 0.44 virtual substrate. Split capacitance-voltage measurements along with quantum-mechanical simulations demonstrate a capacitance-equivalent thickness of 1.3 nm and sub-1-nm equivalent oxide thickness. The effective hole mobility of these devices was extracted and exhibits 3 × and 2.2 × mobility enhancement over universal Si hole mobility, for s-Ge channel thicknesses of ∼6 and ∼ 3 nm, respectively. © 2012 IEEE.