High Mobility High-Ge-Content SiGe PMOSFETs Using Al 2 O 3 /HfO 2 Stacks With In-Situ O 3 Treatment

We developed an Al 2 O 3 /HfO 2 bi-layer gate dielectric with an in-situ O 3 treatment for interface state density (D it ) and gate leakage current density (J g ) reductions on SiGe channels. We observed Ge-content dependent equivalent oxide thickness (EOT) scaling and EOT 0.44 nm was achieved with an MOS capacitor with a Si 0.05 Ge 0.95 substrate. The O 3 treatment enabled application to non-planar device structures and we demonstrated five orders of magnitude lower off currents (I OFF ), a sub-threshold slope of 68 mV/decade, and a very high hole mobility of 457 cm $^{2}\text{V}^{\mathrm {-1}}\text{s}^{\mathrm {-1}}$ at an inversion carrier density (N inv ) of $1\times 10^{13}$ cm $^{\mathrm {-2}}$ for asymmetrically strained SiGe PMOSFETs with Ge% of 65%–70%.