High Mobility High-Ge-Content SiGe PMOSFETs Using Al₂O₃/HfO₂ Stacks with In-Situ O₃ Treatment

We developed an Al2O3/HfO2 bi-layer gate dielectric with an in-situ O3 treatment for interface state density (Dit) and gate leakage current density (Jg) 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 Si0.05Ge0.95 substrate. The O3 treatment enabled application to non-planar device structures and we demonstrated five orders of magnitude lower off currents (Ioff), a sub-threshold slope of 68 mV/decade, and a very high hole mobility of 457 cm2V-1s-1 at an inversion carrier density (Ninv) of 1 × 1013 cm-2 for asymmetrically strained SiGe PMOSFETs with Ge% of 65%-70%.