Fabrication of high-quality p-MOSFET in Ge grown heteroepitaxially on Si

We have successfully demonstrated high-performance p-MOSFETs in germanium grown directly on Si using a novel heteroepitaxial growth technique, which uses multisteps of hydrogen annealing and growth to confine misfit dislocations near the Ge-Si interface, thus not threading to the surface as expected in this 4.2% lattice-mismatched system. We used a low thermal budget process with silicon dioxide on germanium oxynitride (GeO_xN_y) gate dielectric and Si_0.75Ge_0.25 gate electrode. Characterization of the device using cross-sectional transmission electron microscopy and atomic force microscopy at different stages of the fabrication illustrates device-quality interfaces that yielded hole effective mobility as high as 250 cm²/Vs.