Hole Effective Mass of Strained Ge1-X Sn x Alloys P-Channel Quantum-Well MOSFETs on (001), (110), and (111) Ge Substrates

The dependence of effective mass on Sn content, pseudomorphic strain, cap layer thickness, and substrate orientation is theoretically studied for Ge-cap/Ge1-x Sn x /Ge substrate p-channel MOSFETs through six-band k·p method. The Luttinger-like and deformation potential parameters were obtained from the fit of Ge1-x Sn x band structures by the empirical pseudopotential method. The valence band alignment is theoretically determined by the empirical pseudopotential method and the model-solid theory. The high Sn content and thin Ge-cap layer both result the small effective mass at zone center along channel direction of the first subband.