Influence of channel length, thickness, and crystal orientation in ultra-scaled double-gate pMOSFETs

Ultra-scaled silicon double-gate pMOSFETs with different channel lengths and thicknesses, as well as confinement and transport crystal orientations are simulated by the non-equilibrium Green's function (NEGF) approach employing the six-band k·p Hamiltonian. The ballistic ON-state current (Ion) and the subthreshold swing (SS) are extracted from the I-V curves to evaluate the device performances. It is found that the optimal crystal orientation is dramatically different for different channel lengths and thicknesses. To understand such device behaviors, band structures, average ballistic hole velocities, and source-to-drain tunneling are calculated and compared.