Simulation Study of Germanium p-Type Nanowire Schottky Barrier MOSFETs

Ambipolar currents in germanium p-type nanowire Schottky barrier (SB) metal-oxide-semiconductor field-effect transistors were calculated fully quantum mechanically by using the multiband k ·p method and the nonequilibrium Green´s function approach. We investigated the performance of devices with [100], [110], and [111] channel orientations, respectively, by varying the nanowire width, SB height, and equivalent oxide thickness (EOT). The [111]-oriented devices showed the best performance. In comparison to Si as a channel material, Ge is more desirable because more current can be injected into the channel, resulting in steeper subthreshold swing and higher on-state current. Our calculations predict that the Ge channel devices should have an EOT gain of 0.2-0.5 nm over Si channel devices.