On the Operation Modes of Dual-Gate Reconfigurable Nanowire Transistors

We investigate the operation modes of a dual-gate reconfigurable field-effect transistor (RFET). To this end, dual-gate silicon-nanowire FETs are fabricated based on anisotropic wet etching of silicon and nickel silicidation yielding silicide-nanowire Schottky junctions at source and drain. We compare the program gate at source (PGAS) with the more usual program gate at drain (PGAD) operation mode. While in PGAD mode, ambipolar operation is suppressed, switching is deteriorated due to the injection through a Schottky barrier. Operating the RFET in PGAS mode yields a switching behavior close to a conventional MOSFET. This, however, needs to be traded off against strongly nonlinear output characteristics for small bias voltages. Our measurement results are supported by transport simulations employing a nonequilibrium Green's function approach.