Enhanced channel modulation in dual-gated silicon nanowire transistors.

Dual-gated silicon nanowire (SiNW) field-effect transistors (FETs) have been fabricated by using electron-beam lithography. SiNW devices (W approximately 60 nm) exhibit an on/off current ratio greater than 10(6), which is more than 3 orders of magnitude higher than that of control devices prepared simultaneously having a large channel width (approximately 5 microm). In addition, by changing the local energy-band profile of the SiNW channel, the top gate is found to suppress ambipolar conduction effectively, which is one of the factors limiting the use of nanotube or nanowire FETs for complimentary logic applications. Two-dimensional numerical simulations show that the gate-induced electrostatic control is improved as the channel width of the FETs decreases. Therefore, enhanced channel modulations can be achieved in these dual-gated SiNW devices.