We have demonstrated a 70-nm n-channel tunneling field-effect transistor (TFET) which has a subthreshold swing (SS) of 52.8 mV/dec at room temperature. It is the first experimental result that shows a sub-60-mV/dec SS in the silicon-based TFETs. Based on simulation results, the gate oxide and silicon-on-insulator layer thicknesses were scaled down to 2 and 70 nm, respectively. However, the ON/ OFF current ratio of the TFET was still lower than that of the MOSFET. In order to increase the on current further, the following approaches can be considered: reduction of effective gate oxide thickness, increase in the steepness of the gradient of the source to channel doping profile, and utilization of a lower bandgap channel material

A tunneling field-effect transistor (TFET) is considered one of the most promising alternatives to a metal-oxide-semiconductor field-effect transistor due to its immunity to short-channel effects. However, TFETs have suffered from low on-current, severe ambipolar behavior, and gradual transition between on- and off -states. To address those issues, the authors have proposed hetero-gate-dielectric TFETs. The proposed device enhances on-current, suppresses ambipolar behavior, and makes abrupt on-off transition by replacing the source-side gate insulator with a high-k material, which induces a local minimum of the conduction band edge at the tunneling junction.

An L-shaped tunnel FET (TFET), which features band-to-band tunneling (BTBT) perpendicular to the channel direction, is experimentally demonstrated for the first time. It is more scalable than other vertical-BTBT-based TFET designs and provides more than $1000\times $ higher ON-current ( $I_{{\mathrm{\scriptscriptstyle ON}}}$ ) than a conventional planar TFET with the same gate overdrive ( $V_{\mathrm{ov}}$ ) of 0.8 V, due to improved subthreshold swing ( $S$ ) and larger tunnel junction area. Its temperature dependence, constant $S$ , and nonlinear output characteristics are discussed.

The design of gate-all-around (GAA) MOSFETs was optimized and compared with that of double-gate MOSFETs. We discussed the optimal ratio of the fin width to the gate length and investigated short-channel effects of GAA MOSFETs. Using three-dimensional simulations, we confirmed that short-channel effects were properly suppressed although the fin width was the same as the gate length in GAA MOSFETs. Finally, we compared cubical channel GAA MOSFETs with cylindrical-channel ones. As a result, it was observed that the latter showed the maximized ratio of the fin width to the gate length up to 1.2.