Ferroelectric Nanogap-Based Steep-Slope Ambipolar Transistor.

The subthreshold swing (SS) of metal-oxide-semiconductor field-effect transistors is limited to 60 mV dec -1 at room temperature by the Boltzmann tyranny, which restricts the scaling of the supply voltage. A nanogap-based transistor employs a switchable nanoscale air gap as the channel, offering a steep-slope switching process. Meanwhile, nanogaps featuring even sub-3 nm can efficiently block the current flow, exhibiting the potential for tackling the short-channel effect. Here, an electrically switchable ferroelectric nanogap to construct steep-slope transistors, is exploited. An average SS of 15.9 mV dec -1 across 5 orders and a minimum SS of 13.23 mV dec -1 are obtained in the high current density range. The transistor exhibits excellent performance with near-zero off-state leakage current and a maximum on-state current of 202 µA µm -1 at V DS  = 0.5 V. In addition, the transistor can turn off with either a positive or negative increase in the gate voltage, exhibiting ambipolar characteristics.