Extraordinary transport characteristics and multivalue logic functions in a silicon-based negative-differential transconductance device

High-performance negative-differential transconductance (NDT) devices are fabricated in the form of a gated p⁺-i-n⁺ Si ultra-thin body transistor. The devices clearly display a Λ-shape transfer characteristic (i.e., Λ-NDT peak) at room temperature, and the NDT behavior is fully based on the gate-modulation of the electrostatic junction characteristics along source-channel-drain. The largest peak-to-valley current ratio of the Λ-NDT peak is greater than 10⁴, the smallest full-width at half-maximum is smaller than 170 mV, and the best swing-slope at the Λ-NDT peak region is ∼70 mV/dec. The position and the current level of the Λ-NDT peaks are systematically-controllable when modulating the junction characteristics by controlling only bias voltages at gate and/or drain. These unique features allow us to demonstrate the multivalue logic functions such as a tri-value logic and a quattro-value logic. The results suggest that the present type of the Si Λ-NDT device could be prospective for next-generation arithmetic circuits.