Programmable logic gate based on controlled quenching of series-connected negative differential resistance devices

The unique characteristics of resonant-tunneling (RT) devices, such as the negative differential resistance (NDR), can be used to construct compact functional circuits. In this work, we propose and experimentally demonstrate a new circuit that takes full advantage of the NDR feature in RT devices. The circuit features three NDR devices connected in series and is driven by a clocked bias voltage V/sub BIAS/. The function of the circuit can be selected as one of the six logic functions (AND, OR, NAND, NOR, XOR, and XNOR) by control voltages and the amplitude of V/sub BIAS/. This flexible functionality indicates that our circuit can be applied to the implementation of programmable logic circuits, which will provide cost-effective prototypes for modern circuit designs.