Design of multi-threshold threshold gate using MOS-NDR circuits suitable for CMOS process

We demonstrate a multi-threshold threshold gate (MTTG) based on a series and parallel connection of several MOS-NDR circuits. A MOS-NDR circuit is made of five standard Si-based metal–oxide–semiconductor field-effect-transistor (MOS) devices. It can show the negative-differential-resistance (NDR) characteristic in its current–voltage (I–V) curve by adjusting suitable parameters for the MOS transistors. The operation principle of this MTTG is based on the monostable-bistable transition logic element (MOBILE), which the output voltage goes to the low or high state depending on the relative current-peak conditions of the series-connected NDR circuits by supplying a clocked voltage. The weight of this MTTG is defined by the gate width of the MOS device in the MOS-NDR circuit. It is different from the design using the area of the resonant tunneling diode as the weight in the other NDR-based MTTG circuit. A great advantage of this MOS-NDR-based MTTG is that we can design the application using the standard CMOS technology without the need of compound semiconductor.