Noise and Process Variation Tolerant, Low-Power, High-Speed, and Low-Energy Full Adders in CNFET Technology

In this paper, a number of novel 1-bit full adder cells using carbon nanotube field-effect transistor devices are presented. First of all, some two-input XOR/XNOR circuits are proposed, and then, they are employed to form 1-bit full adders. Totally, five full adders with driving power and one without driving power are proposed in this paper, each of which has its own merits. Simulations with regard to supply power scaling and different load conditions confirm the superiority of the proposed cells compared with the previously reported ones in terms of power, delay, power-delay product (PDP), and Energy-delay product (EDP). Also embedding the proposed full adders in the large circuits,such as ripple carry adder (RCA), with a wide word length shows that they have better power, speed, and PDP with regard to their counterparts. Furthermore, the susceptibility of the full adders against both input noise and process variations (diameter deviations of carbon nanotubes) is studied. In terms of noise, the proposed cells have a close competition to their counterparts, and they are robust against high amplitude of noises. In terms of process variation, the proposed cells with driving power display the most robustness compared with their counterpart.