Design and Simulation of an Efficient Quaternary Full-Adder Based on Carbon Nanotube Field Effect Transistor

The essential reason for implementing multilevel processing systems is to reduce the number of semiconductor elements and hence the complexity of system. Multilevel processing systems are realized much easier by carbon nanotube field effect transistors (CNTFET) than MOSFET transistors due to the CNTFET transistors’ adjustable threshold voltage capabilities. In this paper, an efficient quaternary full-adder based on CNTFET technology is presented which consists of two half adder blocks, a quaternary decoder and a carry generator circuit. In the proposed architecture, the base-two and base-four circuit design techniques are combined to take the full advantages of both techniques namely simple implementation and low chip area occupation of the entire proposed quaternary full-adder. The proposed structure is evaluated using the Stanford 32nm CNTFET library in HSPICE software. The simulation results for the proposed full-adder structure utilizing a supply voltage of 0.9 volts, reveals the power consumption, propagation delay and energy index equal to 2.67 μW, 40 ps, and 10.68 aJ, respectively.