fault-tolerant adder design in quantum-dot cellular automata

Quantum-dot cellular automata (qca) are an emerging technology and a possible alternative for faster speed, smaller size, and low power consumption than semiconductor transistor based technologies. previously, adder designs based on conventional designs were examined for implementation with qca technology. this paper utilizes the qca characteristics to design a fault-tolerant adder that is more powerful in terms of implementing robust digital functions. by considering two-dimensional arrays of qca cells, fault properties of such block adder can be analyzed in terms of misalignment, missing and dislocation cells. in order to verify the functionality of the proposed device, some physical proofs are provided. the results confirm our claims and its usefulness in designing digital circuits.