The Fundamental Primitives with Fault-Tolerance in Quantum-Dot Cellular Automata

Abstract

Since conventional CMOS technology has met its development bottleneck, an alternative technology, quantum-dot cellular automata (QCA), attracted researchers’ attention and was studied extensively. The manufacturing process of QCA, however, is immature for commercial production because of the high defect rate. Seeking for designs that display excellent performance shows significant potentials for practical realizations. In the paper we propose a 5 × 5 module, which not only can implement three-input majority gate but also can realize five-input majority gate by adding another two inputs. A comprehensive analysis is made in terms of area, number of cells, energy dissipation and fault tolerance against single-cell omission defects. In order to testify the superiority of the proposed designs, preexisting related designs are tested and compared. Weighing up above four kinds of factors and technical feasibility, proposed majority gates perform fairly well. Further, we take full adders and multi-bit adders as illustrations to display the practical application of proposed majority gates. The detailed comparisons with previous adders reveal that proposed 5 × 5 module behaves well in circuits, especially the high degree of fault tolerance and the relatively small area, complexity and QCA cost, thereby making it more suitable for practical realizations in large circuit designs.