QCA-based fault-tolerant XOR Gate for reliable computing with high thermal stability

The XOR gate is an essential element in the design of digital circuits due to its versatility and usefulness. The design of XOR gate in this paper is based on Quantum-dot Cellular Automata (QCA) 2D planner technology with no line-to-line intersections. The output amplitude is improved by redundant cell-based design, which also helped reliability and fault tolerance outperform. The proposed XOR gate achieves fault tolerance to single-cell addition and missing-cell defects from 68.48% to 95.33%. In addition, the proposed XOR gate is also fault-tolerant against multiple-cell missing defects, as verified from the simulations. Furthermore, high thermal stability makes the circuit reliable for QCA-based digital design applications. The digital design applications such as 4-bit B2G code converter and a 4-bit parity checker are designed from this XOR gate, utilizing 438 and 414 cells, respectively. This demonstrates its effectiveness in designing fault resilient and reliable circuit designs for various applications.