An Optimized Clocking Scheme for Nanoscale Quantum-dot Cellular Automata Circuit

Quantum-dot cellular automata (QCA) is an emerging and developing technology, which is characterized by ultra-fast switching frequency, ultra-dense manufacturing and low power dissipation compared to CMOS technology, so QCA is one of the attractive alternatives to the current conventional CMOS. With the development of QCA technology, the automation technology for nanoscale QCA circuit design process has been extensively studied. In this work, a novel two-dimensional timing scheme with large clock region, suitable feedback loop, plain layout and non-crossing underlying structure was presented. The proposed novel two-dimensional timing scheme in this work not only to solve the clocked metal wire crossing problems, but also significantly reduce the difficulty of the manufacturing, compared with the existing optimal timing scheme. Finally, in order to prove the superiority of the proposed timing scheme, several circuits were implemented based on the proposed timing scheme by using QCADesigner. And it demonstrates that the area and the latency of the circuits are improved compared with circuit using the existing typical timing schemes.