USE: A Universal, Scalable, and Efficient Clocking Scheme for QCA.

Quantum-dot cellular automata (QCA) is an emerging technology, conceived in face of nanoscale limitations of CMOS circuits, with exceptional integration density, impressive switching frequency, and remarkable low-power characteristics. Several of the current challenges toward the progress of QCA technology is related to the automation of the design process and integration into existing design flows. In this regard, this paper proposes the universal, scalable, efficient (USE), and easily manufacturable clocking scheme. It solves one of the most limiting factors of existing clock schemes, the implementation of feedback paths and easy routing of QCA-based circuits. Consequently, USE facilitates considerably the development of standard cell libraries and design tools for this technology, besides avoiding thermodynamics problems. Case studies presented in this paper reveal an area reduction of up to factor 5 and delay decrease by up to factor 3 in comparison with an existing advanced clocking scheme.