Framework for QCA Layout Generation and Rules for Rotated Cell Design

Abstract

Quantum-dot Cellular Automata (QCA) is a nontransistor-based nanotechnology circuit design paradigm. The circuits are implemented by using cells having quantum dots and electrons. There are several cell configurations with varying combinations of electrons and quantum dots. But the widely used cells have the four-dot two-electron structure. Circuits are realized and validated by using QCADesigner. However, the layouts are developed manually by using this tool. Layouts are not entirely automated in QCA. Hence, in this work, the existing QCA tools and the different techniques proposed in the literature to improve the QCA layout generation are analyzed and a complete framework for QCA layout generation is proposed. It also explores the gap that needs to be filled to achieve a reliable CAD tool for QCA layout generation. In addition to that, to design circuits using rotated cells, design rules and cost functions are proposed. Novel circuits of multiplexer and D-flip-flop are also proposed using rotated cells. The proposed designs have better output polarization compared to other designs. Verification is done in QCADesigner.