Fabricatable Interconnect and Molecular QCA Circuits

When exploring computing elements made from technologies other than complementary metal-oxide-semiconductor, it is imperative to investigate circuits and systems assuming realistic physical implementation constraints. This paper looks at molecular quantum-dot cellular automata (QCA) devices within this context. With molecular QCA, physical coplanar wire crossings may be very difficult to fabricate in the near to midterm. Here, we consider how this will affect interconnect. We introduce a novel technique to remove wire crossings in a given design in order to facilitate the self-assembly of real circuits - thus, providing meaningful and functional design targets for both physical and computer scientists. The proposed methodology eliminates all wire crossings with minimal logic gate/node duplications. Simulation results based on existing QCA circuits and other benchmarks are presented, and suggest that further investigation is needed.