Partitioning and placement for buildable QCA circuits

ABSTRACT

Quantum-dot Cellular Automata (QCA) is a novel computing mechanism that can represent binary information based on spatial distribution of electron charge configuration in chemical molecules. In this paper, we present partitioning and placement algorithms for a large-scale automatic QCA layout. The purpose of zone partitioning is to initially partition a given circuit such that a single clock potential modulates the interdot barriers in all of the QCA cells within each zone. We then place these zones during our placement step. We identify several objectives and constraints that will enhance the buildability of QCA circuits and use them in our optimization process. The results are intended to define what is computationally interesting and could actually be built within a set of predefined constraints.

REFERENCES

• 1: C. Lent, B. Isaksen, and M. Lieberman, "Molecular quantum-dot cellular automata," J. Am. Chem. Soc., pp. 1056--1063, 2003.
• 2: M. Lieberman, S. Chellamma, B. Varughese, Y. Wang, C. Lent, G. Bernstein, G. Snider, and F. Peiris, "Quantum-dot cellular automata at a molecular scale," Annals of the New York Academy of Science, pp. 225--239, 2002.
• 3: Ramprasad Ravichandran , Nihal Ladiwala , Jean Nguyen , Mike Niemier , Sung Kyu Lim, Automatic cell placement for quantum-dot cellular automata, Proceedings of the 14th ACM Great Lakes symposium on VLSI, April 26-28, 2004, Boston, MA, USA [doi>10.1145/988952.989033]
• 4: Jason Cong , Sung Kyu Lim, Performance driven multiway partitioning, Proceedings of the 2000 conference on Asia South Pacific design automation, p.441-446, January 2000, Yokohama, Japan [doi>10.1145/368434.368736]
• 5: K. Sugiyama, S. Tagawa, and M. Toda, "Methods for visual understanding of hierarchical system structures," IEEE Trans. Syst. Man,. Cybern, pp. 109--125, 1981.