Novel robust single layer wire crossing approach for Exclusive OR Sum of Products logic design with Quantum-dot Cellular Automata

It is well known that for a VLSI design typically interconnections among components consume the largest amount of layout area. In order for QCA (Quantum-dot Cellular Automata) to be the future substitute for CMOS (Complementary Metal-Oxide Semiconductor), the interconnection problem needs to be solved efficiently. In this paper, a new robust single layer wire crossing method is proposed. This new method does not involve any circuit overhead. The new method has only one cell type and removes the need to have two cells types in the same circuit layout, an advantage that will remove a serious source of defects for the future QCA fabrication. To make use of the available CMOS experience in logic design automation, the new wire crossing method is integrated into new 2-input and 3-input XOR designs to form a powerful logic design tools for the ESOP (Exclusive OR Sum of Products) algorithm. The proposed wire crossing and XOR designs are used to create a single layer even parity generator with different word length up to 32-bits, full adder, and two forms of 5-2 compressor using QCA. All the presented designs are simulated with QCA Designer and shown superior results as compared to previously reported designs.