Quantum Dot Structures Measuring Hamming Distance for Associative Memories

ABSTRACT This paper describes new quantum-dot circuits that measure a Hamming distance by using the Coulomb repulsion effect between quantum dots. Measuring similarity between patterns expressed by a Hamming distance is a basic function for various information processing. Quantum dot structures realizing these circuits are also proposed, which will be constructed by using the well-controlled nanocrystalline floating-dot MOSFET technology. For room temperature operation, the simple quantum-dot circuit requires a tunnel junction capacitance of less than 0.01 aF, but the multi-quantum-dot circuit using thermal-assisted tunneling allows to use the capacitance of up to 0.1 aF. This technique is useful for designing practical single-electron circuits performing intelligent information processing.