“Reversible and Directional Self-Assembly of Bio-Molecular Templates for Nanotechnology Interconnects”
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In recent years, the exponential growth in semiconductor technology has been sustained by extending the capabilities of top-down manufacturing processes based on lithography to shorter and shorter wavelengths. Unfortunately, the costs of these top-down approaches are projected to be prohibitive at sizes and tolerances in the nanometer size range. In response, a new paradigm has arisen based on the bottom-up or molecular engineering approach to the mass replication of nanoscale electronic circuits that promises to be cheaper, more flexible, and efficient. Control of interconnections emerges as one of the major challenges in the development of these bottom-up approaches. Microtubules (MT) are self-assembled subcellular proteinaceous filaments with nanometer scale diameters and micrometer scale lengths. MTs are biopolymers assembled from two, related protein monomers; a and b tubulin. The aspect ratio of MT, the reversibility of their assembly and their ability to be metallized by electroless plating make them excellent candidates to serve as templates for the fabrication of nanowires. Within the cell, the slower-growing microtubules minus ends are tethered to microtubule-organizing centers, and the faster growing plus ends extend into the cytoplasm. g-tubulin, a tubulin isoform, is believed to nucleate MTs by forming nucleation complexes (NC). Our work focuses on developing technology for bottom-up approaches to nano-electronics manufacturing inspired by biological processes. The ability to interface biological structures, such as MT to an inorganic substrate is a prerequisite to the development of such an approach toward the controlled fabrication of nanoscale interconnects between microelectronic devices on silicon wafer. Our “in situ” approach to manufacturing a MT interconnection on a silicon wafer using biomolecular templates consists of (a) a starting electrode functionalized with a derivatized MT nucleating complex (cap) via specific ligands, (b) controlled growth of MTs from the starting electrodes toward a target electrode, (c) binding of the MT plus end to capping agent bound to the target electrode via specific ligands, and (d) disassembly of uncapped MTs and subsequent metallization of interconnecting protein template.