Nanowire nanocomputer as a finite-state machine

Abstract

Implementation of complex computer circuits assembled from the bottom up and integrated on the nanometer scale has long been a goal of electronics research. It requires a design and fabrication strategy that can address individual nanometer-scale electronic devices, while enabling large-scale assembly of those devices into highly-organized, integrated computational circuits. We describe how such a strategy has led to the design, construction, and demonstration of a nanoelectronic finite-state machine (nanoFSM). The system was fabricated using a design- oriented approach enabled by a deterministic, bottom-up assembly process that does not require individual nanowire registration. This methodology allowed construction of the nanoFSM through modular design employing a multi-tile architecture. Each tile/module consists of two interconnected crossbar nanowire arrays, with each cross-point consisting of a programmable nanowire transistor node. The nanoFSM integrates 180 programmable nanowire transistor nodes in three tiles or six total crossbar arrays, and incorporates both sequential and arithmetic logic, with extensive inter-tile and intra-tile communication that exhibits rigorous input/output (I/O) matching. Our system realizes the complete 2-bit logic flow and clocked control over state registration that are required for a FSM or computer. The programmable multi-tile circuit was also re-programmed to a functionally-distinct 2-bit full adder with 32-set matched and complete logic output. These steps forward and the ability of our new design-oriented deterministic methodology to yield more extensive multi-tile systems, suggest that proposed general-purpose nanocomputers can be realized in the near future.