Crossbar architecture for tera-scale integration

As far as the fabrication of ultradense crossbars is related to correspondingly dense wire arrays, the crossbar route to tera-scale integration depends on the availability of preparation techniques for wire arrays with density of 106 cm-1 or more. For a planar arrangement this density implies a pitch of 10 nm or less, beyond the current possibility and close to the theoretical limit, assuming for the cross-point a minimum area of 10 nm2. Further increase of density can only be achieved organizing the nanowires in a three-dimensional fashion. This paper describes a planar top-down process for the preparation of vertically arranged poly-silicon nanowires. The technique is expected to allow the production of wire arrays with linear density (projected on the surface) larger than those achievable with any other proposed top-down processes. Used for the fabrication of the bottom wire array of crossbars, this process should allow an eventual cross-point density of the order of 1012 cm-2, thus being a candidate technology for tera-scale integration.