title: Cantilever arrays with self-aligned nanotips of uniform height.
abstract: Cantilever arrays are employed to increase the throughput of imaging and manipulation at the nanoscale. We present a fabrication process to construct cantilever arrays with nanotips that show a uniform tip-sample distance. Such uniformity is crucial, because in many applications the cantilevers do not feature individual tip-sample spacing control. Uniform cantilever arrays lead to very similar tip-sample interaction within an array, enable non-contact modes for arrays and give better control over the load force in contact modes. The developed process flow uses a single mask to define both tips and cantilevers. An additional mask is required for the back side etch. The tips are self-aligned in the convex corner at the free end of each cantilever. Although we use standard optical contact lithography, we show that the convex corner can be sharpened to a nanometre scale radius by an isotropic underetch step. The process is robust and wafer-scale. The resonance frequencies of the cantilevers within an array are shown to be highly uniform with a relative standard error of 0.26% or lower. The tip-sample distance within an array of up to ten cantilevers is measured to have a standard error around 10 nm. An imaging demonstration using the AFM shows that all cantilevers in the array have a sharp tip with a radius below 10 nm. The process flow for the cantilever arrays finds application in probe-based nanolithography, probe-based data storage, nanomanufacturing and parallel scanning probe microscopy.
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, NL-7500 AE Enschede, The Netherlands. w.w.koelmans@alumnus.utwente.nl
authors.forename: W W
authors.initials: WW
authors.lastname: Koelmans
authors.forename: T
authors.initials: T
authors.lastname: Peters
authors.forename: E
authors.initials: E
authors.lastname: Berenschot
authors.forename: M J
authors.initials: MJ
authors.lastname: de Boer
authors.forename: M H
authors.initials: MH
authors.lastname: Siekman
authors.forename: L
authors.initials: L
authors.lastname: Abelmann