US Patent 7431856 - Nanotip fabrication by spatially controlled etching

http://www.freepatentsonline.com/7431856.html

Nanotips probes are being developed for a variety of applications including microscopy, lithography, and data storage on the nanoscale. This patent from Canadian researchers teaches a method for sharping such nanotips for higher resolution performance. Claim 1 reads:

1. A method of fabricating nano-tips comprising:

placing a precursor nano-tip with an apex and shank in a vacuum chamber;

admitting an etchant gas to said vacuum chamber to perform field assisted etching by preferential adsorption of said etchant gas on said shank in the presence of an applied electric field; and

gradually reducing the applied electric field to confine the adsorption of said etchant gas to said shank as etching progresses.