A method of fabricating high aspect ratio micromechanical tips is
provided. The method includes, but is not limited to, forming an etchant
protective island on a surface of a silicon substrate with the silicon
substrate exposed around the island; isotropically etching the silicon
substrate by reactive ion etching around the protective island to
partially undercut the silicon substrate beneath the protective island;
anisotropically etching, by deep reactive ion etching, the silicon
surrounding the island to a desired depth to define a tip shaft of the
desired height supported at a base by the substrate; removing the
protective island from the tip; and sharpening the top of the tip shaft
to an apex. Using the method, micromechanical tips having heights greater
than at least 30 .mu.m have been obtained while maintaining the vertical
sidewall necessary for both AFM and scanning near-field microwave
microscopy (SNMM) profiling applications.