Controllable excimer-laser fabrication of conical nano-tips on silicon thin films

Abstract

We have found conditions for the reproducible, direct laser fabrication of sharp conical tips with heights of about 1 μm and apical radii of curvature of several tens of nanometers. An individual cone is formed when single-crystalline silicon on a silica substrate is irradiated with a single pulse from a KrF excimer laser, homogenized and shaped to a circular spot several microns in diameter. Atomic force microscopy and field-emission scanning electron microscopy were used to characterize these structures. A simple mechanism of formation based on movement of melted material is proposed. Our results suggest that this technique could produce even smaller structures by optimizing the laser processing geometry.