Processing of nano-holes and pores on SiO2 thin films by MeV heavy ions

Scanned beams of 0.1 MeV/u Au-197 ions were employed for the bombardment of silicon oxide films thermally grown on silicon (10 0) substrates. Subsequently the films were etched in aqueous HF solution (1% and 4%) for various times and at different temperatures. Scanning force microscopy and transmission electron microscopy images of etched films reveal conical holes with diameters from 20 to 350 nm, depending on the HF concentration and etching time. For a fixed etching temperature, hole size increased roughly linearly with etching time, and for a fixed etchant concentration, it varied exponentially with etching temperature. These porous surfaces were tested for trapping of nano-particles, as templates for deposition of porous films, and for localized etching of the Si substrate. (C) 2003 Elsevier Science B.V. All rights reserved.