Fabrication of nanostructures by dry etching using dewetted Pt islands as etch-masks

A method for fabrication of nano-scale GaN structure by inductively coupled plasma etching is proposed, exploiting a thermal dewetting of Pt thin film as an etch-mask. The nano-scale Pt metal islands were formed by dewetting of continuous film on SiO2 dielectric materials during the rapid thermal annealing process. For the Pt films with thickness of 30 nm, temperatures of > 600°C initiate pattern formation and the dewetting of Pt films. Controlling the annealing temperature and time as well as the thickness of Pt metal film could manifest the size and density of Pt islands. The activation energy for initiation of Pt metal dewet was calculated to be 23.2 kJ/mole. The islands show good resistance against dry etching using CF4 based plasma for dielectric etching, indicating that the metal island by dewetting of thin film is suitable for etch mask in the fabrication of nano-scale structures. This fabrication method was also proven to be effective in the fabrications of GaN nanocolumns with widths as small as nanometer scale.