Fabrication of high-aspect ratio silicon nanopillars and nanocones using deep reactive ion etching

Abstract

Bosch type processes have been employed to fabricate nanostructured Si surfaces. Nanopillars and nanocones in Si have been fabricated using different techniques for Ni micromasking. Plasma redeposition of Ni was found to be responsible for Si pillar formation with diameters varying in the submicron range. A possibility to produce tilted nanopillars with tilt angles up to as high as 25° has been demonstrated. In other method, previously deposited and annealed thin Ni films were employed. Smaller Ni nanoislands were obtained, and the formation of Si nanocones was demonstrated using longer passivation steps. In this case, reflection coefficients as low as 1.2% were obtained for the optimized etching process time.