On-Demand Fabrication of Si/SiO(2) Nanowire Arrays by Nanosphere Lithography and Subsequent Thermal Oxidation

We demonstrate the fabrication of the large-area arrays of vertically aligned Si/SiO(2) nanowires with full tunability of the geometry of the single nanowires by the metal-assisted chemical etching technique and the following thermal oxidation process. To fabricate the geometry controllable Si/SiO(2) nanowire (NW) arrays, two critical issues relating with the size control of polystyrene reduction and oxide thickness evolution are investigated. Through analyzing the morphology evolutions of polystyrene particles, we give a quantitative description on the diameter variations of polystyrene particles with the etching time of plasma etching. Based on this, pure Si NW arrays with controllable geometry are generated. Then the oxide dynamic of Si NW is analyzed by the extended Deal-Grove model. By control, the initial Si NWs and the thermal oxidation time, the well-aligned Si/SiO(2) composite NW arrays with controllable geometry are obtained.