Generally applicable self-masked dry etching technique for nanotip array fabrication

Well-aligned nanotip arrays were fabricated by electron cyclotron resonance (ECR) plasma process using gas mixtures of silane, methane, argon, and hydrogen. The resultant tips have nanoscale apexes (similar to1 nm) with high aspect ratios (similar to50), which were achieved by simultaneous SiC nanomask formation and dry etching during ECR plasma process. This technique was applied to a variety of substrates such as silicon, polycrystalline silicon, gallium nitride, gallium phosphide, sapphire, and aluminum, indicating its general applicability. High-resolutiontransmission electron microscopy and Auger depth profile analyses revealed that the SiC cap, with Si:C ratio of 1:1, exhibited 3C-SiC and 2H-SiC structure on Si and GaP, respectively, with heteroepitaxial relationship. This one-step self-masked dry etching technique enables the fabrication of uniform nanotip arrays on various substrates over large area at low process temperatures, thereby demonstrating a high potential for practical industrial application.