NEMS fabrication of metal coated sub-wavelength size aperture array and its optical characterization

We successfully fabricated the sub-wavelength size silicon oxide aperture array as a near-field optical probe in order to examine the possible light resonance-tunneling phenomenon. Initially, using a magnetic enhanced reactive ion etching (MERIE) system, a (50 x 50) array of the (5 x 5) m2 size patterns was fabricated on the silicon wafer followed by V-groove formation using alkaline solution Si bulk micromachining. The silicon oxide aperture array with sub-wavelength size was revealed after the water-diluted HF acid etching. The nano-size aperture on the top of the pyramidal array with an opening rate of ∼ 27 nm/min was carefully controlled with (50:1) water-diluted HF acid solution. The Al thin film was thermally evaporated on the (50 x 50) array pattern and for sub wavelength size aperture fabrication. The initial diameter greater than 300 nm of the aperture was reduced down to ∼ 100 nm. The far-field diffraction pattern was clearly observed. The optical intensity revealed the extra-ordinary amounts of the light transmission through the nano-aperture array