Electron beam induced SiO2 etch selectivity and its application to oxide nano-aperture formation

The influence of SiO2 etch selectivity induced by electron beam irradiation on the nano-fabrication of sub-wavelength size aperture has been investigated. Initially, oxide hollow pyramids were prepared by square-dot patterning and V-groove formation using TMAH etching of Si and thermal oxidation followed by backside Si removal. The opening of nano-size apertures at oxide pyramid apexes was carried out by wet SiO2 etching with and without electron beam exposure. It was observed that the aperture diameter varies according to the electron beam exposure, the reason of which can be attributed to the enhanced oxide etch rate due to electron beam irradiation. Direct verification using a double aperture and details of electron beam influence will be discussed.