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Open Access Nano Express

Triangle pore arrays fabricated on Si (111) substrate by sphere lithography combined with metal-assisted chemical etching and anisotropic chemical etching

Hidetaka Asoh, Kosuke Fujihara and Sachiko Ono*

Author affiliations

Department of Applied Chemistry, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo, 192-0015, Japan

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Citation and License

Nanoscale Research Letters 2012, 7:406  doi:10.1186/1556-276X-7-406

Published: 19 July 2012

Abstract

The morphological change of silicon macropore arrays formed by metal-assisted chemical etching using shape-controlled Au thin film arrays was investigated during anisotropic chemical etching in tetramethylammonium hydroxide (TMAH) aqueous solution. After the deposition of Au as the etching catalyst on (111) silicon through a honeycomb mask prepared by sphere lithography, the specimens were etched in a mixed solution of HF and H2O2 at room temperature, resulting in the formation of ordered macropores in silicon along the [111] direction, which is not achievable by conventional chemical etching without a catalyst. In the anisotropic etching in TMAH, the macropores changed from being circular to being hexagonal and finally to being triangular, owing to the difference in etching rate between the crystal planes.

Keywords:
Silicon; Metal-assisted chemical etching; Colloidal crystal templating; Sphere lithography; Anisotropic chemical etching; Triangle pore arrays