High-aspect-ratio GaAs pores and pillars with triangular cross section

High-aspect-ratio structures of GaAs pore arrays and pillar arrays with a triangular cross section were fabricated by a combination of the electrochemical etching of a pre-etched (111) GaAs substrate and anisotropic chemical etching. The formation of deep pores with an ordered interpore distance (e.g., 200 nm diameter, 70 mu m depth, and high aspect ratio of 350) was successfully accomplished. The inverted pyramid-like prepits with a two-dimensional hexagonal array, which were formed by colloidal crystal templating, could act as initiation sites and guide the growth of pores along the [111] crystallographic direction. Moreover, the diameter of the pores of anodized GaAs could be easily controlled by post-chemical etching. The applied technique using the anisotropic chemical etching demonstrated the feasibility of the present method by the fabrication of high-aspect-ratio prismlike pillar arrays in GaAs. (C) 2011 Elsevier B.V. All rights reserved.