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 μm 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.

Research Highlights
► We examine the fabrication of ordered microstructured GaAs using a combination of site-selective anodization and anisotropic etching.
► At the optimum conditions for anodization and chemical etching, GaAs pore arrays or prismlike pillar arrays with a high aspect ratio, respectively, are fabricated.
► The formation of deep pores with an ordered interpore distance (e.g., 200 nm diameter, 70 micron depth, and high aspect ratio of 350) is accomplished.