Fabrication of microstructures by wet etching of anodic aluminum oxide substrates

Anodic aluminum oxide (AAO) was used as substrates of microstructure fabrication. Complex structures with high aspect ratios were obtained by the single-step wet etching of the AAO substrates. Structures with different shapes and aspect ratios could be simultaneously obtained with vertical sidewalls. The surface morphology of the fabricated structures could be tailored. It is expected that various MEMS/NEMS devices can be built using this technique.