GaAs Microarrays by Noble-Metal Assisted Chemical Etching

Abstract

Microarrays of n-GaAs were fabricated for both (100) and (111) by colloidal crystal templating, ion sputtering and chemical etching using nanosized Au particles as the etching catalyst. Since self-organized polystyrene spheres were used as a mask, Au particles were selectively deposited at sites resulting in the formation of Au honeycomb pattern on GaAs. Microsized GaAs column arrays were achieved by chemical etching of GaAs, where the honeycomb-patterned Au metals were deposited. Although ordered column structures were obtained for both planes, different anisotropic etching patterns were observed by Au-assisted chemical etching between n-GaAs (100) and (111). The crystal-face orientation strongly affects the etching morphology and the rate of metal-assisted chemical etching.