Micro-patterning of ZnO single crystal surface by anisotropic wet-chemical etching

Anisotropic chemical etching behavior of ZnO single crystal surface was investigated by using patterned resist masks prepared by electron beam lithography. Particularly, etching with aqueous solutions of HCl and CH3COOH was examined for (0001¯) surface of ZnO. The obtained micro-patterns were characterized by scanning electron microscope and laser microscope. In the concave structure formation, the facets of {101¯1¯} were developed independent of the etchants. However, a roundish bottom face of the pits consisted of {101¯n¯} (n>1) planes of ZnO was observed only in the sample etched in HCl solution. These results indicated that the resultant shape of the microstructure is strongly affected by reaction kinetics.