In this paper, we deposited ZnO thin films by RF magnetron sputtering at room temperature from un-doped targets. Wet chemical etching of ZnO films in (NH4)(2)CO3 and NH4OH solutions were examined. For comparison, hydrochloric acid was also used as an etchant. The NH (x) -based alkaline solutions provide well-controlled etching rate, and smooth surface and sidewall profiles. Although NH (x) -based alkaline solution etch rates for ZnO were relatively low, they were enhanced with the use of a H3O stabilizer. In this case, the NH4OH solution went from reaction-dominant mode to diffusion-dominant mode, which is beneficial for smooth surface morphology.