This work elucidates the surface morphologies of dry-etched ZnO films formed by reactive ion etching using a Cl-2/Ar mixture. The root-mean-square (rms) roughness and etching rate were obtained by varying the gas flow ratio, the radio-frequency (rf) plasma power, and the chamber pressure. Atomic force microscopy results and surface topographies are discussed. The rms roughness is highest, 24.20 nm, at a Cl-2/Ar flow rate of 150/10 SCCM (SCCM denotes cubic centimeter per minute at STP), a working pressure of 190 mTorr, and a rf power of 300 W. Such films are suitable for use as roughened transparent contact layers in light-emitting diodes. Bearing ratio analysis reveals that under the aforementioned condition, the nanorods covered 25.4% of the total surface area and their maximum height was approximately 150.83 nm. Moreover, high and low etching rates of 300 and 16 angstrom/min were obtained at rf powers of 300 and 50 W, respectively, supporting the ZnO-based devices and the gate-recess process. (C) 2009 American Vacuum Society. [DOI:10.1116/1.3212914]