Inductively coupled plasma reactive ion etching (ICP-RIE) of ZrO2:H solid electrolyte films was investigated using BCl3-based plasma. ZrO2: H etch rates were studied as a function of the BCl3/Ar chemistry, ICP coil power, bias voltage, and working pressure. Scanning electron microscopy and atomic force microscopy were employed to characterize the etch rate and root-mean-square surface roughness of etched samples. It was found that in comparison with Cl-2-based gas mixtures, pure BCl3 plasma results in a high etch rate of ZrO2: H layer, suggesting an abundance of B and BCl radicals made up of a volatile compound such as BxOy, BCl-O, and Zr-Cl bond. In addition, Auger electron spectroscopy analysis exhibits that the BCl3-based etching process produces no change in surface stoichiometry of the ZrO2:H films. (c) 2005 The Electrochemical Society.