Plasma etch damage to sputtered indium-zinc-oxide (IZO) layers in the form of changes in the film stoichiometry was investigated using Auger Electron Spectroscopy (AES). While damage resulting from pure chemical etching processes is usually constrained to the surface vicinity, ion-assisted chemical etching of IZO in Ar/CH4/H-2 plasmas produces a Zn-rich layer, whose thickness (similar to 50 nm) is well-above the expected stopping range of Ar ions in IZO (similar to 1.5 nm). Based on AES depth profiles as a function of plasma exposure time, it is concluded that the observed Zn enrichment and In depletion deep into the IZO film are driven by the implantation of hydrogen atoms. (C) 2007 Elsevier B.V. All rights reserved.