[[abstract]]The reactive ion etching of the transparent conductor, indium tin oxide (ITO), in methane/hydrogen plasmas has been characterized. It is shown that ITO can be selectively etched on GaAs and AlGaAs. Anisotropic structures and gratings with submicrometer dimensions in ITO are presented. Application of the etching process to the fabrication of highly sensitive metal–semiconductor–metal (MSM) photodetectors with interdigitated ITO fingers is demonstrated.[[fileno]]2030161010138[[department]]電機工程學