Abstract: A gas dispersion window for a plasma etching or plasma deposition reactor including a housing having a chamber in which an article can be treated with plasma. The housing includes at least one inlet port connected to an interior of the chamber through which process gas can be supplied to the chamber. A radiofrequency energy source is arranged to pass radiofrequency energy into the chamber and induce plasma in the interior of the chamber by activating, with an electric field induced by the radiofrequency energy source, process gas supplied to the chamber through the inlet port. A dielectric window formed by spaced apart first and second dielectric members has an inner surface thereof forming part of an inner wall of the chamber. Radiofrequency energy passes from the radiofrequency energy source to the interior of the chamber through the dielectric window.