Production and control of planar microwave plasmas for materials processing

This paper is a review of the current understanding for the operation of the non-magnetized large-area planar microwave plasma sources with emphasis on the high-density surface-wave plasmas. The paper starts with a review of the various plasma source designs currently in use and short comparison of microwave and lower-frequency RF plasmas. Then the most important phenomena in such plasmas (occurrence of standing-wave eigenmode resonance densities, density dependence of the impedance, energy balance, stability, multi-valued power-density dependence, mode jumps, memory and hysteresis loops, self-tuning ability, local plasma resonance, non-collisional heating) are revisited with simple two-dimensional models. For each phenomenon references to more detailed theoretical treatment and experimental studies are given and a few key experimental curves are reproduced. At the end some unresolved problems are listed.