Photoemission Optogalvanic Spectroscopy: A New In-Situ Plasma Diagnostic

One of the major limitations of current plasma processing technology is an inability to monitor surface properties, other than reaction rate or surface reflectivity, in-situ. We describe a new plasma diagnostic technique, photoemission optogalvanic spectroscopy, which can be used to monitor surface contamination, etching rates, and end points. The method may also be useful as a diagnostic for discharge electronic processes, such as sheath ionization and the role of secondary emission in maintaining the plasma.