Real-time measurements of plasma/surface interaction by plasma-amplified photoelectron detection

A new method, based on the photoelectric effect, is described for real-time, in situ monitoring of metal or semiconductor surfaces during plasma exposure. As an example of the application of this technique, the effect of both sputter and reactive gas plasma exposure is studied for graphite, silicon, and aluminum surfaces. Results are consistent with the formation of a surface-passivating layer of fluoride on aluminum and penetration of fluorine into the silicon bulk during exposure to the CF4+Ar etching plasma. An application of this technique for endpoint detection monitoring is described.