电容耦合射频放电的电子加热
Electron heating, mechanisms of plasma generation, and electron dynamics in dif-ferent types of capacitively coupled radio frequency (CCRF) discharges relevant forindustrial applications are investigated by a combination of di® erent experimen-tal diagnostics, simulations and models. Geometrically symmetric and asymmetricsingle frequency discharges operated at low pressures, geometrically symmetric dualfrequency discharges operated at two substantially di® erent frequencies and two sim-ilar frequencies (fundamental and second harmonic with variable phase shift betweenthe driving voltages) as well as hybrid capacitively/inductively coupled (CCP-ICP)RF discharges are studied. Electron heating is found to be strongly a® ected byphenomena characteristic for a certain discharge type, that do not occur in another.At low pressures the generation of highly energetic electron beams by the expand-ing sheath is observed. Such beams propagate through the entire plasma bulk andare re° ected at the opposing plasma boundaries, if the electron mean free path islong enough. An analytical model demonstrates that these beams lead to an en-hanced high energy tail of the electron energy distribution function and are, there-fore, closely related to stochastic heating