EVOLUTION OF THE ELECTRON-ENERGY-DISTRIBUTION FUNCTION DURING RF DISCHARGE TRANSITION TO THE HIGH-VOLTAGE MODE

The electron-energy-distribution function (EEDF) in low-pressure argon and helium rf discharges has been measured during the discharge transition from the low-voltage to the high-voltage mode using a recently developed high-resolution Langmuir probe technique. When the transition occurs, the EEDF becomes Maxwellian because of increased electron-electron collisions arising from a sharp rise in electron density and a steep fall in electron temperature caused by gamma-electron injection.