Capacitive Electron Cooling in an Inductively Coupled Plasma Source/Capacitively Coupled Plasma Bias Reactor

Abstract

An electron cooling mechanism has been found in an inductively coupled plasma (ICP) source/capacitively coupled plasma (CCP) bias reactor. From the results of the measured electron energy probability function (EEPF), it was found that the temperature of low-energy electrons epsilon < 5 eV decreased with electron density when the bias power exceeded 100 W. In the case of a high-density plasma with an electron density of around 10(11)/cm(3), capacitive coupling is a cause of significant ion loss, and electron wall loss is also enhanced to maintain the flux balance. Because of this flux balance, the potential barrier that must be overcome by electrons in the sheath collapse phase decreases further. This change in potential barrier enhances the wall loss of low-energy electrons below 5 eV, and the effective electron temperature decreases with an increase in bias power.