Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas

The total energy lost per electron-ion pair lost epsilon(T) is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost epsilon(T) is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured epsilon(T) from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated epsilon(T) from the depleted EEDFs has a value that is similar to the measured epsilon(T). (C) 2015 AIP Publishing LLC.