The nonlocal and local property of the electron energy distribution function in a low-pressure inductively coupled plasma

Abstract

Electron energy distribution functions (EEDFs) at different radial positions are measured by a rf compensated Langmuir probe in a low-pressure solenoidal inductively coupled plasma. It is found that the measured EEDFs for trapped electrons with total energy epsilon < e phi(w) (wall potential) are a function of only total energy, while the EEDFs for free electrons that can escape plasma are functions of radial position and total energy. The depletion energy of the EEDFs in the free electron range is determined not only by the wall potential but also by the electron canonical momentum p(theta). These results are consistent with the nonlocal electron kinetic theory. (C) 2000 American Institute of Physics. [S1070-664X(00)03709-5].