Evolution of the electron energy distribution function in a planar inductive argon discharge

The evolution of the electron energy distribution function (EEDF) over a pressure range of 5–100 mTorr is investigated in a planar inductive argon discharge. It is found that the EEDF, which appears to be a bi-Maxwellian distribution with a two-temperature structure at low pressures, evolves into a Druyvesteyn-like distribution as the pressure increases. The electron energy diffusion coefficient, which describes electron heating, is calculated under the same discharge conditions using discharge parameters and numerical results show that the heating of low-energy electrons is enhanced as the pressure increases resulting in a transition of the EEDF to a Druyvesteyn distribution.