LOW-PRESSURE CAPACITIVE RF DISCHARGE MECHANISM EXPERIMENTAL-STUDY

Low pressure capacitive rf discharges (CRFD) in noble gases were experimentally studied. The (CRFD) discharge I-V characteristics, spatial structures, and electric field spatial distributions were investigated within the frequency range omega(Li), V-i much less than omega(Le), V-e. Charged particle motion in near-electrode sheathes, electron emission from the electrodes, plasma properties, and discharge edge effects are discussed. The characteristic features of the discharge under investigation were found to be the following. The applied rf voltage was mainly localized inside a near-electrode sheath. The sheath intrinsic quasi-stationary electric field plays a key role in the discharge mechanism. Intense high-energy electron beams are generated in the near-electrode sheath. The electron beams cause a non-Maxwellian energy spectrum of the near-electrode plasma. A qualitative model of low-pressure capacitive rf discharge based on extensive experimental data is proposed.