DYNAMIC POTENTIAL FORMATION OF A RF-SHEATH NEAR THE SUBSTRATE IN A DCDISCHARGE PLASMA

The dynamic potential formation of a radio-frequency (rf) sheath near the substrate was experimentally studied over a wide range of the freq uency under a fixed plasma density produced by an Ar de discharge plas ma. Potential structures of the rf sheath obtained by detecting spatia l profiles of the crest and trough potentials in the rf oscillation pr ovided a strong frequency dependence. The sheath thickness of the trou gh potential expanded in the high-frequency region unlike the rf elect rode in the conventional capacitively coupled rf discharge plasma. The potential well with a depth of an electron temperature formed in fron t of the substrate on the crest profile in the low-frequency region. S imilar experiments in a CF4 de discharge plasma producing negative ion s were also performed. The virtual anode formed in the crest profile a nd its potential height grew with increasing applied frequency.