Investigation of the E- and H-modes of Operation in an Inductively Coupled Rf Discharge

The inductively coupled RF discharge is known to exhibit two modes of operation depending on the level of incident power. Dominant capacitive coupling (E-mode discharge) occurs at low-power level while at high power, dominant inductive coupling (H-mode discharge) is obtained. In this work, we investigate the characteristics of the E-mode and H-mode discharges generated in a planar coil inductively coupled configuration at RF drive frequency of 13.56 MHz in Argon. Parameters used to characterize the discharges include the electron temperature Te, electron density ne and plasma potential Vs. Besides these, the electrical characteristics (RMS coil current Icoil and voltage Vcoil) of the coil antenna are also investigated, from which the efficiency of the transfer of RF power to the plasma, η is determined. This power transfer efficiency η is then correlated to the plasma density for both the modes of operation. [