Impedance characteristics of LF driven ferroinductor coupled discharge

Full Text:We present impedance characteristics of a Low Frequency inductively coupled discharge where instead of an inductor-like RF antenna we used a ferromagnetic core with a primary winding (ferroinductor). A dense (>1012 cm-3), highly ionized ( 30-40%) plasma was obtained in this ferroinductor at gas pressures as low as 10-4 Torr. In a wide frequency range the core and winding losses were found to be low compared to the LF power delivered to the plasma. The driving frequency could be very low compared to typical inductively coupled discharges. The input impedance was found to be almost purely active (cosφ 0.9), and it was possible to achieve various input resistances (e.g. 50 Ohm in the whole investigated range of frequencies, powers and pressures, which made unnecessary any matching box between the LF driver and the ferroinductor coupled plasma device. Such a combination of properties makes this kind of discharge attractive for many applications