Magnetic and Pressure Effects on E-H Mode Transition Power and Electron Energy Distribution in Helical Antenna-Coupled RF Plasma

We used helical antenna-coupled radio frequency (RF) plasmas to study the evolution of mode transition power and electron kinetics under different applied magnetic fields argon pressures. Langmuir probe emission spectrum data indicate that discharge changes from capacitive coupling E inductive H through a strong mixed (E + H). One reason for this strongly ionization is antenna structure, which increases coupling. Furthermore, $\text{E}\to \text{H}$ threshold decreases with increasing pressure regardless whether there field, presence field significantly power. The energy distribution function (EEDF) curve has Druyvesteyn shape at low RF mode). range, binding electrons by causes EEDF deviate Maxwellian shape. As increases, tends toward during mode. appears act like drag on process, particularly very