Effects of Axial Magnetic Field and Faraday Shield on Characteristics of RF Produced Plasma Using Spiral Antenna

Influences of the axial magnetic field and Faraday shield on the performance of RF produced plasma using a spiral antenna are investigated. The RF power and filling pressure dependences, antenna-plasma coupling, Ar line intensities and spatial profiles of plasma parameters are studied. With the magnetic field and/or without a Faraday shield, the threshold input power for plasma initiation is lowered and the antenna-plasma coupling is improved. In addition, a collisionless heating mechanism is suggested. With the increase in the applied magnetic field, the ion saturation current increases and shows a peaked radial profile; in the low-pressure range it shows a nearly flat axial profile.