EFFECTS OF AXIAL MAGNETIC-FIELD AND FARADAY SHIELD ON CHARACTERISTICSOF RF PRODUCED PLASMA USING SPIRAL ANTENNA

Influences of the axial magnetic field and Faraday shield on the perfo rmance 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 st udied. With the magnetic field and/or without a Faraday shield, the th reshold input power for plasma initiation is lowered and the antenna-p lasma coupling is improved. In addition, a collisionless heating mecha nism is suggested. With the increase in the applied magnetic field, th e ion saturation current increases and shows a peaked radial profile; in the low-pressure range it shows a nearly flat axial profile.