Outer Ring-Shaped Radio Frequency Magnetized Plasma Source for Target Utilization in Specific Area

Abstract

A capacitively coupled radio frequency outer ring-shaped magnetized plasma discharge has been proposed with a concentrically monopole arrangement of magnets to erode the target in a specific area, especially, near the chamber wall. The three concentric monopole magnet arrangements with a center magnet and magnets in setups: 1) three circles; 2) two circles; and 3) one circle were investigated. From the magnetic flux lines profiles, it was found that the magnetic flux density in component parallel to the target surface has a peak magnitude in the outer circle of magnets for all setups. Ring-shaped plasma in the specific outer area was observed. The ion saturation current, $I_{\text {isat}}$ were 0.6, 0.79, and 0.46 mA, for setups 1)–3), respectively, at $r = 47$ mm, where $r = 0$ mm is the center of the target. It was found that $I_{\text {isat}}$ is very high in the outer target region near the chamber wall for setups 1) and 2), where $I_{\text {isat}}$ for setup 3) decreases slowly. The results showed that the target utilization could be controlled in the outer specific area near the discharge chamber wall.