Outer Circular Ringshaped RF Magnetized Plasma for Specificarea Target Utilization by Magnetic Monopole Arrangement

Abstract

We have proposed a radio frequency (RF) magnetized outer circular ring-shaped plasma sputtering source with a concentrically monopole arrangement of magnets with each gap of $d =5$mm for specific area target utilization [1–3]. The three setups, that is, with a center magnet, and type (a): magnet arrangement with three circles, type (b): magnet arrangement with two circles, and type (c): magnet arrangement with one circle are investigated from the point of view of specific area target utilization. The experiments were performed in stainless-steel cylindrical RF discharge chamber with outer diameter of 235 mm, inner diameter of 160 mm and 195 mm in height, where Ar gas pressure of 1.50 [Pa], and RF power of 50 [W] at 13.56 [MHz] are used to produce the plasma. From the 2D magnetic flux lines and their profiles, it is found that the magnetic flux density in component parallel to the target surface has a peak outside the exterior circle of magnets for all setups. Ring-shaped plasma in the specific outer area is observed at the position with the peak magnetic flux density and its diameter depends on a number of magnet circles. The results show that the target utilization can be controlled in the outer specific region near the wall. The typical RF magnetized plasma discharge, the RF discharge voltages, the self-bias dc voltages and the radial profiles of ion saturation currents, electron temperature and plasma density have been also investigated.