High purity RF-sputter type metal ion source for non-mass-separated ion beam deposition

High purity RF-sputter type metal ion source has been developed for non-mass separated ion beam deposition. An Fe or Cu rod target of purity 99.999% or 99.9999%, respectively, was DC-sputtered inside an RF inductively generated Ar plasma. Optical emission spectroscopy from the plasma region (Fe case) indicated that emission from Fe* becomes larger than that of Ar* when DC bias voltage of -1 kV was applied. This result agreed with our previous mass spectroscopic results that Fe⁺ ion intensity overcomes that of Ar⁺ because of an efficient Penning ionization of sputtered and evaporated Fe particles. Cu films deposited on Si substrate at RT with the ion source showed non-columnar structure at a substrate bias voltage of -150 V, whereas only columnar structure was obtained with no bias voltage. This tendency qualitatively agreed with the case of Fe film formation obtained in our mass separated IBD