Magnetron with gas injection through hollow cathodes machined in sputtered target

• Published in: Surface & coatings technology 2001-12, Vol.148 (2), p.296-304
• Main Authors: Musil, J, Baroch, P, Poláková, H, Vlček, J, Nam, K.H, Han, J.G
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Exact sciences and technology; Gas injection inside discharge; Hollow cathodes; Magnetron; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Reactive sputtering
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/S0257-8972(01)01335-4

This article reports on a magnetron equipped with a target with holes. The holes machined in sputtered target can sustain hollow cathode discharges and/or inject the sputtering gas directly inside the magnetron discharge. This magnetron operates on the same principle as a gas-jet. It is shown that the size and number of holes can efficiently control I– V characteristics of the magnetron. The holes of large (≥2 mm) diameter can sustain hollow cathode discharges, which intensify the magnetron discharge. On the contrary, the holes of small (≤1 mm) diameter influences the I– V characteristics much less and allow: (i) to introduce the sputtering gas directly inside the discharge; and (ii) to compensate a gas density reduction in front of target when the magnetron is operated at high (≥100 W/cm 2) target power densities. Special attention is devoted to reactive sputtering. There is great difference in the deposition rate a D of films in the case when the sputtering gas is fed to the chamber or to the discharge through the holes. It is shown that for the gas feed to chamber, a D of the nitride films, sputtered from target with four holes of diameter 2 mm, is equal to that of pure metal films sputtered from a full target in argon. On the contrary, for the gas feed to discharge, a D of the oxide films, sputtered from target with four holes of diameter 2 mm, is very low, 40 times smaller compared to a D of metal films sputtered from a full target in argon. The magnetron discharge with an extremely low deposition rate is very suitable for cleaning and activation of surfaces prior to the film deposition.