| AVS 66th International Symposium & Exhibition | |
| Thin Films Division | Monday Sessions |
| Session TF+SE-MoA |
| Session: | HiPIMS and Reactive HiPIMS for Novel Thin Films |
| Presenter: | Jon Tomas Gudmundsson, University of Iceland |
| Authors: | H. Hajihoseini, University of Iceland M. Cada, Academy of Sciences of the Czech Republic Z. Hubicka, Academy of Sciences of the Czech Republic S. Unaldi, LPGP Université Paris-Sud, France M.A. Raadu, KTH Royal Institute of Technology, Sweden N. Brenning, KTH Royal Institute of Technology, Sweden J.T. Gudmundsson, University of Iceland D. Lundin, LPGP Université Paris-Sud, France |
| Correspondent: | Click to Email |
Three different ways to quantify the degree of ionization in sputtering magnetrons are discussed [1]. Then we move on to explored the effect of the magnetic field strength |B| and geometry (degree of balancing) on the deposition rate and ionized flux fraction Fflux in dc magnetron sputtering (dcMS) and high power impulse magnetron sputtering (HiPIMS) when depositing titanium. The HiPIMS discharge was run in two different operating modes. The first one we refer to as ’fixed voltage mode’ where the cathode voltage is kept fixed at 625 V while the pulse repetition frequency is varied to achieve the desired time average power (300 W). The second mode we refer to as ’fixed peak current mode’ is carried out by adjusting the cathode voltage to maintain a fixed peak discharge current and by varying the frequency to archive the same average power. Our results indicate that the dcMS deposition rate is weakly sensitive to variations in the magnetic field while the deposition rate during HiPIMS operated in fixed voltage mode changes from 30% to 90% of the dcMS deposition rate as |B| decreases [2]. In contrast, when operating the HiPIMS discharge in fixed peak current mode the deposition rate increases only slightly with decreasing |B|. In fixed voltage mode, for weaker |B| the higher the deposition rate, the lower the Fflux. The measured quantities, the deposition rate and ionized flux fraction, are then related to the ionization probability αt and the back attraction probability of the sputtered species βt. We show that the fraction of the ions of the sputtered material that escape back attraction increases by 30% when |B| is reduced during operation in fixed peak current mode while the ionization probability of the sputtered species increases with increased discharge current when operating in fixed voltage mode.
[1] A. Butler, N. Brenning, M. A. Raadu, J. T. Gudmundsson, T. Minea and D. Lundin, Plasma Sources Science and Technology, 27(10) (2018) 105005
[2] H. Hajihoseini, M. Čada, Z. Hubička, S. Unaldi, M. A. Raadu, N. Brenning, J. T. Gudmundsson and D. Lundin, Plasma, submitted for publication, April 2019