| 1. |
- Kubart, Tomas, et al.
(author)
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Modelling of sputtering yield amplification in serial reactive magnetron co-sputtering
- 2012
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In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 206:24, s. 5055-5059
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Journal article (peer-reviewed)abstract
- Serial magnetron co-sputtering can be used to increase the deposition rate in reactive deposition of thin films. The increase in deposition rate is achieved by sputtering yield amplification through doping the sputtering target by a heavy element. The dopant is introduced by means of sputtering from an auxiliary target onto a rotating primary magnetron. During sputtering of the primary target, the dopant is implanted into the target surface. Here we present a model describing the serial co-sputtering technique. The model is based on the binary collision approximation and takes into account the dynamical sputtering and mixing at the target surface. As an example, W and Bi doping in reactive sputter deposition of Al2O3 is analyzed. W is shown to be very efficient dopant which can increase the deposition rate for oxide up to 100% with 1.6 at.% of W in the resulting coating. Doping by Bi is not very effective due to the low surface binding energy of Bi. The simulations show that sputtering yield amplification can be realized in the serial co-sputtering setup with rotating magnetrons.
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| 2. |
- Austgen, M, et al.
(author)
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Sputter yield amplification by tungsten doping of Al(2)O(3) employing reactive serial co-sputtering : process characteristics and resulting film properties
- 2011
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In: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 44:34, s. 345501-
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Journal article (peer-reviewed)abstract
- The deposition rate of reactively sputtered Al(2)O(3) coatings is demonstrated to increase by 80% upon tungsten doping of the used aluminium target. This effect is based on the recoil of the sputtering species at implanted dopants below the target surface and is termed sputter yield amplification. For the investigation of this effect, a novel type of magnetron sputter deposition system is employed that facilitates serial co-sputtering. In this technique doping of the elementary target is enabled by a dynamic sputtering process from an auxiliary cathode. In our case, the rotating aluminium target is dynamically coated with tungsten from this auxiliary cathode. Since the primary target rotates, the auxiliary cathode is placed in series with the primary erosion zone. The deposition rate of Al(2)O(3) can be considerably increased in this process already for very low concentrations of approximately 1% of tungsten in the resulting film. A characterization of the dynamics of reactive sputtering as a function of target rotation speed is performed.
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| 3. |
- Kubart, Tomas, 1977-, et al.
(author)
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Modelling of sputtering yield amplification effect in reactive deposition of oxides
- 2010
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In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 204:23, s. 3882-3886
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Journal article (peer-reviewed)abstract
- Many reactive sputter deposition applications require high deposition rates. The primary limiting parameters in magnetron sputtering are the target power dissipation and sputtering yields of the target elements. In reactive deposition of oxides, the deposition rate is of particular interest due to the low sputtering yield of most commonly used oxides. Traditional high rate techniques rely on a feedback control of the oxygen partial pressure to prevent formation of oxide on the target and hence enable operation in the transition area. An alternative approach, based on target doping, is presented in this paper.By doping the sputtering target with heavy elements, it is possible to substantially enhance the sputtering yield and hence the deposition rate. Simulations of the partial sputtering yield values for aluminium from doped targets sputtered in reactive atmosphere have been carried out. The Monte Carlo based TRIDYN computer code has been used for simulations. The program has been used to find out optimum alloying conditions to obtain maximum partial sputtering yield for deposition of Al2O3. Our simulations indicate that the sputtering yield amplification in reactive sputtering may lead to much higher relative deposition rate increase than in a nonreactive case. The highest relative increase may be achieved in the transition region but substantial increase is predicted also in the oxide mode.
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