| 1. |
- Kubart, Tomas, et al.
(författare)
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Modelling of sputtering yield amplification in serial reactive magnetron co-sputtering
- 2012
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 206:24, s. 5055-5059
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Tidskriftsartikel (refereegranskat)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.
(författare)
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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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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 44:34, s. 345501-
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Modelling of sputtering yield amplification effect in reactive deposition of oxides
- 2010
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 204:23, s. 3882-3886
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Tidskriftsartikel (refereegranskat)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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| 4. |
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| 5. |
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| 6. |
- Sarakinos, Kostas, et al.
(författare)
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The effect of the backscattered energetic atoms on the stress generation and the surface morphology of reactively sputtered vanadium nitride films
- 2008
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 516:14, s. 4568-4573
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Tidskriftsartikel (refereegranskat)abstract
- During the reactive magnetron sputtering of transition metal nitrides in an Ar-N-2 ambient, Ar+ and N-2(+) plasma ions are neutralized upon impingement on the target and are backscattered towards the growing film as neutral Ar and N species, respectively. Based on simulations, as well as on plasma and on film characterization techniques we manifest the relationship between the bombardment by the backscattered energetic atoms and the properties of reactively sputtered vanadium nitride (VN) films. Depending on the N-2 flow (q(N2)) two bombardment regimes are established. In the first regime, (q(N2) less than 20 seem) the contribution of the N species to the energetic bombardment is insignificant. The major bombarding species in this regime are the backscattered Ar species, as well as positive plasma ions and sputtered atoms. These species have relatively low energies and subplantation ratios and thus, their energy is transferred to the surface of the growing film. In the second regime (q(N2) greater than 20 scent) the backscattered N atoms are the major bombarding species and their flux to the growing film increases with increasing the N-2 flow. We argue that the backscattered N atoms have higher energy and subplantation ratio in comparison to the other bombarding species. As a result, a higher part of their energy is dissipated in the bulk of the film. The two bombarding regimes correlate well with the residual compressive stresses and the surface roughness of the films. Films grown at q(N2)less than20 seem exhibit low compressive stresses and their roughness drops when q(N2) is increased. This consistent with the low subplantation ratio and the transfer of the energy of the bombarding species to surface the growing film. The compressive stresses of films grown at q(N2) greater than 20 seem are higher, than those of the films grown in the first regime, and increase with increasing N-2 flow. This is attributed to the subplantation of the bombarding N species in the growing film.
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| 7. |
- Sarakinos, Kostas, et al.
(författare)
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The role of backscattered energetic atoms in film growth in reactive magnetron sputtering of chromium nitride
- 2007
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Ingår i: Journal of Physics D. - : Institute of Physics. - 0022-3727 .- 1361-6463. ; 40:3, s. 778-785
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Tidskriftsartikel (refereegranskat)abstract
- In this work the impact of backscattered energetic atoms on film growth in reactive sputtering of CrNx (x less than= 1) is manifested. We use film and plasma characterization techniques, as well as simulations in order to study the dynamics of the target-discharge-film interactions. The results show that the primary bombarding species of the growing film are N-2(+) plasma ions, which are neutralized and backscattered by the target in the form of atomic N. It is shown that the backscattered N atoms have energies which are significantly higher than those of other bombarding species, i.e. the backscattered Ar atoms, the sputtered atoms and the plasma ions. Moreover, it is found that CrN films exhibit compressive stresses of 2.6 GPa and a density close to the bulk value. We attribute these properties to the bombardment by backscattered energetic atoms, in particular N. Pure Cr films are also studied for reference.
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| 8. |
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| 9. |
- Alami, J., et al.
(författare)
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On the deposition rate in a high power pulsed magnetron sputtering discharge
- 2006
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 89:15, s. 154104-
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the high pulse current and the duty cycle on the deposition rate in high power pulsed magnetron sputtering (HPPMS) is investigated. Using a Cr target and the same average target current, deposition rates are compared to dc magnetron sputtering (dcMS) rates. It is found that for a peak target current density I-Tpd of up to 570 mA cm(-2), HPPMS and dcMS deposition rates are equal. For I-Tpd greater than 570 mA cm(-2), optical emission spectroscopy shows a pronounced increase of the Cr+/Cr-0 signal ratio. In addition, a loss of deposition rate, which is attributed to self-sputtering, is observed.
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| 10. |
- Alami, J., et al.
(författare)
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On the phase formation of titanium oxide films grown by reactive high power pulsed magnetron sputtering
- 2009
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Ingår i: Journal of Physics D. - : Institute of Physics. - 0022-3727 .- 1361-6463. ; 42:11, s. 115204-
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Tidskriftsartikel (refereegranskat)abstract
- High power pulsed magnetron sputtering is used for the growth of titanium dioxide (TiO(2)) films at different working pressures and orientations of the substrate with respect to the target surface. In the case of substrates oriented parallel to the target surface, the increase in the working pressure from 0.5 to 3 Pa results in the growth of crystalline TiO(2) films with phase compositions ranging from rutile to anatase/rutile mixtures. When depositions are performed on substrates placed perpendicularly to the target surface, rutile films that consist of TiO(2) nanocrystals embedded in an amorphous matrix are obtained at 0.5 Pa. Increase in the working pressure leads to the deposition of amorphous films. These findings are discussed in the light of the energetic bombardment provided to the growing film at the various deposition conditions.
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