Abstract

Translate

The Hollow Cathode Gas Flow Sputtering (GFS) provides special plasma conditions and is of extensive interest as a more affordable alternative to the high vacuum sputtering techniques. In the case of the tubular cathode a circular outlet symmetry stipulates homogeneity issues for both metallic and reactive deposition regimes. Using the results of Direct Simulation Monte Carlo (DSMC), we propose an external coaxial attachment which is manufactured and examined in a nozzle and a diffuser positioning. The impact on the homogeneity of Ti and ${TiO}_{2}$ films is examined using profilometry and spectral ellipsometry. Our results demonstrate that the use of the nozzle attachment significantly enhances film homogeneity from about 3 ${cm}^{2}$ to more than 12 ${cm}^{2}$ . It also secures better process control in terms of oxygen stoichiometry and film thickness. Some crucial general issues of the reactive GFS process are discussed.

Full text

Turn on search term navigation

Translate

1. Introduction

Sputtering is one of the most significant deposition methods utilized for depositing thin films across various applications (industrial coatings on glass, wear-resistant coatings, photovoltaics, electronics and others) [1,2,3]. Among the sputtering techniques, magnetron sputtering is widely employed in the industry but is prone to target poisoning due to hysteresis behavior during reactive sputtering, which also impacts the deposition rate [4,5,6]. Gas flow sputtering (GFS), based on hollow cathode discharge, demonstrates several key advantages over conventional low-pressure sputtering techniques. Among the practical ones are much higher deposition rates and much lower costs of systems construction, the reactive gas inlet is placed outside the cathode, which prevents poisoning of the cathode surface (Figure 1b) [7,8,9,10]. GFS takes advantage of the thermalization of sputtered atoms and subsequent transport to the substrate by forced convection, there is no high energy impact to the substrates used and layers deposited, which is usually assessed as plasma damage [11,12,13]. It provides a high plasma density compared to magnetron sputtering and an adjustable, comparably low kinetic energy of ions (about kT up to few eV) using pulsed plasma operation [13,14,15,16,17,18,19,20]. High-pressure metallic mode sputtering combined with gas flow assistance facilitates exceptionally high deposition rates compared to alternative sputtering methods [1,8,21].

In typical hollow cathode GFS, the laminar argon flow has the highest velocity in the middle of a cathode [22]. This causes inhomogeneous mass transport across the outlet and radially thinning metallic films [9,23,24]. This problem is well-known and addressed in the literature to the multiple cathode systems or to the optimized cathode dimensions [25,26,27], which makes the system more complex with added costs. A larger target-to-substrate distance can improve the homogeneity of the films but simultaneously causes their larger porosity [24,28].

Moreover, the overall process control deteriorates due to (i) a significant drop in sputtering gas pressure at the outlet and (ii) a spread or unsteady gas stagnation point.

Direct simulations Monte Carlo (DSMC) are widely used in industry to optimize gas dynamics in vacuum processes [29,30], to simulate charge transfer in plasmas [31,32,33], and to upscale deposition systems [29,34,35]. Pressure ranges from low pressures < 1 Pa to high pressures > 100 Pa can be simulated [36,37,38]. We exploited this tool to conduct speculative homogeneity improvements. Various coaxial accessories were of interest. Titanium oxide was taken as one of the most investigated and widely used oxides in technology. Its microstructure and oxygen stoichiometry are known to correlate with optical properties strongly.

This study is aimed to optimize gas dynamics in the GFS deposition process. The use of different coaxial accessories matching hollow cylindric targets is simulated by DSMC and benchmarked. To approve the simulated findings, the homogeneity of Ti and ${TiO}_{2}$ films is evaluated by profilometry and spectral ellipsometry.

2. Methodology

This work used the hollow cathode gas flow sputtering system as shown in Figure 1, the argon gas supply is behind the sputter source (1) the substrate is fixed on a heatable substrate holder (2) which can be also heated from the treatment station (3). Figure 1b shows the Principle of Gas Flow Sputtering, by applying a voltage between the hollow cathode and the anode, a glow discharge with a high plasma density occurs inside the hollow cathode. The sputtered material is effectively transported by argon gas flow to the outlet of the hollow cathode towards the surface of the substrate, where $O_{2}$ is realized by reactive deposition (which prevents interaction with the target surface), and the sputtered atoms can react with some of the offered $O_{2}$ and build the film at the substrate surface. A diffuser and nozzle attachments were fixed at the outlet of the GFS source as shown in Figure 2. The parameters for titania deposition were based on our previous experience [11]. Since the diffuser accessory blocks the reactive gas inlet (Figure 2b), we did not use it further. A 3.1 mm thick low-iron soda lime glass type Diamant (Saint-Gobain Glass, Cologne, Germany) and 50 × 50 ${mm}^{2}$ size was used as a substrate. The glass substrates were cleaned with acetone and then dried with nitrogen gas before deposition. Depositions were conducted without intentional heating. High-purity (99.99% Ti) tubular targets of 60 mm length, 50 mm outer, and 40 mm inner diameters were taken. A discharge power was 500 W in pulse mode with 100 kHz frequency, 2 µs pulse duration, and +50 V reverse voltage. These settings were found to deliver denser titania films at low deposition temperatures. Base and process pressures were 1.4 × $10^{- 2}$ mbar and 0.35 mbar, respectively. Argon gas flow of 1000 sccm was used for sputtering. Oxygen gas flow was set after optimization based on optical transmittance to 80 sccm for the blank outlet and to 5 sccm for the nozzle outlet. The distance between oxygen inlets and a substrate was set to 25 mm in both cases. All films were deposited for 150 s.

The thicknesses of deposited Ti thin films were evaluated by profilometer (DektakXT, Bruker, Billerica, MA, USA), where it is necessary to have a step in the film profile on the substrate, which was achieved using marked with edding before the deposition and removed afterward with acetone. The optical properties of the ${TiO}_{2}$ films were characterized by the Sentech Ellipsometer SE 850 with a µ-spot (which focuses the beam to 200 microns in diameter at the polarizer unit), the measurements were carried at 70° incident angle, and the data were measured at a spectral range between 280 and 850 nm, the measured refractive index is shown at $λ$ = 550 nm.

The Direct Simulation Monte Carlo has been applied for the GFS deposition process. For this purpose, the Linux 96xCPU cluster and the elaborated simulation software developed by Dr. A. Pflug (Fraunhofer IST, Braunschweig, Germany) [39] were used. The geometric model of our system was built by the finite-element mesh generator: Gmsh^® [40]. The Direct Simulation Monte Carlo (DSMC) to model the gas flows and distribution of neutral particles was used [41]. We used a 2D model instead of a 3D model to reduce the simulation time and adapt the simulated deposition parameters to this circumstance. This approach was validated in our previous works [38,42]. Following this approach, we set 2D-flows as 31.83 sccm for Ar gas and 2.547 sccm for $O_{2}$ gas. The relevant length of a substrate holder was set to 100 mm and the target-to-substrate distance was the same as it was in depositions.

3. Results and Discussion

To improve the homogeneity of metal films, the so-called diffuser accessory (see Figure 2b) was proposed and approbated using DSMC. The optimum opening angle ( $α$ ) was found to vary in the range 60–80° [43], but overall homogeneity even degraded compared to the bare source (as will be seen later in the Deposition section). The opening angle $α$ used in this work was 67°. Considering the former experience of successful use of the coaxial gas nozzle in metal-organic chemical vapor deposition (MOCVD) reactors [44], we applied the very same accessory, positioning it inversely (Figure 2c) which resulted in much better homogeneity. Furthermore, this geometry made the reactive sputtering possible as well.

3.1. Simulation

It can be seen from the gas simulation (Figure 3) that the argon pressure inside the hollow cathode becomes higher if the nozzle attachment is used. The oxygen pressure over the substrate surface is also higher in this case. Higher pressure implies, larger diffusion gradients toward the substrate and more intense bombardment of the surface by ions.

To characterize the spreading of gases more quantitatively we extracted the (p( $O_{2}$ )/p(Ar)) ratio profile from the simulations and measured the oxygen partial pressure (p( $O_{2}$ )) directly (Figure 4).

The latter was conducted with the help of oxygen Frontal ZIROX E2010.B0 which was placed over the substrate at various radial distances from the center. Since the measuring head was 10 mm large, we implied around 5 mm remoteness from the substrate surface. We note that the (p(Ar)) represents with some approximation a delivery of titanium species at a fixed discharge power. Both estimations demonstrate a remarkably effective and homogeneous delivery of oxygen to the substrate when the nozzle is used.

3.2. Deposition

Figure 5a presents the thickness values measured by profilometer across differently deposited metal titanium films (excluding the use of reactive gas). The x-axis represents a radial distance from the center of the sample. For quantitative comparison, the impacts of the outlet accessories on homogeneity are given using criterium h:

(1) $h = \frac{d_{c} - d_{20}}{d_{c}} \times 100 %$

where

d_{c}

is the thickness in the film’s center and

d_{20}

is the thickness at a 20 mm distance from the center. According to Figure 5a the thickness decreases at 20 mm distance from the center by 43% using the diffuser and by 28%, without any outlet. The best homogeneity of a 6% difference in thickness was achieved by using the nozzle accessory.

A Ti target was used to deposit metallic titanium and titania thin films. Since we used a reactive GFS process, the oxide forms right on the substrate surface during film growth. This fact stipulates two features: (i) no plasma damage by accelerated oxygen ions and (ii) the importance of the mixing degree of argon and oxygen over the substrate. The insufficient homogeneity of deposited layers still hinders the wider application of the GFS method [17,23]. The problem of the metal-to-oxygen ratio in the middle of a deposition zone was signified in our previous work on titania films [11]. Figure 5b shows the ellipsometry measurements of the ${TiO}_{2}$ -films. A two-layer model was used for fitting the corresponding ellipsometry spectra in SpectraRay software. The model layer stack included one dense Brendel layer for the ${TiO}_{2}$ film and one effective medium approximation (EMA) layer, consisting of 50% ${TiO}_{2}$ and 50% air, which usually describes the roughness of the film. It can be seen that the ${TiO}_{2}$ -films deposited with the nozzle attachment revealed within a 40 mm circular area, remarkably better thickness homogeneity than the film deposited ordinarily. It is also valid for the refractive index. The refractive index is higher for the ordinary film in the center probably due to its oxygen under stoichiometry. Indeed, the refractive index is known to correlate with ${TiO}_{2}$ density which increases with oxygen deficiency [45,46]. The absorption index k was found to be lower (0.00639) for titania deposited using the nozzle compared to the ordinary one (0.00917) in the frame of the optical model (see Figure 5b), which supports the suggested difference in the oxygen stoichiometry sample [47,48,49,50]. In sum, the nozzle attachment increased the homogeneous area of titania films from 3 ${cm}^{2}$ to more than 12 ${cm}^{2}$ and allowed to strongly decrease the reactive gas consumption.

4. Conclusions

In conclusion, we demonstrated a successful implementation of the gas pressure simulations to improve the GFS process. The coaxial nozzle attachment was found to significantly improve the film’s homogeneity in both metallic and reactive deposition modes. This concept was transposed from a 1 cm nozzle width in MOCVD to a 4 cm diameter of the tubular hollow cathode in GFS. It was surprisingly auspicious and allowed improving the film’s homogeneity from about 3 ${cm}^{2}$ to more than 12 ${cm}^{2}$ . Much better process control in terms of oxygen stoichiometry and film thickness was reached for ${TiO}_{2}$ . This improved gas flow distribution leads to more uniform film thickness and refractive index. The question if any parasitic sputtering from the inner surface of such attachment occurs will be addressed in the upcoming investigations.

Author Contributions

Conceptualization, N.A. and R.M.; methodology, N.A. and R.M.; software, N.A., S.K. and A.P.; validation, N.A., R.M., B.S. and A.P.; formal analysis, N.A.; investigation, N.A. and R.M.; resources, B.S.; data curation, N.A. and T.L.; writing—original draft preparation, N.A.; writing—review and editing, R.M.;proofreading, N.A., B.S. and R.M.; visualization, N.A. and R.M.; supervision, N.A. and R.M.; project administration, B.S.; funding acquisition, B.S. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Conflicts of Interest

The authors declare no conflicts of interest.

Footnotes

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Figures

View Image - Figure 1. (a) Top-view photo of the GFS deposition chamber. (b) Schematic cross-section representation of the GFS deposition process reproduced from Alktash et al. [11]. Copyright © 2023, the authors, licensed under CC BY 4.0 DEED.

Figure 1. (a) Top-view photo of the GFS deposition chamber. (b) Schematic cross-section representation of the GFS deposition process reproduced from Alktash et al. [11]. Copyright © 2023, the authors, licensed under CC BY 4.0 DEED.

View Image - Figure 2. Schematic cross-section of the GFS source with (a) no attachment (blank); with (b) diffuser attachment and with (c) nozzle attachment. (d) Front look to the blank outlet. For better visibility argon and oxygen gas inlets are shown larger than they are.

Figure 2. Schematic cross-section of the GFS source with (a) no attachment (blank); with (b) diffuser attachment and with (c) nozzle attachment. (d) Front look to the blank outlet. For better visibility argon and oxygen gas inlets are shown larger than they are.

View Image - Figure 3. Middle cross-section of the GFS-sputtering source. (a) 2D-simulated argon pressure distribution for three considered source outlets. (b) 2D-simulated oxygen pressure distribution for two relevant source outlets.

Figure 3. Middle cross-section of the GFS-sputtering source. (a) 2D-simulated argon pressure distribution for three considered source outlets. (b) 2D-simulated oxygen pressure distribution for two relevant source outlets.

Figure 4. (a) Frontal pressure ratio (p([Forumla omitted. See PDF.])/p(Ar)) profile at around 5 mm distance from the substrate. Pressure was extracted from the simulations. (b) Measured frontal p([Forumla omitted. See PDF.]) profile over substrate. Same gas flows as for deposition were delivered but no plasma was ignited during p([Forumla omitted. See PDF.]) measurements.

$View Image - Figure 5. (a) Thickness data for titanium films measured from the center to the edge of the sample. (b) Comparison of the [Forumla omitted. See PDF.]-films deposited with and without nozzle attachment in terms of thickness and refractive index obtained from ellipsometry.$

Figure 5. (a) Thickness data for titanium films measured from the center to the edge of the sample. (b) Comparison of the [Forumla omitted. See PDF.]-films deposited with and without nozzle attachment in terms of thickness and refractive index obtained from ellipsometry.

References

1. Jirátová, K.; Čada, M.; Naiko, I.; Ostapenko, A.; Balabánová, J.; Koštejn, M.; Maixner, J.; Babii, T.; Topka, P.; Soukup, K. et al. Plasma Jet Sputtering as an Efficient Method for the Deposition of Nickel and Cobalt Mixed Oxides on Stainless-Steel Meshes: Application to VOC Oxidation. Catalysts; 2023; 13, 79. [DOI: https://dx.doi.org/10.3390/catal13010079]

2. Cai, L.; Zhu, F. Toward efficient and stable operation of perovskite solar cells: Impact of sputtered metal oxide interlayers. Nano Sel.; 2021; 2, pp. 1417-1436. [DOI: https://dx.doi.org/10.1002/nano.202000290]

3. Kumar, A.; Jaiswal, J.; Tsuchiya, K.; Mulik, R.S. Modern Coating Processes and Technologies. Coating Materials: Computational Aspects, Applications and Challenges; Verma, A.; Sethi, S.K.; Ogata, S. Springer Nature: Singapore, 2023; pp. 33-80. [DOI: https://dx.doi.org/10.1007/978-981-99-3549-9_3]

4. Shapovalov, V.I. Modeling of Reactive Sputtering and mdash;History and Development. Materials; 2023; 16, 3258. [DOI: https://dx.doi.org/10.3390/ma16083258]

5. LARS-ERIK, G. Hollow Cathode Deposition of Thin Films; Uppsala University: Uppsala, Sweden, 2006; 56.

6. Desch, N.; Lake, M. Formation of pure anatase TiO₂ using the reactive pulsed dc magnetron sputtering method for controlling the target poisoning state. Appl. Res.; 2023; 3, e202300003. [DOI: https://dx.doi.org/10.1002/appl.202300003]

7. Ishii, K.; Kurokawa, K.; Yoshihara, S. High-rate deposition of titanium dioxide films with photocatalytic activities by gas flow sputtering. IEICE Trans. Electron.; 2004; 87, pp. 232-237.

8. Muhl, S.; Pérez, A. The use of hollow cathodes in deposition processes: A critical review. Thin Solid Film.; 2015; 579, pp. 174-198. [DOI: https://dx.doi.org/10.1016/j.tsf.2015.02.066]

9. Bolotov, M. The Deposition of Thin Metal Films in Low Temperature Plasma of Hollow Cathode Glow Discharge. Proceedings of the 2020 IEEE 40th International Conference on Electronics and Nanotechnology (ELNANO); Kyiv, Ukraine, 22–24 April 2020; pp. 90-94. [DOI: https://dx.doi.org/10.1109/ELNANO50318.2020.9088874]

10. Kapran, A.; Hippler, R.; Wulff, H.; Olejnicek, J.; Pisarikova, A.; Cada, M.; Hubicka, Z. Characteristics of a pulsed hollow cathode discharge operated in an Ar+O2 gas mixture and deposition of copper nickel oxide thin films. Vacuum; 2023; 215, 112272. [DOI: https://dx.doi.org/10.1016/j.vacuum.2023.112272]

11. Alktash, N.; Muydinov, R.; Erfurt, D.; Hartig, M.; Gajewski, W.; Szyszka, B. Indigenous facility of the unipolar pulsed power generation for gas flow sputtering of titania films. Rev. Sci. Instrum.; 2023; 94, 075104. [DOI: https://dx.doi.org/10.1063/5.0148807]

12. Butcher, K.S.A.; Georgiev, V.; Georgieva, D. Recent Advances in Hollow Cathode Technology for Plasma-Enhanced ALD—Plasma Surface Modifications for Aluminum and Stainless-Steel Cathodes. Coatings; 2021; 11, 1506. [DOI: https://dx.doi.org/10.3390/coatings11121506]

13. Abe, S.; Takahashi, K.; Mukaigawa, S.; Takaki, K. Comparison of plasma characteristics of high-power pulsed sputtering glow discharge and hollow-cathode discharge. Jpn. J. Appl. Phys.; 2020; 60, 015501. [DOI: https://dx.doi.org/10.35848/1347-4065/abcd78]

14. Sakuma, H.; Ishii, K. Gas flow sputtering: Versatile process for the growth of nanopillars, nanoparticles, and epitaxial thin films. J. Magn. Magn. Mater.; 2009; 321, pp. 872-875. [DOI: https://dx.doi.org/10.1016/j.jmmm.2008.11.053]

15. Paduraru, C.; Belkind, A.; Becker, K.; Lopez, J.; Delahoy, A.; Guo, S.Y. Pulsed DC, Gas-Flow Hollow Cathode Discharge: A source for sputter-Deposition. Proceedings of the SVC Annual Technical Conference Proceedings; San Francisco, CA, USA, 3–8 May 2003; Volume 46.

16. Somekh, R. The thermalization of energetic atoms during the sputtering process. J. Vac. Sci. Technol. A Vac. Surf. Film; 1984; 2, pp. 1285-1291. [DOI: https://dx.doi.org/10.1116/1.572396]

17. Ishii, K. High-rate low kinetic energy gas-flow-sputtering system. J. Vac. Sci. Technol. A; 1989; 7, pp. 256-258. [DOI: https://dx.doi.org/10.1116/1.576129]

18. Saitou, Y.; Sakuma, H.; Ishii, K. Estimations of Plasma Parameters and Bias-Sputtering of Cu Films in Gas-Flow-Sputtering Operating at 1-Torr Pressure Region. Trans. Mater. Res. Soc. Jpn.; 2005; 30, pp. 311-314.

19. Morgner, H.; Neumann, M.; Straach, S.; Krug, M. The hollow cathode: A high-performance tool for plasma-activated deposition. Surf. Coat. Technol.; 1998; 108–109, pp. 513-519. [DOI: https://dx.doi.org/10.1016/S0257-8972(98)00633-1]

20. Goebel, D.M.; Becatti, G.; Mikellides, I.G.; Lopez Ortega, A. Plasma hollow cathodes. J. Appl. Phys.; 2021; 130, 050902. [DOI: https://dx.doi.org/10.1063/5.0051228]

21. Linss, V.; Bivour, M.; Iwata, H.; Ortner, K. Comparison of low damage sputter deposition techniques to enable the application of very thin a-Si passivation films. Proceedings of the AIP Conference Proceedings; Bodrum, Turkey, 4–8 September 2019; Volume 2147.

22. Hoffman, D.; Singh, B.; Thomas, J.H., III. Handbook of Vacuum Science and Technology; Elsevier: Amsterdam, The Netherlands, 1997.

23. Jung, T.; Westphal, A. High rate deposition of alumina films by reactive gas flow sputtering. Surf. Coat. Technol.; 1993; 59, pp. 171-176. [DOI: https://dx.doi.org/10.1016/0257-8972(93)90078-3]

24. Delahoy, A.E.; Guo, S.Y.; Paduraru, C.; Belkind, A. Reactive-environment, hollow cathode sputtering: Basic characteristics and application to Al₂O₃, doped ZnO, and In₂O₃:Mo. J. Vac. Sci. Technol. A; 2004; 22, pp. 1697-1704. [DOI: https://dx.doi.org/10.1116/1.1723289]

25. Olejnicek, J.; Smid, J.; Perekrestov, R.; Ksirova, P.; Rathousky, J.; Kohout, M.; Dvorakova, M.; Kment, S.; Jurek, K.; Cada, M. et al. Co₃O₄ thin films prepared by hollow cathode discharge. Surf. Coat. Technol.; 2019; 366, pp. 303-310. [DOI: https://dx.doi.org/10.1016/j.surfcoat.2019.03.010]

26. Zouzelka, R.; Olejnicek, J.; Ksirova, P.; Hubicka, Z.; Duchon, J.; Martiniakova, I.; Muzikova, B.; Mergl, M.; Kalbac, M.; Brabec, L. et al. Hierarchical TiO₂ Layers Prepared by Plasma Jets. Nanomaterials; 2021; 11, 3254. [DOI: https://dx.doi.org/10.3390/nano11123254] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/34947602]

27. Mihailova, D. Sputtering Hollow Cathode Discharges Designed for Laser Applications: Experiments and Theory. Ph.D. Thesis; Technische Universiteit Eindhoven: Eindhoven, The Netherlands, 2010; [DOI: https://dx.doi.org/10.6100/IR672762]

28. Tobias, K. Hohlkathoden-Gasflußsputtern zur Verschleißschutzbeschichtung von Kunststoffen; Fraunhofer-Institut für Schicht- und Oberflächentechnik IST: Braunschweig, Germany, 1998; 98.

29. Venkattraman, A.; Alexeenko, A.A. Direct simulation Monte Carlo modeling of metal vapor flows in application to thin film deposition. Vacuum; 2012; 86, pp. 1748-1758. [DOI: https://dx.doi.org/10.1016/j.vacuum.2012.02.044]

30. Thiruppathiraj, S.; Ryu, S.M.; Uh, J.; Raja, L.L. Direct-simulation Monte Carlo modeling of reactor-scale gas-dynamic phenomena in a multiwafer atomic-layer deposition batch reactor. J. Vac. Sci. Technol. A; 2021; 39, 052404. [DOI: https://dx.doi.org/10.1116/6.0000993]

31. Serikov, V.; Kawamoto, S.; Nanbu, K. Particle-in-cell plus direct simulation Monte Carlo (PIC-DSMC) approach for self-consistent plasma-gas simulations. IEEE Trans. Plasma Sci.; 1999; 27, pp. 1389-1398. [DOI: https://dx.doi.org/10.1109/27.799817]

32. Kim, J.S.; Hur, M.Y.; Song, I.C.; Lee, H.J.; Lee, H.J. Simulation of Low-Pressure Capacitively Coupled Plasmas Combining a Parallelized Particle-in-Cell Simulation and Direct Simulation of Monte Carlo. IEEE Trans. Plasma Sci.; 2014; 42, pp. 3819-3824. [DOI: https://dx.doi.org/10.1109/TPS.2014.2368145]

33. Zuppardi, G.; Francesco, R. Direct Simulation Monte Carlo Method in Industrial Applications. Methods Appl. Tenutosi A Santa Fe; 2009; 6, pp. 1-18.

34. Jimenez, F.J.; Dew, S.K.; Field, D.J. Comprehensive computer model for magnetron sputtering. II. Charged particle transport. J. Vac. Sci. Technol. A; 2014; 32, 061301. [DOI: https://dx.doi.org/10.1116/1.4894270]

35. Sohn, I.; Seo, I.; Lee, S.; Jeong, S. Improved modeling of material deposition during OLED manufacturing using direct simulation monte carlo method on GPU Architecture. Int. J. Precis. Eng. Manuf.-Green Technol.; 2019; 6, pp. 861-873. [DOI: https://dx.doi.org/10.1007/s40684-019-00068-7]

36. Tonneau, R.; Moskovkin, P.; Pflug, A.; Lucas, S. TiOx deposited by magnetron sputtering: A joint modelling and experimental study. J. Phys. D Appl. Phys.; 2018; 51, 195202. [DOI: https://dx.doi.org/10.1088/1361-6463/aabb72]

37. Ivchenko, D.; Zhang, T.; Mariaux, G.; Vardelle, A. On the Validity of Continuum Computational Fluid Dynamics Approach Under Very Low-Pressure Plasma Spray Conditions. J. Therm. Spray Technol.; 2017; 6, pp. 3-13. [DOI: https://dx.doi.org/10.1007/s11666-017-0658-y]

38. Scherg-Kurmes, H. Deposition von Transparenten Leitfähigen Oxiden mit Hoher Ladungsträgermobilität bei Niedriger Prozesstemperatur und Deren Integration in Photovoltaik-Zellen: Numerische Simulation der Physikalischen und Chemischen Vorgänge während der Deposition; Technische Universitaet Berlin: Berlin, Germany, 2017.

39. Pflug, A. Simulation & Digital Services. Available online: https://www.ist.fraunhofer.de/en/expertise/simulation-digital-services.html (accessed on 30 September 2023).

40. Geuzaine, C.; Remacle, J.F. Gmsh: A Three-Dimensional Finite Element Mesh Generator with Built-in Pre- and Post-Processing Facilities. Available online: http://gmsh.info/ (accessed on 30 September 2023).

41. Pflug, A.; Siemers, M.; Melzig, T.; Schulz, P. DSMC and PICMC documentation. Available online: https://www.ist.fraunhofer.de/de/kompetenzen/simulation-digital-services/dsmc-picmc.html (accessed on 12 July 2021).

42. Koerner, S. Entwicklung Einer Flexiblen Beschichtungstechnologie zur Herstellung von Transparenten Leitfähigen OXIDEN für CuInGaSe2-Solarzellen; Technische Universitaet Berlin: Berlin, Germany, 2023; 196.

43. Liu, T. Computer-Aided Modeling and Simulation of Methods for Optimizing the Output Flow of an Existing Gas Flow Sputtering System. 2018; p. 78; unpublished Master Thesis

44. Stadel, O.; Schmidt, J.; Markov, N.; Samoilenkov, S.; Wahl, G.; Jimenez, C.; Weiss, F.; Selbmann, D.; Eickemeyer, J.; Gorbenko, O.Y. et al. Single source MOCVD system for deposition of superconducting films onto moved tapes. J. Phys. IV; 2001; 11, pp. Pr3-1087-Pr3-1094. [DOI: https://dx.doi.org/10.1051/jp4:20013136]

45. Huang, C.; Tsao, C.; Hsu, C. Study on the photocatalytic activities of TiO₂ films prepared by reactive RF sputtering. Ceram. Int.; 2011; 37, pp. 2781-2788. [DOI: https://dx.doi.org/10.1016/j.ceramint.2011.04.030]

46. Mergel, D.; Buschendorf, D.; Eggert, S.; Grammes, R.; Samset, B. Density and refractive index of TiO₂ films prepared by reactive evaporation. Thin Solid Film.; 2000; 371, pp. 218-224. [DOI: https://dx.doi.org/10.1016/S0040-6090(00)01015-4]

47. Shakoury, R.; Zarei, A. Optical and Structural Properties of TiO₂ Thin Films Deposited by RF Magnetron Sputtering. Silicon; 2019; 11, pp. 1247-1252. [DOI: https://dx.doi.org/10.1007/s12633-018-9897-x]

48. Mohamed, S.; Kappertz, O.; Leervad Pedersen, T.; Drese, R.; Wuttig, M. Properties of TiOx coatings prepared by dc magnetron sputtering. Phys. Status Solidi; 2003; 198, pp. 224-237. [DOI: https://dx.doi.org/10.1002/pssa.200306597]

49. Jiang, J.; Li, B.; Zhang, Z.; Hu, P.; Zhang, F.; Cheng, H.; Yang, F. Influence of the Oxygen Partial Pressure on the Composition and Optical Properties of Electron-beam Evaporated TiOx Films. Phys. Status Solidi; 2002; 193, pp. 69-77. [DOI: https://dx.doi.org/10.1002/1521-396X(200209)193:1<69::AID-PSSA69>3.0.CO;2-4]

50. Wiatrowski, A.; Wojcieszak, D.; Mazur, M.; Kaczmarek, D.; Domaradzki, J.; Kalisz, M.; Kijaszek, W.; Pokora, P.; Mańkowska, E.; Lubanska, A. et al. Photocatalytic Coatings Based on TiOx for Application on Flexible Glass for Photovoltaic Panels. J. Mater. Eng. Perform.; 2022; 31, pp. 6998-7008. [DOI: https://dx.doi.org/10.1007/s11665-022-06655-1]

© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

A Coaxial Nozzle Attachment Improving the Homogeneity of the Gas Flow Sputtering

Content area

Abstract

Full text