Reactive HiPIMS deposition of Al-oxide thin films using W-alloyed Al targets
| Autor: | Helmut Riedl, T. Wojcik, L. Zauner, Szilárd Kolozsvári, Jiří Čapek, Tomáš Kozák, S. Kagerer, P.H. Mayrhofer, Petr Zeman |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Alumina R-HiPIMS depozice Analytical chemistry Oxide oxid hlinitý Surfaces and Interfaces General Chemistry Partial pressure Sputter deposition Condensed Matter Physics Polymorph structures Surfaces Coatings and Films Amorphous solid Target poisoning chemistry.chemical_compound chemistry Physical vapor deposition Materials Chemistry polymorfní struktury Deposition (phase transition) oxidace terče R-HiPIMS deposition High-power impulse magnetron sputtering Thin film |
| Zdroj: | Surface and Coatings Technology. 422:127467 |
| ISSN: | 0257-8972 |
| DOI: | 10.1016/j.surfcoat.2021.127467 |
| Popis: | The outstanding oxidation resistance, thermo-mechanical stability, and chemical inertness of alumina, but also the synthesis of phase pure polymorphs attract particular attention in academia and industry. Especially, the difficulties regarding the synthesis of α- or γ-structured Al2O3 by physical vapor deposition techniques are still strong limitations. Within this study, we investigated in detail the influence of 2 at.% tungsten in the Al-target on the process stability and phase formation during reactive DC magnetron sputtering as well as high power impulse magnetron sputtering (HiPIMS) of Al2O3-based coatings. The small addition of W to the Al target allows to increase the oxygen partial pressure by more than 200% while maintaining a stable deposition process. Ion mass spectroscopy measurements yield a promising high fraction of 16O+ and 32O2+, when operating the W-containing target in the metal-to-poisoned transition mode. A significant increase of 16O+ is further provided by the target surface oxide in poisoned mode. Detailed time-of-flight ion mass spectroscopy investigations during one HiPIMS pulse show a clear temporal separation of the individual ions arriving at the substrate plane during the pulse on-time, allowing for controlled ion attraction by synchronizing the bias pulse to the discharge impulse. Equal amounts of 27Al+ and 32O2+ can be attracted using a bias on-time between 400 μs and 900 μs in the “off-time” (after glow) leading to a dense and nano-crystalline coating. Detailed electron microscopy investigations show the presence of metallic phase fractions for higher duty cycles (7.5%). Decreasing the duty cycle to 3.75% leads to amorphous coatings when operating the Al-target at the highest oxygen partial pressure in metallic mode. |
| Databáze: | OpenAIRE |
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