2020 Fiscal Year Annual Research Report
Elucidation of plasma-assisted atomic layer etching (ALE) mechanism for magnetic materials using organic gas
| Project/Area Number |
20J10393
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| Research Institution | Osaka University |
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Principal Investigator |
Basher Abdulrahman H. 大阪大学, 工学研究科, 特別研究員(DC2)
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| Project Period (FY) |
2020-04-24 – 2022-03-31
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| Keywords | Thermal ALE / DFT simulation / Etching of metals |
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| Outline of Annual Research Achievements |
The chemical reaction mechanisms for hexafluoroacetylacetone (hfacH) and acetylacetone (acacH) have be investigated with pure and oxidized Ni. From the investigated mechanisms, we found that molecules have F atoms are more stable on a NiO surface because the negatively charged F atoms repulse with O atoms in the NiO surface. As a result, they do not allow C atoms to interact with Ni atoms that can cause the decomposition of these molecules. Moreover, this repulsing force will decrease the needed energy (the used temperature) to volatilize the metal complex and H2O molecules that cause the etching of oxidized metals. On the other hand, if F atoms are replaced with H atoms, the positively charged H atoms may interact with the O atoms in the surface which cause the dissociation of these molecules.
In addition, I found that the decomposition state of hfacH, trifluoroacetylacetone (tfacH), and acacH are more stable on a pure metallic surface. There are a barrier energy, relatively small, which can be passed by increasing the surface temperature. These results confirm that there is a self-limiting step when the oxidized metal etched thermally by these molecules.
From these results we can announce that hfacH gas is the best gas for thermal ALE from the following gases: hfacH, tfacH, acacH, and formic acid (fa) gas.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
After I could prove that hfacH gas is the best beta-diketone etchant gas for thermal ALE of metals, I suppose to test the reported results experimentally at Prof. Kessel lab in Eindhoven University of Technology (TU/e) but it has not done yet because I could not travel to Netherlands as we are still struggling with the pandemic COVID-19.
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| Strategy for Future Research Activity |
I am going to find the differences of the chemical reactions when hfacH molecules interact with other metals and their oxidized surfaces to generalized what I found for all metals. In addition, I expect the practical part of this study will be done in October 2021 at Prof. Kessel lab in Eindhoven University of Technology (TU/e) as it is planned.
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[Journal Article] Stability of Hexafluoroacetylacetone Molecules on Metallic and Oxidized Nickel Surfaces in Atomic Layer Etching (ALE) Processes2020
Author(s)
Abdulrahman H. Basher, M. Krstic, T. Takeuchi, M. Isobe, T. Ito, M. Kiuchi, K. Karahashi, W. Wenzel, and S. Hamaguchi,
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Journal Title
Journal of Vacuum Science & Technology A
Volume: 38, 022610
Pages: 1-8
DOI
Peer Reviewed / Open Access / Int'l Joint Research
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