SRF2023 - List of Authors (Blick, R.H.)

Paper	Title	Page
MOPMB016	Successful Al₂O₃ Coating of Superconducting Niobium Cavities by Thermal ALD	104
	G.K. Deyu, W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany R.H. Blick, I. González Díaz-Palacio, R. Zierold University of Hamburg, Hamburg, Germany
	Funding: This work is supported by the BMBF under the research Grant 05K19GUB. Al₂O₃ is one of the potential insulator materials in the superconductor-insulator-superconductor (SIS) multilayer coatings of superconducting radio-frequency (SRF) cavities for pushing their performance limits. We report on the successful coating of two 1.3 GHz Tesla-shaped SRF cavities with 18 nm and 36 nm layers of Al₂O₃ deposited by thermal atomic layer deposition (ALD). The coating recipe was developed by thermal atomic layer deposition (ALD). The coating recipe was optimized with respect to different the applied process parameters such as exposure and purge times, substrate temperature and flow rates. After a proof-of-principle Al₂O₃ coating of a cavity, second the cavity maintained its maximum achievable accelerating field of more than 40 MV/m and no deterioration was observed [1]. On the contrary, an improvement of the surface resistance above 10 MV/m has been observed, which is now further under investigation. [1].Wenskat, Marc, et al. "Successful Al₂O₃ coating of superconducting niobium cavities with thermal ALD." Superconductor Science and Technology 36.1 (2022): 015010.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB016
About •	Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WECBA01	Successful SIS Multilayer Activities on Cavities and Samples Using ALD
	I. González Díaz-Palacio, R.H. Blick, C. Saribal, R. Zierold University of Hamburg, Hamburg, Germany G.K. Deyu, W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Theoretically SIS multilayers predict to delay vortex penetration allowing for operation gradients more than the double of bulk Nb cavities and Q-values two orders of magnitude above. The University of Hamburg focuses on Atomic Layer Deposition (ALD) as most promising coating technique. In a proof-of principle experiment thermal ALD of Al₂O₃ was successfully applied to two 1.3GHz single-cell cavities achieving gradients above 40MV/m without any deterioration in Q-value [1]. Studies using plasma-enhanced ALD (PEALD) on planar samples focus on AlN and NbTiN as dielectric and superconductor material, respectively. The deposition process and post-deposition treatments have been optimized by studying the superconducting properties in magneto-transport and in vibrating sample magnetometry of the films. Different compositions, thicknesses, and thermal annealing treatments have been investigated with respect to their resistance, magnetization, flux trapping efficiency, thermal conductance, elemental composition, and crystallinity. Within this presentation, the aggregated results of all those measurements will be presented and discussed in detail. [1] Marc Wenskat et al 2023 Supercond. Sci. Technol. 36 015010
	Slides WECBA01 [4.209 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Successful Al₂O₃ Coating of Superconducting Niobium Cavities by Thermal ALD

104

G.K. Deyu, W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
R.H. Blick, I. González Díaz-Palacio, R. Zierold
University of Hamburg, Hamburg, Germany

Funding: This work is supported by the BMBF under the research Grant 05K19GUB.
Al₂O₃ is one of the potential insulator materials in the superconductor-insulator-superconductor (SIS) multilayer coatings of superconducting radio-frequency (SRF) cavities for pushing their performance limits. We report on the successful coating of two 1.3 GHz Tesla-shaped SRF cavities with 18 nm and 36 nm layers of Al₂O₃ deposited by thermal atomic layer deposition (ALD). The coating recipe was developed by thermal atomic layer deposition (ALD). The coating recipe was optimized with respect to different the applied process parameters such as exposure and purge times, substrate temperature and flow rates. After a proof-of-principle Al₂O₃ coating of a cavity, second the cavity maintained its maximum achievable accelerating field of more than 40 MV/m and no deterioration was observed [1]. On the contrary, an improvement of the surface resistance above 10 MV/m has been observed, which is now further under investigation.
[1].Wenskat, Marc, et al. "Successful Al₂O₃ coating of superconducting niobium cavities with thermal ALD." Superconductor Science and Technology 36.1 (2022): 015010.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB016

About •

Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WECBA01

Successful SIS Multilayer Activities on Cavities and Samples Using ALD

I. González Díaz-Palacio, R.H. Blick, C. Saribal, R. Zierold
University of Hamburg, Hamburg, Germany
G.K. Deyu, W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Theoretically SIS multilayers predict to delay vortex penetration allowing for operation gradients more than the double of bulk Nb cavities and Q-values two orders of magnitude above. The University of Hamburg focuses on Atomic Layer Deposition (ALD) as most promising coating technique. In a proof-of principle experiment thermal ALD of Al₂O₃ was successfully applied to two 1.3GHz single-cell cavities achieving gradients above 40MV/m without any deterioration in Q-value [1]. Studies using plasma-enhanced ALD (PEALD) on planar samples focus on AlN and NbTiN as dielectric and superconductor material, respectively. The deposition process and post-deposition treatments have been optimized by studying the superconducting properties in magneto-transport and in vibrating sample magnetometry of the films. Different compositions, thicknesses, and thermal annealing treatments have been investigated with respect to their resistance, magnetization, flux trapping efficiency, thermal conductance, elemental composition, and crystallinity. Within this presentation, the aggregated results of all those measurements will be presented and discussed in detail.
[1] Marc Wenskat et al 2023 Supercond. Sci. Technol. 36 015010

Slides WECBA01 [4.209 MB]

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)