Contribution to a conference proceedings

PUBDB-2025-04416

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Interface Studies of Nb-AlN-NbTiN Multilayers grown by PEALD

Gonzalez Diaz-Palacio, I.Extern* ; Preece, L. S.Extern*DESY* ; Deyu, G. K.Extern* ; Turner, D. ; Moros, A. ; Reyes, D. ; Garcia Blanco, M. ; Noei, H.DESY* ; Macpherson, A. ; Stierle, A.XFEL.EU*DESY* ; Hillert, W.CFEL*Extern* ; Wenskat, M.DESY*

2025

Abstract: Superconducting–Insulating–Superconducting (SIS) multilayers offer a promising approach to surpass the accelerating gradients and quality factors of standard bulk-Nb SRF cavities†. Plasma-enhanced atomic layer deposition (PEALD) stands out as a key technique for the next-generation thin-film-based SRF cavities, providing conformal coatings on highly structured, three-dimensional substrates without shadowing effects and with sub-nm thickness precision. This poster contributes to thin-film SRF R&D through dedicated material studies. The results presented correspond to Nb–AlN–NbTiN multilayers grown by PEALD, focusing on the S–I and I–S interfaces. Depth-resolved X-ray photoelectron spectroscopy (XPS) and cross-sectional energy-dispersive X-ray spectroscopy (EDX) are employed to assess the film stoichiometry and detect any interdiffusion or deposition residues. Side effects induced by high-temperature post-deposition annealing–required to obtain high-Tc NbTiN‡–are systematically investigated. Lastly, complementary studies on Superconducting–Superconducting (SS) Nb–NbTiN bilayers–grown without the AlN interlayer–underscore the crucial role of AlN as an effective diffusion barrier.

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Contributing Institute(s):

1. Supraleitende Beschleuniger Technologie (MSL)

Research Program(s):

1. 621 - Accelerator Research and Development (POF4-621) (POF4-621)

Experiment(s):

1. Superconductivity Radio Frequency Research and Development

Appears in the scientific report 2025

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