Characterization of NbTiN Thin Film Structures

Conference · Tue Oct 01 04:00:00 EDT 2019

OSTI ID:1975501

Beverstock, David ^[1]; Smolyaninova, Vera; Kelley, Michael ^[2]; Valente, Anne-Marie ^[2]

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1. College of William and Mary, Williamsburg, VA (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

Approaching the bulk Nb material RF performance limits has urged development of alternative superconducting materials for superconducting radio frequency (SRF) accelerator cavities for further performance enhancement. A promising theory has predicted that thin film structures of superconductor-insulator-superconductor (SIS) [1] can delay magnetic flux penetration in accelerator cavities to higher fields. A candidate superconductor for the SIS structures is NbTiN. A few key aspects of SIS structures development are high quality individual layers, sharp interfaces and optimum thickness for first flux penetration (Hfp) delay. High quality monocrystalline NbTiN films are deposited by reactive DC magnetron sputtering. In a parallel development, interface quality was assessed by depositing bilayers of 3 nm NbTiN with ~1 nm AlN repeated up to 16 times with no increase in roughness of the structure. The stacked layers form a metamaterial, which could exhibit Tc greater than bulk NbTiN [2]. This contribution presents the characterization of the surface, material and superconductivity of NbTiN with concentration on the Hfp enhancement for 200 to 5 nm films and multilayer nanostructures.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1975501
• Report Number(s): JLAB-ACC-19-3163; DOE/OR/23177-6248
• Country of Publication: United States
• Language: English