Work

Optimization of superconducting niobium nitride thin films via high-power impulse magnetron sputtering

Year: 2024

Type: article

Abstract: We report a systematic comparison of niobium nitride thin films deposited on oxidized silicon substrates by reactive DC magnetron sputtering and reactive high-power impulse magnetron sputtering (HiPIMS). After determining the nitrogen gas concentration that produces the highest superconducting critical temperature for each process, we characterize the dependence of the critical temperature on film thickness. The optimal nitrogen concentration is higher for HiPIMS than for DC sputtering, and HiPIMS produces higher critical temperatures for all thicknesses studied. We attribute this to the HiPIMS process enabling the films to get closer to optimal stoichiometry before beginning to form a hexagonal crystal phase that reduces the critical temperature, along with the extra kinetic energy in the HiPIMS process improving crystallinity. We also study the ability to increase the critical temperature of the HiPIMS films through the use of an aluminum nitride buffer layer and substrate heating.

Source: Superconductor Science and Technology

DOI: 10.1088/1361-6668/ad921a

Authors: Hudson T Horne, Collin M Hugo, Brandon C Reid, Daniel F Santavicca

Institution: University of North Florida

Language: English

Topic: Superconducting and THz Device Technology

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Division of Electrical, Communications and Cyber Systems

Awards: MRI: Acquisition of a Magnetron Sputtering Thin Film Deposition System for Research and Teaching at the University of North Florida, G3359489589, Collaborative Research: Kinetic Inductance in Superconducting Nanowire Microwave Devices