Specific Process Knowledge/Thin film deposition/Deposition of Vanadium Nitride

The content on this page, including all images and pictures, was created by DTU Nanolab staff, unless otherwise stated.

Feedback to this page: click here

Vanadium Nitride (VN_x)

Vanadium nitride (VN_x, commonly cubic δ-VN near the stoichiometric composition) is a refractory transition-metal nitride that combines high hardness, good thermal and chemical stability, and metallic electrical conductivity. Its properties depend strongly on the N/V ratio, vacancy concentration, strain, crystalline quality, film thickness and oxygen contamination. Reactive magnetron sputtering therefore provides considerable control over the phase, microstructure, resistivity and superconducting behaviour of VN_x films.

A particularly important property of VN is superconductivity. High-quality reactively sputtered films can exhibit superconducting transition temperatures, T_c, approaching 9 K, while thinner or more disordered films generally show lower and broader transitions. Because T_c is sensitive to nitrogen vacancies, strain and lattice parameters, deposition conditions and subsequent processing must be carefully controlled when the films are intended for cryogenic devices.

VN is being investigated as an alternative superconducting nitride for quantum and low-temperature technologies. Demonstrated or proposed applications include superconducting nanowire single-photon detectors, terahertz and infrared hot-electron bolometers, low-loss microwave components and resonators, and other superconducting structures in which kinetic inductance and fast non-equilibrium electron dynamics are important. Single-photon detectors are particularly relevant to quantum communication, quantum optics, photon-counting experiments and low-light imaging. VN remains less established than NbN, NbTiN or TiN, but its combination of superconductivity, mechanical robustness and compatibility with reactive sputter deposition makes it an interesting material for further quantum-device development.

Outside superconducting applications, VN_x is also studied as a hard and wear-resistant coating, a conductive diffusion-barrier material, and an electrode or catalyst material. In all these applications, stoichiometry and defect structure are decisive; nominal N₂ percentage in the sputtering gas should therefore not be interpreted directly as the value of x in VN_x.

Deposition of Vanadium Nitride

At DTU Nanolab, VN_x thin films are deposited by reactive sputtering from an elemental V target in an Ar/N₂ atmosphere.

The preferred tool for this application is the cluster-based multi-chamber high-vacuum sputtering system, commonly referred to as the "Cluster Lesker." The qualified process is described in detail here:

• Deposition of Vanadium Nitride (VN_x) using reactive pulsed-DC sputtering in Sputter-System Metal-Oxide (PC1), Source 5 (3-inch target)

As of October 2026, a 3-inch V target with a thickness of 0.125 inches is available for use in PC1 or PC3.

Comparison of sputter systems for reactive deposition

	Sputter-System Metal-Oxide (PC1)	Sputter-System Metal-Nitride (PC3)
General description	Reactive pulsed DC Reactive HiPIMS (high-power impulse magnetron sputtering)	Reactive pulsed DC Reactive HiPIMS (high-power impulse magnetron sputtering)
Stoichiometry	Tunable	Tunable
Film thickness	Limited by process time Deposition rate is approximately 0.1 nm/s and depends on the Ar/N2 ratio and applied power	Limited by process time Deposition rate is approximately 0.1 nm/s and depends on the Ar/N2 ratio and applied power
Process temperature	Up to 600 °C	Up to 600 °C
Step coverage	Some step coverage possible	Some step coverage possible
Film quality	Deposition on one side of the substrate Film properties, including stoichiometry, can be tuned through the process parameters	Deposition on one side of the substrate Film properties, including stoichiometry, can be tuned through the process parameters
Batch size	Many smaller samples Up to ten 100 mm or 150 mm wafers	Many smaller samples Up to ten 100 mm or 150 mm wafers
Allowed materials	Most vacuum-compatible materials, provided that they do not outgas significantly and are not highly toxic; see the cross-contamination sheets	Most vacuum-compatible materials, provided that they do not outgas significantly and are not highly toxic; see the cross-contamination sheets