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Specific Process Knowledge/Thin film deposition/Deposition of NbTi

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Niobium Titanium (NbTi)

Niobium–titanium (Nb‑Ti) is a ductile, readily machinable alloy that merges niobium’s superconductivity with titanium’s strength, yielding a rigid, corrosion‑resistant material valued in cryogenic and high‑field environments. Thin films are produced chiefly by magnetron sputtering, where the Nb/Ti ratio and post‑anneal determine phase purity, resistivity, and the superconducting critical temperature (≈ 9.2 K for near‑eutectic compositions). In microelectronics, Nb‑Ti can act as a robust diffusion barrier, gate or contact metal, and mechanically compliant liner. Yet, its signature role is as a superconductor: kilometer-length multifilament Nb-Ti wires carry mega-ampere currents in MRI scanners, particle-accelerator magnets, and experimental fusion coils under magnetic fields approaching 10 T. Ultrathin Nb‑Ti nanowires serve in superconducting nanowire single‑photon detectors, kinetic‑inductance detectors, and low‑loss microwave resonators, while Nb‑Ti/Al bilayers enable Josephson junctions and rapid single‑flux‑quantum circuits. The alloy’s radiation tolerance, thermal stability, and moderate atomic number support cryogenic beam‑line components and X‑ray filters, and its biocompatibility and wear resistance extend its usefulness to medical implants and protective MEMS coatings, underscoring Nb‑Ti’s versatility wherever robust, easily processed superconducting or barrier films are required.

Sputter deposition of Niobium Nitride

Users can deposit NbTi in either the Sputter-System (Lesker) or the Sputter-System Metal-Nitride(PC3) (Preferable option)

Comparison of sputter systems for alloy deposition

Sputter-System Metal-Nitride(PC3) Lesker sputter system
Generel description
  • DC/Pulsed DC
  • HIPIMS (high-power impulse magnetron sputtering) (require 3-inch target)
  • DC sputtering (not tested)
Stoichiometry
  • NbTi (Sputter-System Metal-Nitride(PC3)) NbTi 67/33 At.% (4" target)
  • Unknown
Film thickness
  • Limited by process time.
  • Deposition rate (0.6 nm/s) is likely faster than Sputter-System (Lesker)
  • Limited by process time.
  • Deposition rate unknown
Process temperature
  • Up to 600 °C
  • Up to 400 °C (Room temperature from 2021)
Step coverage
  • Some step coverage possible
  • Some step coverage possible but amount unknown
Film quality
  • Deposition on one side of the substrate
  • Properties including tunable stoichiometry (requires process development)
  • Deposition on one side of the substrate
  • Unknown quality
  • Likely O-contamination
Batch size
  • Many smaller samples
  • Up to 10*100 mm or 150 mm wafers
  • Several smaller samples
  • 1-several 50 mm wafers
  • 1*100 mm wafers
  • 1*150 mm wafer
Allowed materials
  • Almost any as long as they do not outgas and are not very toxic, see cross-contamination sheets
  • Almost any as long as they do not outgas and are not very toxic, see cross-contamination sheets