Negative dispersion in γ-Mo2N/Si(100) films

Molybdenum nitride films γ-Mo
₂
N/Si have been fabricated with reactive magnetron sputtering of metal target in (N
₂
+ Ar) gas mixture. Phase composition of the films has been defined with RHEED. Refractive index and extinction coefficient of γ-Mo
₂
N thin films have been evaluated with laser ellipsometry at λ = 632.8 and 488.0 nm. Negative dispersion has been found for refractive index of γ-Mo
₂
N in visible spectral range. Upper limit of γ-Mo
₂
N film thickness measurable with laser ellipsometry has been estimated to be ~80 nm.