Chemical vapor deposition of vanadium, niobium, and tantalum nitride thin films

Vanadium, niobium, and tantalum nitride thin films were synthesized from homoleptic dialkylamido metal complexes and ammonia by atmospheric pressure chemical vapor deposition with high growth rates at low substrate temperatures (200-400[degrees]C). Depositions were successfully carried out on silicon, glass, vitreous carbon, and boron substrates. The films showed good adhesion to the substrates and were chemically resistant. The films were characterized by Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, ellipsometry, and transmission electron microscopy. Reflectance and transmission spectra for the tantalum nitride films were also recorded. Hydrogen in the films was determined by hydrogen forward recoil scattering spectrometry. The vanadium nitride coatings were slightly nitrogen-rich VN (N/M ratio 1.05-1.15). They were polycrystalline as deposited and displayed metallic properties. The niobium nitride films had N/M ratios of 1.35 [plus minus] 0.05 and were golden colored by reflection and conducting. In contrast, the tantalum nitride films had N/M ratios of 1.7 [plus minus] 0.1 and were transparent, pale yellow colored in transmission and insulating. The stoichiometry and physical properties suggest that the films consist of Ta[sub 3]N[sub 5]. The hydrogen content of the films diminished as the deposition temperature increased, but all had significant amounts of hydrogen present. 26 refs., 5 figs., 4 tabs.