CHEMICAL-VAPOR DEPOSITION OF VANADIUM, NIOBIUM, AND TANTALUM NITRIDE THIN-FILMS

Vanadium, niobium, and tantalum nitride thin films were synthesized fr om homoleptic dialkylamido metal complexes and ammonia by atmospheric pressure chemical vapor deposition with high growth rates at low subst rate temperatures (200-400-degrees-C). Depositions were successfully c arried out on silicon, glass, vitreous carbon, and boron substrates. T he films showed good adhesion to the substrates and were chemically re sistant. The films were characterized by Rutherford backscattering spe ctrometry, X-ray photoelectron spectroscopy, ellipsometry, and transmi ssion electron microscopy. Reflectance and transmission spectra for th e tantalum nitride films were also recorded. Hydrogen in the films was determined by hydrogen forward recoil scattering spectrometry. The va nadium 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 +/- 0.05 and were golden colored by reflection and conducting. In contrast, the tantalum nitride films had N/M ratios of 1.7 +/- 0.1 and were transpa rent, pale yellow colored in transmission and insulating. The stoichio metry and physical properties suggest that the films consist of Ta3N5. The hydrogen content of the films diminished as the deposition temper ature increased, but all had significant amounts of hydrogen present.