Atmospheric pressure chemical vapor deposition of aluminum nitride thin films at 200–250 °C

The atmospheric pressure chemical vapor deposition of aluminum nitride coatings using hexakis(dimethylamido)dialuminum, Al₂(NMe₂)₆, and ammonia precursors is reported. The films were characterized by ellipsometry, transmission electron microscopy, x-ray photoelectron spectroscopy, and Rutherford backscattering spectrometry. The films were deposited at 200–250 °C with growth rates up to 1000 Å/min. They displayed good adhesion to silicon, vitreous carbon, and glass substrates and were chemically inert, except to concentrated hydrofluoric acid. Rutherford backscattering analysis showed that the N/Al ratio ranged from 1.1 to 1.2. Refractive indexes were 1.8–1.9. The films were smooth and amorphous by transmission electron microscopy.