Metalorganic chemical vapor deposition of aluminum nitride on vertical surfaces

•Aluminum nitride thin films deposited on vertical Si(1 1 1) surfaces using MOCVD.•The films have high quality wurtzite structure and c-axis orientation.•Full width at half maximum of the 0002 in-plane X-ray rocking curve is 1.70°–3.44°.•The film thickness reduces at a rate of 0.8–1.2 nm/μm down the vertical surfaces.•Reducing the deposition pressure improves the film conformality and morphology.