Films containing boron, nitrogen, and hydrogen have been deposited at reduced pressure by reacting diborane and ammonia at 250°–600°C. Deposition rates as high as 15 nm/min (150 Å/min) have been achieved with thickness uniformities and reproducibilities better than ±3%. The films have been characterized by measuring infrared spectra, refractive index, optical absorption in the ultraviolet and visible, stress, chemical inertness, etch rates in a plasma, step coverage, and adhesion.