Abstract
Boron nitride films have been deposited by a metal organic chemical vapor deposition (MO‐CVD). The reaction between ammonia and triethylboron 
is carried out in the temperature range of 750°–1200°C with the molar ratio of 
. Colorless and transparent films are obtained at temperatures of 950°–1100°C with the molar ratio of 20–70. The composition of the films, N/B, is found to vary from 0.46 to 1.0. For a fixed 
, the deposition rate increases with temperature up to 1000°C and then decreases. The deposition rate shows an Arrhenius‐type behavior in the temperature range of 750°–1000°C. X‐ray diffraction studies indicate that the crystal structure of the films is hexagonal. The energy of the direct allowed transition, obtained from optical measurements, is estimated to be 5.90 eV.