Chemical vapor deposition of boron nitride using premixed borontrichloride and ammonia

Chemical vapor deposition (CVD) of boron nitride (BN) is most readily performed using BCl₃ and NH₃, which are brought into the deposition zone through two separate tubes. This causes some problems: inadequate mixing leading to a nonuniform deposit, formation of solid intermediates, etc. To avoid these problems, the process was performed by mixing BCl₃ and NH₃ at elevated temperatures (120–220 °C) prior to entering the deposition zone. The reaction between them took place by the forming of volatile stoichiometric B–N compounds (trichloroborazine and iminochloroborane), which were then transported through a single tube into a deposition zone. The resulting deposit was found to be hexagonal boron nitride.