The plasma‐enhanced chemical vapor deposition (PECVD) of boron nitride films was studied using polymeric cyanoborane, (CNBH2)n, a material previously examined by thermally activated CVD. The PECVD procedure yields boron nitride coatings containing ≅20 wt% paracyanogen as a contaminant. This impurity can be removed by heat treatment under vacuum or in an ammonia atmosphere. The boron nitride coatings are hexagonal and appear to be boron deficient. The PECVD process takes place at 300°C, measured at the backside of the substrate, as compared with 600°C in the thermally activated CVD pr