Thin films containing cubic phase boron nitride have been synthesized using an ion beam extracted from a borazine (B3H3H6) plasma.We report on x-ray diffractometry, hardness tests, and Auger analysis of the deposited films. The x-ray diffractometer peak corresponding to cubic phase boron nitride was detected while peaks corresponding to hexagonal phase were usually absent. Consistent with the presence of cubic phase indicated by the x-ray analysis, the indentation hardness of boron nitride-coated substrates was higher than the same uncoated substrates. Auger compositional profiles indicated a film stoichiometry corresponding to boron nitride and suggested that the deposition method produced an intermixing layer between the boron nitride film and the substrate.