Abstract
Formation and deposition processes of boron nitride (BN) films are discussed. BN films were sythesized from boran-ammonia (BH3NH3) with a 4-coordinated structure by RF plasma CVD with tungsten filament heating. The deposited BN films are structurally cubic (four-coordinated) or turbostratic (three-coordinated), which strongly depends on the tungsten filament temperature, total gas pressure and RF power. That is, BH3NH3 can be changed to both cubic and turbostratic structures.
The etching rate of turbostratic BN (t-BN) increases with increasing emission intensity I(Hα) in the gas plasma, where I(Hα) is the spectral intensity at the wavelength of 656 nm corresponding to the emission from the atomic hydrogen by plasma excitement and filament heating. The atomic hydrogen causes the preferential chemical ecthing of t-BN, thus contributing greatly to the growth of cBN in the films.
