DEPOSITION AND CHARACTERIZATION OF BORON-NITRIDE THIN-FILMS

Boron nitride (BN) thin films have been deposited on single-crystal Si(100) wafers using electron beam evaporation of B with simultaneous bombardment by nitrogen and argon ions. Fourier transform IR spectroscopy and high resolution transmission electron microscopy revealed the consecutive deposition at 400-degrees-C of an initial layer of amorphous BN 20 angstrom thick, 20-60 angstrom of preferentially oriented hexagonal BN, and a final layer of single-phase polycrystalline cubic material. The growth sequence of the layers is believed to result primarily from increasing biaxial compressive stresses. Increasing the temperature delays the onset of the cubic phase as a result of increased annealing processes. Increasing the ion momentum lowers the temperature of the onset of this phase.