OPTICAL-PROPERTIES OF BORON-NITRIDE THIN-FILMS

Boron nitride thin films were deposited onto crystalline silicon and alkali halide substrates by plasma-enhanced chemical vapour deposition of BF3, N2, H-2 and Ar gas mixtures. Films were prepared on both powered and grounded electrodes of the capacitatively coupled system. The deposits were analysed by ellipsometry, Fourier transform IR spectroscopy and UV spectroscopy to determine their optical properties. The relative composition was determined using nuclear reactions induced by 1 MeV deuteron bombardment and Auger spectroscopy. Ion bombardment during growth was found to affect the optical properties of the material, since films prepared with low flows of argon and those placed on the live electrode have smaller refractive indices, larger IR absorption peaks for the cubic phase, and wider optical gaps.