STRUCTURE AND OPTICAL-PROPERTIES OF BORON-NITRIDE THIN-FILMS PREPAREDBY PECVD

Boron nitride (BN) thin films were deposited from borane dimethylamine and nitrogen using a plasma enhanced CVD technique at low temperature . The deposited films were characterized by X-ray diffraction, XPS spe ctroscopy, infrared absorption spectroscopy, and scanning electron mic roscopy. All the films crystallized in the hexagonal form of BN, and c onsisted of microcrystals with about 50 nm grain size. Optical reflect ance and transmittance measurements of the films were recorded in the wavelength range 220-2500 nm. The optical constants, refractive index n and extinction coefficient k, of the films were calculated from thes e experimental data, by a numerical method based on the use of Fresnel 's formalism via an iterative process. An optical gap E-g of about 3.6 eV has been deduced. (C) 1997 Elsevier Science S.A.