Synthesis and characterization of c-BN films prepared by ion beam assisted deposition and triode sputtering

Boron nitride films deposited on unheated c-Si substrates by ion beam assisted deposition (IBAD) and triode sputtering (TS) techniques are studied. The composition, micro:structure and crystallinity of the films obtained by the two techniques are compared The methods of characterization used in this study are: X-ray photo-electron, infrared, and Raman spectroscopies. High-resolution cross sectional TEM is used to confirm the optical results. In the case of films prepared by IBAD, the ion energy was 350-500 eV. The films were prepared from different gas mixtures of nitrogen and argon, boron was supplied by evaporation of elemental boron. TS films were prepared with 100% of nitrogen, the boron was supplied by sputtering a pure boron target. This study shows that, in comparison with TS samples, IBAD samples have higher chemical and physical stability. The par-tide-size dependence of frequencies and damping of optical phonons is studied for all samples from the analysis of Raman scattering and infrared spectra. A very important difference between the particle-sizes of IBAD and TS samples is observed. A progressive chemical etching by nitric acid at 80 degrees C combined with infrared characterization was successfully performed on IBAD samples deposited at low ion flux and announces a mixture of sp(2) and sp(3) phases with high content of sp(3) structure. All results are in full agreements with TEM results. (C) 1999 Elsevier Science S.A. All rights reserved.