Formation and characterisation of c-BN thin films deposited by microwave PECVD

Boron nitride thin films were deposited on silicon substrates at low temper ature by plasma-enhanced chemical vapour deposition (PECVD), with a microwa ve surfatron launcher. An organometallic compound, borane-dimethylamine, wa s used as the boron precursor. To promote the growth of the cubic phase, a negative self-bias was applied to the sample holder by means of a 13.56-MHz RF signal. A very high fraction of c-BN was achieved as revealed by infrar ed spectrometry. The assignation of the characteristic TO absorption band w as ascertained by the observation of its LO associated mode by performing t he IR transmission spectra at non-normal incidence. The deposited films are well adherent and do not delaminate even after 6 months in the atmosphere, and they exhibit a very low roughness, as observed by atomic force microsc opy. (C) 2001 Elsevier Science B.V. All rights reserved.