This work describes a systematic study of the preparation of nano-crystalline thin h-BN films by Plasma-Enhanced Chemical Vapor Deposition (PECVD) technique. The samples were prepared at low temperatures using B2H6 and N2 as gas precursors. It is shown that the flow ratio among these gases has an important influence on the size of the crystallites (deduced by Raman spectroscopy). The 2H6/N2 flow ratio was varied from 1,6 x 10-2 to 6.7 x 10-4 leading to films presenting a crystallite size, which varied from 90 nm to amorphous, respectively. The XRD spectra show two peaks at 2 values around 42° and 44°, which are associated to <img src="http:/img/fbpe/bjp/v32n2a/menor.gif"> 110 <img src="http:/img/fbpe/bjp/v32n2a/maior.gif"> and <img src="http:/img/fbpe/bjp/v32n2a/menor.gif"> 100 <img src="http:/img/fbpe/bjp/v32n2a/maior.gif"> h-BN crystalline directions, indicating, a <img src="http:/img/fbpe/bjp/v32n2a/menor.gif"> 002 <img src="http:/img/fbpe/bjp/v32n2a/maior.gif"> preferential orientation for the h-BN crystallites. The thermo-mechanical properties, as stress, hardness, and Young modulus were also studied and correlated with the structural properties. The composition of the films was obtained by RBS and EDS indicating Boron to Nitrogen ratio, close to stoichiometry for all the studied deposition conditions.
