The introducing of fluorine into the deposition of BN : A successful method to obtain high-quality, thick cBN films with low residual stress

Cubic boron nitride films were synthesized on silicon substrates by DC-bias-assisted DC jet chemical vapor deposition in an Ar-N₂-BF₃-H₂ system. By this method, the deposition of cBN at high gas pressure of 50 torr became possible, and the conditions of cBN CVD approached to those of diamond CVD. cBN films with low residual stress (1-2 GPa) and with large crystal size of up to several hundred nanometers were obtained and clear Raman peaks of cBN appeared. Furthermore, the deposition rate was as high as 0.3 μm/min at the initial stage and over 20-μm-thick BN films were obtained for a 3-h deposition. These remarkable improvements are attributed to the preferential etching effect of fluorine to sp² bonds and the decrease of the bombarding energy of ions. © 2001 Elsevier Science B.V. All rights reserved.