Deposition of ternary boron-carbon-nitrogen (BCN) layers by thermal decomposition of tris(dimethylamino)boran

Trials to deposit BCN layers onto heated hardmetal substrates by the therma l decomposition of tris(dimethylamino)boran, as the single source precursor , were carried out. Thermal decompositions, without gas-phase activation, l ed to the formation of h-BN and graphite. Within the tested temperature ran ge from 800 degrees C to 1300 degrees C, h-BN was mainly deposited at low t emperatures and the amount of graphite increased with increasing temperatur e. Depositions carried out with Ta filaments for gas activation led to an i ncrease in the evaporation of Ta. Because of this, BCN layers containing la rge amounts of Ta were deposited. The Ta content in the BCN layer could be minimized by pre-carburizing the Ta filaments and/or by increasing precurso r concentration during deposition. The deposits were characterized by Raman and infrared (IR) spectroscopy as well as X-ray diffraction and scanning e lectron microscopy.