Highly-resistant SiCBN films prepared by a simple spin-coating process with poly(borosilazane)

Amorphous silicon-carbon-boron-nitrogen (SiCBN) ceramic films, stable at high temperatures, were prepared by spin-coating Si or SiO2/Si substrates with poly( borosilazane) solution under different conditions, followed by pyrolysis at 900-1100 degrees C. A range of film thicknesses of 100-500 nm was achieved by varying the concentration of the polymeric solutions. SEM and AFM micrographs of the films exhibited a crack-free, fairly smooth and dense surface morphology with an average roughness of 2-4 angstrom. The surface hardness and elastic modulus of the SiCBN films were found, by nanoindentation measurement, to be 7.48 GPa and 65.65 GPa, respectively. AES analysis of the SiCBN films revealed a homogenous composition with a Si : B ratio of similar to 2.4. In particular, the SiCBN films pyrolyzed at 900 degrees C exhibit extraordinary stability under isothermal oxidation at 1000 degrees C for 8 h in air with a resulting mass loss of only 0.1%. In addition, the SiCBN film pyrolyzed at 900 degrees C under vacuum acts as an electrical insulator, exhibiting a sheet resistance of 10(14) Omega cm(-2) at room temperature.