A comparative study on the structure and hardness enhancement of a-BON/nc-TiN films prepared by low and high RF frequency PAMOCVD

Amorphous (a)-BON/nanocrystal (nc)-TiN bilayer coatings were deposited on a p-type silicon(1 0 0) substrate by low and high RF frequency plasma-assisted metal–organic chemical vapor deposition(PAMOCVD) system, using tetrakisdimethylaminotitanium(TDMAT, [(CH3)2N]4Ti) and trimethylborate(TMB, (CH3O)3B) as TiN and BON precursors, respectively. We used Ar gas as a plasma source and N2 gas as a reactive and additional nitrogen source. In this study, we have mainly investigated the relationship between the hardness and the structure of the coating layers by the effects of deposition parameters such as frequency, deposition time and substrate temperature. The results show that the surface structure of the top layer and the interface structure of layer-by-layer affect the hardness enhancement in bilayered a-BON/nc-TiN thin films. The as-grown films were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM) and nano indenter.