Parameters Effects On The Phase Structure Of Boron Nitride Films

Hexagonal Boron Nitride(h-BN) and Cubic Bornn Nitride(c-BN) attract widespread interest as promising materials for many potential applications because of their unique physical and chemical properties. The oriented h-13N films were prepared by MW-ECR-CVD, Radio Frequency(RF) coupled PECVD and RF magnetron sputtering technologies. The samples were characterized by various methods including FTIR, XRD, AFM, XPS etc.. and the dependence of deposition parameters on the growth of oriented h-BN films was investigated systemically. The results showed that the oriented h-BN films deposition are possible only at proper partial pressure of reactive gas. For the first time, the crucial role of substrate temperature on the oriented growth of h-BN was founded: at low temperature, the horizontal growth rate of the film is faster than the vertical growth rate after nucleation, the result is that the c axis of the deposited h-BN film is parallel to the surface of the substrate, at high temperature, the vertical growth rate is faster than the horizontal growth rate, oriented h-BN film of base plane paralleling to the substrate surface is resulted. At the same time, it was found that the random orientation of the film was caused by the negative bias applied to the 晄ubstrate. BN films with certain cubic phase content were prepared by RF magnetron / sputtering and hot filament assisted MW-ECR-CVD technology, and the effects of RF power and electrical current of hot filament on the formation of cubic phase were studied respectively. The results show that cubic phase formation is possible only at proper RF power and the electrical current of hot filament is very important to the deposition of c-BN. In addition, the effects of negative bias on the enhanced nucleation of BN films were studied theoretically.