Production and structural characterization of BN/TiN multilayers

A pulsed excimer laser was used to evaporate targets of boron nitride and t itanium nitride in an attempt to produce hard thin films on crystalline sil icon substrates. The films were either pure TiN or BN layers, as well as al ternating multilayers and mixed layers. Deposition could be assisted by ion bombardment. The films were characterized by Auger electron spectroscopy, Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction. A se lection of films was also studied by profilometry in order to determine dep osition rate and the type of stress present. The level of stress in TiN fil ms was also a function of the deposition temperature and could be varied wi th the use of ion bombardment. Amorphous, cubic, and hexagonal BN films wer e produced and the effect of the stress of the substrate on these layers wa s investigated. Multilayers were stressed, having alternating layers of nan ocrystalline TiN and amorphous BN. Mixtures consisted of nanometer-sized re gions of crystalline TiN and sp(2) coordinated boron nitride. FTIR spectra and high-resolution transmission electron microscope pictures suggested tha t in the mixtures, boron nitride planes tended to parallel the surface of t he TiN grains. No sign of stress-driven formation of cubic BN was observed in the multilayers nor in the nanosized mixtures, regardless of the stress level present in them; neither was there any sign of titanium borides or ot her structures that might increase the hardness of the films. (C) 2000 Amer ican Institute of Physics. [S0021-8979(00)05003-9].