PHASE-FORMATION IN THE N-B-TI SYSTEM

In this work we report some experimental results on the N-B-Ti system. Boron nitride thin films were prepared by rf sputtering and then ion implanted with 200 keV Ti+ ions at various doses. The films were characterized by scanning electron microscopy (SEM), glancing incidence X-ray diffraction (GXRD), secondary neutral mass spectrometry (SNMS) and nano-indentation, both in the as-deposited and ion implanted condition and also after thermal annealing. SEM pictures show the development of various microstructures as the Ti-dose increases. GXRD shows that TiB2 is formed at low doses while TiN prevails at high doses. At very high doses, elemental Ti is predominantly observed. Hardness and Young's modulus increase as the Ti dose increases up to saturation values. Ti depth profiles of specimens implanted at various doses show a radiation enhanced diffusion of Ti at low doses. However the Ti diffusivity is reduced with the appearance of TiB2 and TiN phases.