Investigation of profiles of implanted Ti atoms over the depth of boron nitride nanocrystalline ceramic exposed to high radiation doses and fluxes with subsequent annealing

Results are presented of an investigation of distribution profiles of impla nted Ti atoms at high implantation doses (fluence around 10(17) cm(-2)) ove r the depth of boron nitride (BN) nanocrystalline ceramic. It is observed t hat the concentration maxima of implanted impurities are shifted into the s ubstrate under post-implantation annealing in vacuum at 950 degrees C. This behavior of the implanted impurities in BN is directly the opposite of tha t observed in earlier studies of polycrystalline aluminum oxide ceramic exp osed to similar ion thermal treatment. The effective diffusion coefficient of titanium atoms in BN under thermal annealing is estimated. The Ti/O conc entration ratio in the layer modified as a result of implantation and subse quent annealing at 950 degrees C is close to stoichiometric TiO2. A simulta neous increase in the concentration of carbon and nitrogen atoms in the sur face layers of BN samples was observed as a result of annealing at 830 and 950 degrees C. (C) 1999 American Institute of Physics. [S1063-7850(99)01008 -3].