SUPER-HARD CUBIC BN LAYER FORMATION BY NITROGEN ION-IMPLANTATION

Microcrystalline and amorphous boron thin films were implanted with nitrogen ions at energies from 25 to 125 keV and with doses from 2 X 10(17) to 1 X 10(18) at./cm(2) at temperatures below 200 degrees C. The structure of boron nitride phases after ion implantation, formation of phases and phase transformations were investigated by TEM and TED methods. The cubic boron nitride phase is revealed. The microhardness of the formed films was satisfactorily explained in terms of chemical compound formation by polyenergetic ion implantation. The influence of the copper impurity on the formation of the cubic boron nitride phase is demonstrated. It has also been shown that low concentrations of copper promote cubic BN boundary formation.