EARLY NITRIDING STAGE OF EVAPORATED-TI THIN-FILMS BY N-ION IMPLANTATION

The early growth stage of epitaxial titanium nitride (TIN) films, form ed by implanting nitrogen ions (N-2(+)) with 62 keV into 100-nm-thick evaporated-Ti films, was studied by transmission electron microscopy, Rutherford backscattering spectrometry and elastic recoil detection an alysis. Evaporated-Ti films spontaneously absorb hydrogen (H) from the interior of the NaCl substrate, and then TiHx partially grows in addi tion to the hcp-Ti. The implantation of N into evaporated-Ti films exp ands the hcp-Ti lattice and reduces the H concentration in the evapora ted-Ti film. The former induces the hcp-fcc transformation and then le ads to the growth of (001)-oriented TiNy by the occupation of N in oct ahedral (O) sites in the fcc-Ti sublattice. The latter induces contrac tion of the fcc-Ti sublattice by the escape of H from (110)-oriented T iHx and then leads to the growth of (110)-oriented TiNy by the occupat ion in O sites of the H-escaped metastable fcc-Ti lattice by N. The ni triding mechanism of epitaxial Ti thin films is discussed. (C) 1997 Am erican Vacuum Society.