Nitriding of Evaporated-Ti Thin Films by Ion Implantation

Abstract

Nitrogen ions ( N2 +) with 62 keV have been implanted into 100-nm-thick Ti films evaporated on thermally cleaned NaCl substrates. Unimplanted and N-implanted Ti films have been examined by transmission electron microscopy, Rutherford backscattering spectrometry and elastic recoil detection analysis. The analysis has provided evidence that N-implantation results in the epitaxial formation of NaCl-type TiN y and simultaneously induces the release of H from evaporated-Ti films containing TiH x . The nitriding of evaporated-Ti films is mainly divided into two elemental processes. One is accompanied by the hcp-fcc transformation and the other is not. The formation mechanism for TiN y is discussed.

Characterization of Deposited and Nitrogen-implanted Titanium Films

“…The reflections indicated by the four-index system and the three-index system with asterisks are obtained from the hcp-Ti and TiH x crystallites, respectively. The growth of both hcp-Ti and TiH x agrees with the results of previous papers [14][15][16]: Ti films deposited on NaCl substrates spontaneously absorbed hydrogen (H) atoms from the interior of the NaCl, and then Fig. 1(a), whereas the 00 · 2 and 01 · 1 reflections in Fig.…”

“…Detailed descriptions of the preparation method for deposited Ti films were presented in earlier papers [14,18]. The ultimate pressure of the working chamber evacuated by means of an ion pump and a Ti sublimation pump was less than 4 × 10 −9 Torr before deposition, and the pressure during deposition was 6 × 10…”

“…Recently, it was reported that NaCl-type (110)-and (001)-oriented TiN y crystallites were 'epitaxially' grown by the N-implantation into CaF 2 -type (110)-oriented TiH x and (03 · 5)-oriented hcp-Ti in the deposited Ti films held at room temperature (RT), respectively [14][15][16]; here, the term 'epitaxially' is used to denote the situation of partially inheriting the atomic arrangements of unimplanted TiH x and hcp-Ti. However, the detailed 'epitaxial' nitriding processes of Ti films with the domains of TiH x and hcp-Ti during N-implantation, as well as the epitaxial growth processes of (110)-oriented TiH x and (03 · 5)-oriented hcp-Ti in deposited Ti films, have not yet been sufficiently understood.…”

Carbonizing Processes of Titanium Thin Films by Carbon-Implantation

“…The detailed descriptions of the preparation of Ti films were presented in earlier papers [18,19]. Carbon ions (C + ) of 26 keV were implanted into the deposited Ti films at an angle of 30…”

“…We focus our attention on the transformation process from the oriented hcp-Ti to preferentially oriented TiC y in the film with the dose of C, taking account of the variation of the lattice constants of hcp-Ti and TiC y . The results were also discussed with those of a self-consistent charge discrete variational (DV)-Xα molecular orbital (MO) calculation [17] and the epitaxial hcp-fcc transformation mechanism of hcp-Ti by N-implantation [18,19].…”