Control of epitaxial orientation of TiN thin films grown by N-implantation

Abstract Nitrogen ions (N 2 + ) with 62 keV have been implanted into 100-nm thick films prepared by evaporation of Ti on thermally cleaned NaCl substrates held at room temperature (RT) and 250°C. Unimplanted and N-implanted Ti films have been examined mainly by transmission electron microscopy. The evaporated films grown at RT consisted of (03·5)- and (21·0)-oriented hcp-Ti, and (110)-oriented CaF 2 -type TiH x . The N-implantation into the (03·5)-oriented hcp-Ti and (110)-oriented TiH x , results in the epitaxial growth of the (001)- and (110)-oriented TiN y , respectively, whereas nitriding of the (21·0)-oriented hcp-Ti gives rise to the growth of (110)-oriented TiN y rotated by ∼9° with respect to that grown from the (110)-oriented TiH x . On the other hand, the Ti films grown at 250°C consisted of only the (03·5)-oriented hcp-Ti. It has been clearly shown that only the (001)-oriented TiN y film is epitaxially grown by N-implantation into the as-grown (03·5)-oriented hcp-Ti. The control of epitaxial orientation of the TiN y films grown by N-implantation and nitriding mechanism of epitaxial Ti thin films are discussed.