Temperature and substrate influence on the structure of TiNxOy thin films grown by low pressure metal organic chemical vapour deposition

This paper presents the growth and characterization of titanium oxinitride (TiNxOy) films grown by low pressure metal organic chemical vapour deposition (LP-MOCVD). The film nitrogen content, obtained by Rutherford backscattering spectroscopy (RBS), increases as the growth temperature increases (from 23 at.% at 450°C to 46 at.% at 750°C). Below 550°C, the films do not show any X-ray diffraction pattern. Above 550°C, the deposited films present the (111) and (200) TiN textures. Films deposited on (100) Si exhibit a 2θ shift to higher Bragg angles, depending on the N/O ratio. These shifts are explained by using a substitutional oxygen model. Moreover, the atomic structure of such materials is described from this behaviour in terms of lattice vacancies and N/O substitutions, leading to different titanium valencies confirmed by X-ray photoelectron spectroscopy (XPS) analysis.