Microstructure and mechanical properties of titanium nitride optical coatings made by DC magnetron sputtering

Titanium nitride (TiNx) thin films were grown by DC (Direct Current) magnetron sputtering method onto Si(100) substrates by varying time of deposition to produce films with variable thickness (d TiN) in the range of 20-120 nm. The grown TiNx films were characterized by studying their structure, composition, and mechanical properties. Nuclear reaction analysis (NRA) combined with Rutherford backscattering spectrometry (RBS) analyses indicate that the grown films were stoichiometric TiN. Grazing incidence X-ray diffraction (GIXRD) measurements indicate that the texturing of the TiN films changes as a function of dTiN. The (111) and (002) peaks appear initially; with increasing d TiN, (111) becomes intense while (002) disappears. Dense, columnar grain structure was evident for the films in scanning electron microscopy analyses. The residual stress dTiN~120 nm was 1.07 GPa in compression while thinner samples exhibit higher values of stress