Thermal behaviour of chromium nitride/titanium–titanium carbonitride multilayers

• Magnetron sputtering of chromium nitride/titanium–titanium carbonitride layers
• High temperature in-situ observations of structural changes up to 550 °C performed
• Formation of crystalline TiN,TiCxNy, Cr2N, and metallic Cr phases observed
• Aberrant variations of the cell parameters of the Ti metal phase were found.

Chromium nitride/titanium–titanium carbonitride multilayers composed of a 40 nm Cr interface followed by a 4.4 μm thick Cr2N layer, a 150 nm thick Ti layer, and  a 1 μm thick TiCxNy top layer were deposited on silicon wafers by magnetron sputtering. The structural changes and the phase content changes of these multilayer samples were studied by means of high-temperature in-situ X-ray diffraction experiments at temperatures up to 550 °C. The lattice constants of the Cr phase as well as the Ti phase display an aberrant expansion behaviour during these experiments which is influenced by the defect structure, a nitrogen incorporation, and residual stress in the layers. The results were compared with structural data obtained by ex-situ transmission electron microscopy investigations of pristine and heated material, revealing phase separation and strong diffusion phenomena.