LAUSR

Abstract We report the mechanical properties of Cr-doped AlN thin films synthesized by reactive magnetron co-sputtering technique with different Cr concentrations (0, 2, 4, 6 and 11 at%). Surface chemical analysis and crystal structure studies of Cr doped AlN films are carried out using X-ray photoelectron spectroscopy (XPS) and grazing incidence X-ray diffraction (GIXRD) techniques. All these films are crystallized with wurtzite structure and grown predominantly along a-axis orientation in the absence of secondary phases belonging to Cr. The surface morphology and RMS roughness are measured by atomic force microscope (AFM). The residual stress of these films exhibit a tensile behavior and it decreases with Cr concentration as calculated by sin 2 ψ technique. Indentation hardness of these films is measured by nanoindentation technique, which is ranged from 17.5 to 23.0 GPa. However, indentation modulus is enhanced with Cr concentration due to strong p-d hybridization between Cr and N atoms. Indentation impression of these films exhibit a sink-in behavior and gives an evidence of high elastic recovery without radial cracks.