Reduction of residual stress in AlN thin films synthesized by magnetron sputtering technique

We report the reduction in residual stress, the crystal structure, surface morphology and nano-mechanical properties of magnetron sputtered AlN thin films as a function of substrate temperature (Ts, 35–600 °C). The residual stress of these films are varying from tensile to compression with temperature (Ts), calculated by sin2ψ technique. Evolution of crystalline growth of AlN films have been studied by GIXRD and transmission electron microscopy (TEM) and at 400 °C a preferred a-axis orientation is observed. The cross-sectional TEM micrograph and the selected area electron diffraction (SAED) of these film exhibit a high degree of orientation as well as a columnar structure. Hardness (H) has been measured by nanoindentation technique on these films ranged between 12.8 and 19 GPa. [Display omitted] •a-axis preferential orientation was observed at 400 °C substrate temperature AlN thin film (FWHM = 140.8 arcsec).•Columnar structure with an angle tilted to the substrate normal was observed for 400 °C substrate temperature.•Residual stress transition from tensile to compressive was observed for the substrate temperature between 300 °C and 400 °C.