Effect of annealing on the structural and mechanical properties of Ba0.7Sr0.3TiO3 thin films

Mechanical properties and surface characterizations of Ba0.7Sr0.3TiO3 thin films deposited on silicon substrate by metalorganic decomposition (MOD) method under different annealing temperatures were investigated. Hardness, Young's modulus and the contact stress–strain of the films were achieved by nanoindentation techniques. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to characterize the structure of Ba0.7Sr0.3TiO3 thin films. The X-ray diffraction results showed that Ba0.7Sr0.3TiO3 thin films exhibited a high (1 1 0)-orientation and presented a pure perovskite-type structure. The grain size and surface roughness increased as the annealing temperature increased. As well, the hardness and Young's modulus increased as the annealing temperature increased from 600 to 800 °C, with the best results obtained at 800 °C. In addition, contact stress–strain relationships and elastic recovery are also discussed.