Effects of annealing temperatures on crystalline quality of silicon based (Ba_0.3Sr_0.7)(Zn_1/3Nb_2/3)O₃ dielectric ceramic thin films by sol–gel process

(Ba_0.3Sr_0.7)(Zn_1/3Nb_2/3)O₃ (BSZN) dielectric ceramic thin films were fabricated on Pt(111)/Ti/SiO₂/Si(100) substrates by sol–gel method followed by annealing in O₂ atmosphere at different temperatures. The effects of annealing temperatures on the crystalline quality of the ceramic thin films have been investigated in brief. Scanning electron microscope shows that the surface morphologies of the samples are crack-free and compact with well-crystallized structures. The grain sizes of the thin films annealed at different temperatures increase with the increase in the annealing temperatures from 700 to 900 °C. The XRD results showed that the sample at 900 °C exhibits well-crystallized structures with the strongest intensity of the main phases. The surface root-mean-square (RMS) roughness values of the samples decrease with the increase in the annealing temperatures. The thin film possesses the minimum RMS value when the annealing temperature is 900 °C, whose crystalline quality is the highest in all samples. In short, 900 °C is of the optimal annealing temperature with best dielectric properties. The dielectric constant and loss tangent of the sample annealed at 900 °C are 38.5 and 0.005 at 10 kHz, respectively.