Effect of annealing temperature on the characteristics of sol–gel-driven TaaxLa(1a)xOy thin film spin-coated on Si substrate as a high-k gate dielectric was studied. TaaxLa(1a)xOy thin films with different amounts of a were prepared (as-prepared samples). X-ray diffraction measurements of the as-prepared samples indicated that Ta0.3xLa0.7xOy film had an amorphous structure. Therefore, Ta0.3xLa0.7xOy film was chosen to continue the present studies. The morphology of Ta0.3xLa0.7xOy films was studied using scanning electron microscopy and atomic force microscopy techniques. The obtained results showed that the size of grain boundaries on Ta0.3xLa0.7xOy film surfaces was increased with increasing annealing temperature. Electrical and optical characterizations of the as-prepared and annealed films were investigated as a function of annealing temperature using capacitance–voltage (C–V) and current density–voltage (J–V) measurements and the Tauc method. The obtained results demonstrated that Ta0.3xLa0.7xOy films had high dielectric constant (27), wide band gap (4.5 eV), and low leakage current density (106 A/ cm2 at 1 V).
