Effect of Y, Gd, Dy, and Ce doping on the microstructural and electrical properties of sol-gel-deposited ZrO₂ film

ZrO₂ films doped with Y, Gd, Dy, and Ce at a concentration of ∼13 cation atom were deposited by a sol-gel technique, and the early-stage dopant effect on the stabilization of the high temperature phase and dielectric properties was systematically compared after a low-temperature annealing process (400C). The high temperature phase formation of the ZrO₂ films was hindered by the Y, Gd, and Dy doping, thereby reducing the dielectric constant. In addition, the hysteresis was significantly increased via electron trapping, which was attributed to the increase in the number of oxygen vacancies possibly due to the difference in the valence number of the dopants with that of the substituted Zr atoms. However, the dielectric constant of the ZrO₂ film doped with tetravalent Ce atoms increased without retarding the stabilization of the high temperature phase and degrading the hysteresis characteristics.