Relationship between electrical properties and stress field in solid electrolyte thin films

Stress in yttria stabilized zirconia (YSZ) thin films was controlled by using various substrates, which had different thermal expansion coefficient (TEC), and electrical properties of the films were measured to study the relationship between the stress filed and electrical properties. Thin films of YSZ were deposited by PLD method on Al₂O₃ and AlN substrates. Because TEC of YSZ is larger than that of the substrates, tensile stress field was introduced into the films at room temperature. Measured stress value by XRD was varied from 0.7 to 1.7 GPa at R.T. This value is significantly higher than literature value. However, the films also showed different lattice volume on the different substrates. Although electrical properties in the films showed different tendencies by the substrates, both stress field and lattice volume were different. Hence, stress dependence of electrical properties was not clearly observed.