Using the macroscopic scale to predict the nano-scale behavior of YSZ thin films

• Determination of the grain tilt based on pole figure analyses.
• Determination of the columnar tilt based on cross section images.
• Determination of the compositional gradient at nano-scale via STEM–EDX and ADF–STEM.
• Correlation between the values of composition at macroscopic- and nano-scale.
• Development of a stress model to predict grain tilt.

In this work, Yttria-stabilized zirconia (YSZ) thin films were deposited using dual reactive magnetron sputtering. By varying the deposition conditions, the film morphology and texture of the thin films are tuned and biaxial alignment is obtained. Studying the crystallographic and microstructural properties of the YSZ thin films, a tilted columnar growth was identified. This tilt is shown to be dependent on the compositional gradient of the sample. The variation of composition within a single YSZ column measured via STEM–EDX is demonstrated to be equal to the macroscopic variation on a full YSZ sample when deposited under the same deposition parameters. A simple stress model was developed to predict the tilt of the growing columns. The results indicate that this model not only determines the column bending of the growing film but also confirms that a macroscopic approach is sufficient to determine the compositional gradient in a single column of the YSZ thin films.