Influence of the target-substrate distance on the growth of YSZ thin films

The reduction of yttria-stabilized zirconia (YSZ) thickness is one of the aims of current studies to lower the process temperature of the Solid Oxide Fuel Cells. Bulk YSZ has been extensively used as electrolyte. However, thin films change the fundamental aspects of the oxygen ion conduction due to the occurrence of nano-effects. Therefore, the understanding of the microstructure and crystallinity would open the possibility to manipulate the YSZ properties. This work describes some features of YSZ thin films produced by dual magnetron sputtering. Target-substrate distance was varied creating a compositional gradient along the films. Moreover, a tilt of the lattice from 0° to 45° was identified when changing the yttrium content. The use of a simple stress model allows predicting this tilt, when taking into consideration the compositional gradient in any region of the YSZ layer. The calculated tilt angles, based on experimental results from SEM, EDX and profilometry, are in good agreement with the results obtained via the azimuthal angle from XRD measurements.