Influence of target-substrate distance and composition on the preferential orientation of yttria-stabilized zirconia thin films

The use of yttria-stabilized zirconia (YSZ) thin films calls for a controlled deposition with full understanding on the influence of deposition parameters on the crystallographic properties of YSZ. YSZ thin films were deposited using magnetron sputtering from two sources, enabling to modify the sample composition in a flexible way. The influence of target-substrate (T-S) distance and the Y content on the crystallographic orientation were studied under different chamber pressures. Correlations were found under both conditions. This way, a two-dimensional map was obtained by showing the change in preferential orientation as a function of sample composition. This map shows the existence of two different trends depending on the pressure. At low pressure, the addition of Y and the decrease in T-S distance, change the orientation from 200] to a complete 111] out-of-plane orientation resulting in a competition between the fastest growth direction and the lowest surface energy. However, a different trend was observed at high pressure, where T-S distance and composition do not influence the preferential orientation of the film.