Thin films of Ba0.7Sr0.3TiO3 were prepared by chemical solution deposition, and Er was used as a dopant in order to decrease the leakage current and to improve the film lifetime under a direct-current electric field. The (Ba+Sr)/Ti ratio in the precursor solution was modified so as to facilitate doping at A sites, B sites or both A and B sites. It was observed that, when (Ba+Sr)/Ti = 1, the dopant had little effect upon the dielectric constant, but decreased both the loss tangent and the leakage current. A current transient (peak) was observed prior to resistance degradation in both undoped and Er-doped samples and was related to O migration under a direct-current bias. It was shown that Er-doping effectively decreased the O vacancy mobility.

Oxygen Vacancy Motion in Er-Doped Barium Strontium Titanate Thin Films. J.Wang, S.Trolier-McKinstry: Applied Physics Letters, 2006, 89[17], 172906 (3pp)