Leakage current characteristics of SrTiO3/LaNiO3/Ba0.67Sr0.33TiO3/SrTiO3 heterostructure thin films.

There is an urgent demand to explore new approaches of improving the electric breakdown strength of the ferroelectric thin-film capacitor without the degradation of the high dielectric constant. In this work, LaNiO₃/Ba_0.67Sr_0.33TiO₃ (LNO/BST) thin film and SrTiO₃(STO)/LNO/BST/SrTiO₃ (STO) were prepared by using radio frequency (RF) magnetron sputtering technique and ultrathin STO insulator layers were inserted between the LNO/BST and metal electrodes (Au or Pt) to improve the electric breakdown strength and the leakage current of the LNO/BST thin film. X-ray diffraction (XRD) and scanning electron microscopy (SEM) investigations revealed that these multilayer thin films show compact, smooth and uniform morphologies. The leakage current density of STO/LNO/BST/STO thin film was decreased by one order of magnitude and breakdown strength of STO/LNO/BST/STO thin film was enhanced from 0.72 to 1.26 MV·cm⁻¹ compared with that of LNO/BST thin film. Moreover, the dielectric constant of the STO/LNO/BST/STO thin film keeps at the same level as that of LNO/BST thin film, and dielectric loss of the STO/LNO/BST/STO thin film was decreased slightly compared with that of LNO/BST thin film. [ABSTRACT FROM AUTHOR]