Leakage current characteristics of SrTiO_(3)/LaNiO_(3)/Ba_(0.67)Sr_(0.33)TiO_(3)/SrTiO_(3 )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,LaNiO_(3)/Ba_(0.67)Sr_(0.33)TiO_(3)(LNO/BST) thin film and SrTiO_(3)(STO)/LNO/BST/SrTiO_(3)(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-1compared 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.