Greatly enhanced breakdown strength of Pt/LNO/BST/Au thin films by regulating the space charge limited current though the dielectrics/electrode interface modification

Abstract

Abstract Carrier injection is the most common and critical issue which significantly affects the electric breakdown strength (Eb) of the dielectric films since the dielectric thin films usually work under a rather higher applied electric field compared with its bulk forms. As so far, many efforts have been devoted to gain a more insightful understanding of the conduction mechanism behind the carrier injection. Recently growing interest is focused on using proper method of regulating these mechanisms to restrain the carrier injection for an ultrahigh Eb in the dielectric films. Here, a simple but effective approach is introduced that aims at regulating the space charge limited current (SCLC) for a restrained electrons injection by the dielectrics/electrode interface modification. An ultrathin SrTiO3 (STO) layer was inserted between the Pt/LaNiO3/Ba0.67Sr0.33Ti0.989Mn0.003Y0.008O3 (Mn/Y doped BST) dielectric thin films and the Au electrode. With the interface modification, the potential barrier at the dielectrics/electrode interface for electrons injection was significantly increased, and the SCLC was retrained. It was also found that the STO layer can further reduce the dielectric loss of the films. Consequently, the leakage current of the thin film was decreased by at least two order magnitude and the breakdown strength of the thin film was at least twice as high as that of untreated films with little effect on the dielectric constant. It should be helpful as a potential strategy to improve the breakdown strength and dielectric performance of dielectric thin films simultaneously.