Leakage current characteristics of Bi_(3.15)Nd_(0.85)Ti_3-xZr_xO_(12) thin films

摘要

Thin films of Bi_(3.15)Nd_(0.85)Ti3O_(12) (BNT) and Bi_(3.15)Nd_(0.85)Ti_(3-x)Zr_xO_(12) (BNTZ_x, x = 0.1 and 0.2) were fabricated on Pt/TiO_2/SiO_2/Si(100) substrates by a chemical solution deposition (CSD) technique at 700 ℃. Structures, surface morphologies, leakage current characteristics and Curie temperature of the films were studied as a function of Zr ion content by X-ray diffraction, atomic force microscopy, ferroelectric test system and thermal analysis, respectively. Experimental results indicate that Zr ion substitution in the BNT film markedly decreases the leakage current of the film, while almost not changing the Curie temperature of the film, which is at about 420-460 ℃. The decrease of the leakage current in BNTZ_X films is that the conduction by the electron hopping between Ti~(4+) and Ti~(3+) ions is depressed because Zr~(4+) ions can block the path between two adjacent Ti ions and enlarge hopping distance.