Leakage current of sol-gel derived Pb(Zr, Ti)O-3 thin films having Pt electrodes

The electrical conduction behaviors of sol-gel derived Pb(Zr, Ti)O-3 (PZT) thin films on Pt electrodes were analyzed based on a fully depleted film, t hermionic field emission, and space charge limited conduction model in the low and high electric field regions, respectively. For films having thickne sses ranging from 150 to 250 nm, no thickness-dependent variation in the di electric constant was observed due to the relatively large thicknesses. The rather small film-thickness-dependent leakage current characteristics in t he low-field region elucidates that the positive space charge density in th e film is about 10(18) cm(-3), which is a smaller value than that of the sp utter deposited (Ba, Sr)TiO3 thin films by an order of magnitude. The calcu lated interfacial potential barrier height and effective mass of electrons were 0.93 eV and 0.09m(0), respectively. The slope larger than 2 from the l og J vs log V plot in the high-field region implies that the energy level o f electron traps are continuously distributed in the energy band gap. (C) 1 999 American Institute of Physics. [S0003-6951(99)04847-0].