Dependence of ferroelectric characteristics on the deposition temperature of (Pb,Sr)TiO3 films

Abstract

The pulsed laser deposition (PLD) of (Pb,Sr)TiO3 (PSrT) films on Pt/SiO2/Si at low substrate temperatures (T-s, ranging from 300 to 450 degrees C, has been investigated. The PLD PSrT films prepared at low Ts exhibit ferroelectric proper-ties, good crystallinity, and no significant interdiffusion between the PSrT film and the Pt bottom electrode. The conduction mechanism is identified as Schottky emission at low electric fields and as Poole-Frenkel emission at high electric fields. PSrT films grown at appropriate T, yield fewer interface states and fewer trapping states, leading to a smaller leakage current. The enhanced (100) preferred orientation of PSrT films deposited at T-s= 350-400 degrees C exhibits optimum ferroelectricity. In addition, the dielectric constant and ferroelectricity are associated with the preferred orientation. This shows that the electrical characteristics strongly rely on the preferred orientation and trapping states, which could be controlled by varying the substrate temperature (T, <= 450 degrees C during PLD.