The Effect of Deposition Temperature and Postanneal on the Bi3.63Pr0.3Ti3O12 thin Films Prepared by RF-Magnetron Sputtering Method

Praseodymium doped Bi4Ti3O12 (BTO) thin films with composition Bi3.63Pr0.3Ti3O12 (BPT) were successfully prepared on Pt/Ti/SiO2/Si substrates by RF-magnetron sputtering method at substrate temperatures ranging between 500 degrees and 750 degrees C. The structural phase and orientation of the deposited films were investigated in order to understand the effect of the deposition temperature on the properties of the BPT films. As the substrate temperature was increased to 700 degrees C, the films started showing a tendency of assuming a c-axis preferred orientation. At lower temperatures, however, polycrystalline films were formed. The Pt/BPT/Pt capacitor showed an interesting dependence of the remnant polarization (2P(r)) as well as dc leakage current values on the growth temperature. The film deposited at 650 degrees C showed the largest 2P(r) of 29.6 mu C/cm(2). With the increase of deposited temperature, the leakage current densities of films decreased at the same applied field and the film deposited at 750 degrees C exhibited the best leakage current characteristics. In addition, the ferroelectric fatigue and Raman measurements were carried out on the as-prepared, postannealed in air and postannealed in oxygen BPT films. It was revealed that the BPT film postannealed in air exhibited the weakest fatigue-resistance characteristics and highest frequency shifted Raman vibration modes, indicating the highest oxygen vacancy concentration in this film.