Structural, microstructural, optical and electrical properties of (Pb,Ba,Sr)TiO_3 films growth on conductive LaNiO_3-coated LaAO_3(100) and Pt/Ti/SiO_2/Si substrates

摘要

The ferroelectric and dielectric properties of lead barium strontium titanate (PBST) thin films are investigated on different bottom electrode and substrate such as Pt, LaNiO_3 and Pt/Ti/SiO_2/Si, LaAlO_3(100), respectively. X-ray diffraction results indicate that the PBST and LaNiO_3 films on LaAlO_3(100) single crystal substrate are highly (100)-oriented whereas the PBST films on Pt/Ti/SiO_2/Si are polycrystalline. The results indicate strong effects of bottom electrode on the dielectric permittivity and tunability of the PBST films. The dielectric permittivity and tunability for the highly (100)-oriented PBST films on LaNiO_3/LaAlO_3(100) structure were 1238% and 65%, respectively, at 100 kHz, while PBST films prepared on Pt/Ti/SiO_2/Si substrate, showed a dielectric permittivity of 520 and tunability of 47%, at 100 kHz. A slight shift of the phase transition temperature to lower temperatures was observed for highly (100)-oriented films in comparison to the polycrystalline films. Electrical properties should depend strongly on orientation and bottom electrode, which is reflected in our experimental observations.