Effects of Sputtering Conditions on Microstructure and Ferroelectric Properties of RF-Sputtered Bi3.25La0.75Ti3O12 Thin Films

Abstract

The Bi3.25La0.75O12 films were prepared on the Pt/TiO2/SiO2/Si substrate using RF-magnetron sputtering method. The effects of sputtering conditions, including sputtering pressure, oxygen partial pressure and substrate temperature on microstructure, ferroelectric properties were investigated. When deposited at low substrate temperature (room temperature), the BLT thin film exhibits preferentially c-axis oriented. With the increasing of substrate temperature, the (117) diffraction peak become stronger, indicating the changing of the microstructure in the BLT films. The BLT film samples deposited at 4.5-6Pa exhibit desired bismuth-layered structure, with no any preferred orientation. However, when BLT films were deposited above 5 Pa, some weak pyrochlore diffraction peaks appear in the X-ray diffraction pattern. The Pr is a maximum for the BLT film deposited at 5 Pa with O2/Ar ratio 1/5 and decreases with both decreasing and increasing deposition pressure.