Effect of Bi_4Ti_3O_(12) seeding layer on the structural and ferroelectric properties of Bi_(3.25)La_(0.75)Ti_3O_(12) thin films fabricated by a metalorganic decomposition method

摘要

Ferroelectric Bi_(3.25)La_(0.75)Ti_3O_(12) (BLT) thin films with Bi_4Ti_3O_(12) (BTO) seeding layers were deposited onto a Pt/Ti/SiO_2/Si substrate using a metalorganic decomposition method. The effects of variation in the thickness on the microstructural and ferroelectric characteristics were investigated. The BLT thin films with 5-nm-thick BTO seeding layers with a Pt bottom electrode showed that the presence of BTO seeding layer induced a significant change in the crystallinity. This results in an improvement of the (117) orientation compared with BLT thin films without the BTO seeding layer. The 5-nm-thick BTO seeding layer in the BLT/BTO/Pt/Ti/SiO_2/Si structure also prevents the diffusion of Bi into the Pt bottom electrode. The BLT thin films with 5-nm-thick BTO seeding layers showed larger remanent polarization and better fatigue properties compared with the films without the seeding layer. The remanent polarization (2P_r) of BLT thin films without seeding layer and with 5-nm-thick BTO seeding layer annealed at 650℃ were 20.6 and 30 μC/cm~2, respectively.