Effect of TiO2 seeding layer on crystalline orientation and ferroelectric properties of Bi3.15Nd0.85Ti3O12 thin films

Bi3.15Nd0.85Ti3O12 (BNT) thin films with and without a TiO2 seeding layer were fabricated on Pt/Ti/SiO2/Si substrates by sol-gel method at 750°C. The effect of seeding layer on structural and electrical properties of BNT thin films was investigated. X-ray diffraction pattern shows that the BNT thin film deposited directly on Pt/Ti/SiO2/Si substrate exhibits predominantly (117) and (001) orientation while the BNT thin film grow on Pt/Ti/SiO2/Si substrate with a TiO2 seeding layer show a highly α axis orientation with the (200) strongest peak. The BNT thin film with a TiO2 seeding layer is a more dense and homogeneous than that deposite directly on Pt/Ti/SiO2/Si substrate. The Pr and Ec values of BNT films with and without TiO2 layer are 43.6 and 26μC/cm2, and 91 and 80.5 kV/cm, respectively. The fatigue test exhibits a very strong fatigue endurance up to 109 cycles for both films. The addition of TiO2 seeding layer does not decrease the fatigue characteristic of BNT thin film. The leakage current density are generally in the order of 10-6-10-5 A/cm2 for both samples.