Reduction of leakage current and large enhancement of ferroelectric properties in Sb doped Bi4Ti3O12 ferroelectric thin film with Sb doped Bi2Ti2O7 as buffer layer

Perovskite phase ferroelectric thin films Bi4-xSbxTi3O12 (Sb(x)-BIT) and pyrochlore crystal phase thin films Bi2-ySbyTi2O7 (Sb(y)-BTO) with different Sb concentration have been fabricated on Pt(111)/Ti/SiO2/Si(100) substrates through sol-gel method respectively. Test results show that the doping Sb can significantly reduce the leakage current of films. Especially when x = 0.04, y = 0.3 the leakage current characteristics of Sb(0.04)-BIT and Sb(0.3)-BTO both to achieve the optimal, and the ferroelectric properties Sb(0.04)-BIT are also improved. By the same means, constructed the Sb(0.04)-BIT/Sb(0.3)-BTO system with Sb(0.3)-BTO as buffer layer and Sb(0.04)-BIT as ferroelectric layer. The properties of BIT ferroelectric thin films are improved by the doping of Sb element and the addition of buffer layer. This is mainly reflected in that compared to pristine BIT the leakage current of Sb(0.04)-BIT/Sb(0.3)-BTO system decreases rapidly from the initial 8.8 × 10−4 A/cm2 to the current 7.2 × 10−10 A/cm2, the residual polarization 2Pr of the system increases sharply from 9.5 to 70.8 µC/cm2 and fatigue endurance up to more than 1010 switching cycles.