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

Abstract

Perovskite phase ferroelectric thin films Bi_4-xSb_xTi₃O₁₂ (Sb_(x)-BIT) and pyrochlore crystal phase thin films Bi_2-ySb_yTi₂O₇ (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.

Keywords:

• Sb doping；bismuth titanate；ferroelectric thin film；leakage current；ferroelectricity；butter layer

Disclosure statement

The authors have no financial or non-financial conflicts of interest.

Additional information

Funding

This work was supported by the research Funds of Liaoning Provincial Department of Education (LJ2019012 and LJ2020007) and Fund of Science and Technology Bureau, Liaoning Province (No.22-101-0-26).