Ferroelectric enhancement of La-doped BaTiO3 thin films using SrTiO3 buffer layer

Abstract

Pulsed laser deposition (PLD) was used to fabricate La0.01Ba0.99TiO3 (LBTO) thin films on MgO/TiO2/SiO2/Si substrates with and without SrTiO3 (STO) buffer layer. LBTO films deposited on STO layers exhibited enhanced ferroelectricity and decreased leakage current (9 × 10- 7 A/cm2 at 50 kV/cm), conductivity, and Hall mobility, compared to those of LBTO films on MgO substrate. The remanent polarization (Pr) and coercive field (Ec) for LBTO thin films on STO buffered MgO substrate dramatically improved, 36.5 μC/cm2 and ~ 220 kV/cm, compared to those for LBTO thin films on MgO substrate, 3 μC/cm2 and ~ 60 kV/cm. The degradation of Pr and Ec after 105 switching test is less than 0.1% for LBTO thin films on STO buffered MgO substrate. This work demonstrates a route to a lead-free ferroelectric thin film for nonvolatile memories and electro-optic devices.