Structure and electrical properties of La and Nb co-modified Sr0.8Bi2.2Ta2O9 thin films

Polycrystalline Sr 0.8 La 0.1 Bi 2.1 Ta 2 O 9 (SLBT), Sr 0.8 Bi 2.2 Ta 1.5 Nb 0.5 O 9 (SBTN), Sr 0.8 La 0.1 Bi 2.1 Ta 1.5 Nb 0.5 O 9 (SLBTN) were fabricated on Pt/Ti/SiO 2 /Si substrates by metalorganic decomposition. Well-saturated hysteresis loops with remanent polarization (2 P r ) around 24 μC/cm 2 and coercive field (2 E c ) around 112 kV/cm are obtained on Pt/SLBTN/Pt capacitors. Imprints, shifts of hysteresis loops along the voltage axis, are observed after heat treatment of poled Pt/SLBTN/Pt capacitors. Pt/SLBTN/Pt capacitors show excellent fatigue resistance with no polarization reduction up to 10 9 switches. The dc leakage current density of Pt/SLBTN/Pt capacitors is in the order of 10 −8 A/cm 2 below 100 kV/cm. These results indicate that the La 3+ and Nb 5+ co-modification is an effective way to improve the ferroelectric properties of Sr 0.8 Bi 2.2 Ta 2 O 9 (SBT) thin films.