Ferroelectric properties and leakage current mechanisms in SrBi 2(V 0.1Nb 0.9) 2O 9 (SBVN) thin films

Abstract

Ferroelectric properties and leakage current mechanisms of polycrystalline SrBi 2(V 0.1Nb 0.9) 2O 9 (SBVN) thin films were studied. SBVN films were deposited on Pt/SiO 2/ n-Si substrate by rf-magnetron sputtering and then annealed at 700 °C for 60 min in air. The films showed excellent ferroelectric properties in terms of larger remnant polarization (2 P r) of 25 μC/cm 2 (2 E c∼200 kV/cm), fatigue free characteristics up to ≥10 8 switching cycles and low current density of 10 −8 A/cm 2 at 100 kV/cm. XRD and SEM investigations indicate that the sputtered films exhibit a dense, well crystallized microstructure having random orientations and with a rather smooth surface morphology. The improved ferroelectric and leakage current characteristics obtained at lower processing temperature are attributed to the larger polarizability attained through increased rattling space in the distorted Nb(V)O 6 of the perovskite block due to the partial substitution of Nb with smaller V ions. The leakage current density of the SBVN thin films was studied at higher temperatures and the data were fitted with the Schottky and Poole–Frenkel emission models.