Crystallization and properties of PbO-doped Ba0.7Sr0.3TiO3 films

摘要

Ferroelectric Ba0.7Sr0.3TiO3 films were fabricated using a PbO-doped barium strontium titanate sol-gel precursor. Ba0.7Sr0.3TiO3 thin films with 0, 10, 20, and 30 at.%PbO doping were deposited on bare silicon, and platinum coated silicon substrates, using spin coating. The influence of PbO doping both on the film microstructure and properties was studied. Doping in excess of 20 at.%PbO was found to markedly decrease film porosity, while enhancing crystallization by decreasing the annealing temperature required for the formation of the perovskite phase from above 650 degreesC to 500 degreesC. Electrical characterization of the films demonstrated their excellent properties for electronic device application. Films with 20 at.%PbO doping had room temperature dielectric constant and dissipation factor of 268 and 0.95%, respectively (measured at 10 kHz), with tunability from 30% to 75% and commutation quality factor in excess of 10(5) (for bias field from 200 to 800 kV/cm). Room temperature leakage current were measured to be as low as 2.45x10(-9) A/cm(2) (at bias field of 250 kV/cm). (C) 2004 American Institute of Physics.