Effect of excess bismuth concentration on dielectric and electrical properties of fully crystallized Bi2Mg2/3Nb4/3O7 thin films

The fully crystallized Bi2Mg2/3Nb4/3O7 (BMN) films deposited at 400 degrees C were characterized as a function of excess bismuth amount. The films with 15 mol % excess bismuth amount were fully crystallized having a monoclinic structure at 300 degrees C. The dielectric constant of the films deposited at 400 degrees C increases with increasing excess bismuth amount and the films with 15 mol % excess bismuth exhibit a dielectric constant of 128 and a dissipation factor of 0.2%. The crystallized BMN films with 170 nm thickness exhibit breakdown strengths above 600 kV/cm (>= 10 V), irrespective of excess bismuth amount and a leakage current density of 2x10(-8) A/cm(2) at 590 kV/cm. The conduction of crystallized BMN films was controlled by Schottky emission mechanism having a Schottky barrier height of 0.2-0.35 eV. (C) 2007 American Institute of Physics.