Effect of thickness on electrical properties of bismuth-magnesium niobate pyrochlore thin films deposited at low temperature

Abstract

Bi 2 Mg 2 ∕ 3 Nb 4 ∕ 3 O 7 (BMN) pyrochlore thin films were deposited at 25 and 100°C on Cu∕Ti∕Si substrates by pulsed laser deposition. Dielectric and leakage current properties of BMN films are investigated as a function of film thickness. The critical thicknesses showing the thickness dependence of dielectric constant are approximately 50 and 70nm in BMN films deposited at 25 and 100°C, respectively. The capacitances of interfacial layers in the films deposited at 25 and 100°C are approximately 5.5 and 3.9pF, respectively. The thickness dependence of leakage current characteristics was attributed to the copper diffusion into the BMN films. An intrinsic conduction of BMN films was controlled by Schottky emission and the barrier height was estimated as 0.9–1.2eV in the temperature range from 25to100°C. Film thickness in terms of leakage current characteristics is limited above 100nm for embedded capacitor applications.