Maxwell-Wagner instability in bilayer dielectric stacks

The Maxwell-Wagner effect, the enhanced charge migration to the interface of a stack of two dielectrics with different conductances, is shown to cause asymmetric leakage current and electrical breakdown behavior for different electrode polarities. For this purpose, metal-insulator-silicon capacitors were fabricated consisting of bilayered silicon dioxide-lanthanum zirconate dielectric stacks. Maxwell-Wagner instability and Debye polarization can be distinguished upon comparing electron injection from both sides of the stack. The Maxwell-Wagner charges have relaxation times that are nearly five orders of magnitude larger than the Debye polarization, suggesting the long-lasting influence of these trapped charges in nanolaminated dielectric systems. (C) 2009 American Institute of Physics. [doi:10.1063/1.3236532]