Improvement of energy density in SrTiO3 film capacitor via self-repairing behavior

Abstract Self-repairing behavior of SrTiO 3 film capacitor was explored to improve the energy density. With Au and Al being deposited on SrTiO 3 thin films as top electrode, the breakdown processes were investigated by a real-time optical microscope system. A high electric field of the electrode edge attributed to edge effect provided the “trigger factor” for the self-repairing behavior. Absorbed water not only provided “mobile phase” for self-repairing process which significantly enhanced breakdown strength but also, and equally important, it supplied additional polarization charges to raise dielectric constant. As a result of the concurrent increase in E b and e r , a higher energy density of 15.7 J/cm 3 is achieved. A leakage current platform was observed in the self-repairing process and the thickness of a new layer Al 2 O 3 film generated from self-repairing process was estimated according to Ohm's law and breakdown strength. Using relative humidity dependence of breakdown voltage, the maximum breakdown field was explored to realize the optimum self-repairing capability.