Controlling the Electrical Characteristics of ZrO2/Al2O3/ZrO2 Capacitors by Adopting a Ru Top Electrode Grown via Atomic Layer Deposition

Abstract

The electrical characteristics of metal-insulator-metal (MIM) capacitors consisting of a ZrO2/Al2O3/ZrO2 (ZAZ) dielectric film, a TiN bottom electrode (BE), and two different top electrodes (TEs; TiN and Ru) are examined. The enhanced property in the leakage current density versus equivalent oxide thickness (J-t(ox)) plot is observed in the MIM structure with the Ru TE for the ZAZ film with specific film thickness of approximate to 4.6 nm. Especially, the J due to the electron injection from the TiN BE was significantly decreased for the Ru TE case compared to the TiN TE sample at 1-2 MV cm(-1) electric field region. These extraordinary behaviors are found to have originated the change in the oxygen vacancy density in the ZAZ film, which induces Poole-Frenkel emission through the reaction with the active oxygen during the Ru TE fabrication process. The difference in nonlinearity of the capacitance-voltage (C-V) curve also indicates a different trap density at the interface of ZAZ and the TiN BE, suggesting a change in the oxygen vacancy density in the ZAZ film.