High Temperature Ta/MnO2 Capacitors

The paper presents results on high temperature stability of tantalum capacitors with MnO2 cathodes (Ta/MnO2 capacitors). The critical role of silver migration on high temperature stability of these capacitors was demonstrated. Replacing of silver in the top coating with electrochemically plated nickel provides a radical improvement in the high temperature stability of the Ta/MnO2 capacitors. Nickel plating was performed on top of transition multilayer comprising two carbon layers separated by hydrophobic blocking layer. We discuss possible mechanisms of the improvement in the high temperature stability of Ta/MnO2 capacitors due to the new technology.