Electron transport in tantalum nanolayers: Low temperature characteristics

The leakage current value for the various temperatures and applied voltage are frequently used as the reliability indicator for tantalum capacitors. Leakage current provides the information on the insulating layer thickness, its homogeneity and the number of defects in the tested sample. The leakage current is a result of the random process of charge carrier transport and its DC component gives then information about the first statistical moment of this process. Capacitor structure can be in the first approximation considered as an ideal metal-insulator-semiconductor (MIS) structure. The low temperature measurements of VA characteristics are compared for the tantalum capacitors with manganese dioxide cathode and tantalum capacitors with conducting polymer cathode. Different behavior was observed in normal mode between these two technologies. Leakage current decreases with decreasing temperature for capacitors with MnO2cathode while for capacitors with conducting polymer cathode the leakage current increases.