Characterization of thin film tantalum oxide capacitors on polyimide substrates

Dept. of Electr. Eng., Arkansas Univ., Fayetteville, AR
IEEE Transactions on Advanced Packaging (Impact Factor: 1.28). 09/1999; 22(3):499 - 509. DOI: 10.1109/6040.784504
Source: IEEE Xplore

ABSTRACT Thin film tantalum oxide capacitors were fabricated on flexible
polyimide substrates and characterized. The capacitance and dielectric
constant were found to be independent of frequency from 100 MHz-1 GHz.
The leakage current-voltage (I-V) characteristics of the virgin tantalum
oxide capacitors were erratic. Both current-induced and
temperature-induced annealing effects on virgin capacitors were
observed. It was found that the defects of the capacitors depend, not
only on the tantalum oxide dielectric, but also on the underlying
electrode. Copper particulates embedded in the bottom electrode were the
primary cause of electrical shorts. The conduction mechanism was found
to be ionic. The ionic conduction activation energies are linearly
dependent on the applied electric field, ranging from 0.47 eV for an
electric field of 0.13 MV/cm to 0.38 eV for 0.73 MV/cm

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