Inkjet printing of metal-oxide-based transparent thin-film capacitors

摘要

We report on the inkjet printing of transparent, thin-film capacitors (TTFCs) composed of indium-zinc-oxide electrodes and a tantalum-oxide-based dielectric on glass substrates. The printing parameters were adapted for the sequential deposition of functional layers, resulting in approximately 100-nm-thick transparent capacitors with a uniform thickness. The relatively high electrical resistivity of the electrodes is reflected in the frequency dispersive dielectric behaviour, which is explained in terms of an equivalent circuit. The resistivity of the electrode strongly decreases with the number of printing passes; consequently, any misalignment of the printed layers is detected in the measured response. At low frequency, the TTFCs show a stable intrinsic dielectric response and a high capacitance density of ~280 nF/cm~2. The good dielectric performance as well as the low leakage-current density (8 × 10~(-7) A/cm~2 at 1 MV cm~(-1)) of our capacitors indicates that ink-jet printing can be used to produce all-printed, high-quality electrical devices.