High-Speed Complementary Integrated Circuit with a Stacked Structure Using Fine Electrodes Formed by Reverse Offset Printing

A reverse offset-printed stacked-structure complementary ring oscillator and operational amplifier (OPA) circuits were constructed on a large-area substrate. Uniform and fine electrodes were fabricated using reverse offset printing with a width of 30 μm and a channel length of 10 μm. Compared to silver nanoparticle electrodes constructed using inkjet printing, a narrow line with a width of 1/5 or less could be formed. All components except the insulating film were formed using a solution process with the printing method. The complementary integrated circuit had a stacked structure, wherein a p-type organic thin-film transistor (OTFT) was stacked on an n-type OTFT with a common gate electrode layer. Because the source and drain electrode layers of the n- and p-type OTFTs were separated, different self-assembled monolayers could be treated using a simple method. The complementary ring oscillator circuit oscillated at a frequency of 2 kHz (12.5 V, five stages) and operated at 1.25 V (96 Hz, nine stages). The fabricated OPA circuit had an output/input voltage ratio of 20. Additionally, it operated over 40 times faster than a similar circuit formed by inkjet printing. Fine electrodes formed by reverse offset printing are useful for improving the performance and miniaturization of printed organic integrated circuits.