High performance printed N and P-type OTFTs enabling digital and analog complementary circuits on flexible plastic substrate

This paper presents a printed organic complementary technology on flexible plastic substrate with high performance N and P-type Organic Thin Film Transistors (OTFTs), based on small-molecule organic semiconductors in solution. Challenges related to the integration of both OTFT types in a common complementary flow are addressed, showing the importance of surface treatments. Stability on single devices and on an elementary complementary digital circuit (ring oscillator) is studied, demonstrating that a robust and reliable flow with high electrical performances can be established for printed organic devices. These devices are used to manufacture several analog and digital building blocks. The design is carried out using a model specifically developed for this technology, and taking into account the parametric variability. High-frequency measurements of printed envelope detectors show improved speed performance, resulting from the high mobility of the OTFTs. In addition, a compact dynamic flip–flop and a low-offset comparator are demonstrated, thanks to availability of both n-type and p-type OTFTs in the technology. Measurement results are in good agreement with the simulations. The circuits presented establish a complete library of building blocks for the realization of a printed RFID tag.

► A printed organic complementary technology on flexible plastic substrate with high performance has been developed.
► The P-OSC layer crystallization has been optimized as well as the injection SAM of the N-OTFTs to increase the mobility.
► The surface cleaning between the N- and P-OSC deposition is necessary to decrease the contact resistance of P-OTFTs.
► Several functional digital and analog circuits have been processed.
► The designed circuits realize a complete building block library for the design of RFID tags with integrated AM receivers.