Towards high frequency performances of ultra-low voltage OTFTs: Combining self-alignment and hybrid, nanosized dielectrics

By combining an ultra-thin dielectric layer with a self-aligning process, an ultra-low voltage Organic Thin-Film Transistor (OTFT) with a 100 kHz cutoff frequency was obtained. The devices are fabricated using a single-mask, photolithographic self-alignment technique compatible with the use of standard photoresists and not requiring any further chemical treatment. This technique allows a dramatic reduction of the parasitic capacitances thus leading to a remarkable increase of the cutoff frequency, even with organic semiconductors with a relatively low mobility. These characteristics make the reported approach suitable for the fabrication of basic building blocks for high frequency applications. In this paper, the main electrical parameters of ultra-low voltage, self-aligned devices are reported, and their complete frequency characterization is provided.