Low-Cost Submicrometer Organic Field-Effect Transistors

Low-cost fabrication of circuits with organic field-effect transistors (OFETs) as basic devices requires solution-based technologies. However, then the carrier mobility values can hardly exceed 0.01-0.1 cm(2) V-1 s(-1). For a cut-off frequency above 100 kHz to 1 MHz, relevant for broader applications, and an operation voltage below 10 V, the channel length of the transistors should be smaller than 1-10 mu m. Considering inevitable parasitic capacitances one must envisage submicrometer channel lengths. Demonstrations of different patterning have so far realized neither resolution nor alignment accuracy desired, and photolithography is too costly for the submicrometer regime. Here, an overview is given of short-channel OFETs based on the definition of the submicrometer structures by undercutting, and preparation of the devices using additional simple steps of well established microelectronics technology without any of the costly steps such as high temperature treatments, high resolution lithography, and ion implantation.