High‐Frequency fT and fmax in Organic Transistors: Performance and Perspective

Abstract

Abstract In state‐of‐the‐art organic transistors, the transit frequency fT is reported to be fT = 40 MHz for vertical organic transistors, where a voltage‐normalized fT corresponds to 0.36 MHz V−2. The reported highest fT for conventional organic transistors is fT = 160 MHz, where the voltage‐normalized fT is 0.1 MHz V−2. While the reported transit frequency fT of n‐MOSFETs for silicon technology when normalized by the applied biases exceeds 300 GHz V−2. The reported carrier mobility of organic semiconductors is over 100 cm2 V−1 s−1, which is almost an order of magnitude lower than that of silicon. However, the transit frequency fT of organic transistors lags far behind silicon technology by about six orders of magnitude at a comparable device length below 300 nm. In this work, a technology computer‐aided design (TCAD) simulator is adjusted to the experimental DC and AC characteristics of the 200 nm device length vertical organic permeable‐base transistors (OPBTs) based on C60 as semiconductor. The AC performance of the devices is investigated and quantitatively analyzed the influence and contribution of key design, structure and material parameters that determine fT and fmax. The feasible ways to enhance and optimize the highest achievable fT and fmax are identified to reach the GHz−range and overcome the limitations to high‐frequency operation in organic transistors.

Keywords

• gigahertz
• OPBTs
• organic transistors
• TCAD simulation
• transit frequency and maximum oscillation frequency