Sub-100 nm Patterning of P3HT with Enhanced OFET Device Performance by Dose Optimization of Electron Beam-Induced Cross-Linking

Poly(3-hexylthiophene) (P3HT) has been extensively utilized as a p-type semiconductor material in organic electronics for numerous years. The patterning of P3HT is essential for various applications, including addressable sensor arrays, complementary logic circuits, and RFID tags. This process not only mitigates crosstalk between adjacent transistors but also enhances device speed and reduces parasitic capacitances. However, patterning P3HT poses significant challenges due to its incompatibility with various resists commonly employed in lithographic processes, which can lead to performance degradation in P3HT-based devices. This study addresses these issues by employing the electron beam-induced cross-linking (EBIC) method. This technique allows for the patterning of P3HT without the need for conventional preprocessing elements such as resists. Dose values of moderate beam energy were optimized to circumvent any potential performance degradation during the patterning process. These advancements have significantly enhanced the performance of organic field-effect transistors (OFETs) by increasing the I_ON/I_OFF ratio by about 6 orders of magnitude, reducing the subthreshold swing, and decreasing the interface trap density by an order of magnitude. This work presents a direct and efficacious approach to pattern P3HT-based OFETs, demonstrating their substantial potential to overcome challenges in polymer patterning, reduce device dimensions, and improve overall device performance.