Studies of polymer-based field effect transistors

As part of search for alternative semiconducting technologies, polymers which can be processed to change electrical characteristics from highly insulating (resistivity ~10⁸ Ω cm) to highly conducting (conductivity ~10⁵ S cm^-1) are now under increasing investigation. In this paper, we describe the fabrication technology and electrical performance of poly(3-hexylthiophene), P3HT, thin film metal-insulator-semiconductor field effect transistors, MISFETs. These FETs were fabricated on heavily doped Si substrates using laser direct-write technology. I-V characteristics of these types of MISFETs showed typical FET-like pinch-off behavior at high negative V_DS biases. Polymer-based thin film MISFETs are sensitive to light and oxygen. However, passivation layers provide a practical solution. In our present research, conventional photoresist materials have been chosen as encapsulation materials. The electrical characteristics of polymer MISFET have been monitored over 3 months. Our passivation results show encapsulation can greatly enhance the stability of polymer MISFETs