Parylene-based polymeric dielectric top-gate organic field-effect transistors exposed to a UV/ozone environment

Organic field-effect transistors (OFETs) structured with a top-gate configuration have several advantages, such as better charge-carrier injection, easy gate line designing, and encapsulation or protection of devices, over those configured with a bottom-gate architecture. In particular, Poly (para-xylylene) (Parylene) -based polymer and its derivatives are considered suitable insulating materials for these transistors, due to thin film formation through a low-temperature vapor deposition process, superior barrier properties, and excellent dielectric characteristics. In this study, we analyzed two types of Parylene dielectrics (Parylene-C and Parylene -AF) considering their thin film formation process, surface, insulating, and OFET operation characteristics. Furthermore, we investigated the durability of the top-gate based OFETs composed of two polymer dielectrics while it was exposed to a UV/ozone environment. Also, we could fabricate UV/ozone durable top-gate OFETs composed by a bilayer with both Parylene dielectrics. We expect, therefore, that these results will help the selection and use of versatile dielectric layers for top-gate based OFETs.