Oxide semiconductors have emerged as promising materials for electronic device applications due to their unique combination of electrical, optical, and structural properties. These materials exhibit high mobility, transparency in the visible spectrum, and low leakage current, making them suitable for the active layer in thin film transistors (TFTs) used in the backplanes of cutting edge displays. However, the demand for next generation displays has driven the development of deformable displays using non traditional substrates rather than rigid ones. Conventional inorganic g ate dielectric materials, such as SiOx and AlOx, face integration challenges in flexible devices due to their brittle nature, temperature limitations of deformable substrates, and high costs. Organic materials offer a solution with their flexibility and lo w processing temperatures. Organic gate dielectrics are typically fabricated using solution processes like spin coating. However, these methods often compromise film quality due to residual impurities and thermal damage during post coating baking steps, ne gatively impacting their electrical and physical properties. Unlike most polymers, poly(chloro paraxylylene) (Parylene) can be deposited via vacuum based pyrolysis CVD at low temperatures, resulting in pinhole free films with excellent step coverage. This method allows for conformal coating and uniform thickness over complex structures, minimizing interface issues encountered with other techniques. Additionally, the properties of the parylene family can be tailored through functionalization. 
In this work, parylene based polymer gate dielectrics were evaluated as alternatives for oxide TFTs. Three types of conventional parylene (Parylene C, Parylene D, and Parylene AF4) were tested for transistor applications. Additionally, two custom synthesized parylene ty pes were examined, both showing higher dielectric constants compared to conventional variants. Parylene Ethynyl achieved more than double the dielectric constant through click chemistry, while Parylene OH exhibited a significantly higher dielectric constan t and UV reactive nature, enabling UV crosslinking. The intrinsic photo reactive nature of parylene allows for direct patterning with UV radiation, eliminating the need for additional photoresist. The vacuum based vapor process ensures excellent interface quality without impurities or voids for both conventional and custom synthesized variants. Parylene shows promise for a wide range of applications