Optimization of the patterning processing and electrical characteristics of a photopatternable organosiloxane-based gate dielectric for organic thin-film transistors

A ultraviolet (UV)-crosslinkable organosiloxane-based organic-inorganic hybrid gate dielectric for use in organic thin-film transistors was fabricated. The hybrid dielectric was synthesized via a sol-gel reaction using a mixture of a Si-based alkoxide, which contained a UV-crosslinkable organic functional group for photopatternability and a Zr-based alkoxide, which provided for a high dielectric constant (~5.5). To obtain a precisely patterned dielectric layer with a linewidth of 3 μm, the prebake temperature and the UV irradiation time were optimized by investigating the evolution of the chemical structure and analyzing the photopolymerization kinetics of the UV-crosslinkable organic group. In addition, chemical groups that caused current leakage were eliminated by controlling the post-bake temperature, resulting in a gate dielectric with a dielectric strength of 1.2 MV/cm.