Solution processed dielectric layer was fabricated with octamethylcyclotetrasiloxane (OMTS) by UV/ozone oxidation and thermal annealing. Annealing temperatures of 100°C, 300°C, and 500°C were examined and their dielectric properties were characterized on structures of metal–insulator–silicon (MIS) capacitor and thin film transistor (TFT) with solution-processed zinc-tin-oxide (ZTO) semiconductor. Chemical changes from the UV/ozone oxidation and annealing were analyzed by FTIR and XPS. For the 500°C annealed dielectric layer with UV/ozone oxidation, no hysteresis in capacitance–voltage (C–V) measurement was detected having a high dielectric constant (k) of 5.52. The OMTS film can be applicable as a gate dielectric layer towards intensive development of printed electronics.