Solution-deposited oxide TFTs and backplanes

Metal oxide semiconductors are developing rapidly.¹ The high mobility of the oxides enables their use for OLED displays or high speed LCD switching. Solution deposition methods of fabrication are attractive for low cost manufacturing of large area electronics and so there is interest in the formation of the oxide semiconductors from solution.² InGaZn oxide semiconductor TFTs were processed from solution by the sol-gel method. The precursors were mostly metal nitrates and the Zn nitrate precursor was found to give better results than the Zn acetate precursor. Various metal compositions were studied and all of the solutions were at 0.1 M concentration in anhydrous 2-methoxyethanol solvent. Films were annealed in the range 350 °C to 500 °C for 1 hour in ambient air and processed TFTs were annealed at 180C.