热处理气氛对溶胶-凝胶法制备a-InGaZnO TFT器件的影响

Effect of annealing on characteristics of amorphous InGaZnO thin film transistors fabricated by sol-gel technical

采用溶胶-凝胶法制备了非晶铟镓锌氧化物(a-IGZO)薄膜,通过热重-差热示差技术分析了a-IGZO形成机理,并研究了热处理对a-IGZO薄膜的结构和光电性能影响。并用于薄膜晶体管(TFT)的有源层,制备的a-IGZO TFT,其具有明显的转移特性,其关态电流为10-11 A,退火能够改善a-IGZO TFT器件性能,器件的开关比提高了两个数量级。

The amorphous InGaZnO（a-IGZO） thin films were fabricated by sol-gel technology.The IGZO sol-gel was prepared by dissolving indium nitrate hydrate,zinc acetate dehydrate and gallium nitrate with a molar ratio of 1∶1∶2 in methanol at room temperature.The concentration of the metal ions was maintained at 0.3mol/L.The mixed sol was then stirred continuously at 70℃ for 1h using a water bath until a clear and transparent homogeneous sol was formed.The a-IGZO thin film was spinning coated on the chip with a speed of 2000r/min.Then the film was hearted on hot plate at 150℃ for 15min and annealed at 350℃ for 1h in air and vacuum atmosphere.As a result,air annealing improved the transmittance of the a-IGZO thin film,while the vacuum atmosphere decreased the transmittance.The optical transmittance of the a-IGZO thin films annealed in air can reach to average 80%.All the thin films had smooth surface and the roughness RMS was less than 0.6nm.The a-IGZO films annealed in vacuum atmosphere＇s roughness is bigger than that in air.The TFT＇s transfer characteristic was improved in vacuum atmosphere.The off current of the a-IGZO TFT annealed in vacuum atmosphere was 10-11A,and the Ion/Ioff was 104.