Stability study of indium tungsten oxide thin-film transistors annealed under various ambient conditions

Abstract

Amorphous tungsten-doped indium oxide thin-film transistors (a-IWO-TFTs) are prepared by RF sputtering and annealed in air, O-2, and N-2 ambients. The influence of annealing ambient on the electrical characteristics and stability of the a-IWO-TFTs is investigated. It is found that the characteristics and stability are improved in O-2 and N-2 ambients, which can be explained by the reduction of structural defects and oxygen vacancies. When annealed in O-2, the TFT device with saturation mobility of 27.55cm(2)V(-1)s(-1), threshold voltage of 0.5V and drain current on-off ratio of 10(8) is obtained. After an applied V-GS of 25 and -25V for 2000s in darkness, the values of Delta V-th are 4.5 and -0.92V, respectively.