Low-temperature, nontoxic water-induced high-k zirconium oxide dielectrics for low-voltage, high-performance oxide thin-film transistors

The fabrication of water-induced amorphous high- k zirconium oxide (ZrO x ) dielectrics has been proposed with the objective of achieving high performance and reducing costs for next generation displays. In this study, the as-prepared ZrO x thin films were fabricated by a sequential process, including a UV-assisted photochemical treatment and a thermal annealing process at temperatures lower than 300 °C. It is observed that the leakage current density of ZrO x thin films decreases, and the capacitance increases with increasing annealing temperatures. To verify the application possibilities of ZrO x thin films as gate dielectrics in complementary metal-oxide semiconductor (CMOS) electronics, both n-type In 2 O 3 and p-type NiO x channel layers were integrated with ZrO x dielectrics and their corresponding electrical performances were examined. The In 2 O 3 /ZrO x thin film transistor (TFT) annealed at 250 °C exhibited a high electron mobility of 10.78 cm 2 V −1 s −1 , a small subthreshold swing of 75 mV dec −1 , and a large on-off current ratio ( I on / I off ) of around 10 6 , respectively. Moreover, the p-type NiO x /ZrO x TFT exhibited an I on / I off of 10 5 and a hole mobility of 4.8 cm 2 V −1 s −1 . It is noted that both n- and p-channel oxide TFTs on ZrO x could be operated at voltages lower than 4 V. The low-temperature fabrication process marks a great step towards the further development of low-cost, all-oxide CMOS electronics on flexible substrates. High-performance n- and p-type metal-oxide thin-film transistors are fabricated on ZrO x high- k dielectrics via a nontoxic water-inducement method.