Performance enhancement of amorphous indium-zinc-oxide thin film transistors by microwave annealing

The effect of microwave annealing on the field effect mobility and threshold voltage of amorphous indium zinc oxide (a-IZO) thin film transistors (TFTs) is reported. A control device with traditional hotplate annealing at 200 °C for 1 h was applied for comparison. The results show that both microwave annealing and low-temperature hotplate annealing increase the field effect mobility from 12.3 cm2/V s in as-deposited state to ∼19 cm2/V s in annealed state. However, the negative shift in threshold voltage with microwave annealing (from 0.23 V to −2.86 V) is smaller than that with low-temperature hotplate annealing (to −9 V). A mechanism related with the electrical properties of a-IZO material is proposed. This rapid low-temperature annealing technology makes a-IZO TFTs promising for use in flexible, transparent electronics.