Development of annealing process for solution-derived high performance InGaZnO thin-film transistors

• Electrical characteristics of the IGZO TFTs evaluated with annealing method and temperature.
• The RTA process exhibited high off-current and subthershold slope due to fast annealing process time.
• The CTA process exhibited low subthreshold slope and low drive current.
• The post RTA process effectively improves the interface trap state generated by the RTA process.

The influences of the annealing process on solution-derived InGaZnO thin-film transistors (TFTs) were investigated. Operation characteristics of IGZO TFTs were obtained from high temperature processes: rapid thermal annealing (RTA) at 600 °C and conventional thermal annealing (CTA) at 500 °C. It is found that the RTA increases the on-current and off-current of TFTs. The CTA decreases off-current and improves the interfacial property. Meanwhile, a two-step annealing process, comprising RTA and CTA, increases on-current and decreases off-current and is considered as the optimal annealing procedure. Another two-step annealing process, comprising CTA and RTA, increases on-current but increases off-current, simultaneously.

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