Investigating addition effect of hafnium in InZnO thin film transistors using a solution process

The effects of adding Hf into a InZnO (IZO) system, particularly the electrical characteristics of their thin film and thin film transistors (TFTs), were investigated as a function of atomic concentration from 0 to 10 at.% of Hf and Ga/Zn. Because Hf has a high affinity for oxygen in IZO system, the Hf suppresses carrier generation more effectively than does Ga. At 10 at.% of Hf/Zn atomic concentration, the HfInZnO TFTs showed wider on-to-off ratios than those of GaInZnO TFTs due to the low standard-electrode-potential of Hf and sharp subthreshold swings due to low trap density.