A thin-film transistor (TFT) with a Ti-IGZO channel layer and Hf1-xAlxO gate dielectric is proposed to improve the performance and reliability of the device. The experimental results show that in three types of TFTs based on HfO2/IGZO, Hf1-xAlxO/IGZO and Hf1-xAlxO/Ti-IGZO gate dielectric/channel structures, the Hf0.88Al0.12O/Ti (2.0%)-IGZO TFT exhibits the best device performance with the subthreshold swing of 86 mV dec-1, field-effect mobility of 28.63 cm2V-1s-1 and on/off current ratio of 3.26 × 108. In particular, it shows a hysteresis voltage as low as 0.02 V and a threshold voltage shift after 1000 s positive/negative gate bias stress/white light illumination of 0.134 V/-0.089 V/-0.195 V, compared with 0.45 V and 0.612 V/-0.507 V/-0.657 V of the HfO2/IGZO TFT. These improvements are due to the incorporation of Ti into the IGZO channel, which reduces defect density, while adding Al to HfO2 improves surface roughness to inhibit surface scattering and charge capture during stress testing.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)