Suppress temperature instability of InGaZnO thin film transistors by N2O plasma treatment, including thermal-induced hole trapping phenomenon under gate bias stress

An abnormal subthreshold leakage current is observed at high temperature, which causes a notable stretch-out phenomenon in amorphous InGaZnO thin film transistors (a-IGZO TFTs). This is due to trap-induced thermal-generated holes accumulating at the source region, which leads to barrier lowering on the source side and causes an apparent subthreshold leakage current. In order to obtain superior thermal stability performance of a-IGZO TFTs, conducting N2O plasma treatment on active layer was expected to avert defects generation during SiO2 deposition process. Reducing defects generation not only suppresses subthreshold current stretch-out phenomenon but also significantly improves the bias stress stability in a-IGZO TFTs at high temperature.