Investigation on mechanism for instability under drain current stress in amorphous Si-In-Zn-O thin-film transistors

► We studied instability mechanism under positive bias in Si-In-Zn-O thin-film transistor. ► The density of states was constant as the positive bias stress (PBS) time increases. ► Thus, defect creation during the PBS is not dominant mechanism for the instability. ► The instability under PBS is due to charge trapping by density of states.