Mechanism of positive bias stress-assisted recovery in amorphous-indium-gallium-zinc-oxide thin-film transistors from negative bias under illumination stress

作者：Um Jae Gwang; Mativenga Mallory; Jang Jin^*

来源：Applied Physics Letters, 2013, 103(3): 033501.

DOI：10.1063/1.4813747

We have analyzed the effect of applying positive bias stress (PBS) to amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) immediately after applying negative bias under illumination stress (NBIS). By monitoring TFT current-voltage and capacitance-voltage characteristics, we found that PBS facilitates the recovery process. NBIS results in positive charge trapping at the active-layer/gate-insulator interface and the formation of shallow donors in the bulk a-IGZO when neutral oxygen vacancies are ionized by hole capture. In addition to the release of trapped positive charges from the active-layer/gate-insulator interface during the PBS-assisted recovery, ionized oxygen vacancies are neutralized by electron capture and relax back to their original deep levels-well below E-F.

• 出版日期2013-7-15