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The effects of post‐annealing on amorphous InGaZnO (a‐IGZO) TFTs with ultrathin atomic layer deposited (ALD) AlOxgate insulator (GI) were investigated. The non‐annealed devices exhibited uncontrollable gate leakage current while postannealing in either oxygen (O2) or nitrogen (N2) exhibited noticeable improvements. Optimizing O2‐annealed devices demonstrated the most optimal performance, including a low subthreshold swing of 61.6 mV/dec and a high on/off current ratio over 109. Capacitance‐voltage and X‐ray photoelectron spectroscopy analyses further revealed the underlying mechanism of defect elimination at the AlOx/a‐IGZO interface. [ABSTRACT FROM AUTHOR]

The influence of H2O on self‐aligned top‐gate (SATG) a‐ InGaZnO thin‐film transistor (TFT) was systematically investigated by performing the high‐temperature high‐humidity (HTHH) test (50 °C, 80% RH). Though initial electrical characteristics were well maintained, the stability under positive bias stress (PBS) was considerably deteriorated, including an abnormal negative Vth shift, degraded SS, and increased off current. The mechanism of H2O‐induced instability was proposed to be the dissociation of H2O molecules and the migration of hydrogen (H) atoms into the a‐IGZO channel. The hydrogen diffusion and doping effects in SATG a‐IGZO TFTs were further proved by SiNx‐passivated TFTs with regulated H content in SiNx layers. [ABSTRACT FROM AUTHOR]