Improvement in Bias Stress Stability of Solution-Processed Amorphous InZnO Thin-Film Transistors via Low-Temperature Photosensitive Passivation

We report the enhancement in the electrical performance of solution-processed amorphous InZnO (a-IZO) thin-film transistors (TFTs) through incorporation of low-temperature photosensitive polysilsesquioxane (P-PSQ) passivation. P-PSQ passivated TFTs recorded smaller V
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shift of 1.5 V after positive bias stress test despite annealing at 180°C. Analysis of secondary ion mass spectrometry and x-ray photoelectron spectroscopy showed that higher concentration of hydrogen reduced the amount of oxygen vacancies in the passivated IZO channel which promotes better stability against bias stress. Also, the time evolution of the V
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was defined in which the activation energy for each sample was extracted. Passivated TFT also showed minimal change upon exposure to humidity test. Overall, low-temperature P-PSQ passivation is an effective barrier against atmospheric effects for solution-processed oxide TFTs.