The Hump Phenomenon and Instability of Oxide TFT Were Eliminated by Interfacial Passivation and UV plus Thermal Annealing Treatment

作者：Li, Yilin; Yao, Rihui^*; Zhong, Jinyao; Yang, Yuexin; Liang, Zhihao; Fu, Yubin; Zeng, Xuan; Su, Guoping; Ning, Honglong^*; Peng, Junbiao

来源：ACS Applied Electronic Materials, 2023, 5(9): 4846-4862.

DOI：10.1021/acsaelm.3c00649

• thin-film transistor
• hump phenomenon
• instability
• interfacial passivation
• coplanar

In this work, we propose a simple and efficient interfacialmodificationmethod for thin-film transistor (TFT)-1 with poor stability underbias stress. For conventional top-contact TFT-2, the sputtering passivationlayer will cause the device to be in a short-circuit condition. Weused inverted coplanar-structured TFT-3 to separate the high conductivitylayer from the S/D electrodes to avoid the short-circuit failure ofthe device, but this will cause a hump effect. Ultraviolet treatmentand air annealing were performed on TFT-3 simultaneously to obtainTFT-4 with high mobility (& mu;(sat) = 45.5 cm(2) V-1 s(-1)), steep subthresholdswing (SS = 86 mV/dec), and good bias stability (& PLUSMN;20 V, 3600s, NBS: -0.1 V, PBS: +0.9 V, PGDBS: +0.5 V). The forward andreverse tests of TFT-1 and TFT-4 after the PGDBS test show that TFT-4has a good stability of the asymmetric electrical bias. Finally, XRR,XPS, AFM, and contact angle were tested to further investigate thematerial mechanisms. In this paper, we show that the interfacial passivationof TFT can effectively isolate the invasion of external water/oxygenand compensate for interfacial defects and dangling bonds. The decompositionand rearrangement of the oxide are induced by UV + thermal annealing,which optimizes the stacking pattern of the cells, effectively reducingthe defect states and eliminating parasitic channels and the humpphenomenon. Finally, an amorphous oxide semiconductor (AOS)-TFT instrumentwith high mobility and good stability is prepared. The method in thispaper addresses the problem that the passivation layer cannot be preparedby sputtering, which is a cost-effective process.