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We examine low-temperature fabricated InSnO/ZnO (ITO/ZnO) heterojunction thin-film transistors (TFTs) with high mobility and excellent stability. The effects of ITO thickness (0, 2, 4, 6, and 8 nm) on performance of the ITO/ZnO TFTs are studied. For the devices with a 6-nm ITO layer, a field-effect mobility (₅₄) of 55. 50 cm 2 /Vs, a subthreshold swing (SS) of 113. 22 mV/decade, a turn-on voltage (V₎₍) of −3 V, and an on/off current ratio (I₎₍/I₎₅₅) over 10 7 are obtained. Besides, the devices demonstrate excellent stability with a threshold voltage shift of 0. 68 and −0. 25 V under the positive and negative gate-bias stress, respectively. Operation mode of the ITO/ZnO TFTs is analyzed. The results show that potential well at ITO/ZnO heterointerface forms electronic accumulation, which is beneficial to improve the ₅₄ of the ITO/ZnO TFTs. Our work promotes applications of the oxide TFTs to back-end-of-line (BEOL) circuits.
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