High‐Performance Back‐Channel‐Etched Thin‐Film Transistors with an InGaO/InZnO Stacked Channel

• Published in: Physica status solidi. A, Applications and materials science Applications and materials science, 2020-03, Vol.217 (5), p.n/a
• Main Authors: Zhao, Mingjie, Zhang, Zewang, Xu, Yingchao, Xu, Daisheng, Zhang, Jiyan, Huang, Zhangchao
• Format: Article
• Language: English
• Subjects: Acid resistance; back-channel-etchedstructures; Contact resistance; Electric contacts; InGaO; InZnO; oxide semiconductors; Semiconductor devices; Thermal stress; thin-film transistors; Threshold voltage; Transistors
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201900773

Back‐channel‐etched (BCE) thin‐film transistors (TFTs) with an InGaO/InZnO stacked channel are developed, in which the InGaO and InZnO provide a highly acid‐resistant back channel and a high‐mobility front channel, respectively. The electrical performance of the TFT is optimized by adjusting the InGaO thickness. The best performance is achieved for the TFT with 10 nm thick InGaO. A thinner InGaO layer leads to inferior performance due to damage during the back‐channel‐etching process, while a thicker InGaO layer results in a hump effect and significant negative shifts in the threshold voltage (Vth) and turn‐on voltage (Von), which should be ascribed to the large total carrier number in the channel. The optimal TFT exhibits a high saturated field‐effect mobility of 28.9 cm2 V−1 s−1, a near‐zero Vth of −0.17 V, a Von of −0.49 V, a low subthreshold swing of 0.12 V dec−1, a high on‐to‐off current ratio of 3.5 × 109, and a low contact resistance between the source/drain (S/D) electrodes and channel. The TFT also exhibits high stability under bias thermal stress. Back‐channel‐etched thin‐film transistors (TFTs) with an InGaO/InZnO stacked channel are developed, in which the InGaO and InZnO provide a highly acid‐resistant back channel and a high‐mobility front channel, respectively. The optimal TFT exhibits excellent electrical performance with a high saturated field‐effect mobility of 28.9 cm2 V−1 s−1. The TFT also exhibits high stability under bias thermal stress.