MgZnO-Based Negative Capacitance Transparent Thin-Film Transistor Built on Glass

• Published in: IEEE journal of the Electron Devices Society 2021, Vol.9, p.798-803
• Main Authors: Yu, Fangzhou, Hong, Wen-Chiang, Li, Guangyuan, Li, Yuxuan, Lu, Ming, Lu, Yicheng
• Format: Article
• Language: English
• Subjects: Augmented reality; Capacitance; Eyewear; Ferroelectric materials; Ferroelectricity; Glass; Logic gates; Negative capacitance; Nickel; Semiconductor devices; Substrates; subthreshold swing; Thin film transistors; thin-film transistor; Transistors; transparent electronics; Visible spectrum; Zinc; Zinc oxide
• ISSN: 2168-6734; 2168-6734
• DOI: 10.1109/JEDS.2021.3108904

We demonstrate the first wide bandgap oxide based negative capacitance transparent thin-film transistor (NC-TTFT) built on glass. The Mg 0.03 Zn 0.97 O (MZO) semiconductor served as the channel layer and ferroelectric Ni 0.02 Mg 0.15 Zn 0.83 O (NMZO) serves in the gate stack. The Al-doped ZnO (AZO) is employed as the transparent conductive oxide (TCO) for source and drain electrodes. The NC-TTFT on glass shows an average optical transmittance of 91 % in the visible spectrum. The subthreshold swing (SS) value is significantly reduced over the reference transparent thin-film transistor (TTFT) without a ferroelectric layer. The minimum SS value of the NC-TTFT reaches 17 mV/dec. With normally-off operation and high on/off current ratio of 107, this NC-TTFT on glass technology shows promising potential for wearable systems such as augmented reality (AR) smart glasses.