Temperature-Dependent Operation of InGaZnO Ferroelectric Thin-Film Transistors With a Metal-Ferroelectric-Metal-Insulator- Semiconductor Structure

• Published in: IEEE electron device letters 2021-12, Vol.42 (12), p.1786-1789
• Main Authors: Sun, Chen, Zheng, Zijie, Han, Kaizhen, Samanta, Subhranu, Zhou, Jiuren, Kong, Qiwen, Zhang, Jishen, Xu, Haiwen, Kumar, Annie, Wang, Chengkuan, Gong, Xiao
• Format: Article
• Language: English
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">a -IGZO; Annealing; Carrier density; charge trapping; ferroelectric; Ferroelectric materials; Ferroelectricity; Gallium; Hafnium oxide; High temperature; HZO; Indium gallium zinc oxide; Insulators; Logic gates; MFMIS; MIS (semiconductors); Semiconductor device measurement; Semiconductor devices; Switches; Temperature; Temperature dependence; Temperature measurement; TFTs; Thin film transistors; Threshold voltage; Transistors; Voltage measurement; Zirconium
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2021.3121677

We report the temperature-dependent operation of back-end-of-line (BEOL) compatible amorphous indium-gallium-zinc-oxide ( {a} -IGZO) ferroelectric thin-film transistors (FeTFTs) with a large memory window (MW) more than 3 V. Our {a} -IGZO FeTFTs have a metal-ferroelectric-metal-insulator-semiconductor (MFMIS) stru- cture with Zr-doped HfO 2 (HZO) as the ferroelectric layer. Characteristics of {a} -IGZO FeTFTs are investigated in the temperature range of −40 °C to 100 °C. We found that: Firstly, the remanent polarization ( {P}_{\text {r}} ) of the HZO film increases with 2{P}_{\text {r}} from \sim 35~ {\mu }\text{C} /cm 2 at −40 °C to \sim 40~ {\mu }\text{C} /cm 2 at 100 °C. Secondly, enhancement in MWs at high temperatures is observed, achieving MWs larger than 3.5 V when the temperature is higher than 60 °C. Thirdly, for the threshold voltage ( {V}_{\text {TH}} ) at high temperatures, there is a competition between the negative shift caused by higher carrier concentration in the {a} -IGZO channel and positive shift due to the charge trapping at the floating gate in the MFMIS structure. This could be explored to realize good {V}_{\text {TH}} stability.