Noble-Metal-Free, Polarity-Switchable IGZO Schottky Barrier Diodes

• Published in: IEEE transactions on electron devices Vol. 70; no. 6; pp. 1 - 7
• Main Authors: Li, Yuzhi, Zhou, Yue, Guo, Chan, Zou, Shenghan, Lan, Linfeng, Gong, Zheng
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Annealing; Controllability; Copper; Diffusion layers; Electric contacts; Electrical properties; Electrodes; Gallium; Indium gallium zinc oxide; Indium tin oxide; Indium tin oxides; Indium-gallium-zinc oxide (IGZO); metal oxide (MO); Metal oxides; Metals; Noble metals; Optimization; Schottky barrier diode (SBD); Schottky barriers; Schottky diodes; Sputtering; switchable polarity; Switches; Zinc oxide
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2023.3267755

In this work, noble-metal-free, polarity-switchable indium-gallium-zinc oxide (IGZO) Schottky barrier diodes (SBDs) with a vertically stacked structure of copper (Cu)/AlO<inline-formula> <tex-math notation="LaTeX">_{\textit{x}}</tex-math> </inline-formula>/IGZO/indium-tin oxide (ITO) were demonstrated for the first time. The polarity of the SBDs can be manipulated through a simple postannealing process in N<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>. Without annealing, the as-fabricated IGZO SBD works in a negative operation mode (i.e., the dominating current flow direction is from the bottom ITO electrode to the top Cu electrode). The optimized SBD working in the negative mode exhibits excellent electrical properties with a rectification ratio of 2.12 <inline-formula> <tex-math notation="LaTeX">\times</tex-math> </inline-formula> 10<inline-formula> <tex-math notation="LaTeX">^{6}</tex-math> </inline-formula>, a Schottky barrier height of 0.87 eV, and an ideality factor of 1.26. After annealing in N<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>, the IGZO SBD switches to a positive operation mode. Through optimization, the positive SBD exhibits a rectification ratio of 4.24 <inline-formula> <tex-math notation="LaTeX">\times</tex-math> </inline-formula> 10<inline-formula> <tex-math notation="LaTeX">^{5}</tex-math> </inline-formula>, a Schottky barrier height of 0.83 eV, and an ideality factor of 1.43. The mechanism of polarity inversion behavior for the IGZO SBDs was discussed in detail by taking the Cu diffusion and contact modification via the AlO<inline-formula> <tex-math notation="LaTeX">_{\textit{x}}</tex-math> </inline-formula> inserting layer into account. This work sheds light on the development of noble-metal-free metal oxide (MO) SBDs with controllable polarities and the future integration of MO SBDs with other electron devices.