Demonstration of α-InGaZnO TFT Nonvolatile Memory Using TiAlO Charge Trapping Layer

• Published in: IEEE transactions on nanotechnology Vol. 17; no. 6; pp. 1089 - 1093
• Main Authors: Zhang, Wei, Liang, Renrong, Liu, Libin, Yu, Guofang, Wang, Jing, Xu, Jun, Ren, Tian-Ling
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum oxide; Charge materials; charge trapping; Composite materials; Display devices; Gallium; Indium gallium zinc oxide; Logic gates; Nonvolatile memory; Programming; Semiconductor devices; thin film transistor; Thin film transistors; TiAlO; Transmission electron microscopy; Trapping; Zinc oxide; α-InGaZnO
• ISSN: 1536-125X; 1941-0085
• DOI: 10.1109/TNANO.2018.2810885

Amorphous indium gallium zinc oxide (α-InGaZnO) thin-film transistors using as nonvolatile memories (TFT-NVMs) with an Al 2 O 3 /TiAlO/Al 2 O 3 charge trapping engineered structure have been demonstrated experimentally at low thermal budget of 300 °C. The high-k composite TiAlO layer with a high trap state density and a high dielectric constant was prepared by sputtering at room temperature as a charge trapping material. According to the high-resolution transmission electron microscopy analyses, the Al 2 O 3 /TiAlO/Al 2 O 3 gate stack exhibited sharp interfaces and a uniform distribution of Ti and Al elements in the TiAlO film. The programming and retention characteristics of the fabricated α-InGaZnO TFT-NVMs were investigated in detail. The TFT-NVMs exhibited excellent programming characteristics with a large memory window of around 5.74 V under a 16 V programming voltage. It can also maintain a memory margin of about 5 V after 10 years, indicating only ~15% charge loss. This paper suggests that α-InGaZnO TFT-NVMs using the high-k TiAlO composite material as the charge trapping material are promising for future nonvolatile memories applications in display technology, flexible and wearable electronics.