Effects of Ambient/Carrier Gas on Amorphous InGaZnO-Based Thin-Film Transistors Using Ultrasonic Spray Pyrolysis Deposition

• Published in: IEEE transactions on electron devices Vol. 68; no. 6; pp. 2729 - 2735
• Main Authors: Liu, Han-Yin, Chang, Che-Lun, Hsu, Pei-Huang, Chen, Wei-Ting, Chang, Teng-Yuan, Lee, Ching-Sung, Shih, Shun-Cheng, Hsu, Wei-Chou
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustics; Ambient/carrier gas; Amorphous materials; Carrier gases; Deposition; Gallium; Gases; Hypoxia; Indium gallium zinc oxide; Indium tin oxide; indium–gallium–zinc oxide (InGaZnO); Interface stability; Nitrogen; oxygen deficiency; Radio frequency; Semiconductor devices; Spray pyrolysis; Sputtering; Substrates; Thin film transistors; Thin films; thin-film transistor (TFT); Transistors; ultrasonic spray pyrolysis deposition (USPD); Zinc oxide
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2021.3074107

This study investigates how ambient/carrier gases affect the material characteristics of amorphous indium-gallium-zinc oxide (a-InGaZnO) thin films deposited using the ultrasonic spray pyrolysis deposition (USPD) method. Nitrogen and air are used as the ambient/carrier gases in this study. The crystallinity, oxygen deficiency, energy bandgap, and trap level in the a-InGaZnO thin films are analyzed. The performance of the thin-film transistors (TFTs) based on a-InGaZnO with different ambient/carrier gases is investigated as well. It is found that oxygen deficiency is suppressed when air is used as the ambient/carrier gas. When nitrogen is used as the ambient/carrier gas to deposit a-InGaZnO thin film, the TFT shows higher field-effect mobility and saturation mobility. However, when the a-InGaZnO thin film is deposited with air as the ambient/carrier gas, the subthreshold swing, ON-/ OFF-current ratio, interface trap density, and stability of the TFT are improved. This study demonstrates how ambient/carrier gases in the USPD system affect the performance of a-InGaZnO TFT.