DC sputtered amorphous In–Sn–Zn–O thin-film transistors: Electrical properties and stability. (February 2016)

• Record Type: Journal Article
• Authors: Nakata, Mitsuru; Zhao, Chumin; Kanicki, Jerzy
• Is Part Of: Solid-state electronics. Volume 116(2016)
• Page Start: 22
• Page End: 29
• Publication Date: 2016-02
• Subjects: Thin-film transistors -- Amorphous In–Sn–Zn–O -- Field-effect mobility -- Electrical stability; Semiconductors -- Periodicals; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.sse.2015.11.025
• Languages: English
• ISSNs: 0038-1101

Abstract

Highlights: An analytical field-effect mobility model is proposed for dc sputtered a-ITZO TFTs. Device characteristics are extracted using both a least square error linear fitting method and a second derivative method. The a-ITZO film thickness and oxygen gas flow ratio are optimized. The oxygen gas flow ratio influences both device characteristics and stability of a-ITZO TFTs. Improved electrical stability is achieved for a-ITZO TFTs in comparison to that of a-IGZO TFTs. Abstract: In this study, we investigated the electrical properties of DC sputtered amorphous In–Sn–Zn–O (a-ITZO) thin-film transistors (TFTs) fabricated under various process conditions. Fabricated a-ITZO TFTs achieved a threshold voltage ( V T ) of 1.0 V, subthreshold swing ( SS ) of 0.38 V/dec and field-effect mobility ( μ eff ) of around 30 cm 2 /V s. An analytical field-effect mobility model is proposed for a-ITZO TFTs with key parameters extracted using different methods. The impacts of a-ITZO channel thickness and oxygen gas flow ratio on device performance were evaluated. Finally, the a-ITZO TFT bias-temperature stress (BTS) induced electrical instability was studied. In comparison to amorphous In–Ga–Zn–O (a-IGZO) TFTs, improved electrical stability was observed for a-ITZO TFTs using exactly the same BTS conditions.