Device characteristics of amorphous In-Ga-Zn oxide thin-film transistors with varying channel thickness

• Published in: Semiconductor science and technology Vol. 28; no. 12; pp. 125014 - 125019
• Main Authors: Lee, Min-Jung, Lee, Su Jeong, Lee, Tae Il, Lee, Woong, Myoung, Jae-Min
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.12.2013; Institute of Physics
• Subjects: amorphous IGZO TFT; Applied sciences; bias stress stability; channel thickness optimization; Electronics; Exact sciences and technology; oxide TFT; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; thin-film transistor; Transistors; Thickness; Voltage threshold; Charge carrier trapping; Output voltage; Size effect; Oxides; Thin film transistor; Optimization; Voltage capacity curve
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/0268-1242/28/12/125014

Channel thickness of thin-film transistors (TFTs) having amorphous In-Ga-Zn oxide channels has been optimized based on the device performance characteristics including output characteristics, transfer characteristics, and bias stress stability. The device performance initially improved as the channel thickness increased from 20 to 30 nm, but subsequently deteriorated with further increasing thickness to 40 nm. The 30-nm-channel TFT exhibited threshold voltage close to 0 V, the highest field-effect mobility (µFE), highest on off ratio, and smallest threshold voltage shift under bias stress. The observed channel-thickness-dependent changes in device characteristics are attributed to the collective contribution of interface traps, fixed oxide charges, and mobile charges.