On the Origin of Improved Charge Transport in Double-Gate In-Ga-Zn-O Thin-Film Transistors: A Low-Frequency Noise Perspective

• Published in: IEEE electron device letters Vol. 36; no. 10; pp. 1040 - 1043
• Main Authors: Yong Xu, Chuan Liu, Amegadez, Paul Seyram K., Gi-Seong Ryu, Huaixin Wei, Balestra, Francis, Ghibaudo, Gerard, Yong-Young Noh
• Format: Journal Article
• Language: English
• Published: IEEE 01.10.2015; Institute of Electrical and Electronics Engineers
• Subjects: Dielectrics; Double gate; Engineering Sciences; IGZO; Logic gates; Low-frequency noise; metal oxide semiconductor; Micro and nanotechnologies; Microelectronics; Thin film transistors; thin-film transistor; IGZO; metal oxide semiconductor; Double gate; thin-film transistor; low-frequency noise
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2015.2467164

Low-frequency noise (LFN) in double-gate (DG) In-Ga-Zn-O (IGZO) thin-film transistors (TFTs) is studied to investigate the origin of performance improvement. We found that thinning down the IGZO film enhances such improvements. With 7-nm IGZO, the mobility is raised by a factor of 3.77, and the subthreshold slope is reduced to 0.17 V/decade from single-gate to DG mode. Device simulations show that bulk transport inside IGZO film emerges as the two gates field effects get coupled. The LFN results reveal a transport transition from surface to bulk and disclose the superior bulk transport that experiences slight phonon scattering with a small Hooge parameter α H = 4.44 × 10 -3 whereas the surface transport undergoes serious charge trapping with surface trap densities about 2 × 10 11 eV -1 cm -2 .