High-Performance a-InGaZnO Thin-Film Transistors with Extremely Low Thermal Budget by Using a Hydrogen-Rich Al2O3 Dielectric

• Main Authors: Yan Shao, Xiaohan Wu, Mei-Na Zhang, Wen-Jun Liu, Shi-Jin Ding
• Format: Article
• Language: English
• Published: SpringerOpen 2019-04-01
• Series: Nanoscale Research Letters
• Subjects: Amorphous In-Ga-Zn-O; Thin-film transistor; Room temperature; Atomic layer deposition; Hydrogen-rich Al2O3
• Online Access: http://link.springer.com/article/10.1186/s11671-019-2959-1
• ISSN: 1931-7573; 1556-276X

Abstract Electrical characteristics of amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) are compared by using O2 plasma-enhanced atomic layer deposition Al2O3 dielectrics at different temperatures. High-performance a-IGZO TFTs are demonstrated successfully with an Al2O3 dielectric deposited at room temperature, which exhibit a high field-effect mobility of 19.5 cm2 V− 1 s− 1, a small subthreshold swing of 160 mV/dec, a low threshold voltage of 0.1 V, a large on/off current ratio of 4.5 × 108, and superior negative and positive gate bias stabilities. This is attributed to the hydrogen-rich Al2O3 dielectric deposited at room temperature in comparison with higher deposition temperatures, thus efficiently passivating the interfacial states of a-IGZO/Al2O3 and the oxygen vacancies and improving conductivity of the a-IGZO channel by generating additional electrons because of enhanced hydrogen doping during sputtering of IGZO. Such an extremely low thermal budget for high-performance a-IGZO TFTs is very attractive for flexible electronic application.