Stability study of solution-processed zinc tin oxide thin-film transistors

• Published in: Electronic materials letters Vol. 11; no. 6; pp. 964 - 972
• Main Authors: Zhang, Xue, Ndabakuranye, Jean Pierre, Kim, Dong Wook, Choi, Jong Sun, Park, Jaehoon
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 01.11.2015; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials; 전자/정보통신공학; solution process; oxide semiconductor; thin-film transistor; reliability
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-015-5209-4

In this study, the environmental dependence of the electrical stability of solution-processed n -channel zinc tin oxide (ZTO) thin-film transistors (TFTs) is reported. Under a prolonged negative gate bias stress, a negative shift in threshold voltage occurs in atmospheric air, whereas a negligible positive shift in threshold voltage occurs under vacuum. In the positive bias-stress experiments, a positive shift in threshold voltage was invariably observed both in atmospheric air and under vacuum. In this study, the negative gate-bias-stress-induced instability in atmospheric air is explained through an internal potential in the ZTO semiconductor, which can be generated owing to the interplay between H 2 O molecules and majority carrier electrons at the surface of the ZTO film. The positive bias-stress-induced instability is ascribed to electron-trapping phenomenon in and around the TFT channel region, which can be further augmented in the presence of air O 2 molecules. These results suggest that the interaction between majority carriers and air molecules will have crucial implications for a reliable operation of solution-processed ZTO TFTs.