Chemical durability engineering of solution-processed oxide thin films and its application in chemically-robust patterned oxide thin-film transistorsElectronic supplementary information (ESI) available: SB + HBP ZTO channel patterns, leakage current-voltage curves of ALD-Al2O3 films, X-ray photoelectron spectra of SB ZTO films, SBP + HB ZTO channel patterns, transfer curves of SBP + HB ZTO TFTs, and schematic processes sequences for Mo S/D patterning, Fig. S1-S6. See DOI: 10.1039/c6tc04094b

• Main Authors: Cho, Sung Woon, Kim, Da Eun, Kang, Won Jun, Kim, Bora, Yoon, Dea Ho, Kim, Kyung Su, Cho, Hyung Koun, Kim, Yong-Hoon, Kim, Yunseok
• Format: Article
• Language: English
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c6tc04094b

For the fabrication of solution-processed oxide thin-film transistors (TFTs), most studies have focused on the sol-gel coating of oxide films with high mobility, but the inevitable wet-based channel or metal patterning processes to integrate the circuits (individual TFTs + metal-lines) on large-area TFT back-planes have been excluded due to unintentional electrical degradation of conventional In and Zn based oxide channels and additional post-processes (etch-stopper and recovery process). The incorporation of Sn-O bonds in oxide films can enhance their electrical performance and chemical durability and minimize electrical degradation during wet-based metal patterning, but conversely, it makes wet-based channel patterning difficult. Using Sn-O incorporation and temperature-controlled thermal annealing, based on the chemical reaction route, we were able to engineer the chemical durability of sol-gel coated Sn-incorporated ZnO (ZTO) films into inferior (with weak M-O bonds) and robust states (with strong M-O bonds). Well-patterned solution-processed ZTO channels were formed in a chemically weak state and reinforced into a chemically robust state for metal patterning via the combination (soft-bake → pattern → hard bake) of chemical durability engineering and a wet-etching process, which induced uniformly patterned, highly electrical, chemically robust ZTO channels with a low leakage current (∼10 11 A), superior electrical performance (2.0 ≤ μ FE ≤ 3.2 cm 2 V −1 s −1 ), and chemical robustness against metal wet etchants. All wet-based approaches are designed to integrate the circuits (individual TFTs + metal-lines) on large-area solution-processed oxide TFT back-planes: (i) sol-gel channel coating, (ii) channel wet patterning, and (iii) electrode wet patterning in solution systems. The chemical durability of solution-processed oxide films was engineered via Sn-incorporation and thermal-treatment, which was applied for large-area TFT circuit integration.