Low-temperature crosslinked soluble polyimide as a dielectric for organic thin-film transistors: enhanced electrical stability and performance

• Published in: JPhys materials Vol. 7; no. 1; pp. 15017 - 15026
• Main Authors: Yoo, Sungmi, Kim, Kyeongmin, Kim, Cho Long, Choi, Seong Hun, Won, Jong Chan, Ahn, Taek, Kim, Yun Ho
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2024
• Subjects: cross-linking network; Crosslinking; Diamines; Dicarboxylic anhydride; Dielectrics; Insulation; Leakage current; Low temperature; mobility; polyimide; polymer dielectric; Semiconductor devices; Stability; Thin film transistors; Threshold voltage
• ISSN: 2515-7639; 2515-7639
• DOI: 10.1088/2515-7639/ad1ea0

Abstract We have prepared a low-temperature cross-linked soluble polyimide (SPI) as a dielectric material for organic thin-film transistors (OTFTs) to improve their electrical stability. Two types of SPIs (DOCDA/6FHAB and 6FDA/6FHAB) were synthesized by a one-step polymerization process using 5-(2,5-dioxytetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA) and hexafluoroisopropylidene diphthalic anhydride (6FDA) as the dianhydrides and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FHAB) as a diamine. To further enhance the electrical performance, the SPI thin films were crosslinked with methylated/ethylated (hydroxymethyl)benzoguanamine (HMBG) through a low temperature process at 160 °C. Crosslinking considerably improved the insulating properties, resulting in a substantial reduction in leakage current from 10 −7 A cm −2 to 10 −9 A cm −2 at 2.0 MV cm −1 . When crosslinked SPIs were used as gate dielectrics in OTFTs, device stability and reliability, as measured by the off-current, threshold voltage, and hysteresis, improved significantly. Our results demonstrate the potential of crosslinked SPIs as effective gate dielectric materials for advanced organic thin-film transistors.