Improved Electrical and Temporal Stability of In-Zn Oxide Semiconductor Thin-Film Transistors With Organic Passivation Layer

Abstract

Solution-processed In-Zn oxide (IZO) semiconductor thin-film transistors (TFTs) were fabricated with passivation layers of either poly(methyl methacrylate) (PMMA) or cyclic transparent optical polymer (CYTOP). According to the transfer curves obtained on the day of fabrication and after 200 days, the drain-source current of the IZO TFT without a passivation layer decreased by approximately 37 %. For the PMMA-passivated IZO TFT, it decreased by approximately 31 %. The current for the CYTOPpassivated IZO TFT showed significantly lower, only 7 % deterioration. Hence, the CYTOP-passivated IZO TFT exhibited improved electrical stability under long term ambient storage. This was attributed to the difference in the chemical composition of the two polymers, as CYTOP is a fluoropolymer, while PMMA is an ester group containing organic polymer. We show, passivation of the active layer with the proper organic film improves the stability of the high-performance solution-processed IZO TFTs.