InSnZnO Thin-Film Transistors With Vapor- Phase Self-Assembled Monolayer as Passivation Layer

Bottom-gate InSnZnO (ITZO) thin-film transistors (TFTs) with back channels modified by a self-assembled monolayer (SAM) as a passivation layer are proposed. The SAMs are prepared by a vapor-phase deposition method based on three types of triethoxysilane with three different alkyl chain lengths. Vapor-phase reactions are much less sensitive to variations in humidity and reagent purity, are more practical than the solution-phase method, and generate more reproducible results. After the SAMs are treated, a densely packed and highly hydrophobic interface is formed on the top of the devices, and the electrical performance of the ITZO TFTs is greatly improved, especially with the SAM with a chain length of 18 carbon atoms. More importantly, it is also found that SAMs with a long alkyl chain length are beneficial for bias stress stability.