Surface-Functionalized Interfacial Self-Assembled Monolayers as Copper Electrode Diffusion Barriers for Oxide Semiconductor Thin-Film Transistor

The stability and control of copper (Cu) electrode application in oxide semiconductor indium gallium zinc oxide (IGZO) can improve the resistance–capacitance (RC) delay, which is greatly critical for realizing high resolution and large area display devices. However, to suppress Cu diffusion into IGZO that causes degradation in the reliability and performance of electric devices requires the study of increasingly thinner diffusion barriers, and surface-functionalized interfacial self-assembled monolayer (SAM) with a thickness of several nanometers can be a promising and viable candidate. We newly confirmed that the proper selection of surface-functionalized interfacial SAM with polarity functional group and alkyl chain length on IGZO can control both the blocking of Cu diffusion and the reinforcing of electron transfer. With this advanced Cu diffusing prevention system by SAM, we expect to greatly enhance the electrical stability of the IGZO thin-film transistor (TFT) with a Cu electrode.