Solution‐Free UV‐Based Direct Surface Modification of Oxide Films for Self‐Patterned Metal‐Oxide Thin‐Film Transistors

Abstract

AbstractIn thin‐film device fabrication, particularly using a solution process, self‐patterning is effective in reducing the fabrication steps by eliminating the conventional photolithography process. Here, solution‐free ultraviolet (UV)‐based direct surface modification is introduced for self‐patterning of solution‐processed oxide semiconductors. The direct surface modification is carried out by selectively irradiating UV light on a SiO2 film, creating regions with different surface energies. This surface energy difference induces different wetting behaviors of spin‐coated indium‐gallium‐zinc‐oxide (IGZO) precursor film, enabling the direct self‐patterning. By optimizing the surface modification conditions and the channel design, self‐patterned IGZO thin‐film transistors (TFTs) are successfully fabricated. The self‐patterned IGZO TFTs exhibit low off‐state current (<10−12 A), high on/off ratio (≈108), and low gate‐leakage level without using any channel etching process. The results show that the direct surface modification can be a good candidate for realizing self‐patterned IGZO TFTs.