Vacuum-free solution-based metallization (VSM) of a-IGZO using trimethylaluminium solution

Abstract

This research demonstrates a method to reduce the resistance of amorphous indium–gallium–zinc–oxide (a-IGZO) using a “vacuum-free solution-based metallization” (VSM) process, which revolutionizes the metallization process thanks to its simplicity, by simply dipping the a-IGZO into trimethyl aluminium (TMA, (CH₃)₃Al) solution. From the XPS results, it was found that oxygen vacancies were generated after the VSM process, resulting in the enhanced conductivity. Various metallization time and solution temperature conditions were investigated, and the measured conductivity of the a-IGZO could be enhanced up to 20.32 S cm⁻¹, which is over 10⁵ times larger compared to that of the untreated a-IGZO. By utilizing the VSM process, self-aligned top-gate (SATG) a-IGZO thin-film-transistors (TFTs) were successfully fabricated, and to provide an explanation for the mechanism, X-ray photoelectron spectroscopy (XPS) was employed.