Etching characteristics and surface modification of InGaSnO thin films under Cl₂/Ar plasma

Indium gallium tin oxide (IGTO) thin films have the potential for high mobility and low-temperature processing, which makes them suitable for applications such as display backplanes and high-voltage switching devices. However, very few studies have investigated the plasma-etching characteristics of IGTO and changes in its properties after etching. In this study, the etching characteristics of IGTO were investigated using Cl₂/Ar plasma, and changes in surface properties were analyzed. Results showed that the etch rate increased with an increase in the proportion of Cl₂, with the highest etch rate observed at 69 nm min⁻¹ in pure Cl₂ plasma with a gas flow rate of 100 sccm. Furthermore, increased radio-frequency power caused a rise in the etch rate, while a process pressure of 15 mTorr was optimal. The primary etching mechanism for IGTO thin films under Cl₂ plasma was a chemical reaction, and an increased work function indicated the occurrence of defects on the surface. In addition, the etching process reduced the surface roughness of Cl₂-containing plasma, whereas the etching process in pure Ar plasma increased surface roughness. This study contributes to a better understanding of the plasma-etching characteristics of IGTO and changes in its properties after etching, providing valuable insights for IGTO-based applications.