Inductively coupled plasma etching of hafnium-indium-zinc oxide using chlorine based gas mixtures

We report the etching characteristics of a stacked hafnium-indium-zinc oxide (HIZO) with a photoresist using the gas mixture of chlorine and argon (Cl₂/Ar). The etching behaviors of HIZO have been investigated in terms of a source power, a bias power and a chamber pressure. As the concentration of Cl₂ was increased compared to pure Ar, the etch rate of HIZO film was found slightly different from that of indium-zinc oxide (IZO) film. Moreover, to investigate the etching mechanism systematically, various inspections were carried out such as atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) depending on the portion of Cl₂. Additionally, we compared the etching mechanism of HIZO film with IZO film to confirm the difference of chemical bonds caused by the influence of hafnium doping.