Dry Etching Characteristics of ZnO Thin Films for the Optoelectronic Device by Using Inductively Coupled Plasma

In this study, we carried out an investigation of the etching characteristics (etch rate, selectivity to SiO2) of ZnOthin films in N2/Cl2/Ar inductivity coupled plasma. A maximum etch rate and selectivity of 108.8 nm/min and,3.21, respectively, was obtained for ZnO thin film at a N2/Cl2/Ar gas mixing ratio of 15:16:4 sccm. The plasmaswere characterized by optical emission spectroscopy. The x-ray photoelectron spectroscopy analysis showed theefficient destruction of oxide bonds by ion bombardment. An accumulation of low volatile reaction products on theetched surface was also shown. Based on this data, an ion-assisted chemical reaction is proposed as the main etchmechanism for plasmas containing Cl2.