Etching mechanism of Y2O3 thin films in high density Cl2/Ar plasma

In this study Y2O3 thin films were etched with an inductively coupled plasma. The etch rate of Y2O3 and the selectivity of Y2O3 to YMnO3 were investigated by varying the Cl2/(Cl2+Ar) gas mixing ratio. The maximum etch rate of Y2O3 and the selectivity of Y2O3 to YMnO3 were 302 Å/min and 2.4, respectively, at a Cl2/(Cl2+Ar) gas mixing ratio of 0.2. Based on x-ray photoelectron spectroscopy analysis, it was concluded that the Y2O3 thin film was dominantly etched by Ar ion bombardment and was assisted by the chemical reaction of a Cl radical. This result was confirmed by secondary ion mass spectroscopy analysis with the presence of a Y–Cl bond at 124.4 (amu).