Etching Mechanism on HfAlO3 Thin Films Using Adaptively Coupled Plasma System

By using an adaptively coupled plasma system, the etching rate of HfAlO3 thin films and their selectivity to SiO2 thin films were investigated as a function of gas mixture ratio. The chemical reaction on the surface was investigated by X-ray photoelectron spectroscopy (XPS). From the results, we can discern that the etching of HfAlO3 thin films follows the ion-assisted chemical etching. Moreover, Hf and Al on the surface were removed by chemical reactions with the Cl radicals, and by physical bombardments.