Role of Hydrogen Peroxide in Alkaline Slurry on the Polishing Rate of Polycrystalline Ge2Sb2Te5 Film in Chemical Mechanical Polishing

Abstract

In chemical mechanical polishing (CMP), the polishing rate of Ge2Sb2Te5 (GST) films increases sharply with H2O2 concentration up to 0.2 wt % and then increases slightly with a further increase in H2O2 concentration up to 3.0 wt %. However, the polishing rate of SiO2 films increases very slightly with H2O2 concentration up to 3 wt %. Polishing selectivity of GST films to SiO2 films of over 100:1 can therefore be achieved by adding H2O2 to the slurry. To understand the mechanism of GST CMP with H2O2, we investigated the chemical reaction behavior on the GST film surface using potentiodynamic measurement and X-ray photoelectron spectroscopy.