Oxidant addition effect on Ge2Sb2Te5 phase change film chemical mechanical polishing

We studied the oxidant addition effect on chemical mechanical polishing (CMP) of Ge2Sb2Te5 (GST) phase change film. Atomic force microscopy and scanning electron microscopy (SEM) were used to characterize GST CMP performance. The surface roughness was reduced from 2.9 to 0.8 nm by oxidant (H2O2) addition. The surface chemical state of GST after being dipped in static condition ( absence of polishing) was measured by X-ray photoelectron spectroscopy (XPS) and the surface top view conducted by SEM. The data showed that Ge, Sb, and Te had been oxidized by H2O2 and the surface oxide layer was formed. The oxidation mechanisms of GST alloy are briefly discussed in terms of XPS spectra and oxide theory. Finally, the chemical effect on the GST CMP process is discussed and presented with previous results. (C) 2008 The Electrochemical Society.