Acid and Surfactant Effect on Chemical Mechanical Polishing of Ge2Sb2Te5

We report about the effect of acids and surfactants on the chemical mechanical polishing (CMP) of Ge2Sb2Te5(GST). A scanning electronic microscope was used to measure the material removal rate. An atomic force microscope was adopted to characterize the surface quality. On the basis of the polishing results, the GST CMP process was promoted by the additives with an increase in the molecular chain length and the O/OH number. A possible reaction mechanism was presented. Furthermore, the comparison of the electrical property of GST films before and after CMP revealed that the polished GST film possessed a higher resistivity due to the surface oxidation, which would be beneficial for reducing the high reset current of the phase-change memory cells.