Chemical mechanical polishing of Ge2Sb2Te5 in alkaline slurry

Chemical mechanical polishing of Ge2Sb2Te5 (GST) films in alkaline slurry is studied. It is found that the GST removal rate reaches maximum at pH = 11.0. This phenomenon is considered to be related to static corrosion of the GST material, and thus, the test of open circuit potential (OCP) along with pH value changes is performed, which has a same variation as the removal rate. A further calculation of the difference between OCP and Ge, Sb, and Te reaction equilibrium potential can provide a better understanding of the relationship between the removal rate and static corrosion. The GST polishing mechanism is more deeply explored using x-ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectrometry. These measurements reveal that the elements of Ge, Sb, and Te have a different removal process for GST material polishing. (C) 2017 American Vacuum Society.