Evaluation of Hydrogen Peroxide on Chemical Mechanical Polishing of Amorphous GST

Abstract

As chemical mechanical polishing (CMP) becomes an essential step for fabrication phase change memory (PCM) device, industry always concerns that aggressive chemical components in the slurry might affect the composition and reliability of the phase change material Ge2Sb2Te5 (GST). In this study, we evaluated typical slurry component hydrogen peroxide on amorphous GST CMP. Silica-based slurries without H2O2 and with H2O2 at low (0.5wt%) and high concentrations (5wt%) were used for investigation. First, the polishing performance was compared. Then, auger electron spectroscopy (AES) was adopted to analyze the depth profile of Ge, Sb, Te and O for GST samples processed by different concentrations' H2O2. We also evaluated the phase change properties as a function of ageing time for those samples. To further evaluate the effect of H2O2 induced surface oxidation layer on PCM device, thermal simulation was used to compare the difference of thermal consumption and distribution during the operation.