Chemical Mechanical Polishing of Ge₂Sb₂Te₅ Using Abrasive-Free Solutions of Iron Trichloride

Chemical mechanical polishing (CMP) of amorphous Ge₂Sb₂Te₅ (GST) is studied using aqueous solutions of iron trichloride (FeCl₃) as possible abrasive-free slurries. The polishing performance of abrasive-free solutions is compared with abrasive-containing (3wt% colloidal silica) slurry in terms of polishing rate and surface quality. The experimental results indicate that the abrasive-free solutions have a higher polishing rate and better surface quality. In order to further investigate the polishing mechanism, post-CMP GST films using the abrasive-free solutions and abrasive-containing slurry are characterized by x-ray photoelectron spectroscopy. Finally, it is verified that the abrasive-free solutions have no influence on the electrical property of the post-CMP GST films through the resistivity test.