Mechanism of amorphous Ge₂Sb₂Te₅ removal during chemical mechanical planarization in acidic H₂O₂ slurry

In this paper, chemical mechanical planarization (CMP) of amorphous Ge₂Sb₂Te₅ (a-GST) in acidic H₂O₂ slurry is investigated. It was found that the removal rate of a-GST is strongly dependent on H₂O₂ concentration and gradually increases with the increase in H₂O₂ concentration, but static etch rate firstly increases and then slowly decreases with the increase in H₂O₂ concentration. To understand the chemical reaction behavior of H₂O₂ on the a-GST surface, potentiodynamic polarization curve, surface morphology and cross-section of a-GST immersed in acidic slurry are measured and the results reveal that a-GST exhibits a from active to passive behavior for from low to high concentration of H₂O₂. Finally, a possible removal mechanism of a-GST in different concentrations of H₂O₂ in the acidic slurry is described.