ELECTROCHEMICAL CHARACTEMZATION OF GE2SB2TE5 FILMS IN POTASSIUM HYDROXIDE CHEMICAL-MECHANICAL POLISHING SLURRY

摘要

Ge2Sb2Te5 is considered to be the best phase change material for C-RAM. In this paper, Electrochemical behavior of Ge2Sb2T.es films has been investigated in potassium hydroxide slurry at different PH value and different H2O2 concentration. Electrochemical measurements were performed with Solartron ST1287, including open circuit potential (OCP), potentiodynamic polarization sweep and linear polarization resistance (LPR). OCP results indicate that Ge2Sb2Tes alloy films show a passive behavior when PH value is 10, and the films presented a passive-active transition when PH value changes to 11 and 12 at OCP. LPR results indicate that the films form a protective layer which prevents corrosion when PH value is 10 and the films accelerates corrosion from 11 to 12. In potentiodynamic polarization sweep measurements, The shape of the curves changes little with different PH value and H2O2 concentration, which shows that the reactions at the alloy-slurry interface are the same. The corrosion alloy films surface were analyzed by X-ray Photoelectron Spectroscopy (XPS). XPS analysis indicates Te were eroded firstly and Ge and Sb was removed later.