Microstructure and crystallization kinetics of Ge₂Sb₂Te₅–Sn phase change materials

In this paper, the effects of Sn doping on the microstructure and electrical properties of amorphous and crystalline Ge₂Sb₂Te₅ thin films are reported. The thin films bonding states are measured through X-ray photoelectron spectroscopy (XPS) and micro-Raman spectroscopy, which prove that the bonding states of Ge₂Sb₂Te₅–Sn thin films regularly change with the additions of various Sn contents. Sn atoms alter the chemical surrounding of Te atoms significantly, having a low impact on the bonding environment of Sb atoms, since the additional Sn atoms bond with Te atoms and lead to the SnTe phase formation. Both the homogeneity of bonding characteristics and crystallinity in Ge₂Sb₂Te₅–Sn thin films are improved. The atomic arrangement of the crystalline states Ge₂Sb₂Te₅–Sn thin films is also obtained. It could be inferred that the Sn addition lead to higher crystalline interplanar spacing and arrangement of many disordered atoms. Furthermore, the corresponding activation energy value (E_A) of Ge₂Sb₂Te₅–Sn thin films is calculated. This display that the E_A values of Ge₂Sb₂Te₅–Sn increase compared to the pure Ge₂Sb₂Te₅ thin films, since the Ge₂Sb₂Te₅–Sn thin film structures are stabilized due to the compressed bonds and various bonding states.