Agenda

Résumé : 

In recent years, phase changed memories based Ge rich Ge₂Sb₂Te₅ alloys receive considerable interest for their high writing speed and thermal stability, suitable for automotive and embedded applications. This stability results from the fact that these alloys do not crystallize congruently but experience multiple phase separation steps upon crystallization. Several efforts have been devoted to identify these crystalline phases, which unfortunately usually reported unrealistic chemical compositions due to the phase overlapping in polycrystalline structures. In this work, using in-situ synchrotron X-ray diffraction and advanced transmission electron microscopy based technique (electron energy loss spectroscopy – EELS), we provide a detail analysis of crystallization mechanisms and phase identification on several material systems such as canonical Ge₂Sb₂Te₅, Ge rich Ge₂Sb₂Te₅ and their Nitrogen doping alloys. Elemental diffusion under the impacts of surrounded crystalline environment and electrical polarization within the memory cells will also be discussed.