The improvement of endurance characteristics in a superlattice-like material-based phase change device

Abstract

Improvement of endurance characteristics has been a hot area of research in phase change memory. The property of phase change material is believed plays an important role in the device endurance. Repeated SET-RESET operation always leads to material failure problems, such as composition deviation and phase separation. Moreover, the quality of the electrode and the electrode contact also determine the endurance characteristics. In this study, carbon nanolayers were periodically inserted into the phase change material Ge2Sb2Te5 (GST) to fabricate a superlattice-like (SLL) structure. Although some C bonded with part of the Ge, Sb, and Te atoms, more C atoms prefer nanometer-scale clusters at the grain boundary in the SLL film. The typical local configuration of GST was unchanged when artificial C nanolayers fabricated. Transmission electron microscopy experiments revealed that the bonded C atoms and nano-scale C clusters may occupy the spontaneously created holes and defects, preventing composition deviation of the phase change material and prolonging the electrode service life. The contact surface between the phase change material and the electrode is also improved. As a result, we found that the endurance cycle could be improved by up to 10E6 for GST/C SLL film-based device.