Increasing the Atomic Packing Efficiency of Phase‐Change Memory Glass to Reduce the Density Change upon Crystallization

Abstract

Abstract Phase‐change memory (PCM) is a promising candidate for next‐generation memory technology due to the fast switching and large property contrast between the crystalline and amorphous phases. However, the large difference of mass density between these two phases is one of the major factors that lead to the failure of PCM devices. In this work, it is discovered that the carbon alloying remarkably reduces the density change of GeSb film (GeSbC), a chalcogen‐free material with high stability and good switching properties, from ≈6% to ≈3%. In particular, it is focused on the mechanism how carbon affects the structure of GeSbC alloys through X‐ray photoelectron spectroscopy and ab initio calculations, demonstrating that this dopant has increased the packing efficiency by forming small tetrahedral clusters in the bonding region of the glass. The results have important implications on the design of durable phase‐change memory materials.