Intermixing suppression through the interface in GeTe/Sb2Te3 superlattice

Phase-change memory using a superlattice composed of GeTe and Sb2Te3 periodic structures has been attracting attention for increasing switching speed and reducing energy consumption. However, so-called "atomic intermixing through the interfaces" was a major challenge for realizing devices. The effect was analyzed by molecular dynamics simulation, transmission electron microscopy and spin transport. We found that S atoms significantly decrease the free energy of formation in the Ferro phase of GeTe, and experimentally demonstrate that the superlattice fabricated using a GeTe target with 3 at% of S greatly suppress the intermixing.