Innovative Doping Strategy to Control Segregation and Crystallization Kinetics in Ge‐Rich GeSbTe Alloys

Phase‐change memory (PCM) based on Ge‐rich GeSbTe (GGST) alloys have been demonstrated to be a reliable nonvolatile memory technology that meets the stringent specifications of automotive applications. Further material engineering of the GGST alloy through innovative doping could pave the way for future sub‐18 nm technology nodes and device ultimate scaling. This study investigates the impact of progressive Ge substitution by a dopant element (D) in standard GGST alloys featuring an Sb‐over‐Te ratio lower than one and addresses both amorphous phase properties and crystallization behavior. Electrical, structural, and vibrational analyses show that D incorporation increases resistivity and improves thermal stability of the amorphous phase despite a reduced Ge content. D incorporation also modifies the stoichiometry of the segregated GeSbTe (GST) phase during crystallization. Indeed, a higher D content promotes the formation of an Sb‐rich phase (i.e., featuring a high Sb‐over‐Te ratio) and alters the crystallization kinetics. This evolution suppresses the metastable cubic phase and favors a direct transition from the amorphous phase towards the stable hexagonal phase. These findings highlight that Ge‐substitution‐based doping provides an effective route to tune amorphous stability and phase evolution, offering a robust strategy for optimizing GGST materials for advanced PCM applications.