Material engineering of GexTe100−x compounds to improve phase-change memory performances

• Tellurium-rich GeTe alloys exhibit stable programming characteristics and can sustain endurance up to 107 cycles.
• Germanium-rich compounds show an unstable RESET state during repeated write/erase cycles, probably affected by Ge segregation.
• Strong improvement of data retention departing from Ge50Te50 stoichiometric composition.

In this paper we provide a detailed physical and electrical characterization of Germanium Telluride compounds (GexTe100−x) targeting phase-change memory applications. Thin films of Germanium-rich as well as Tellurium-rich phase-change materials are deposited for material analysis (XRD, resistivity and optical characterization). GexTe100−x compounds are then integrated in lance-type analytical phase-change memory devices allowing for a thorough analysis of the switching characteristics, data retention and endurance performances. Tellurium-rich GeTe alloys exhibit stable programming characteristics and can sustain endurance up to 107 cycles, while Germanium-rich compounds show an unstable RESET state during repeated write/erase cycles, probably affected by Ge segregation. Finally we demonstrate that data retention is strongly improved departing from Ge50Te50 stoichiometric composition.