Material engineering of Ge_xTe_(100-x) compounds to improve phase-change memory performances

摘要

In this paper we provide a detailed physical and electrical characterization of Germanium Telluride compounds (Ge_xTe_(100-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). Ge_xTe_(100-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 10~7 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 Ge_(50)Te_5o stoichiometric composition.