Impact of Ge–Sb–Te compound engineering on the set operation performance in phase-change memories

The phase-change memory (PCM) technology is considered as one of the most attractive non-volatile memory concepts for next generation data storage. It relies on the ability of a chalcogenide material belonging to the Ge–Sb–Te compound system to reversibly change its phase between two stable states, namely the poly-crystalline low-resistive state and the amorphous high-resistive state, allowing the storage of the logical bit. A careful study of the phase-change material properties in terms of the set operation performance, the program window and the electrical switching parameters as a function of composition is very attractive in order to enlarge the possible PCM application spectrum. Concerning the set performance, a crystallization kinetics based interpretation of the observed behavior measured on different Ge–Sb–Te compounds is provided, allowing a physics-based comprehension of the reset-to-set transition.

Research highlights
► The reported research is very attractive in order to enlarge the possible PCM application spectrum.
► The introduction of an increasing antimony (Sb) concentration has the effect of making the set operation more efficient.
► An increasing operation current has been ascribed to an increasing average coordination number or to a change in network connectivity/topology induced by the Sb-enrichment.
► A decreasing program window, as well as threshold voltage, has been related to a decreasing energy gap in the amorphous phase of Ge–Sb–Te alloys with higher Sb concentration.
► A better performance in terms of the reset-to-set transition has been interpreted in the framework of the crystallization kinetics, invoking a growth-driven mechanism induced by a higher Sb concentration.