Low-field amorphous state resistance and threshold voltage drift in chalcogenide materials

A detailed investigation of the time evolution for the low-field resistance R/sub off/ and the threshold voltage V/sub th/ in chalcogenide-based phase-change memory devices is presented. It is observed that both R/sub off/ and V/sub th/ increase and become stable with time and temperature, thus improving the cell readout window. Relying on a microscopic model, the drift of R/sub off/ and V/sub th/ is linked to the dynamic of the intrinsic traps typical of amorphous chalcogenides, thus providing for the first time a unified framework for the comprehension of chalcogenide materials transient behavior.