Temperature acceleration of structural relaxation in amorphous Ge2Sb2Te5

Abstract

The structural relaxation (SR) process in an amorphous chalcogenide material (Ge2Sb2Te5) is studied by electrical measurements on phase-change memory devices. SR induces a change in the conduction regime from Poole to Poole–Frenkel transport, evidencing a temperature accelerated defect-annihilation process. Based on an Arrhenius kinetics with distributed activation energies, a temperature-acceleration law is shown, relating the time to reach a specific relaxed state to the temperature during isothermal experiments. This law is demonstrated comparing the time evolution of resistance for different temperatures. These results allow for a significant time reduction in reliability testing of devices and materials affected by SR.

Direct observations of Ge2Sb2Te5 recording marks in the phase-change disk

“…Since the data stability of phase-change devices relies on such physical properties, to describe the nature of structural relaxation is an important issue. Ielmini et al [19][20][21] examined the structural relaxation of the amorphous Ge 2 Sb 2 Te 5 by electrical measurements and suggested that the structural relaxation originates from the defect annihilation with a decrease in the concentration of localized states associated with structural disorder. Also, the development of the medium-range order in phase-change materials such as Ge 2 Sb 2 Te 5 ͑Ref.…”

Impact of DoS changes on resistance drift and threshold switching in amorphous phase change materials

“…From previous publications [8][9][10] it is well known that the temporal dependence of the resistance drift in phase change memory devices can be described by a power law, R(t)=R 0 ⋅ (t/t 0 ) ν , with R 0 = R(t 0 ), the resistance at an arbitrary time t 0 and ν an empirical materials parameter. In thin films, however, the amorphous-as-deposited material has already undergone drift after deposition, prior to the beginning of the measurement.…”

Role of activation energy in resistance drift of amorphous phase change materials

“…In contrast to many other works [16,25,28,39,40], the resistance is measured directly during annealing in all the experiments performed within this work.…”