Critical Quenching Speed Determining Phase of Ge2Sb2Te5 in Phase--Change Memory

During the phase-change process of Ge
₂
Sb
₂
Te
₅
in PRAM (Phase--hange Random Access Memory), phase-change dynamics are strongly dependent on the quenching speed, i.e. the cooling speed of melted phase--change material. Here we report the relation between quenching speed of programming pulse and phases of Ge
₂
Sb
₂
Te
₅
in phase--change memory in detail. The existence of critical quenching speed is identified, which determines amorphous and crystalline phases in melting followed by quenching operation.