Phase change heterostructure, and phase change memory device including the same

A phase change memory device comprising:

• a plurality of memory cells,
• each of the plurality of memory cells including a first electrode, a second electrode spaced apart from the first electrode, and a phase change heterostructure between the first electrode and the second electrode,
• the phase change heterostructure including a plurality of phase change material layers and a plurality of thermal barrier layers alternately stacked on each other,
• wherein a thermal conductivity of a material of the plurality of thermal barrier layers is lower than a thermal conductivity of a material of the plurality of phase change material layers, and
• wherein the plurality of phase change material layers and the plurality of thermal barrier layers are alternately stacked directly on each other so a corresponding one of the plurality of phase change material layers is directly connected to an overlying one of the plurality of thermal barrier layers and an underlying one of the plurality of thermal barrier layers.