Patent ID: 7781753

Claim:
A multi-value recording phase-change memory device comprising: a first electrode layer and a second electrode layer, both formed spaced apart from each other on an insulating layer formed on a substrate; and a memory layer formed between said first and second electrode layers on said insulating layer and containing a phase-change material layer formed from a phase-change material which is stable in either an amorphous phase or a crystalline phase at room temperature, wherein said memory layer includes a plurality of mutually isolated sub-memory layers between said first and second electrode layers on said insulating layer, each of said sub-memory layers having a same thickness on said insulating layer and made of the same phase-change material; and at least one of a width of each of said plurality of sub-memory layers or a length of each of said plurality of sub-memory layers between said first and second electrodes differs from each other among said plurality of sub-memory layers.