| 摘要 |
A multi-level cell (MLC) phase-change memory device divides data into data groups each comprising multiple bits of data, and stores each of the data groups in a selected phase-change memory cell. A data group is stored in a selected phase-change memory cell by applying a pulse current to the selected phase-change memory cell with a pulse current characteristic corresponding to a data value of the data group. The pulse current characteristic can comprise, for instance, a magnitude, downward slope, or duration of the pulse current. Data is read from a selected phase-change memory cell by sensing a voltage of a bitline connected to the selected phase-change memory cell and comparing the sensed voltage simultaneously with a plurality of reference voltages. |
