Method for storing data in a nonvolatile memory
AssigneeSTMicroelectronics S.r.l.
InventorsMarco Pasotti, Guido De Sandre, Giovanni Guaitini, David Iezzi, Marco Poles, PierLuigi Rolandi
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Abstract
Described herein is a method for storing a datum in a first and a second memory cells of a nonvolatile memory. The storage method envisages programming the first and second memory cells in a differential way, by setting a first threshold voltage in the first memory cell and a second threshold voltage different from the first threshold voltage in the second memory cell, the difference between the threshold voltages of the two memory cells representing a datum stored in the memory cells themselves.
Claims30
A method for storing data in a nonvolatile memory array having first and second memory cells, comprising:
- programming said first and second memory cells of the memory array in a differential way, wherein said step of programming said first and second memory cells in a differential way comprises:
- setting a first threshold voltage in said first memory cell;
- and
- setting a second threshold voltage different from said first threshold voltage in said second memory cell;
- the difference between the threshold voltages of said first and second memory cells representing a datum stored in the first and second memory cells.
A method for storing data in a nonvolatile memory having first and second memory cells, comprising:
- programming said first and second memory cells in a differential way, wherein said step of programming said first and second memory cells in a differential way includes:
- setting a first threshold voltage in said first memory cell, and
- setting a second threshold voltage different from said first threshold voltage in said second memory cell, the difference between the threshold voltages of said first and second memory cells representing a datum stored in the first and second memory cells;
- and
- re-programming one of said first and second memory cells to store a new datum, wherein said step of re-programming one of said first and second memory cells includes the steps of:
- identifying, between said first and second memory cells, the memory cell having a voltage satisfying a first relation with respect to the threshold voltage of the other memory cell, and
- varying the threshold voltage of the memory cell identified in such a way that it satisfies a second relation, different from said first relation, with respect to the threshold voltage of the other memory cell.
A nonvolatile memory, comprising:
- at least a first and a second memory cells;
- and
- storage means for storing data in said first and second memory cells, including programming means for programming said first and second memory cells in a differential way, the programming means including means for selectively changing a threshold voltage of either the first or second memory cell as required to establish a difference in threshold voltages of the first and second memory cell, the difference representing a selected datum.
A method, comprising:
- addressing first and second memory cells associated with a single datum;
- comparing a threshold voltage of the first memory cell to a threshold voltage of the second memory cell;
- and
- wherein a difference between the threshold voltages of the first and second memory cells represents a datum stored in the first and second memory cells.
A method comprising:
- addressing first and second memory cells of a memory array for storage of a datum;
- and
- charging the first and second memory cells differentially as a way of storing the datum.
A memory device comprising:
- first and second memory cells;
- a programming circuit configured to increase a threshold voltage of the first and second memory cells;
- and
- a comparator circuit configured to compare the threshold voltages of the first and second memory cells, and to output a datum based upon the difference of the threshold voltages of the first and second memory cells.
Dependencies are inferred from the claim text.