Methods and control circuitry for programming memory cells
AssigneeMicron Technology, Inc.
InventorJune Lee
Life of this patent
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Abstract
Methods of programming memory cells and control circuitry for memory arrays facilitate a reduction of program disturb. A memory cell is shifted from a first data state to a second data state if it is desired to alter a first digit of a data value of the memory cell. If it is desired to alter a second digit of the data value of the memory cell, the memory cell is shifted to a third data state if the memory cell is in the first data state and shifted to a fourth data state if the memory cell is in the second data state. The first, second, third and fourth data states correspond to respective non-overlapping ranges of threshold voltages. The threshold voltages corresponding to the fourth data state are greater than the threshold voltages corresponding to the third data state.
Claims25
A method of programming a memory cell, the method comprising:
- if it is desired to alter a first digit of a data value of the memory cell, shifting the memory cell from a first data state to a second data state;
- and
- if it is desired to alter a second digit of the data value of the memory cell, shifting the memory cell to a third data state if the memory cell is in the first data state and shifting the memory cell to a fourth data state if the memory cell is in the second data state;
- wherein the first, second, third and fourth data states correspond to respective non-overlapping ranges of threshold voltages, and wherein the threshold voltages corresponding to the fourth data state are greater than the threshold voltages corresponding to the third data state.
A method of programming a plurality of memory cells of a memory array, the method comprising:
- for each memory cell of the plurality of memory cells for which it is desired to alter a first digit of a data value of those memory cells, shifting those memory cell from a first data state to a second data state;
- and
- for each memory cell of the plurality of memory cells for which it is desired to alter a second digit of the data value of those memory cells, shifting those memory cells to a third data state if those memory cells are in the first data state and shifting those memory cells to a fourth data state if those memory cells are in the second data state;
- wherein the first, second, third and fourth data states correspond to respective non-overlapping ranges of threshold voltages, and wherein the threshold voltages corresponding to the fourth data state are greater than the threshold voltages corresponding to the third data state;
- and
- wherein shifting a data state of a memory cell of the plurality of memory cells comprises performing a programming operation on the memory cells of the plurality of memory cells to change a threshold voltage of each memory cell being shifted from one data state to another.
A control circuitry for a memory array, wherein the control circuitry is configured to:
- shift a memory cell from a first data state to a second data state if it is desired to alter a first digit of a data value of the memory cell;
- and
- if it is desired to alter a second digit of the data value of the memory cell, shift the memory cell to a third data state if the memory cell is in the first data state and shift the memory cell to a fourth data state if the memory cell is in the second data state;
- wherein the first, second, third and fourth data states correspond to respective non-overlapping ranges of threshold voltages, and wherein the threshold voltages corresponding to the fourth data state are greater than the threshold voltages corresponding to the third data state.
Dependencies are inferred from the claim text.