Methods and apparatus utilizing expected coupling effect in the programming of memory cells
AssigneeMicron Technology, Inc.
InventorsFrankie F. Roohparvar, Vishal Sarin
Life of this patent
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Abstract
Methods and memory devices configured to utilize predicted coupling effects of neighboring memory cells in the programming of target memory cells can be utilized to tighten the distribution of threshold voltages for a given bit pattern by compensating for anticipated threshold voltage shift due to capacitive coupling, which can facilitate more discernable Vt ranges, and thus a higher number of bits of data per memory cell. Tightening the distribution of threshold voltages can further facilitate wider margins between Vt ranges, and thus an increased reliability in reading the correct data value of a memory cell.
Claims20
A method of programming a target memory cell in an array of memory cells, comprising:
- determining an expected coupling effect of one or more neighboring memory cells on the target memory cell;
- and
- programming the target memory cell to a target threshold voltage that has been adjusted from a desired threshold voltage at least partially in response to the expected coupling effect;
- wherein determining the expected coupling effect of the one or more neighboring memory cells comprises determining individual expected coupling effects of each of the one or more neighboring memory cells and summing them.
A method of programming a target memory cell in an array of memory cells, comprising:
- determining an expected coupling effect of one or more neighboring memory cells on the target memory cell;
- and
- programming the target memory cell to a target threshold voltage that has been adjusted from a desired threshold voltage at least partially in response to the expected coupling effect;
- wherein programming the target memory cell to the target threshold voltage comprises:
- storing an analog data signal or an equivalent bit pattern at the memory device indicative of the target threshold voltage;
- applying programming pulses to the target memory cell to increase a threshold voltage of the target memory cell;
- determining whether the threshold voltage of the target memory cell has reached the target threshold voltage;
- and
- re-applying programming pulses to the target memory cell if its threshold voltage is less than the target threshold voltage.
A method of programming a target memory cell in an array of memory cells, comprising:
- determining an expected coupling effect of one or more neighboring memory cells on the target memory cell;
- and
- programming the target memory cell to a target threshold voltage that has been adjusted from a desired threshold voltage at least partially in response to the expected coupling effect;
- wherein determining the expected coupling effect of the one or more neighboring memory cells comprises reading threshold voltages of the one or more neighboring memory cells, determining a difference between a desired threshold voltage and the read threshold voltage for each of the one or more neighboring memory cells, multiplying the difference of each of the one or more neighboring memory cells with a corresponding coupling coefficient, and summing the products of the difference and the coupling coefficient corresponding to each of the one or more neighboring memory cells.
A method of programming a target memory cell in an array of memory cells, comprising:
- determining an expected coupling effect of one or more neighboring memory cells on the target memory cell;
- and
- programming the target memory cell to a target threshold voltage that has been adjusted from a desired threshold voltage at least partially in response to the expected coupling effect;
- wherein determining the expected coupling effect of the one or more neighboring memory cells comprises programming memory cells of the array and observing changes in threshold voltages of neighboring memory cells, and statistically analyzing the observed changes to develop expected changes based on various data values of neighboring memory cells.
A method of programming a target memory cell in an array of memory cells, comprising:
- determining an expected coupling effect of one or more neighboring memory cells on the target memory cell using an iterative process;
- and
- programming the target memory cell to a target threshold voltage that has been adjusted from a desired threshold voltage at least partially in response to the expected coupling effect.
A memory device, comprising:
- an array of memory cells;
- circuitry for access of the array of memory cells;
- wherein the circuitry for access is configured to perform a method of programming a target memory cell comprising determining an expected coupling effect of one or more neighboring memory cells on the target memory cell, and programming the target memory cell to a target threshold voltage that has been adjusted from a desired threshold voltage at least partially in response to the expected coupling effect;
- wherein determining the expected coupling effect of the one or more neighboring memory cells comprises determining individual expected coupling effects of each of the one or more neighboring memory cells and summing them.
A memory device, comprising:
- an array of memory cells;
- circuitry for access of the array of memory cells;
- wherein the circuitry for access is configured to perform a method of programming a target memory cell comprising determining an expected coupling effect of one or more neighboring memory cells on the target memory cell using an iterative process, and programming the target memory cell to a target threshold voltage that has been adjusted from a desired threshold voltage at least partially in response to the expected coupling effect.
Dependencies are inferred from the claim text.