Charge retention for flash memory by manipulating the program data methodology
AssigneeSpansion LLC
InventorsSheau-Yang Ch'ng, Mee-Choo Ong, Kian-Huat Hoo
Life of this patent
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Abstract
A method, system and apparatus for determining whether any un-programmed cell is affected by charge disturb by comparing the voltage threshold of the un-programmed cells against a reference voltage. If the voltage threshold for the un-programmed cell exceeds the reference voltage, the failed or defective un-programmed cell will be then be programmed. This will change the defective un-programmed cell to a new programmed value. To account for the location of the failing memory cell, address syndrome bits are used to identify the location of the defective memory cell.
Claims20
A method in a multi-cell memory device, comprising:
- reading a voltage threshold of a cell in an un-programmed state from the multi-cell memory device;
- programming the cell when the voltage threshold of the cell exceeds a reference voltage;
- and
- writing address syndrome data in association with the programming of the cell.
A flash device comprising:
- a plurality of multi-cell memory devices forming a memory array;
- and
- a controller coupled to the plurality of multi-cell memory devices and operative to enable actions including:
- reading a voltage threshold of a cell in an un-programmed state from the multi-cell memory device;
- programming the cell when the voltage threshold of the cell exceeds a reference voltage;
- and
- writing address syndrome data in association with the programming of the cell.
A system for storing information comprising:
- a memory array having a plurality of multi-cell memory devices;
- and
- a controller coupled to the memory array and operative to enable actions including:
- determining a reference voltage that is greater than a range of voltage thresholds within which a cell is in an un-programmed state, which range is used during a read operation to determine whether the cell is in the un-programmed or programmed state;
- reading a voltage threshold of the cell, which cell has been set to be in the un-programmed state;
- programming the cell when the voltage threshold of the un-programmed cell exceeds the reference voltage;
- and
- writing address syndrome data in association with the programming of the cell.
Dependencies are inferred from the claim text.