Read operation for NAND memory
AssigneeMicron Technology, Inc.
InventorsSeiichi Aritome, Akira Goda
Life of this patent
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Abstract
Non-volatile memory devices utilizing a NAND architecture are adapted to perform read operations where a first potential is supplied to a source line selectively coupled to a bit line through a string of series-coupled non-volatile memory cells containing a memory cell targeted for reading, and where a second, different, potential is supplied to other source lines selectively coupled to the bit line through other strings of series-coupled non-volatile memory cells not containing the target memory cell. Supplying a different potential to the other source lines facilitates mitigation of current leakage between the other source lines and the bit line while sensing a data value of the target memory cell.
Claims24
A method of reading a target memory cell of a non-volatile memory device having two or more strings of series-coupled non-volatile memory cells, the method comprising:
- applying a first potential to a first line selectively coupled to a string of series-coupled non-volatile memory cells containing the target memory cell;
- applying a second potential to a second line selectively coupled to the first line through the string of series-coupled non-volatile memory cells containing the target memory cell;
- applying a third potential to one or more third lines selectively coupled to the first line through one or more other strings of series-coupled non-volatile memory cells not containing the target memory cell, wherein the third potential has a value different than the second potential;
- and
- sensing a level of current flow between the first line and the second line to determine a data value of the target memory cell.
A method of reading a target memory cell of a non-volatile memory device having two or more strings of series-coupled non-volatile memory cells, the method comprising:
- precharging, to a first potential, a first line selectively coupled to a string of series-coupled non-volatile memory cells containing the target memory cell;
- applying a second potential to a second line selectively coupled to the first line through the string of series-coupled non-volatile memory cells containing the target memory cell;
- precharging, to a third potential, one or more third lines selectively coupled to the first line through one or more other strings of series-coupled non-volatile memory cells not containing the target memory cell, wherein the third potential has a level greater than a level of the second potential and less than or equal to a level of the first potential;
- and
- sensing a change in voltage level of the first line to determine a data value of the target memory cell.
A method of reading a target memory cell of a non-volatile memory device having two or more strings of series-coupled non-volatile memory cells, the method comprising:
- applying a first potential to a first line that is coupled to a source of a first select gate of one or more first select gates, wherein the one or more first select gates are coupled in series between a first string of series-coupled non-volatile memory cells containing the target memory cell and the first line, and wherein one non-volatile memory cell of the first string of series-coupled non-volatile memory cells is coupled to a drain of one of the first select gates;
- applying a second potential to a second line that is coupled to a drain of a second select gate of one or more second select gates, wherein the one or more second select gates are coupled in series between the first string of series-coupled non-volatile memory cells and the second line, and wherein one non-volatile memory cell of the first string of series-coupled non-volatile memory cells is coupled to a source of one of the second select gates;
- applying a third potential to one or more third lines selectively coupled to the first line through one or more second strings of series-coupled non-volatile memory cells and not selectively coupled to the first string of series-coupled non-volatile memory cells, wherein the third potential has a value different than the second potential;
- and
- sensing a level of current flow through the first string of series-coupled non-volatile memory cells to determine a data value of the target memory cell.
Dependencies are inferred from the claim text.