Erase page check
First Claim
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1. A method performed by a NAND memory device, the method comprising:
- identifying a NAND memory cell of the memory device to test for an incomplete programming, the memory cell configured as a multi-level cell;
shifting a read voltage used to read a first portion of the memory cell a predetermined magnitude toward zero, the read voltage for the first portion having a lowest read voltage of a plurality of read voltages used to read other portions of the memory cell;
reading a value in the first portion of the memory cell using the shifted read voltage;
determining that the memory cell was incompletely programmed based upon the value;
in response to determining that the memory cell was incompletely programmed, mark the memory cell as incompletely programmed; and
wherein shifting the read voltage and reading the value is a user-mode read operation.
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Abstract
Disclosed in some examples are methods, systems, memory devices, and machine readable mediums for performing an erase page check. For example, in response to an unexpected (e.g., an asynchronous) shutdown, the memory device may have one or more cells that did not finish programming. The memory device may detect these cells and erase them or mark them for erasure.
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Citations
20 Claims
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1. A method performed by a NAND memory device, the method comprising:
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identifying a NAND memory cell of the memory device to test for an incomplete programming, the memory cell configured as a multi-level cell; shifting a read voltage used to read a first portion of the memory cell a predetermined magnitude toward zero, the read voltage for the first portion having a lowest read voltage of a plurality of read voltages used to read other portions of the memory cell; reading a value in the first portion of the memory cell using the shifted read voltage; determining that the memory cell was incompletely programmed based upon the value; in response to determining that the memory cell was incompletely programmed, mark the memory cell as incompletely programmed; and wherein shifting the read voltage and reading the value is a user-mode read operation. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A memory device comprising:
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a plurality of NAND memory cells; and a controller, the controller configured to perform operations comprising; identifying a first NAND memory cell of the plurality of NAND memory cells to test for an incomplete programming, the first memory cell configured as a multi-level cell; shifting a read voltage used to read a first portion of the first memory cell a predetermined magnitude toward zero, the read voltage for the first portion having a lowest read voltage of a plurality of read voltages used to read other portions of the first memory cell; reading a value in the first portion of the first memory cell using the shifted read voltage; determining that the memory cell was incompletely programmed based upon the value; in response to determining that the memory cell was incompletely programmed, mark the memory cell as incompletely programmed; and wherein shifting the read voltage and reading the value is a user-mode read operation. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method performed by a NAND device, the method comprising:
testing a NAND memory cell of the memory device for an error caused by interrupting a programming of the NAND memory cell by an asynchronous power loss, the testing comprising; reading the NAND memory cell in a user mode with a first voltage level, the first voltage level being a second voltage level shifted an amount towards a zero voltage level, the second voltage level being a lowest voltage level of a plurality of voltage levels used in a normal read operation on the memory cell; determining, based upon a value read with the first voltage level, that the cell was incompletely programmed; and marking the memory cell as incompletely programmed. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
Specification