Non-volatile memory device and erase method of the same
First Claim
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1. An erase method of a non-volatile memory device including memory cells arranged in a matrix of rows and columns, the erase method comprising:
- erasing the memory cells at the same time; and
performing an erase-verify operation for the erased memory cells, wherein the erase-verify operation is repeated under different bias conditions of the rows, wherein the erase-verify operation includes a first erase-verify operation and a second erase-verify operation which are sequentially performed, and wherein the first erase-verify operation is performed under a first bias condition in which a first read voltage is applied to a first part of the rows and a second read voltage is applied to another part of the rows.
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Abstract
An erase method of a non-volatile memory device including memory cells arranged in a matrix of rows and columns. The memory cells are erased at the same time. An erase-verify operation is performed for the erased memory cells. The erase method is repeated under different bias conditions of the rows. An erase-verify operation is successively performed twice or more under different bias conditions of wordlines to decrease cell current caused by a weak cell which may be produced in a process. Thus, a reliability of an erase-verify operation is enhance to increase a yield.
50 Citations
31 Claims
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1. An erase method of a non-volatile memory device including memory cells arranged in a matrix of rows and columns, the erase method comprising:
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erasing the memory cells at the same time; and performing an erase-verify operation for the erased memory cells, wherein the erase-verify operation is repeated under different bias conditions of the rows, wherein the erase-verify operation includes a first erase-verify operation and a second erase-verify operation which are sequentially performed, and wherein the first erase-verify operation is performed under a first bias condition in which a first read voltage is applied to a first part of the rows and a second read voltage is applied to another part of the rows. - View Dependent Claims (2, 3)
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4. An erase method of a non-volatile memory device including memory cells arranged in a matrix of rows and columns, the erase method comprising:
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erasing the memory cells at the same time; and performing an erase-verify operation for the erased memory cells, wherein the erase-verify operation is repeated under different bias conditions of the rows, wherein the erase-verify operation includes a first erase-verify operation and a second erase-verify operation which are sequentially performed, wherein the erasing the memory cells and the performing an erase-verify operation are repeated within a number of predetermined erase cycles according to results of the first and the second erase-verify operation. - View Dependent Claims (5, 6)
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7. An erase method of a non-volatile memory device including memory cells arranged in a matrix of rows and columns, the erase method comprising:
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erasing the memory cells at the same time; and performing an erase-verify operation for the erased memory cells, wherein the erase-verify operation is repeated under different bias conditions of the rows, wherein the non-volatile memory device is a NAND flash memory device.
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8. An erase method of a non-volatile memory device including a plurality of cell strings each having a first select transistor connected to a string select line, a second select transistor connected to a ground select line, and memory cells being serially coupled between the first and the second select transistors, and each being connected to corresponding wordlines, the erase method comprising:
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erasing the memory cells at the same time; performing a first erase-verify operation while a first read voltage is applied to a part of the wordlines and a second read voltage higher than the first read voltage is applied to another part of the wordlines; and performing a second erase-verify operation while the second read voltage is applied to the part of the wordlines and the first read voltage is applied to the another part of the wordlines. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An erase method of a non-volatile memory device including a plurality of cell strings each having a first select transistor connected to a string select line, a second select transistor connected to a ground select line, and memory cells being serially coupled between the first and the second select transistors, and each being connected to corresponding wordlines, the erase method comprising:
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performing a first erase-verify operation while a first read voltage is applied to first ones of the wordlines and a second read voltage higher than the first read voltage is applied to second ones of the wordlines; performing a second erase-verify operation while the second read voltage is applied to the first ones of the wordlines and the first read voltage is applied to the second ones of the wordlines; and judging an erase operation of the memory cells according to results of the first and the second erase-verify operations. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A non-volatile memory device comprising:
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a string select line connected to a string select transistor; a ground select line connected to a ground select transistor; wordlines connected to memory cells and divided into at least two groups; a row decoder circuit configured to control the wordlines and the string select line and the ground select line; and an erase controller to control the row decoder circuit so that the wordlines of a first group of the wordlines are set to a different bias condition than the wordlines of a second group of the wordlines, in respective first and second erase-verify operations. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. An erase method of a non-volatile memory device including a plurality of cell strings each having a first select transistor connected to a string select line, a second select transistor connected to a ground select line, and memory cells being connected in series between the first and the second select transistors, and each being connected to corresponding wordlines, the erase method comprising:
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applying a first voltage to a gate of the first select transistor; applying the first voltage to a gate of the second select transistor; supplying a sensing current to a drain of the first select transistor; and applying a second voltage higher than 0V to respective control gates of the memory cells. - View Dependent Claims (28, 29)
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30. An erase method of a non-volatile memory device including memory cells arranged in a matrix of rows and columns, the erase method comprising:
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erasing the memory cells at the same time; and performing an erase-verify operation for the erased memory cells, wherein a higher voltage than 0V is applied to each of the rows during the erase-verify operation. - View Dependent Claims (31)
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Specification