Methods of programming memory devices
First Claim
1. A method of programming a three dimensional non-volatile memory device, the three dimensional non-volatile memory device including a plurality of memory cell strings, each cell string including a plurality of memory cells stacked serially in a direction perpendicular to a substrate, the method comprising:
- performing a first erase operation on first memory cells and a second erase operation on second memory cells disposed in a memory cell array, the first memory cells and the second memory cells being erased to a first erased state and a second erased state, respectively, the first erased state being higher in voltage level than the second erased state;
performing a single level cell (SLC) programming operation on the first memory cells, each of the first memory cells being programmed to one of two programmed states, each of the two programmed states being higher in voltage level than the first erased state and each having a different threshold voltage distribution; and
performing a multi-level cell (MLC) programming operation on the second memory cells, a first portion of the second memory cells remaining in the second erased state, a second portion of the second memory cells being programmed to one of at least three programmed states, each of the at least three programmed states being higher in voltage level than the second erased state and each having a different threshold voltage distribution,wherein a lowest programmed state of the first memory cells has a first threshold voltage distribution and the second erased state of the second memory cells has a second threshold voltage distribution, the first threshold voltage distribution being substantially positioned at positive voltage level while the second threshold voltage distribution is substantially positioned at negative voltage level.
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Abstract
Methods of operating non-volatile memory devices are provided including receiving program data and a program address. Memory cells that correspond to the program address are selected from among memory cells in an erased state. The selected memory cells are programmed based on the program data such that each of the selected memory cells is programmed to one of a plurality of programmed states, where threshold voltage distributions of the programmed states are different from each other and are higher than a threshold voltage distribution associated with the erased state. By programming all or a portion of the memory cells corresponding to the erased state to have positive threshold voltages, degradation of the data retention capability of the memory cells may be reduced.
23 Citations
20 Claims
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1. A method of programming a three dimensional non-volatile memory device, the three dimensional non-volatile memory device including a plurality of memory cell strings, each cell string including a plurality of memory cells stacked serially in a direction perpendicular to a substrate, the method comprising:
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performing a first erase operation on first memory cells and a second erase operation on second memory cells disposed in a memory cell array, the first memory cells and the second memory cells being erased to a first erased state and a second erased state, respectively, the first erased state being higher in voltage level than the second erased state; performing a single level cell (SLC) programming operation on the first memory cells, each of the first memory cells being programmed to one of two programmed states, each of the two programmed states being higher in voltage level than the first erased state and each having a different threshold voltage distribution; and performing a multi-level cell (MLC) programming operation on the second memory cells, a first portion of the second memory cells remaining in the second erased state, a second portion of the second memory cells being programmed to one of at least three programmed states, each of the at least three programmed states being higher in voltage level than the second erased state and each having a different threshold voltage distribution, wherein a lowest programmed state of the first memory cells has a first threshold voltage distribution and the second erased state of the second memory cells has a second threshold voltage distribution, the first threshold voltage distribution being substantially positioned at positive voltage level while the second threshold voltage distribution is substantially positioned at negative voltage level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of programming a non-volatile memory device, the method comprising:
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performing a first erase operation on first memory cells and a second erase operation on second memory cells disposed in a memory cell array, the first memory cells and the second memory cells being erased to a first erased state and a second erased state, respectively, the first erased state being higher in voltage level than the second erased state; performing a single level cell (SLC) programming operation on the first memory cells, each of the first memory cells being programmed to one of two programmed states, each of the two programmed states being higher in voltage level than the first erased state and each having a different threshold voltage distribution; and performing a multi-level cell (MLC) programming operation on the second memory cells, a first portion of the second memory cells remaining in the second erased state, a second portion of the second memory cells being programmed to one of at least three programmed states, each of the at least three programmed states being higher in voltage level than the second erased state and each having a different threshold voltage distribution, wherein a lowest programmed state of the first memory cells has a first threshold voltage distribution and the second erased state of the second memory cells has a second threshold voltage distribution, the first threshold voltage distribution is higher in voltage level than the second threshold voltage distribution. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification