Method of equalizing bit error rates of memory device
Provided is a bit error rate equalizing method of a memory device. The memory device selectively performs an error correction code (ECC) interleaving operation according to resistance distribution characteristics of memory cells, when writing a codeword including information data and a parity bit of the information data to a memory cell array. In the ECC interleaving operation according to one example, an ECC sector including information data is divided into a first ECC sub-sector and a second ECC sub-sector, the first ECC sub-sector is written to memory cells of a first memory area having a high bit error rate (BER), and the second ECC sub-sector is written to memory cells of a second memory area having a low BER.
1. A memory system comprising:
a memory device including a control circuit and a memory cell array that includes a plurality of memory cells disposed at intersections between a plurality of word lines and a plurality of bit lines; and
a memory controller configured to control the memory device and including an error correction code (ECC) circuit that is configured to perform an ECC encoding on write data and an ECC decoding on read data,
wherein the ECC circuit is configured to perform the ECC encoding on the write data to generate a codeword including a first sector and a second sector, and to provide the codeword to the memory device,
wherein the control circuit is configured to perform an ECC interleaving operation on the codeword such that the first sector is written to a first portion of the memory cell array and the second sector is written to a second portion of the memory cell array,
wherein the first portion of the memory cell array has a first bit error rate (BER) and the second portion of the memory cell array has a second bit error rate (BER) that is lower than the first BER,
wherein the memory device is a resistive random access memory (RRAM), a magnetoresistive random access memory (MRAM) or a phase-change random access memory (PRAM),
wherein the plurality of memory cells are resistive type memory cells,
wherein each of the plurality of memory cells includes a variable resistor including an upper electrode, a lower electrode and a dielectric between the upper electrode and the lower electrode,
wherein the memory cell array includes a plurality of memory tiles including a first tile and a second tile, and
wherein the first portion of the memory cell array includes opposite edge portions of the first tile and the second tile, and the second portion of the memory cell array includes portions of the first tile and the second tile respectively between the opposite edge portions of the first tile and the second tile.
2. The memory system of claim 1 , wherein the first portion of the memory cell array includes a first portion of the plurality of memory cells connected to a first word line among the plurality of word lines and a second portion of the plurality of memory cells connected to a second word line among the plurality of word lines.
3. The memory system of claim 1 , wherein the ECC interleaving operation includes at least one of a word line interleaving operation, a bank interleaving operation, a bit line interleaving operation, a convolution interleaving operation, a stack layer interleaving operation and a chip interleaving operation.
4. The memory system of claim 1 , wherein a BER of first data written to the first portion of the memory cell array and a BER of second data written to the second portion of the memory cell array are equalized.
5. The memory system of claim 1 , wherein the plurality of memory cells are PRAM type memory cells, and the variable resistor of each of the plurality of PRAM type memory cells is formed of a phase change material.
6. The memory system of claim 1 , wherein the plurality of memory cells are MRAM type memory cells, the variable resistor of each of the plurality of MRAM type memory cells includes a transition metal oxide, and the upper electrode and the lower electrode are magnetic.
7. The memory system of claim 1 ,
wherein the memory cell array includes a plurality of memory tiles including a first tile and a second tile, and
wherein when the control circuit performs a word line interleaving operation on the first tile and the second tile, the control circuit changes a word line addressing of at least one of the first tile and the second tile.
8. The memory system of claim 7 , wherein the first sector and the second sector are written to different relative locations within the plurality of memory tiles.
9. A memory device comprising:
a memory cell array including a plurality of memory cells disposed at intersections between a plurality of word lines and a plurality of bit lines;
an error correction code (ECC) circuit configured to perform an ECC encoding on write data to generate a codeword including a first sector and a second sector, and to provide the codeword to the memory cell array; and
a control circuit configured to perform an ECC interleaving operation on the codeword such that the first sector is written to a first portion of the memory cell array and the second sector is written to a second portion of the memory cell array,
wherein the first portion of the memory cell array has a first bit error rate (BER),
wherein the second portion of the memory cell array has a second bit error rate (BER) that is lower than the first BER,
wherein the memory device is a resistive random access memory (RRAM), a magnetoresistive random access memory (MRAM) or a phase-change random access memory (PRAM),
wherein the plurality of memory cells are resistive type memory cells,
wherein each of the plurality of memory cells includes a variable resistor including an upper electrode, a lower electrode and a dielectric between the upper electrode and the lower electrode,
wherein the memory cell array includes a plurality of memory tiles including a first tile and a second tile, and
wherein the first portion of the memory cell array includes opposite edge portions of the first tile and the second tile, and the second portion of the memory cell array includes portions of the first tile and the second tile respectively between the opposite edge portions of the first tile and the second tile.
10. The memory device of claim 9 , wherein a BER of first data written to the first portion of the memory cell array and a BER of second data written to the second portion of the memory cell array are equalized.
11. The memory device of claim 9 , wherein the first portion of the memory cell array includes a first portion of the plurality of memory cells connected to a first word line among the plurality of word lines and a second portion of the memory cells connected to a second word line among the plurality of word lines.
12. The memory device of claim 9 ,
wherein the memory cell array includes a plurality of memory tiles including a first tile and a second tile,
wherein when the control circuit performs a word line interleaving operation on the first tile and the second tile, the control circuit changes a word line addressing of at least one of the first tile and the second tile, and
wherein the first sector and the second sector are written to different relative locations within the plurality of memory tiles.
13. The memory device of claim 12 , wherein the first sector and the second sector are written to different relative locations within the plurality of memory tiles.
14. The memory device of claim 9 ,
wherein the plurality of memory cells are MRAM type memory cells, and
wherein upper electrode and lower electrode are magnetic.
15. A memory system comprising:
a memory device including a control circuit and a memory cell array including a plurality of memory cells disposed at intersections between a plurality of word lines and a plurality of bit lines, the plurality of memory cells being arranged in a plurality of memory tiles including a first tile and a second tile; and
a memory controller configured to control the memory device and including an error correction code (ECC) circuit that is configured to perform an ECC encoding on write data and an ECC decoding on read data,
wherein the ECC circuit is configured to perform the ECC encoding on the write data to generate a codeword including a first sector and a second sector, and to provide the codeword to the memory device,
wherein the control circuit is configured to perform an ECC interleaving operation on the codeword such that the first sector is written to a first portion of the memory cell array and the second sector is written to a second portion of the memory cell array,
wherein the first portion of the memory cell array has a first bit error rate (BER) and the second portion of the memory cell array has a second bit error rate (BER) that is lower than the first BER,
wherein when the control circuit performs a word line interleaving operation on the first tile and the second tile, the control circuit changes a word line addressing of at least one of the first tile and the second tile,
wherein the memory device is a resistive random access memory (RRAM), a magnetoresistive random access memory (MRAM) or a phase-change random access memory (PRAM),
wherein the plurality of memory cells are resistive type memory cells,
wherein each of the plurality of memory cells includes a variable resistor including an upper electrode, a lower electrode and a dielectric between the upper electrode and the lower electrode, and
wherein the first portion of the memory cell array includes opposite edge portions of the first tile and the second tile, and the second portion of the memory cell array includes portions of the first tile and the second tile respectively between the opposite edge portions of the first tile and the second tile.
16. The memory system of claim 15 , wherein a BER of first data written to the first portion of the memory cell array and a BER of second data written to the second portion of the memory cell array are equalized.
17. The memory system of claim 15 , wherein the first sector and the second sector are written to different relative locations within the plurality of memory tiles.
18. The memory system of claim 15 , wherein the ECC interleaving operation includes at least one of a word line interleaving operation, a bank interleaving operation, a bit line interleaving operation, a convolution interleaving operation, a stack layer interleaving operation and a chip interleaving operation.