Non-volatile memory device and read method thereof

• US 8,576,622 B2
• Filed: 08/30/2011
• Issued: 11/05/2013
• Est. Priority Date: 11/25/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yoon, Sangyong, Park, Ki-tae, Son, Hongrak
• Primary Examiner(s): LE, THONG QUOC
• Application Number:
  US13/221,162
• Publication Number:
  US 20120134207A1
• Time in Patent Office: 798 Days
• Field of Search: 365/185.03, 365/185.18, 365/189.04, 365/219.12, 365/185.09
• US Class Current: 365/185.03
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 11/5678 using amorphous/crystalline phase transition storage elements
• CPC Class Codes: G11C 11/5685 using storage elements comprising metal oxide memory material, e.g. perovskites
• CPC Class Codes: G11C 13/0004 comprising amorphous/crystalline phase transition cells
• CPC Class Codes: G11C 13/0007 comprising metal oxide memory material, e.g. perovskites
• CPC Class Codes: G11C 13/004 Reading or sensing circuits or methods
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits

Abstract

In one embodiment, the method for reading memory cells in an array of non-volatile memory cells includes reading data from a memory cell using a set of hard decision voltages and at least a first set of soft decision voltages based on a single read command.

Claims

1. A method for reading memory cells in an array of non-volatile memory cells, the method comprising:

reading data from a memory cell using a set of hard decision voltages and at least a first set of soft decision voltages based on a single read command.

2. The method of claim 1, wherein the reading reads data from the memory cell using the set of hard decision voltages and at least the first set of soft decision voltages based on the single read command, an address and a resolution indicator, the resolution indicator indicating a number of sets of soft decision voltages.

3. The method of claim 2, wherein if the resolution indicator indicates two sets, the reading reads data from the memory cell using the set of hard decision voltages, the first set of soft decision voltages, and a second set of soft decision voltages.

4. The method of claim 3, wherein a number of soft decision voltages in the second set is greater than in the first set.

5. The method of claim 1, further comprising:

outputting first read results based on the hard decision voltages in response to a first read out command.

6. The method of claim 5, further comprising:

outputting second read results based on the first set of soft decision voltage in response to a second read out command.

7. The method of claim 6, wherein

the reading reads data from the memory cell using the set of hard decision voltages, using the first set of soft decision voltages and using a second set of soft decision voltages in response to the read command;

and further including,

outputting third read results based on the second set of soft decision voltages in response to a third read out command.

8. The method of claim 7, wherein

the outputting second read results outputs a single soft bit for each hard bit output in the outputting first read results;

and

the outputting third read results outputs a single soft bit for each hard bit output in the outputting first read results.

9. The method of claim 5, wherein the outputting second read results outputs a single soft bit for each hard bit output in the outputting first read results.

10. The method of claim 7, wherein the reading step sequentially performs reading data based on the set of hard decision voltages, the first set of soft decision voltages and the second set of soft decision voltages in response to the read command.

11. The method of claim 1, wherein the reading step sequentially performs reading data based on the set of hard decision voltages and the first set of soft decision voltages in response to the read command.

12. The method of claim 7, wherein the reading step comprises:

reading data from the memory cell using the set of hard decision voltages after receipt of the read command;

reading data from the memory cell using the first set of soft decision voltages after receiving the first read out command; and

reading data from the memory cell using the second set of soft decision voltages after receiving the second read out command.

13. The method of claim 5, wherein the reading step comprises:

reading data from the memory cell using the set of hard decision voltages after receipt of the read command; and

reading data from the memory cell using the first set of soft decision voltages after receiving the first read out command.

14. The method of claim 1, wherein the reading step comprises:

reading data from the memory cell using the set of hard decision voltages after receipt of the read command; and

reading data from the memory cell using the first set of soft decision voltages after outputting data read using the set of hard decision voltages.

15. The method of claim 7, wherein the reading comprises:

reading data based on the first set of soft decision voltages in parallel with the outputting first read results; and

reading data based on the second set of soft decision voltages in parallel with the outputting second read results.

16. The method of claim 5, wherein the reading comprises:

reading data based on the first set of soft decision voltages in parallel with the outputting first read results.

17. The method of claim 1, wherein the memory cells are multi-level memory cells.

18. A method for reading memory cells in an array of non-volatile memory cells, the method comprising:

sending a read command;

sending a first read out command;

receiving first read results in response to the first read out command, the first read results being based on a read operation using a set of hard decision voltages;

first determining if errors in the first read results are correctable;

sending a second read out command without sending an associated read command if the first determining determines errors in the first read results are not correctable; and

receiving second read results in response to the second read out command, the second read results being based on a read operation using a first set of soft decision voltages.

19. The method of claim 18, wherein the second read out command is not sent if the first determining determines that errors in the first read results are correctable.

20. The method of claim 18, further comprising:

sending a read resolution in association with the read command, the read resolution indicating a number of soft read operations to perform in conjunction with a hard read operation, the hard read operation being performed based on the set of hard decision voltages, and each soft read operation being performed based on different set of soft decision voltages.

21. The method of claim 20, wherein if the read resolution indicates two soft read operations, the method further comprises:

second determining if errors in the second read results are correctable;

sending a third read out command without sending an associated read command if the second determining determines errors in the second read results are not correctable; and

receiving third read results in response to the third read command, the third read results being based on a read operation using a second set of soft decision voltages.

22. The method of claim 21, the third read out command is not sent if the second determining determines that errors in the first read results are correctable.

23. The method of claim 21, further comprising:

third determining if errors in the second read results are correctable.

24. The method of claim 18, further comprising:

second determining if errors in the second read results are correctable;

sending a third read out command without sending an associated read command if the second determining determines errors in the second read results are not correctable; and

receiving third read results in response to the third read command, the third read results being based on a read operation using a second set of soft decision voltages.

25. The method of claim 24, the third read out command is not sent if the second determining determines that errors in the first read results are correctable.

26. The method of claim 24, further comprising:

third determining if errors in the second read results are correctable.

27. The method of claim 24, wherein

the receiving second read results receives a single soft bit for each hard bit received in the receiving first read results;

and

the receiving third read results receives a single soft bit for each hard bit received in the receiving first read results.

28. The method of claim 18, wherein the receiving second read results receives a single soft bit for each hard bit received in the receiving first read results.

29. The method of claim 18, wherein the memory cells are multi-level memory cells.

30. A non-volatile multi-level memory device, comprising:

an array of non-volatile memory cells;

control logic configured to read data from a memory cell array using a set of hard decision voltages and at least a first set of soft decision voltages based on a single read command.

31. A data storage system, comprising:

the memory device of claim 30; and

a controller configured to supply the read command.

32. An electronic device comprising:

the memory device of claim 30; and

a controller, the controller including an error correction coding unit configured to error correct read results output from the memory device, and the controller including a processor configured to supply the read command.

33. A computing system, comprising:

a processor;

a memory system, the memory system including the memory device of claim 30 and a controller configured to supply the read command; and

a bus communicatively coupling the processor and the memory system.