METHODS OF DETECTING A SHIFT IN THE THRESHOLD VOLTAGE FOR A NONVOLATILE MEMORY CELL

• US 20100008151A1
• Filed: 06/30/2009
• Published: 01/14/2010
• Est. Priority Date: 07/09/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hwang, Sangwon
• Granted Patent: US 8,116,160 B2
• Time in Patent Office: Days
• US Class Current: 365/185.220
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits
• CPC Class Codes: G11C 16/3454 Arrangements for verifying correct programming or for detecting overprogrammed cells
• CPC Class Codes: G11C 16/3459 Circuits or methods to verify correct programming of nonvolatile memory cells
• CPC Class Codes: G11C 2211/5621 Multilevel programming verification
• CPC Class Codes: G11C 7/04 with means for avoiding disturbances due to temperature effects

Abstract

A nonvolatile memory device is operated by programming sample data in the memory device for verification using verify voltage levels derived from an ideal verify voltage Vv associated with a particular temperature range, performing read verify operations on the sample data using the verify voltage Vv associated with the temperature range; and determining a temperature compensation parameter Nc based on results of the read verify operations.

Claims

1. A method of operating a nonvolatile memory device, comprising:

programming sample data in the memory device for verification using verify voltage levels derived from an ideal verify voltage Vv associated with a particular temperature range;

performing read verify operations on the sample data using the verify voltage Vv associated with the temperature range; and

determining a temperature compensation parameter Nc based on results of the read verify operations.

2. The method of claim 1, wherein programming the sample data comprises programming the sample data at N intervals corresponding to Vv through Vv−

(N−

1) Vd, where Vd corresponds to a shift in a threshold voltage Vth for the programmed sample data per unit of temperature.

3. The method of claim 2, wherein determining the temperature compensation parameter Nc comprises determining the temperature compensation parameter Nc based on numbers of the N intervals that pass and fail when performing the read verify operations on the sample data.

4. The method of claim 2, further comprising:

using a temperature compensated voltage Vtemp=Vorg+Nc*Vd as a program voltage, read voltage, and/or verify voltage in the nonvolatile memory device where Vorg is a voltage without temperature compensation associated with data to be programmed, read, and/or verified.

5. The method of claim 4, wherein the memory comprises a flash memory, the method further comprising:

programming a target page in the flash memory using a plurality of the temperature compensated voltages Vtemp.

6. The method of claim 4, wherein the memory comprises a flash memory, the method further comprising:

reading a target page in the flash memory using a plurality of the temperature compensated voltages Vtemp.

7. The method of claim 1, wherein the memory comprises a flash memory, the method further comprising:

reading a target page in the flash memory;

determining if errors in the target page are correctable; and

wherein programming the sample data, performing the read verify operations on the sample data, and determining the temperature compensation parameter are performed when the errors in the target page are not correctable.

8. The method of claim 1, wherein the memory comprises a flash memory.

9. The method of claim 8 wherein the flash memory comprises a NAND, NOR, or a One_NAND type flash memory.

10. The method of claim 1, wherein the memory device is embodied in a memory card device, Solid State Drive (SSD) device, ATA bus device, Serial ATA (SATA) bus device, Small Computer System Interface (SCSI) device, Serial Attached SCSI (SAS) device, Multi-Media Card (MMC) device, Secure Digital (SD) device, memory stick device, Hard Disk Drive (HDD) device, Hybrid Hard Drive (HHD) device, or a Universal Serial Bus (USB) flash drive device.

11. The system of claim 1, wherein the memory device is embodied in a graphics card, a computer, a mobile terminal, a Personal Digital Assistant (PDA), a camera, a game console, an MP3 player, a television, a DVD player, a router, or a GPS system.

12. A method of operating a nonvolatile memory system, comprising:

sending a sample page read command from a host to a memory device;

programming sample data in the memory device for verification using verify voltage levels derived from an ideal verify voltage Vv associated with a particular temperature range;

performing read verify operations on the sample data using the verify voltage Vv associated with the temperature range in the memory device;

providing results of the read verify operations to the host; and

determining a temperature compensation parameter Nc based on the results of the read verify operations at the host.

13. The method of claim 12, wherein programming the sample data comprises programming the sample data at N intervals corresponding to Vv through Vv−

(N−

1) Vd, where Vd corresponds to a shift in a threshold voltage Vth for the programmed sample data per unit of temperature.

14. The method of claim 13, further comprising:

communicating from the host to the memory device at least one temperature compensated voltage Vtemp=Vorg+Nc*Vd for use as a program voltage, read voltage, and/or verify voltage in the nonvolatile memory device where Vorg is a voltage without temperature compensation associated with data to be programmed, read, and/or verified.

15. The method of claim 14, wherein the memory comprises a flash memory, the method further comprising:

programming a target page in the flash memory using a plurality of the temperature compensated voltages Vtemp.

16. The method of claim 14, wherein the memory comprises a flash memory, the method further comprising:

reading a target page in the flash memory using a plurality of the temperature compensated voltages Vtemp.

17. The method of claim 14, wherein the at least one temperature compensated voltage value is stored in cells in the memory device.

18. The method of claim 14, wherein the at least one temperature compensated voltage value is stored in registers in the memory device.

19. The method of claim 12, wherein the memory comprises a flash memory, the method further comprising:

sending a target page read command from the host to the memory device;

reading the target page in the flash memory;

determining if errors in the target page are correctable; and

wherein programming the sample data, performing the read verify operations on the sample data, providing the results of the read verify operations to the host, and determining the temperature compensation parameter are performed when the errors in the target page are not correctable.

20. The method of claim 12, wherein the memory comprises a flash memory.

21. The method of claim 20 wherein the flash memory comprises a NAND, NOR, or a One_NAND type flash memory.

22. The method of claim 12, wherein the memory system is embodied in a memory card device, Solid State Drive (SSD) device, ATA bus device, Serial ATA (SATA) bus device, Small Computer System Interface (SCSI) device, Serial Attached SCSI (SAS) device, Multi-Media Card (MMC) device, Secure Digital (SD) device, memory stick device, Hard Disk Drive (HDD) device, Hybrid Hard Drive (HHD) device, or a Universal Serial Bus (USB) flash drive device.

23. The method of claim 12, wherein the memory system is embodied in a graphics card, a computer, a mobile terminal, a Personal Digital Assistant (PDA), a camera, a game console, an MP3 player, a television, a DVD player, a router, or a GPS system.

24. A method of operating a memory system, comprising:

sending a command for temperature compensation from a host to a nonvolatile memory device; and

retrieving temperature compensated voltage values for performing program, read, and/or verify operations in the memory device.

25. The method of claim 24, wherein the temperature compensated voltage values are stored in cells in the memory device.

26. The method of claim 24, wherein the temperature compensated voltage values are stored in registers in the memory device.

27. A method of operating a nonvolatile memory device, comprising:

programming N groups of sample data in the memory device for verification using verify voltage levels in the range of Vv through Vv+(N−

1)Vd where Vd is a constant value;

performing read verify operations on the N groups of sample data using a verify voltage of (Vv+(N−

1)Vd)/2; and

determining a temperature compensation parameter Nc based on results of the read verify operations.

28. A method of operating a nonvolatile memory device, comprising:

programming N groups of sample data in the memory device for verification using verify voltage levels in the range of Vv through Vv+(N−

1)Vd where Vd is a constant value;

performing read verify operations on the N groups of sample data using a verify voltage of Vv+Vm, where Vm is a constant value; and

determining a temperature compensation parameter Nc based on a number of fail bits determined for each of the N groups.