PROGRAM AND ERASE METHODS FOR NONVOLATILE MEMORY

• US 20090052255A1
• Filed: 08/14/2008
• Published: 02/26/2009
• Est. Priority Date: 08/20/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Kihwan, Moon, Seunghyun
• Granted Patent: US 7,778,083 B2
• Time in Patent Office: Days
• US Class Current: 365/185.190
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/16 for erasing blocks, e.g. arrays, words, groups
• CPC Class Codes: H10B 41/30 characterised by the memory core region
• CPC Class Codes: H10B 41/35 with a cell select transistor, e.g. NAND
• CPC Class Codes: H10B 69/00 Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices

Abstract

Methods of programming or erasing a nonvolatile memory device having a charge storage layer including performing at least one unit programming or erasing loop, each unit programming or erasing loop including applying at least one programming pulse, at least one erasing pulse, at least one time delay, at least one soft erase pulse, at least one soft programming pulse and/or at least one verifying pulse as a positive or negative voltage to a portion (for example, a word line or a substrate) of the nonvolatile memory device.

Claims

1. A method of programming a nonvolatile memory device having a charge storage layer, comprising:

performing at least one unit programming loop, each unit programming loop including,

applying at least two programming pulses to a wordline,

applying at least two time delays to the wordline, and

applying a verifying pulse to the wordline.

2. The method of claim 1, wherein the at least two programming pulses and the at least two time delays are alternately applied, beginning with one of the at least two programming pulses.

3. The method of claim 1, wherein the verifying pulse is applied at the end of the unit programming loop.

4. The method of claim 1, wherein the at least two programming pulses have differing amplitudes.

5. The method of claim 1, wherein the at least two programming pulses have differing durations.

6. The method of claim 1, wherein the at least two programming pulses have differing amplitudes and differing durations.

7. The method of claim 1, wherein the at least two time delays have differing durations.

8. The method of claim 1, wherein the at least one unit programming loop includes at least two unit programming loops.

9. The method of claim 8, wherein the at least two programming pulses in one unit programming loop have different amplitudes from the at least two programming pulses in another unit programming loop.

10. The method of claim 8, wherein the at least two programming pulses in one unit programming loop have different durations from the at least two programming pulses in another unit programming loop.

11. The method of claim 8, wherein the at least two programming pulses in one unit programming loop have different amplitudes and durations from the at least two programming pulses in another unit programming loop.

12. The method of claim 8, wherein the at least two time delays in one unit programming loop have different durations from the at least two time delays in another unit programming loop.

13. The method of claim 8, wherein the at least two unit programming loops includes N (where N is an integer >

2) programming loops.

14. The method of claim 1, wherein the nonvolatile memory device is a charge trap flash memory and the charge storage layer is a charge trap layer.

15. The method of claim 1, wherein the at least two time delays are between 1 us to 900 ms.

16. The method of claim 1, wherein the at least two time delays redistribute or recombine charge within charge storage layer.

17. The method of claim 1, wherein the at least two programming pulses are generated by applying a positive program voltage to a control gate of the nonvolatile memory device.

18. The method of claim 1, wherein the nonvolatile memory device is a NAND flash memory.

19. A nonvolatile memory device, comprising:

an array of memory cell transistors connected by a plurality of word lines and a plurality of bit lines; and

programming logic, performing at least one unit programming loop, wherein for each unit programming loop, the programming logic

applies at least two programming pulses to a selected one of the plurality of word lines and a pass pulse to unselected ones of the plurality of word lines,

applies at least two time delays to the selected one of the plurality of word lines and

applies a verifying pulse to the selected one of the plurality of word lines and a read pulse to unselected ones of the plurality of word lines.

20. A system, comprising:

a memory including

an array of memory cell transistors connected by a plurality of word lines and a plurality of bit lines, and

programming logic performing at least one unit programming loop,

wherein for each unit programming loop, the programming logic applies at least two programming pulses to a selected one of the plurality of word lines and a pass pulse to unselected ones of the plurality of word lines, applies at least two time delays to the selected one of the plurality of word lines and applies a verifying pulse to the selected one of the plurality of word lines and a read pulse to unselected ones of the plurality of word lines; and

a memory controller, for controlling the memory.

21. A system, comprising:

a memory including

an array of memory cell transistors connected by a plurality of word lines and a plurality of bit lines, and

programming logic performing at least one unit programming loop,

wherein for each unit programming loop, the programming logic applies at least two programming pulses to a selected one of the plurality of word lines and a pass pulse to unselected ones of the plurality of word lines, applies at least two time delays to the selected one of the plurality of word lines and applies a verifying pulse to the selected one of the plurality of word lines and a read pulse to unselected ones of the plurality of word lines; and

a controller, for controlling the memory;

a user interface for enabling access to the memory;

a modem permitting information in the memory to be transmitted;

a battery for supplying power to the memory; and

a bus for connecting the memory, the controller, the user interface, the modem and the battery.

22. A method of erasing a nonvolatile memory device having a charge storage layer, comprising:

performing at least one unit erasing loop, each unit erasing loop including,

applying at least two erasing pulses to a wordline,

applying at least two time delays to the wordline, and

applying a verifying pulse to the wordline.

23. The method of claim 22, wherein the at least two erasing pulses and the at least two time delays are alternately applied, beginning with one of the at least two erasing pulses.

24. The method of claim 22, wherein the verifying pulse is applied at the end of the unit erasing loop.

25. The method of claim 22, wherein the at least two erasing pulses have differing amplitudes.

26. The method of claim 22, wherein the at least two erasing pulses have differing durations.

27. The method of claim 22, wherein the at least two erasing pulses have differing amplitudes and differing durations.

28. The method of claim 22, wherein the at least two time delays have differing durations.

29. The method of claim 22, wherein the at least one unit erasing loop includes at least two unit erasing loops.

30. The method of claim 29, wherein the at least two erasing pulses and the at least two time delays are alternately applied, beginning with one of the at least two erasing pulses in each unit erasing loop.

31. The method of claim 29, wherein the verifying pulse is applied at the end of the unit erasing loop in each unit erasing loop.

32. The method of claim 29, wherein the at least two erasing pulses have differing amplitudes in each unit erasing loop.

33. The method of claim 29, wherein the at least two erasing pulses have differing durations in each unit erasing loop.

34. The method of claim 29, wherein the at least two erasing pulses have differing amplitudes and differing durations in each unit erasing loop.

35. The method of claim 29, wherein the at least two time delays have differing durations in each unit erasing loop.

36. The method of claim 29, wherein the at least two erasing pulses in a subsequent unit erasing loop have larger amplitudes than the at least two erasing pulses in a previous unit erasing loop.

47. The method of claim 29, wherein the at least two unit erasing loops includes N (where N is an integer >

2) erasing loops.

38. The method of claim 22, wherein the nonvolatile memory device is a charge trap flash memory and the charge storage layer is a charge trap layer.

39. The method of claim 22, wherein the at least two time delays are between 1 us to 900 ms.

40. The method of claim 22, wherein the at least two time delays redistribute or recombine charge within charge storage layer.

41. The method of claim 22, wherein the at least two erasing pulses are generated by applying a positive program voltage to a substrate of the nonvolatile memory device.

42. The method of claim 22, wherein the nonvolatile memory device is a NAND flash memory.

43. A nonvolatile memory device, comprising:

an array of memory cell transistors connected by a plurality of word lines and a plurality of bit lines; and

programming logic, including an X-decoder, performing at least one unit erasing loop, wherein for each unit erasing loop, the X-decoder applies at least two erasing pulses to a substrate of the nonvolatile memory device, applies at least two time delays, and applies a verifying pulse to plurality of word lines.

44. A system, comprising:

a memory including

an array of memory cell transistors connected by a plurality of word lines and a plurality of bit lines and

erasing logic performing at least one unit erasing loop, wherein for each unit erasing loop, the erasing logic applies at least two erasing pulses to a substrate of the nonvolatile memory device, applies at least two time delays, and applies a verifying pulse to plurality of word lines; and

a memory controller, for controlling the memory.

45. A system, comprising:

a memory including

an array of memory cell transistors connected by a plurality of word lines and a plurality of bit lines and

erasing logic performing at least one unit erasing loop, wherein for each unit erasing loop, the erasing logic applies at least two erasing pulses to a substrate of the nonvolatile memory device, applies at least two time delays, and applies a verifying pulse to plurality of word lines; and

a controller, for controlling the memory;

a user interface for enabling access to the memory;

a modem permitting information in the memory to be transmitted;

a battery for supplying power to the memory; and

a bus for connecting the memory, the controller, the user interface, the modem and the battery.