Non-volatile memory device and method of operating the same

• US 7,796,434 B2
• Filed: 03/14/2008
• Issued: 09/14/2010
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Original Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Inventors: Wang, Jong Hyun, Park, Seong Hun, Kim, Duck Ju, Jang, Chae Kyu, Yang, Joong Seob
• Primary Examiner(s): LUU, PHO M
• Application Number:
  US12/049,253
• Publication Number:
  US 20090122615A1
• Time in Patent Office: 914 Days
• Field of Search: 365/185.18, 365/185.24, 365/185.29, 365/189.09, 365/189.12
• US Class Current: 365/185.18
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles

Abstract

Program voltages of a non-volatile memory device are controlled variably according to a program/erase operation count. The non-volatile memory device includes a program voltage supply unit for applying a program voltage to a memory cell, a program/erase count storage unit for storing a total program/erase operation count of the non-volatile memory device, a program start voltage storage unit for storing levels of program start voltages to be differently supplied according to the program/erase operation count, and a program voltage controller for controlling the program start voltage according to the program/erase operation count.

Claims

1. A non-volatile memory device comprising:

a program voltage supply unit for applying a program voltage to a memory cell;

a program/erase count storage unit for storing a total program/erase operation count of the non-volatile memory device;

a program start voltage storage unit for storing levels of, program start voltages to be differently supplied to the program voltage supply unit according to the program/erase operation count; and

a program voltage controller to select one of the levels of the program start voltages according to the program/erase operation count.

2. The non-volatile memory device of claim 1, wherein the program/erase count storage unit comprises memory having a non-volatile characteristic in which a corresponding count can be stored even when the supply of power is stopped.

3. The non-volatile memory device of claim 1, wherein the program start voltage storage unit comprises a plurality of registers for storing different program start voltages.

4. The non-volatile memory device of claim 1, wherein when the program/erase operation count corresponds to a specific reset reference value, the program voltage controller controls the program start voltage storage unit to transfer a program start voltage, corresponding to the reset reference value, to the program voltage supply unit.

5. A method of operating a non-volatile memory device, the method comprising:

repeatedly performing program/erase operations according to a specific program start voltage until a program/erase operation count corresponds to a first reset reference value;

when the program/erase operation count corresponds to the first reset reference value, decreasing the specific program start voltage; and

repeatedly performing program/erase operations according to the decreased program start voltage until the program/erase operation count corresponds to a second reset reference value that is greater than the first reset reference value.

6. The method of claim 5, wherein the decrease of the specific program start voltage includes decreasing the program start voltage as low as a step voltage and applying the decreased program start voltage.

7. The method of claim 5, further comprising setting the second reset reference value to a reset reference value after the decrease of the specific program start voltage.

8. A method of operating a non-volatile memory device, the method comprising:

providing a plurality of reset reference values that are arranged in an ascending order; and

when a program/erase operation count reaches a specific reset reference value while program/erase operations are performed repeatedly, decreasing a program start voltage and then executing the program/erase operations.

9. The method of claim 8, wherein the execution of the program/erase operations comprises decreasing the program start voltage as low as a step voltage until the program/erase operation count reaches a specific reset reference value.