System and method to reduce disturbances during programming of flash memory cells
View Patent ↗An improved control gate decoding design may reduce disturbances during the programming of flash memory cells. In one embodiment, a control gate line decoder is coupled to a first control gate line associated with a row of flash memory cells in a first sector and to a second control gate line associated with a row of flash memory cells in a second sector.
1. A flash memory system, comprising:
a first sector comprising a first plurality of rows of flash memory cells, the first sector associated with a first source line;
a second sector comprising a second plurality of rows of flash memory cells, the second sector associated with a second source line; and
a control gate line decoder coupled to a control gate voltage source and selectively coupled to only one control gate line associated with one of the first plurality of rows and only one control gate line associated with one of the second plurality of rows, wherein one of the first and second source lines is at a high voltage and the other of the first and second source lines is at a low voltage.
2. The flash memory system of claim 1 , wherein the first sector is associated with a first erase gate line and the second sector is associated with a second erase gate line.
3. The flash memory system of claim 1 , wherein each of the first plurality of rows is associated with a different control gate line.
4. The flash memory system of claim 3 , wherein each of the second plurality of rows is associated with a different control gate line.
5. The flash memory system of claim 1 , wherein the first plurality of rows of flash memory cells and the second plurality of rows of flash memory cells each comprise split gate flash memory cells.
6. The flash memory system of claim 2 , wherein the first plurality of rows of flash memory cells and the second plurality of rows of flash memory cells each comprise split gate flash memory cells.
7. The flash memory system of claim 3 , wherein the first plurality of rows of flash memory cells and the second plurality of rows of flash memory cells each comprise split gate flash memory cells.
8. The flash memory system of claim 4 , wherein the first plurality of rows of flash memory cells and the second plurality of rows of flash memory cells each comprise split gate flash memory cells.
9. A method of programming a flash memory cell, comprising:
activating a selected flash memory cell in a first row in a first sector using a first word line and a first bit line, the first sector associated with a first source line;
coupling a control gate voltage source to a control gate of the selected flash memory cell using a control gate line decoder wherein the control line decoder cannot be selectively coupled to another row within the first sector, wherein the control gate line decoder can be selectively coupled to only one row of flash memory cells in a second sector, the second sector associated with a second source line, wherein the first source line is at a high voltage and the second source line is at a low voltage; and
storing a digital value in a floating gate of the selected flash memory cell.
10. The method of claim 9 , further comprising erasing the selected flash memory cell using an erase gate line.
11. The method of claim 9 , wherein the selected flash memory cell is a split gate flash memory cell.
12. The method of claim 10 , wherein the selected flash memory cell is a split gate flash memory cell.
13. A method of programming and reading a flash memory cell, comprising:
activating a selected flash memory cell in a first row in a first sector using a first word line and a first bit line, the first sector associated with a first source line;
coupling a control gate voltage source to the first row using a control gate line decoder wherein the control gate voltage source cannot be selectively coupled to another row in the first sector, wherein the control gate line decoder can be selectively coupled to only one row in a second sector, the second sector associated with a second source line, wherein the first source line is at a high voltage and the second source line is at a low voltage;
storing a digital value in a floating gate of the selected flash memory cell; and
reading the digital value using a source line of the selected flash memory cell.
14. The method of claim 13 , wherein the storing step comprises adding electrons to the floating gate.
15. The method of claim 13 , further comprising erasing the selected flash memory cell using an erase gate line.
16. The method of claim 15 , wherein the erasing step comprises removing electrons from the floating gate.
17. The method of claim 13 , wherein the first row comprises split gate flash memory cells.
18. The method of claim 14 , wherein the first row comprises split gate flash memory cells.
19. The method of claim 15 , wherein the first row comprises split gate flash memory cells.
20. The method of claim 16 , wherein the first row comprises split gate flash memory cells.