Word line zoned adaptive initial program voltage for non-volatile memory
An apparatus is provided that includes a plurality of word lines that include a plurality of word line zones, a plurality of non-volatile memory cells coupled to the plurality of word lines, and a control circuit coupled to the non-volatile memory cells. The control circuit is configured to determine a corresponding initial program voltage for each of the word line zones. Each corresponding initial program voltage is determined based on a number of program erase cycles.
1. An apparatus comprising:
a plurality of word lines comprising a plurality of word line zones;
a plurality of non-volatile memory cells coupled to the plurality of word lines; and
a control circuit coupled to the non-volatile memory cells, the control circuit configured to determine a corresponding initial program voltage for each of the word line zones, wherein each corresponding initial program voltage is determined based on a number of program erase cycles,
wherein for each word line zone, the control circuit is configured to determine the corresponding initial program voltage based on an average increase of a programmed state threshold voltage position across word lines in the word line zone.
2. The apparatus of claim 1 , wherein the programmed state is a lowest programmed state.
3. The apparatus of claim 1 , wherein for each word line zone, the control circuit is configured to determine the corresponding initial program voltage based on an average increase of a lower tail of a programmed state threshold voltage distribution.
4. The apparatus of claim 3 , wherein the programmed state is a first programmed state above an erased state.
5. The apparatus of claim 1 , wherein each word line zone includes consecutive word lines.
6. The apparatus of claim 1 , wherein each word line zone includes a same number of word lines.
7. The apparatus of claim 1 , wherein a number of word lines in each word line zone varies from word line zone to word line zone.
8. The apparatus of claim 1 , wherein the word line zones are non-overlapping.
9. The apparatus of claim 1 , wherein each word line is included in at most one word line zone.
10. An apparatus comprising:
a plurality of word lines comprising a plurality of word line zones;
a plurality of non-volatile memory cells coupled to the plurality of word lines; and
a control circuit coupled to the non-volatile memory cells, the control circuit configured to determine a first initial program voltage for non-volatile memory cells coupled to a first word line, and a second initial program voltage for non-volatile memory cells coupled to a second word line, wherein the first initial program voltage and the second initial program voltage vary based on a number of program erase cycles,
wherein the control circuit is further configured to determine the first initial program voltage based on an average increase of a lower tail of a programmed state threshold voltage distribution for memory cells coupled to the first word line, and determine the second initial program voltage based on an average increase of a lower tail of the programmed state threshold voltage distribution for memory cells coupled to the second word line.
11. The apparatus of claim 10 , wherein the first initial program voltage differs from the second initial program voltage.
12. The apparatus of claim 10 , wherein the control circuit is further configured to determine the first initial program voltage based on an average increase of a programmed state threshold voltage position of non-volatile memory cells coupled to the first word line, and determine the second initial program voltage based on an average increase of the programmed state threshold voltage position of non-volatile memory cells coupled to the second word line.
13. The apparatus of claim 12 , wherein the programmed state is a lowest programmed state.
14. The apparatus of claim 10 , wherein the programmed state is a first programmed state above an erased state.
15. The apparatus of claim 10 , further comprising a first word line zone that comprises the first word line, and a second word line zone that comprises the second word line.
16. The apparatus of claim 10 , wherein the first word line zone includes a first number of word lines, and the second word line zone includes a second number of word lines different from the first number of word lines.
17. A method comprising:
dividing a first plurality of word lines into a first word line zone and a second plurality of word lines into a second word line zone;
determining an average increase of a programmed state threshold voltage position in the first word line zone;
determining an average increase of a programmed state threshold voltage position in the second word line zone;
determining a first initial program voltage for the first word line zone based on a number of program erase cycles and the determined average increase of a programmed state threshold voltage position in the first word line zone;
determining a first initial program voltage for the first word line zone based on the number of program erase cycles and the determined average increase of a programmed state threshold voltage position in the second word line zone;
applying a single program pulse comprising the first initial program voltage to program non-volatile memory cells coupled to the first plurality of word lines to a programmed state without performing any verify operations; and
applying a single program pulse comprising the second initial program voltage to program non-volatile memory cells coupled to the second plurality of word lines to the programmed state without performing any verify operations.
18. The method of claim 17 , wherein first initial program voltage differs from the second initial program voltage.