Multi-phase method for operating a memory with erase verification, memory and, memory system
A method for operating a memory includes: during the erase phase, applying an erase voltage to the word line, and applying an erase voltage to the select line coupled to a target select gate; during the program phase for select gate, applying a pass voltage to the word line, and applying a program voltage to the select line coupled to the target select gate.
1 . A method for operating a memory, wherein the memory includes a plurality of memory strings, a memory string includes a plurality of memory cells and plurality of select gates, a memory cell is coupled to a word line and a bit line, and a select gate is coupled to a select line, the method including:
during an erase phase:
applying an erase voltage to the word line;
applying the erase voltage to the select line coupled to a target select gate from the plurality of select gates; and
driving the bit line with a non-zero second erase voltage; and
during a program phase for select gate, applying a pass voltage to the word line, and applying a program voltage to the select line coupled to the target select gate.
2 . The method of claim 1 , wherein an erase-verify phase is further included after the erase phase and before the program phase for select gate, and the method further includes:
during the erase-verify phase, applying a first verify voltage to the select line coupled to the target select gate.
3 . The method of claim 2 , wherein the select gate includes a top select gate and a bottom select gate, and the target select gate is the bottom select gate, and the method further includes:
during the program phase for select gate, applying a program select voltage to the top select gate of the memory string at which the target select gate is located, and applying a program prohibition voltage to the top select gates of other memory strings.
4 . The method of claim 3 , wherein a program-verify phase for select gate is further included after the program phase for select gate, and the method further includes:
during the program-verify phase for select gate, applying a second verify voltage to the select line coupled to the target select gate; and
increasing the program voltage in response to a threshold voltage of the target select gate not reaching a target threshold voltage.
5 . The method of claim 4 , further including:
during the program-verify phase for select gate, applying a program select voltage to the top select gate of the memory string at which the target select gate is located, and applying a pass voltage to the top select gates of other memory strings.
6 . The method of claim 4 , further including:
during the program-verify phase for select gate, applying the pass voltage to the word line.
7 . The method of claim 4 , further including:
during the erase phase, applying a hold & release voltage to the top select gate.
8 . The method of claim 1 , wherein a pre-program phase is further included before the erase phase, and the method further includes:
during the pre-program phase, applying a pre-program voltage or the pass voltage to the word line, and applying the pre-program voltage to the select line coupled to the target select gate.
9 . The method of claim 1 , wherein the second erase voltage is greater in value than the erase voltage.
10 . A memory, comprising:
an array of memory cells; and
a peripheral circuit coupled to the array of memory cells, and is configured to:
during an erase phase:
apply an erase voltage to a word line;
apply the erase voltage to a select line coupled to a target select gate from a plurality of select gates; and
drive a bit line with a non-zero second erase voltage; and
during a program phase for select gate, apply a pass voltage to the word line, and apply a program voltage to the select line coupled to the target select gate.
11 . The memory of claim 10 , wherein an erase-verify phase is further included after the erase phase and before the program phase for select gate, and the peripheral circuit is further configured to:
during the erase-verify phase, apply a first verify voltage to the select line coupled to the target select gate.
12 . The memory of claim 11 , wherein the select gate includes a top select gate and a bottom select gate, and the target select gate is the bottom select gate, and the peripheral circuit is further configured to:
during the program phase for select gate, apply a program select voltage to the top select gate of a memory string at which the target select gate is located, and apply a program prohibition voltage to the top select gates of other memory strings.
13 . The memory of claim 12 , wherein a program-verify phase for select gate is further included after the program phase for select gate, and the peripheral circuit is further configured to:
during the program-verify phase for select gate, apply a second verify voltage to the select line coupled to the target select gate; and
increase the program voltage in response to a threshold voltage of the target select gate not reaching a target threshold voltage.
14 . The memory of claim 13 , wherein the select gate further includes a top select gate, and the peripheral circuit is further configured to:
during the program-verify phase for select gate, apply a program select voltage to the top select gate of the memory string at which the target select gate is located, and apply the pass voltage to the top select gates of other memory strings.
15 . The memory of claim 13 , wherein the peripheral circuit is further configured to:
during the program-verify phase for select gate, apply the pass voltage to the word line; and
during the erase phase, apply a hold & release voltage to the top select gate.
16 . The memory of claim 10 , wherein a pre-program phase is further included before the erase phase, and the peripheral circuit is further configured to:
during the pre-program phase, apply a pre-program voltage or the pass voltage to the word line, and apply the pre-program voltage to the select line coupled to the target select gate.
17 . A memory system, including:
a memory controller configured to control a memory to write data or to read data stored in the memory; and
the memory, including:
an array of memory cells; and
a peripheral circuit coupled to the array of memory cells, and configured to:
during an erase phase:
apply an erase voltage to a word line;
apply the erase voltage to a select line coupled to a target select gate from a plurality of select gates; and
drive a bit line with a non-zero second erase voltage; and
during a program phase for select gate, apply a pass voltage to the word line, and apply a program voltage to the select line coupled to the target select gate.
18 . The memory system of claim 17 , wherein an erase-verify phase is further included after the erase phase and before the program phase for select gate, and the peripheral circuit is further configured to:
during the erase-verify phase, apply a first verify voltage to the select line coupled to the target select gate.
19 . The memory system of claim 18 , wherein the select gate includes a top select gate and a bottom select gate, and the target select gate is the bottom select gate, and the peripheral circuit is further configured to:
during the program phase for select gate, apply a program select voltage to the top select gate of a memory string at which the target select gate is located, and apply a program prohibition voltage to the top select gates of other memory strings.
20 . The memory system of claim 19 , wherein a program-verify phase for select gate is further included after the program phase for select gate, and the peripheral circuit is further configured to:
during the program-verify phase for select gate, apply a second verify voltage to the select line coupled to the target select gate; and
increase the program voltage in response to a threshold voltage of the target select gate not reaching a target threshold voltage.