Semiconductor memory including semiconductor oxide
According to one embodiment, a memory includes: a member extending in a first direction and including an oxide semiconductor layer including first to third portions arranged in order from the bit line to the source line; first, second and third conductive layers arranged along the first direction and facing the first to third portions, respectively, the first conductive layer including first material, and each of the second and third conductive layer including a second material different from the first material; a memory cell in a first position corresponding to the first portion, the memory cell including a charge storage layer in the oxide semiconductor layer; a first transistor in a second position corresponding to the second portion; and a second transistor in a third position corresponding to the third portion.
1. A semiconductor memory comprising:
a bit line;
a source line;
a member extending in a first direction from the bit line to the source line and including an oxide semiconductor layer, a first end of the oxide semiconductor layer in the first direction is in contact with the source line, and a second end of the oxide semiconductor layer in the first direction electrically disconnected from the bit line, the oxide semiconductor layer including a first portion, second portion, and third portion arranged in order from the second end to the first end;
first, second and third conductive layers disposed along the first direction, the first conductive layer facing the first portion and including a first material, the second conductive layer facing the second portion and including a second material different from the first material, and the third conductive layer facing the third portion including the second material;
a memory cell in a first position corresponding to the first portion, the memory cell including a charge storage layer in the first portion;
a first transistor in a second position corresponding to the second portion; and
a second transistor in a third position corresponding to the third portion.
2. The semiconductor memory according to claim 1 , wherein
the first material includes at least one of an n-type semiconductor, metal and a conductive compound, and
the second material includes a p-type semiconductor.
3. The semiconductor memory according to claim 1 , wherein
the oxide semiconductor layer extends from the first portion to the source line,
the first transistor includes a first channel region in the second portion, and
the second transistor includes a second channel region in the third portion.
4. The semiconductor memory according to claim 1 , wherein
the member includes a semiconductor layer extending in the first direction,
the memory cell includes a third channel region in the semiconductor layer,
a third end of the semiconductor layer in the first direction is in contact with the source line; and
a fourth end of the semiconductor layer in the first direction is in contact with the bit line.
5. The semiconductor memory according to claim 1 , further comprising:
an insulating layer disposed between the source line and the bit line and covering the first, second and third conductive layers,
wherein the oxide semiconductor layer is provided between the source line and the insulating layer.
6. The semiconductor memory according to claim 1 , wherein
a threshold voltage of the memory cell varies in accordance with an amount of charges in the charge storage layer,
the memory cell retains first data where the threshold voltage of the memory cell is a first value, and
the memory cell retains second data different from the first data where the threshold voltage of the memory cell is a second value different from the first value.
7. The semiconductor memory device according to claim 6 , wherein
the charges are supplied from the source line to the oxide semiconductor layer.
8. A semiconductor memory comprising:
a bit line;
a source line;
a member extending in a first direction from the bit line to the source line and including an oxide semiconductor layer, a first end of the oxide semiconductor layer in the first direction is in contact with the source line, and a second end of the oxide semiconductor layer in the first direction electrically disconnected from the bit line, the oxide semiconductor layer including a first portion, second portion, and third portion arranged in order from the second end to the first end;
first, second and third conductive layers disposed along the first direction, the first conductive layer facing the first portion, the second conductive layer facing the second portion, and the third conductive layer facing the third portion;
a first insulating layer between the oxide semiconductor layer and the first conductive layer, between the oxide semiconductor layer and the second conductive layer, and between the oxide semiconductor layer and the third conductive layer;
a second insulating layer between the first insulating layer and the second conductive layer, a dielectric constant of the second insulating layer higher than a dielectric constant of the first insulating layer;
a third insulating layer between the first insulating layer and the third conductive layer, a dielectric constant of the third insulating layer higher than a dielectric constant of the first insulating layer;
a memory cell in a first position corresponding to first portion, the memory cell including a charge storage layer in the first portion;
a first transistor in a second position corresponding to the second portion; and
a second transistor in a third position corresponding to the third portion.
9. The semiconductor memory according to claim 8 , wherein
the first conductive layer is directly in contact with the first insulating layer.
10. The semiconductor memory according to claim 8 , wherein
the second insulating layer includes at least one of hafnium, aluminum, and tantalum.
11. The semiconductor memory according to claim 8 , wherein
a number density of oxygen atoms of the second insulating layer is higher than a number density of oxygen atoms of silicon oxide.
12. The semiconductor memory according to claim 8 , wherein
a threshold voltage of the memory cell varies in accordance with an amount of charges in the charge storage layer,
the memory cell retains first data where the threshold voltage of the memory cell is a first value, and
the memory cell retains second data different from the first data where the threshold voltage of the memory cell is a second value different from the first value.
13. The semiconductor memory device according to claim 12 , wherein
the charges are supplied from the source line to the oxide semiconductor layer.
14. A semiconductor memory comprising:
a bit line;
a source line;
a member extending in a first direction from the bit line to the source line and including an oxide semiconductor layer, a first end of the oxide semiconductor layer in the first direction is in contact with the source line, and a second end of the oxide semiconductor layer in the first direction electrically disconnected from the bit line, the oxide semiconductor layer including a first portion, second portion, and third portion arranged in order from the second end to the first end;
first, second and third conductive layers disposed along the first direction, the first conductive layer facing the first portion, the second conductive layer facing the second portion, and the third conductive layer facing the third portion;
a first insulating layer between the oxide semiconductor layer and the first conductive layer, between the oxide semiconductor layer and the second conductive layer, and between the oxide semiconductor layer and the third conductive layer;
a second insulating layer between the first insulating layer and the second conductive layer;
a first charge storage layer between the first insulating layer and the second insulating layer
a third insulating layer between the first insulating layer and the third conductive layer;
a second charge storage layer between the first insulating layer and the third insulating layer;
a memory cell in a first position corresponding to the first portion, the memory cell including a third charge storage layer in the first portion;
a first transistor in a second position corresponding to the second portion; and
a second transistor in a third position corresponding to the third portion.
15. The semiconductor memory according to claim 14 , wherein
the first and second charge storage layers are continuous between the first and second transistors.
16. The semiconductor memory according to claim 14 , wherein
the first charge storage layer is isolated from the second charge storage layer.
17. The semiconductor memory according to claim 14 , wherein
the first conductive layer is directly in contact with the first insulating layer.
18. The semiconductor memory according to claim 14 , further comprising:
a fourth insulating layer between the first insulating layer and the first conductive layer; and
a fifth insulating layer between the first insulating layer and the fourth insulating layer.
19. The semiconductor memory according to claim 14 , wherein
a threshold voltage of the memory cell varies in accordance with an amount of charges in the charge storage layer,
the memory cell retains first data where the threshold voltage of the memory cell is a first value, and
the memory cell retains second data different from the first data where the threshold voltage of the memory cell is a second value different from the first value.
20. The semiconductor memory device according to claim 19 , wherein
the charges are supplied from the source line to the oxide semiconductor layer.