Memory cell structure, method of manufacturing a memory, and memory apparatus
The present disclosure relates to a memory cell structure, a method of manufacturing a memory, and a memory apparatus that are capable of providing a memory cell structure of an MRAM, which reduces resistance of drawn wiring to be connected to an MTJ, reduces an area of a memory cell, and avoids performance degradation of the MTJ due to heat. A memory cell includes: a transistor that uses a first diffusion layer formed in a bottom portion of a concave portion formed by processing a silicon substrate into a groove shape, and a second diffusion layer formed in upper end portions of two opposing sidewall portions of the concave portion, to form channels at portions between the first diffusion layer and the second diffusion layer in the two sidewall portions; and a memory element that is disposed below the first diffusion layer. The first diffusion layer is electrically connected to the memory element via a contact formed after the silicon substrate is thinned.
1. A memory device, comprising:
a memory element and a transistor;
wherein a first node of the transistor connects to the memory element,
wherein a word line connects to a gate electrode of the transistor,
wherein a bit line directly connects to a second node of the transistor,
wherein the transistor comprises current paths through channels on opposing sidewalls of the transistor and the current paths are not in contact with a bottom side of the gate electrode, wherein the bottom side is furthest from the bit line, and
wherein, after flowing through the channels, the current paths flow past the bottom side of the gate electrode to the memory element disposed below the bottom side of the gate electrode.
2. The memory device according to claim 1 , wherein
the gate electrode of the transistor is a buried gate structure.
3. The memory device according to claim 2 , wherein
the buried gate structure is within a concave portion in a substrate.
4. The memory device according to claim 3 , wherein
the substrate is an SOI substrate.
5. The memory device according to claim 1 , wherein
the transistor comprises a first diffusion layer formed in a bottom portion of a concave portion, and a second diffusion layer formed in upper end portions of two opposing sidewall portions of the concave portion, to form the channels at portions between the first diffusion layer and the second diffusion layer in the two sidewall portions.
6. The memory device according to claim 5 , wherein
the memory element is disposed below the first diffusion layer.
7. The memory device according to claim 1 , wherein
the first node is disposed on a side of the transistor opposite from the second node.
8. The memory device according to claim 1 , further comprising:
a data line connected to the memory element.
9. The memory device according to claim 8 , wherein
the data line is parallel to the bit line.
10. The memory device according to claim 1 , wherein
the word line is wired in a vertical direction and the bit line is wired in a lateral direction to intersect with the word line.
11. A method of manufacturing a memory device, comprising:
forming a memory element and a transistor;
wherein a first node of the transistor connects to the memory element,
wherein a word line connects to a gate electrode of the transistor,
wherein a bit line directly connects to a second node of the transistor,
wherein the transistor comprises current paths through channels on opposing sidewalls of the transistor and the current paths are not in contact with a bottom side of the gate electrode, wherein the bottom side is furthest from the bit line, and
wherein, after flowing through the channels, the current paths flow past the bottom side of the gate electrode to the memory element disposed below the bottom side of the gate electrode.
12. The method according to claim 11 , wherein
the gate electrode of the transistor is a buried gate structure.
13. The method according to claim 12 , wherein
the buried gate structure is within a concave portion in a substrate.
14. The method according to claim 13 , wherein
the substrate is an SOI substrate.
15. The method according to claim 11 , wherein
the memory element is an MTJ element.
16. The method according to claim 11 , wherein
the transistor comprises a first diffusion layer formed in a bottom portion of a concave portion, and a second diffusion layer formed in upper end portions of two opposing sidewall portions of the concave portion, to form the channels at portions between the first diffusion layer and the second diffusion layer in the two sidewall portions.
17. The method according to claim 16 , wherein
the memory element is disposed below the first diffusion layer.
18. The method according to claim 11 , wherein
the first node is disposed on a side of the transistor opposite from the second node.
19. The method according to claim 11 , further comprising:
a data line connected to the memory element.
20. A memory device, comprising:
a memory element and a transistor;
wherein a first node of the transistor connects to the memory element,
wherein a word line connects to a gate electrode of the transistor,
wherein a bit line connects to a second node of the transistor, and
wherein the transistor comprises current paths through channels on opposing sidewalls of the transistor and the current paths are not in contact with a bottom of the gate electrode, and
wherein the memory element is disposed below a first diffusion layer of the transistor.