Random access memory device utilizing a vertically oriented select transistor
View Patent ↗A memory structure has a vertically oriented access transistor with an annular gate region. A transistor is fabricated such that the channel of the transistor extends outward with respect to the surface of the substrate. An annular gate is fabricated around the vertical channel such that it partially or completely surrounds the channel. A buried annular bitline may also be implemented. After the vertically oriented transistor is fabricated with the annular gate, a storage device may be fabricated over the transistor to provide a memory cell.
1. A memory device comprising:
a substrate;
a non-volatile memory storage device; and
an access device coupled between the substrate and the storage device, said access device comprising:
a vertical channel coupled between a first source/drain and a second source/drain; and
a ring-like gate region disposed about at least a portion of the vertical channel and configured to initiate conduction between the first source/drain and the second source/drain.
2. The memory device, as set forth in claim 1 , wherein the storage device comprises a magnetic tunnel junction.
3. The memory device, as set forth in claim 1 , wherein the vertical channel comprises silicon (Si).
4. The memory device, as set forth in claim 1 , wherein the gate region comprises polysilicon.
5. The memory device, as set forth in claim 1 , wherein the gate region comprises a circular ring.
6. The memory device, as set forth in claim 1 , wherein the gate region is disposed about the vertical channel forming a continuous ring thereabout.
7. The memory device, as set forth in claim 1 , wherein the gate region is disposed at least approximately halfway around a portion of the vertical channel forming a semi-annular ring thereabout.
8. The memory device, as set forth in claim 1 , wherein the gate region is coupled to a wordline of a memory array.
9. The memory device, as set forth in claim 1 , wherein the storage device is coupled to the first source/drain.
10. The memory device, as set forth in claim 9 , comprising a bitline coupled to the second source/drain.
11. The memory device, as set forth in claim 10 , wherein the bitline is configured to form a ring around at least a portion of the channel such that the ring is directly adjacent to the second source/drain.
12. The memory device, as set forth in claim 11 , wherein the bitline is disposed about the vertical channel forming a continuous ring thereabout.
13. The memory device, as set forth in claim 11 , wherein the bitline is disposed at least approximately halfway around a portion of the vertical channel forming a semi-annular ring thereabout.
14. The memory device, as set forth in claim 11 , wherein the bitline comprises polysilicon.
15. A processing system comprising:
a microprocessor; and
a memory device, said memory device comprising:
a substrate;
a non-volatile memory storage device; and
an access device coupled between the substrate and the storage device, said access device comprising:
a vertical channel coupled between a first source/drain and a second source/drain; and
a ring-like gate region disposed about at least a portion of the vertical channel and configured to initiate conduction between the first source/drain and the second source/drain.
16. The processing system as set forth in claim 15 , wherein the storage device comprises a magnetic tunnel junction.
17. The processing system as set forth in claim 15 , wherein the vertical channel comprises silicon (Si).
18. The processing system as set forth in claim 15 , wherein the gate region comprises polysilicon.
19. The processing system as set forth in claim 15 , wherein the gate region comprises a circular ring.
20. The processing system as set forth in claim 15 , wherein the gate region is disposed about the vertical channel forming a continuous ring thereabout.
21. The processing system as set forth in claim 15 , wherein the gate region is disposed at least approximately halfway around a portion of the vertical channel forming a semi-annular ring thereabout.
22. The processing system as set forth in claim 15 , wherein the gate region is coupled to a wordline of a memory array.
23. The processing system, as set forth in claim 15 , wherein the storage device is coupled to the first source/drain.
24. The processing system, as set forth in claim 23 , comprising a bitline coupled to the second source/drain.
25. The processing system, as set forth in claim 24 , wherein the bitline is configured to form a ring around at least a portion of the channel such that the ring is directly adjacent to the second source/drain.
26. The processing system, as set forth in claim 25 , wherein the bitline is disposed about the vertical channel forming a continuous ring thereabout.
27. The processing system, as set forth in claim 25 , wherein the bitline is disposed at least approximately halfway around a portion of the vertical channel forming a semi-annular ring thereabout.
28. The processing system, as set forth in claim 25 , wherein the bitline comprises polysilicon.