Using isolated p-well transistor arrangements to avoid leakage caused by word line/bit line shorts
View Patent ↗Leakage in semiconductors, such as dynamic random access memory (DRAM) devices, caused by word line/bit line shorts can be avoided by locating transistors (e.g., isolator, current limiter, equalize) inside isolated p-wells.
1. A DRAM apparatus, comprising:
a storage cell; and
a bit line structure coupled to said storage cell for accessing said storage cell, said bit line structure including an equalize transistor coupled between said storage cell and an equalize voltage, said equalize transistor located in an isolated p-well.
2. The DRAM apparatus of claim 1 wherein the isolated p-well is negative biased.
3. The DRAM apparatus of claim 2 wherein the isolated p-well is biased to approximately −0.5 volts.
4. The DRAM apparatus of claim 1 wherein the isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
5. The DRAM apparatus of claim 1 wherein the equalize transistor is one of an NFET and an array-type transistor.
6. The DRAM apparatus of claim 5 wherein the isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
7. The DRAM apparatus of claim 1 including a plurality of said storage cells and a plurality of said bit line structures respectively coupled to said storage cells.
8. A DRAM apparatus, comprising:
a storage cell;
a bit line structure coupled to said storage cell for accessing said storage cell, said bit line structure including an isolator transistor coupled to said storage cell and located in an isolated p-well; and
a sense amplifier connected to the isolator transistor, the isolator transistor coupling the sense amplifier to said storage cell.
9. The DRAM apparatus of claim 8 wherein the isolated p-well is negative biased.
10. The DRAM apparatus of claim 9 wherein the isolated p-well is biased to approximately −0.5 volts.
11. The DRAM apparatus of claim 8 wherein the isolated p-well is one of an army p-well associated with said storage cell and a further p-well provided separately from said array p-well.
12. The DRAM apparatus of claim 8 wherein the isolator transistor is one of a thick oxide NFET and an array-type transistor.
13. The DRAM apparatus of claim 12 wherein the isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
14. The DRAM apparatus of claim 8 including a plurality of said storage cells and a plurality of said bit line structures respectively coupled to said storage cells.
15. The DRAM apparatus of claim 8 wherein said bit line structure includes an equalize transistor coupled between said storage cell and an equalize voltage, and located in an isolated p-well.
16. The DRAM apparatus of claim 15 including a plurality of said storage cells and a plurality of said bit line structures respectively coupled to said storage cells.
17. The DRAM apparatus of claim 15 wherein said isolator transistor and said equalize transistor are located in a same isolated p-well.
18. The DRAM apparatus of claim 17 wherein said same isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
19. The DRAM apparatus of claim 15 wherein the last-mentioned isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
20. The DRAM apparatus of claim 19 wherein the first-mentioned isolated p-well is one of said array p-well and a further p-well provided separately from said array p-well.
21. The DRAM apparatus of claim 19 wherein the last-mentioned isolated p-well is negative biased.
22. The DRAM apparatus of claim 15 wherein said bit line structure includes a current limiter transistor in series with said isolator transistor and said equalize transistor, and located in an isolated p-well.
23. The DRAM apparatus of claim 22 wherein said current limiter transistor and said equalize transistor are located in a same isolated p-well.
24. The DRAM apparatus of claim 23 wherein said same isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
25. The DRAM apparatus of clam 23 wherein said isolator transistor is located in said same isolated p-well.
26. The DRAM apparatus of claim 25 wherein said same isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
27. The DRAM apparatus of claim 22 wherein each of said isolated p-wells is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
28. The DRAM apparatus of claim 22 including a plurality of said storage cells and a plurality of said bit line structures respectively coupled to said storage cells.
29. The DRAM apparatus of claim 8 wherein said bit line structure includes a current limiter transistor in series with said isolator transistor and located in an isolated p-well.
30. The DRAM apparatus of claim 29 wherein said current limiter transistor and said isolator transistor are located in a same isolated p-well.
31. The DRAM apparatus of claim 30 wherein said same isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
32. The DRAM apparatus of claim 29 wherein the last-mentioned isolated p-well is negative biased.
33. The DRAM apparatus of claim 29 wherein the last-mentioned isolated p-well is one of an array p-well associated with said storage veil and a further p-well provided separately from said array p-well.
34. The DRAM apparatus of claim 29 wherein the current limiter transistor is one of a thick oxide NFET and an array-type transistor.
35. The DRAM apparatus of claim 29 wherein the first-mentioned isolated p-well is one of an array p-well and a further p-well provided separately from said array p-well.
36. A DRAM apparatus, comprising:
a storage cell; and
a bit line structure coupled to said storage cell for accessing said storage cell, said bit line structure including an equalize transistor coupled between said storage cell and an equalize voltage, and a current limiter transistor in series with said equalize transistor, said current limiter transistor located in an isolated p-well.
37. The DRAM apparatus of claim 36 wherein the isolated p-well is negative biased.
38. The DRAM apparatus of claim 37 wherein the isolated p-well is biased to approximately −0.5 volts.
39. The DRAM apparatus of claim 36 wherein the isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
40. The DRAM apparatus of claim 36 wherein the current limiter transistor is one of a thick oxide NFET and an array-type transistor.
41. The DRAM apparatus of claim 40 wherein the isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
42. The DRAM apparatus of claim 36 including a plurality of said storage cells and a plurality of said bit line structures respectively coupled to said storage cells.
43. The DRAM apparatus of claim 36 wherein said equalize transistor is located in an isolated p-well.
44. The DRAM apparatus of claim 43 wherein said equalize transistor and said current limiter transistor are located in a same isolated p-well.
45. The DRAM apparatus of claim 44 wherein said same isolated p-well is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
46. The DRAM apparatus of claim 43 wherein each of said isolated p-wells is one of an array p-well associated with said storage cell and a further p-well provided separately from said array p-well.
47. The DRAM apparatus of claim 43 including a plurality of said storage cells and a plurality of said bit line structures respectively coupled to said storage cells.
48. A DRAM apparatus, comprising:
a storage cell; and
a bit line structure coupled to said storage cell for accessing said storage cell, said bit line structure including an equalize transistor coupled between said storage cell and an equalize voltage, and a current limiter transistor in series with said equalize transistor, wherein said current limiter transistor is an array-type transistor.