Semiconductor memory device

1 . A semiconductor memory device comprising:

a word line and a bit line arranged to intersect with each other;

a memory cell array region including a plurality of memory cells connected to said word line and said bit line; and

a transfer gate transistor arranged under said memory cell array region.

2 . The semiconductor memory device according to claim 1 , wherein

said bit line is arranged to planarly overlap with an impurity region of said transfer gate transistor over at least a partial longitudinal area of said impurity region, and

a region of said bit line planarly overlapping with said impurity region of said transfer gate transistor substantially has the same potential as said impurity region of said transfer gate transistor.

3 . The semiconductor memory device according to claim 2 , wherein

said bit line is arranged to planarly overlap with said impurity region of said transfer gate transistor over the entire longitudinal area of said impurity region.

4 . The semiconductor memory device according to claim 1 , wherein

a gate electrode part of said transfer gate transistor is arranged to extend along the extensional direction of said bit line.

5 . The semiconductor memory device according to claim 4 , provided with a plurality of said transfer gate transistors, further comprising a gate line, connected with said gate electrode parts of said plurality of transfer gate transistors, extending along the extensional direction of said word line.

6 . The semiconductor memory device according to claim 1 , wherein

an impurity region of said transfer gate transistor is arranged to extend along the extensional direction of said bit line.

7 . The semiconductor memory device according to claim 1 , wherein

said transfer gate transistor includes an n-channel transistor and a p-channel transistor, and

at least either said n-channel transistor or said p-channel transistor of said transfer gate transistor is arranged to extend along the extensional direction of said bit line.

8 . The semiconductor memory device according to claim 7 , further comprising an additional wiring connecting an impurity region of said n-channel transistor, an impurity region of said p-channel transistor and said bit line with each other.

9 . The semiconductor memory device according to claim 8 , wherein

said additional wiring is connected to said bit line on a position outside said word line located on the outermost position of said memory cell array region.

10 . The semiconductor memory device according to claim 1 , wherein

said memory cell array region includes a plurality of sub array regions, and

said bit line includes a main bit line and a sub bit line connected to said main bit line through said transfer gate transistor and arranged on said plurality of sub array regions.

11 . The semiconductor memory device according to claim 1 , wherein

said memory cells include ferroelectric films arranged between said word line and said bit line on the intersectional position between said word line and said bit line.

12 . A semiconductor memory device comprising:

a word line and a bit line arranged to intersect with each other;

a memory cell array region including a plurality of memory cells connected to said word line and said bit line; and

a peripheral circuit transistor having an impurity region, wherein

said bit line is arranged to planarly overlap with said impurity region of said peripheral circuit transistor at least over a partial longitudinal area of said impurity region, and

a region of said bit line planarly overlapping with said impurity region of said peripheral circuit transistor substantially has the same potential as said impurity region of said peripheral circuit transistor.

13 . The semiconductor memory device according to claim 12 , wherein

said bit line is arranged to planarly overlap with said impurity region of said peripheral circuit transistor over the entire longitudinal area of said impurity region.

14 . The semiconductor memory device according to claim 12 , wherein

said peripheral circuit transistor is arranged under said memory cell array region.

15 . The semiconductor memory device according to claim 12 , wherein

said peripheral circuit transistor is arranged outside said memory cell array region.

16 . The semiconductor memory device according to claim 12 , wherein

a gate electrode part of said peripheral circuit transistor is arranged to extend along the extensional direction of said bit line.

17 . The semiconductor memory device according to claim 16 , provided with a plurality of said peripheral circuit transistors, further comprising a gate line, connected with said gate electrode parts of said plurality of peripheral circuit transistors, extending along the extensional direction of said word line.

18 . The semiconductor memory device according to claim 12 , wherein

said impurity region of said peripheral circuit transistor is arranged to extend along the extensional direction of said bit line.

19 . The semiconductor memory device according to claim 12 , wherein

said peripheral circuit transistor includes an n-channel transistor and a p-channel transistor, and

at least either said n-channel transistor or said p-channel transistor of said peripheral circuit transistor is arranged to extend along the extensional direction of said bit line.

20 . The semiconductor memory device according to claim 19 , further comprising an additional wiring connecting an impurity region of said n-channel transistor, an impurity region of said p-channel transistor and said bit line with each other.

21 . The semiconductor memory device according to claim 20 , wherein

said additional wiring is connected to said bit line on a position outside said word line located on the outermost position of said memory cell array region.

22 . The semiconductor memory device according to claim 12 , wherein

said memory cell array region includes a plurality of sub array regions,

said bit line includes a main bit line and a sub bit line arranged on said plurality of sub array regions, and

said peripheral circuit transistor includes a transfer gate transistor interposed between said main bit line and said sub bit line.

23 . The semiconductor memory device according to claim 12 , wherein

said memory cells include ferroelectric films arranged between said word line and said bit line on the intersectional position between said word line and said bit line.