Granted Patent B2

US 7,285,832 · App. 11/192,956 · Granted Oct 23, 2007

Abstract

Claims (28)

1. A multiport memory cell, comprising:

a first word line comprising a gate electrode of a first transistor;

a first bit line pair including a first bit line and a first bit line bar, wherein the first bit line is connected to a first source/drain terminal of the first transistor; and the first bit line bar is connected to a second source/drain terminal of the first transistor;

a second word line comprising a gate electrode of a second transistor;

a second bit line pair including a second bit line and a second bit line bar, wherein the second bit line is connected to a first source/drain terminal of the second transistor; and the second bit line bar is connected to a second source/drain terminal of the second transistor; and

a conductive path between an electrically floating body of the first transistor and an electrically floating body of the second transistor.

2. The memory cell of claim 1 , wherein the first word line overlies a first portion of a common body and wherein the second word line overlies a second portion of the common body.

3. The memory cell of claim 1 , wherein the common body comprises a semiconductor layer overlying a buried isolation layer.

4. The memory cell of claim 3 , wherein the common body is positioned vertically between the buried oxide layer and a gate dielectric layer and wherein the common body is positioned laterally between first and second source/drain regions formed in the semiconductor layer.

5. The memory cell of claim 4 , wherein the first bit line contacts the first source/drain region and the first bit line bar contacts the second source/drain region and further wherein the first transistor includes an isolation structure between the first and second source/drain regions.

6. The memory cell of claim 5 , wherein the common body portion is laterally adjacent to the isolation structure and the first and second source/drain regions and wherein the first word line overlies the body portion and defines a boundary between the body portion and the source/drain regions.

7. The memory cell of claim 5 , wherein the first transistor is configured to form a conductive path from the first source/drain region to the second source/drain region when the first word line is biased ON, and wherein the conductive path circumvents the isolation structure.

8. The memory cell of claim 1 , wherein portions of the first and second word lines are separated by a gap and wherein spacers on sidewalls of the first and second word lines cover the gap wherein the spacers prevent an implant performed after formation of the spacers from introducing an impurity into a portion of the body underlying the gap.

9. The memory cell of claim 1 , further comprising:

a third word line coupled to a gate electrode of a third transistor; and

a third bit line pair including a third bit line and a third bit line bar, wherein the third bit line is connected to a third source/drain terminal of the third transistor and the third bit line bar is connected to a second source/drain terminal of the third transistor;

wherein the conductive path further comprises an conductive path between the first transistor body and the third transistor body.

10. A multi port memory cell, comprising:

a first transistor including a first gate electrode and a second transistor including a second gate electrode, wherein a portion of the first gate electrode is parallel to a portion of the second gate electrode;

spacer structures on first sidewalls of the first and second gate electrodes wherein the spacer structures have a first width;

a spacer mask spanning a distance between the parallel portions of the first and second gate electrodes, wherein the distance is less than twice the first width; and

a contiguous body portion, shared by the first and second transistors, underlying the first and second gate electrodes.

11. The memory cell of claim 10 , further comprising a first bit line pair connected to source/drain regions of the first transistor and an independent second bit line pair connected to source/drain regions of the second transistor.

12. The memory cell of claim 11 , wherein the first transistor includes an isolation structure disposed between the source/drain regions of the first transistor.

13. The memory cell of claim 12 , wherein the body portion is laterally adjacent to the source/drain regions of the first transistor and to the isolation structure and wherein the first gate electrode overlies the body portion and defines a boundary between the body portion and the first and second source/drain regions.

14. The memory cell of claim 13 , wherein a portion of the isolation structure extends under the first gate electrode.

15. The memory cell of claim 10 , further comprising third and fourth transistors including third and fourth gate electrodes respectively, wherein a portion of the first gate electrode is parallel to a portion of the third gate electrode, a portion of the third gate electrode is parallel to the fourth electrode, and a portion of the fourth gate electrode is parallel to the second gate electrode.

16. The memory cell of claim 15 , further comprising spacer structures on sidewalls of the third and fourth transistors wherein the spacers converge each of the parallel portions and wherein the contiguous body portion is shared by the first, second, third, and fourth transistors.

Assignments (32)