SRAM cell comprising FinFETs

1. A Static Random Access Memory (SRAM) cell comprising:

a first long boundary and a second long boundary parallel to a first direction;

a first short boundary and a second short boundary parallel to a second direction perpendicular to the first direction, wherein the first and the second long boundaries are longer than, and form a rectangle with, the first and the second short boundaries;

a CVss line carrying a VSS power supply voltage crossing the first long boundary and the second long boundary, wherein the CVss line is parallel to the second direction;

a bit-line and a bit-line bar on opposite sides of the CVss line, wherein the bit-line and the bit-line bar are configured to carry complementary bit-line signals;

a word-line parallel to the first direction; and

a first CVdd line and a second CVdd line parallel to the first direction and on opposite sides of the word-line, wherein the first CVdd line and the second CVdd line are configured to carry a positive power supply voltage.

2. The SRAM cell of claim 1 , wherein the CVss line is wider than the bit-line and the bit-line bar.

3. The SRAM cell of claim 1 , wherein a ratio of a length of the first long boundary to a length of the first short boundary is greater than about 2.

4. The SRAM cell of claim 1 further comprising:

a p-well region in a center region of the SRAM cell, wherein the CVss line overlaps the p-well region; and

a first and a second n-well region on opposite sides of the p-well region.

5. The SRAM cell of claim 4 further comprising:

a first pull-up Fin Field-Effect Transistor (FinFET) and a second pull-up FinFET formed on the first and the second n-well regions, respectively;

a first pull-down FinFET and a second pull-down FinFET formed on the p-well region; and

a first and a second pass-gate FinFET formed on the first and the second n-well regions, respectively.

6. A Static Random Access Memory (SRAM) cell comprising:

a p-well region;

a first and a second n-well region on opposite sides of the p-well region;

a CVss line carrying a VSS power supply voltage over the p-well region, wherein the CVss line is parallel to an interface between the p-well region and the first n-well region;

a word-line perpendicular to the interface;

a first CVdd line and a second CVdd line perpendicular to the interface and on opposite sides of the word-line, wherein the first CVdd line and the second CVdd line are configured to carry a positive power supply voltage;

a first pull-up Fin Field-Effect Transistor (FinFET) and a second pull-up FinFET in the first n-well region and the second n-well region, respectively;

a first pull-down FinFET and a second pull-down FinFET in the p-well region; and

a first pass-gate FinFET and a second pass-gate FinFET in the first n-well region and the second n-well region, respectively.

7. The SRAM cell of claim 6 further comprising a bit-line and a bit-line bar on opposite sides of the CVss line, wherein the bit-line and a bit-line bar are configured to carry complementary bit-line signals.

8. The SRAM cell of claim 6 further comprising a long boundary and a short boundary, with the short boundary shorter than the long boundary, wherein the CVss line is parallel to the short boundary.

9. The SRAM cell of claim 8 , wherein a length of the long boundary to a length of the short boundary is greater than about 2.

10. The SRAM cell of claim 6 further comprising:

a third pull-up FinFET comprising a gate connected to gates of the first pull-up FinFET and the first pull-down FinFET;

a third pass-gate FinFET cascaded with the third pull-up FinFET; and

a read word-line connected to a gate of the third pass-gate FinFET.

11. The SRAM cell of claim 6 further comprising a third pass-gate FinFET and a fourth pass-gate FinFET, wherein the first pass-gate FinFET and the second pass-gate FinFET form a portion of a first port of the SRAM cell, and wherein the third pass-gate FinFET and the fourth pass-gate FinFET form a portion of a second port of the SRAM cell.

12. A Static Random Access Memory (SRAM) cell comprising:

a p-well region;

a first n-well region and a second n-well region on opposite sides of the p-well region;

a long boundary and a short boundary, with the short boundary shorter than the long boundary;

a CVss line carrying a VSS power supply voltage overlapping the p-well region, wherein the CVss line is parallel to the short boundary;

a bit-line and a bit-line bar on opposite sides of the CVss line, wherein the bit-line and the bit-line bar are configured to carry complementary bit-line signals, and wherein the bit-line and the bit-line bar overlap the first n-well region and the second n-well region, respectively;

a word-line parallel to the long boundary;

a first CVdd line and a second CVdd line parallel to the long boundary and on opposite sides of the word-line, wherein the first CVdd line and the second CVdd line are configured to carry a positive power supply voltage;

a first pull-up Fin Field-Effect Transistor (FinFET) and a second pull-up FinFET in the first n-well region and the second n-well region, respectively;

a first pull-down FinFET and a second pull-down FinFET in the p-well region; and

a first pass-gate FinFET and a second pass-gate FinFET in the first n-well region and the second n-well region, respectively.

13. The SRAM cell of claim 12 , wherein a length of the long boundary to a length of the short boundary is greater than about 2.

14. The SRAM cell of claim 1 , wherein the SRAM cell is a six-transistor (6T) SRAM cells.

15. The SRAM cell of claim 6 , wherein the SRAM cell is a six-transistor (6T) SRAM cells.

16. The SRAM cell of claim 12 , wherein the SRAM cell is a six-transistor (6T) SRAM cells.