Semiconductor device

1. A semiconductor device comprising:

a first memory cell which includes a first memory transistor and a first selector transistor;

a second memory cell which includes a second memory transistor and a second selector transistor;

a first word line electrically coupled to a gate electrode of the first memory transistor and to a gate electrode of the second selector transistor;

a second word line electrically coupled to a gate electrode of the second memory transistor and to a gate electrode of the first selector transistor; and

a first source line electrically coupled to a source region of the first memory transistor and to a source region of the second memory transistor.

2. The semiconductor device according to claim 1 , further comprising:

a first bit line coupled to a drain region of the first selector transistor; and

a second bit line coupled to a drain region of the second selector transistor.

3. The semiconductor device according to claim 1 , wherein the first memory cell further includes a first shared source and drain region between the first memory transistor and the first selector transistor, and

the second memory cell further includes a second shared source and drain region between the second memory transistor and the second selector transistor.

4. The semiconductor device according to claim 3 , wherein the first source and drain region and the second source and drain region have lower impurity concentration than impurity concentrations of the source regions of the first memory transistor and the second memory transistor.

5. The semiconductor device according to claim 1 , wherein the first memory cell and the second memory cell are non-volatile memory cells, which allow an avalanche injection write operation to be performed on the first memory transistor and the second memory transistor thereof.

6. The semiconductor device according to claim 1 , wherein each of the first memory transistor and the second memory transistor includes a charge storage insulating film formed between the gate electrode thereof and a semiconductor substrate of the semiconductor device.

7. The semiconductor device according to claim 1 , wherein each of the first selector transistor and the second selector transistor includes a gate insulating film formed between the gate electrode thereof and a semiconductor substrate of the semiconductor device, and the gate insulating film has a lower withstand voltage than a voltage for erasing to be applied between the first source line and corresponding one of the first word line and the second word line.

8. The semiconductor device according to claim 1 , wherein each of the first selector transistor and the second selector transistor has a gate insulating film formed between the gate electrode thereof and a semiconductor substrate of the semiconductor device, and the gate insulating film has a higher withstand voltage than a voltage for reading to be applied to the gate electrode of each of the first selector transistor and the second selector transistor.

9. The semiconductor device according to claim 1 , wherein the first selector transistor and the first memory transistor alternate their relative positions or orientations in a plurality of such first memory cells in series coupling, and

the second selector transistor and the second memory transistor alternate their relative positions or orientations in a plurality of such second memory cells in series coupling, which are arranged along a side of the plurality of such first memory cells.

10. A semiconductor device comprising:

a first memory cell which includes a first memory transistor and a first selector transistor;

a second memory cell which includes a second memory transistor and a second selector transistor;

a third memory cell which includes a third memory transistor, and includes a third selector transistor which shares a first drain region with the first selector transistor;

a fourth memory cell which includes a fourth memory transistor, and which includes a fourth selector transistor which shares a second drain region with the second selector transistor;

a first word line electrically coupled to a gate electrode of the first memory transistor and to a gate electrode of the second memory transistor;

a second word line electrically coupled to a gate electrode of the third memory transistor and to a gate electrode of the fourth memory transistor;

a first source line electrically coupled to a source region of the first memory transistor and to a source region of the fourth memory transistor;

a second source line electrically coupled to a source region of the second memory transistor;

a third source line electrically coupled to a source region of the third memory transistor;

a first bit line electrically coupled to the first shared drain region; and

a second bit line electrically coupled to the second shared drain region.

11. The semiconductor device according to claim 10 , further comprising:

a first selection line electrically coupled to a gate electrode of the first selector transistor and to a gate electrode of the second selector transistor; and

a second selection line electrically coupled to a gate electrode of the third selector transistor and to a gate electrode of the fourth selector transistor.

12. The semiconductor device according to claim 10 , wherein the first memory cell, the second memory cell, the third memory cell, and the fourth memory cell are non-volatile memory cells, which allow an avalanche injection write operation to be performed on the first memory transistor, the second memory transistor, the third memory transistor, and the fourth memory transistor thereof.

13. The semiconductor device according to claim 10 , wherein each of the first memory transistor, the second memory transistor, the third memory transistor, and the fourth memory transistor includes a charge storage insulating film formed between the gate electrode thereof and a semiconductor substrate of the semiconductor device.

14. The semiconductor device according to claim 10 , each of the first memory transistor, the second memory transistor, the third memory transistor, and the fourth memory transistor includes a floating gate electrode sandwiched between upper and lower insulating films that are formed between the gate electrode thereof and a semiconductor substrate of the semiconductor device.

15. The semiconductor device according to claim 10 , wherein the first memory cell includes a shared source and drain region between the first memory transistor and the first selector transistor,

the second memory cell includes another shared source and drain region between the second memory transistor and the second selector transistor,

the third memory cell includes a further shared source and drain region between the third memory transistor and the third selector transistor, and

the fourth memory cell includes a further shared source and drain region between the fourth memory transistor and the fourth selector transistor.

16. The semiconductor device according to claim 15 , wherein the first shared source and drain region, the second shared source and drain region, the third shared source and drain region, and the fourth shared source and drain region have lower impurity concentrations than respective impurity concentrations of the respective source regions of the first memory transistor, the second memory transistor, the third memory transistor, and the fourth memory transistor, respectively.

17. The semiconductor device according to claim 10 , wherein each of the first selector transistor, the second selector transistor, the third selector transistor, and the fourth selector transistor includes a gate insulating film formed between the gate electrode thereof and a semiconductor substrate of the semiconductor device, and the gate insulating film has a lower withstand voltage than a voltage for erasing to be applied between corresponding one of the first and second word lines, and corresponding one of the first, second and third source lines.

18. The semiconductor device according to claim 10 , wherein each of the first selector transistor, the second selector transistor, the third selector transistor, and the fourth selector transistor includes a gate insulating film formed between the gate electrode thereof and a semiconductor substrate of the semiconductor device, and the gate insulating film has a higher withstand voltage than a voltage for reading to be applied to the gate electrode of each of the first selector transistor, the second selector transistor, the third selector transistor, and the fourth selector transistor.

19. The semiconductor device according to claim 1 , wherein the two source regions coupled to the first source line are disposed at positions aligned in a direction oblique to the first word line and the second word line.

20. The semiconductor device according to claim 1 , wherein an impurity diffusion region is formed beneath each of the source regions, and has a conductivity type which is different from that of each source region.