Memory device comprising an electrically floating body transistor and methods of operating
A semiconductor memory cell comprising an electrically floating body having two stable states is disclosed. A method of operating the memory cell is disclosed.
1. An integrated circuit comprising:
a semiconductor memory array comprising:
a plurality of semiconductor memory cells arranged in a matrix of rows and columns, wherein at least two of said semiconductor memory cells each include:
a memory transistor comprising a bi-stable floating body transistor having a first floating body region and a back-bias region configured to generate impact ionization when said memory cell is in one of first and second states, and wherein said back-bias region is configured so as not to generate impact ionization when the memory cell is in the other of said first and second states; and
an access device;
wherein said access device comprises a second floating body region;
wherein said bi-stable floating body transistor and said access device are electrically connected in series;
wherein said back-bias region is commonly connected to at least two of said plurality of semiconductor memory cells; and
a control circuit controlling an operation of said semiconductor memory array.
2. The integrated circuit of claim 1 , wherein a capacitance of said first floating body region is different from a capacitance of said second floating body region.
3. The integrated circuit of claim 1 , wherein said memory transistor further comprises a first gate region, and said access device further comprises a second gate region.
4. The integrated circuit of claim 3 , wherein a length of the first gate region is less than a length of the second gate region.
5. The integrated circuit of claim 3 , wherein a length of the first gate region is greater than a length of the second gate region.
6. The integrated circuit of claim 3 , wherein a capacitance of the first gate region is different from a capacitance of the second gate region.
7. The integrated circuit of claim 1 , wherein a volume of the first floating body region is smaller than a volume of the second floating body region.
8. The integrated circuit of claim 1 , further comprising at least one dummy gate region between said memory transistor and said access device.
9. The integrated circuit of claim 8 , wherein said memory transistor comprises a first gate region; and
wherein a work function of said at least one dummy gate region is higher than a work function of said first gate region.
10. The integrated circuit of claim 1 , wherein at least one of said at least two of said semiconductor memory cells is a multi-port memory cell.
11. The integrated circuit of claim 1 comprising a fin structure.
12. An integrated circuit comprising:
a semiconductor memory array comprising:
a plurality of semiconductor memory cells arranged in a matrix of rows and columns, wherein at least two of said semiconductor memory cells each include:
a first transistor having a first floating body;
a second transistor having a second floating body;
a buried layer underlying both of said first and second floating bodies;
a first source line region contacting said first floating body;
a first drain region separated from said first source line region and contacting said first floating body;
a first gate insulated from said first floating body;
an insulating member insulating said first floating body from said second floating body;
a second source line region contacting said second floating body;
a second drain region separated from said second source line region and contacting said second floating body; and
a second gate insulated from said second floating body;
wherein said first drain region is electrically connected to said second source line region;
wherein a capacitance of said first floating body is different from a capacitance of said second floating body;
wherein said back-bias region is commonly connected to at least two of said plurality of semiconductor memory cells; and
a control circuit controlling an operation of said semiconductor memory array.
13. The integrated circuit of claim 12 , wherein a volume of said first floating body is less than a volume of said second floating body.
14. The integrated circuit of claim 12 , wherein a length of said first gate is less than a length of said second gate.
15. The integrated circuit of claim 12 , wherein a length of said first gate is greater than a length of said second gate.
16. The integrated circuit of claim 12 , further comprising at least one dummy gate region between said first transistor and said second transistor.
17. The integrated circuit of claim 16 , wherein a work function of said at least one dummy gate region is greater than a work function of said first gate.
18. The integrated circuit of claim 12 , wherein said first transistor and said second transistor have the same conductivity type.
19. The integrated circuit of claim 12 , wherein at least one of said at least two of said semiconductor memory cells is a multi-port memory cell.
20. The integrated circuit of claim 12 comprising a fin structure.