Semiconductor memory having both volatile and non-volatile functionality including resistance change material and method of operating
Semiconductor memory is provided wherein a memory cell includes a capacitorless transistor having a floating body configured to store data as charge therein when power is applied to the cell. The cell further includes a nonvolatile memory comprising a resistance change element configured to store data stored in the floating body under any one of a plurality of predetermined conditions. A method of operating semiconductor memory to function as volatile memory, while having the ability to retain stored data when power is discontinued to the semiconductor memory is described.
1. A semiconductor memory array comprising:
a plurality of semiconductor memory cells arranged in a matrix of rows and columns, wherein each said semiconductor memory cell comprises:
a capacitorless transistor having a floating body having a first conductivity type selected from n-type conductivity type and p-type conductivity type and configured to store data when power is applied to said memory cell and first and second regions located such that at least a portion of said floating body is located between said first and second regions;
a nonvolatile memory comprising a resistance change element configured to store said data stored in said capacitorless transistor upon transfer thereto;
a buried layer region having a second conductivity type selected from said n-type conductivity type and said p-type conductivity type and being different from said first conductivity type;
wherein said buried layer region is commonly connected to at least two of said memory cells;
wherein when said floating body has a first charge level, said nonvolatile memory is configured to a first resistivity level upon transfer of said data to said nonvolatile memory; and
wherein when said floating body has a second charge level, said nonvolatile memory is configured to a second resistivity level upon transfer of said data to said nonvolatile memory.
2. The semiconductor memory array of claim 1 , wherein said resistance change element comprises a phase change material.
3. The semiconductor memory array of claim 1 , wherein said resistance change element comprises a metal-oxide-metal system.
4. The semiconductor memory array of claim 1 , wherein said floating body is configured to store said data as a state of said capacitorless transistor as charge therein.
5. The semiconductor memory array of claim 1 , wherein said nonvolatile memory stores said data stored in said capacitorless transistor upon loss of power to said memory cell, and wherein said memory cell is configured to perform a shadowing process during which said data in said capacitorless transistor is loaded into and stored in said nonvolatile memory.
6. The semiconductor memory array of claim 1 , wherein said capacitorless transistor is fabricated on a silicon on insulator substrate.
7. The semiconductor memory array of claim 1 , wherein said capacitorless transistor is formed in a fin.
8. The semiconductor memory array of claim 1 , wherein said resistance change element comprises a bottom electrode, a resistance change material and a top electrode.
9. The semiconductor memory array of claim 1 , wherein said data stored in said capacitorless transistor is transferred to said nonvolatile memory upon loss of power to said memory array.
10. The semiconductor memory array of claim 1 , wherein said data stored in said capacitorless transistor is transferred to said nonvolatile memory upon receiving an instruction to back up said data stored in said capacitorless transistor.
11. An integrated circuit comprising:
a semiconductor memory array comprising:
a plurality of semiconductor memory cells arranged in a matrix of rows and columns, wherein each said semiconductor memory cell comprises:
a capacitorless transistor having a floating body having a first conductivity type selected from n-type conductivity type and p-type conductivity type and configured to store data when power is applied to said memory cell and first and second regions located such that at least a portion of said floating body is located between said first and second regions;
a nonvolatile memory comprising a resistance change element configured to store data stored in said capacitorless transistor upon transfer thereto;
a buried layer region having a second conductivity type selected from said n-type conductivity type and said p-type conductivity type and being different from said first conductivity type; and
a buried layer terminal electrically connected to said buried layer region;
wherein when said floating body has a first charge level, said nonvolatile memory is configured to a first resistivity level upon transfer of said data to said nonvolatile memory; and
wherein when said floating body has a second charge level, said nonvolatile memory is configured to a second resistivity level upon transfer of said data to said nonvolatile memory; and
a control circuit configured to perform said transfer of said data.
12. The integrated circuit of claim 11 , wherein said resistance change element comprises a phase change material.
13. The integrated circuit of claim 11 , wherein said resistance change element comprises a metal-oxide-metal system.
14. The integrated circuit of claim 11 , wherein said floating body is configured to store said data as a state of said capacitorless transistor.
15. The integrated circuit of claim 11 , wherein said nonvolatile memory stores said data stored in said capacitorless transistor upon loss of power to said memory cell, and wherein said memory cell is configured to perform a shadowing process during which said data in said capacitorless transistor is loaded into and stored in said nonvolatile memory.
16. The integrated circuit of claim 11 , wherein said capacitorless transistor is fabricated on a silicon on insulator substrate.
17. The integrated circuit of claim 11 , wherein said capacitorless transistor is formed in a fin.
18. The integrated circuit of claim 11 , wherein said resistance change element comprises a bottom electrode, a resistance change material and a top electrode.
19. The integrated circuit of claim 11 , wherein said data stored in said capacitorless transistor is transferred to said nonvolatile memory upon loss of power to said memory array.
20. The integrated circuit of claim 11 , wherein said data stored in said capacitorless transistor is transferred to said nonvolatile memory upon receiving an instruction to back up said data stored in said capacitorless transistor.