Active strap magnetic random access memory cells configured to perform thermally-assisted writing

1. A magnetic random access memory (MRAM) cell with a thermally assisted writing procedure comprising

a magnetic tunnel junction formed from a magnetic storage layer, a reference layer, and an insulating layer inserted between the reference layer and the storage layer; and

a first strap portion laterally connecting one end of the magnetic tunnel junction to a first selection transistor;

wherein the cell further comprises a second strap portion extending opposite to the first strap portion and connecting laterally said one end of the magnetic tunnel junction to a second selection transistor,

and in that said first and second strap portions being adapted for passing a portion of current via the first and second selection transistors,

wherein said portion of current comprises a heating current for heating said magnetic tunnel junction to a high temperature threshold.

2. The cell according to claim 1 , wherein the first and second strap portions have a sheet resistance above 200 Ω/square.

3. The cell according to claim 2 , wherein the first and second strap portions have a cross section smaller than 3×10 −11 cm 2 .

4. The cell according to claim 2 , wherein the first and second strap portions are made of tantalum nitride.

5. The cell according to claim 1 , wherein the first and second strap portions connect the magnetic tunnel junction on the side of the storage layer.

6. The cell according to claim 1 , wherein at least part of the storage layer is comprised within the first and second strap portion.

7. The cell according to claim 1 , wherein said portion of current further comprises a field current adapted to generate a magnetic field for aligning the magnetization of the storage layer in accordance with the polarity of the field current.

8. The cell according to claim 1 , wherein said portion of current comprises a field current adapted to generate a magnetic field for aligning the magnetization of the storage layer in accordance with the polarity of the field current.

9. The cell according to claim 1 , further comprising a field line adapted to pass a field current for aligning the magnetization of the storage layer in accordance with the polarity of the field current.

10. The cell according to claim 1 , further comprising a bit line connected to the other end of the magnetic tunnel junction and adapted to pass a spin-polarized write current across the magnetic tunnel junction, via at least one of the selection transistors, for aligning the magnetization of the storage layer in accordance with the flow direction of the spin polarized write current.

11. A magnetic memory device comprising a matrix containing a plurality of magnetic random access memory (MRAM) cells with a thermally assisted writing procedure, each cell comprising a magnetic tunnel junction formed from a magnetic storage layer, a reference layer, and an insulating layer inserted between the reference layer and the storage layer; a first strap portion laterally connecting one end of the magnetic tunnel junction to a first selection transistor; and a second strap portion extending opposite to the first strap portion and connecting laterally the one end of the magnetic tunnel junction to a second selection transistor; said first and second strap portions being adapted for passing a portion of current via the first and second selection transistors, wherein

said portion of current comprises a heating current for heating said magnetic tunnel junction to a high temperature threshold.

12. A method for writing in a magnetic random access memory (MRAM) cell with a thermally assisted writing procedure comprising a magnetic tunnel junction formed from a magnetic storage layer, a reference layer, and an insulating layer inserted between the reference layer and the storage layer; a first strap portion laterally connecting one end of the magnetic tunnel junction to a first selection transistor; and a second strap portion extending opposite to the first strap portion and connecting laterally the one end of the magnetic tunnel junction to a second selection transistor; comprising

during a writing procedure

passing a heating current in said first and second strap portions via the first and second selection transistors for heating said magnetic tunnel junction to a high temperature threshold;

after the magnetic tunnel has reached the high temperature threshold, switching the magnetization of the storage layer.

13. The method according to claim 12 , wherein said switching the magnetization of the storage layer comprises passing a field current in said first and second strap portions via the first and second selection transistors.

14. The method according to claim 12 , wherein the cell further comprising a field line, said switching the magnetization of the storage layer comprising passing a field current in the field line.

15. The method according to claim 12 , wherein the cell further comprising a bit line connected to the other end of the magnetic tunnel junction, said switching the magnetization of the storage layer comprising passing a spin polarized write current across the magnetic tunnel junction, via at least one of the selection transistors.