Magnetic sensor with dual TMR films and the method of making the same

1. A tunneling magnetoresistance (TMR) sensor device, comprising:

a first tunneling magnetoresistance (TMR) resistor comprising a first TMR film, the first TMR film comprising a synthetic anti-ferromagnetic pinned layer having a magnetization direction of a first reference layer orthogonal to a magnetization direction of a first free layer, wherein the first TMR film of the first TMR resistor is disposed on a first bottom lead;

a second TMR resistor comprising a second TMR film, the second TMR film comprising a double synthetic anti-ferromagnetic pinned layer having a magnetization direction of a second reference layer orthogonal to magnetization direction of a second free layer and anti-parallel to the magnetization direction of the first reference layer of the first TMR film, wherein the second TMR film of the second TMR resistor is disposed on a second bottom lead, the second bottom lead being separated from the first bottom lead by a dielectric layer;

a third TMR resistor comprising the second TMR film; and

a fourth TMR resistor comprising the first TMR film, wherein the first, second, third, and fourth TMR resistors are disposed in a same plane.

2. The TMR sensor device of claim 1 , wherein the first TMR resistor is adjacent to the second TMR resistor and the third TMR resistor, the second TMR resistor is adjacent to the first TMR resistor and the fourth TMR resistor, the third TMR resistor is adjacent to the first TMR resistor and the fourth TMR resistor, and the fourth TMR resistor is adjacent to the second TMR resistor and the third TMR resistor.

3. The TMR sensor device of claim 1 , wherein the first reference layer of the first TMR film has a magnetization direction anti-parallel to a magnetization direction of a first pinned layer of the first TMR film.

4. The TMR sensor device of claim 3 , wherein the first TMR film further comprises a first barrier layer, a first spacer layer, and a first antiferromagnet layer, and wherein the first barrier layer is disposed between the first reference layer and the first free layer, the first spacer layer is disposed between the first reference layer and the first pinned layer, and the first antiferromagnet layer is disposed adjacent to the first pinned layer.

5. The TMR sensor device of claim 1 , wherein the second TMR film comprises the second reference layer, a second pinned layer, and a third pinned layer disposed between the second reference layer and the second pinned layer, the second reference layer having a magnetization direction parallel to a magnetization direction of the second pinned layer and anti-parallel to a magnetization direction of the third pinned layer.

6. The TMR sensor device of claim 5 , wherein the second TMR film further comprises a second barrier layer, a second spacer layer, a third spacer layer, and a second antiferromagnetic layer, and wherein the second barrier layer is disposed between the second reference layer and the second free layer, the second spacer layer is disposed between the second reference layer and the third pinned layer, the third spacer layer is disposed between the second pinned layer and the third pinned layer, and the second antiferromagnet layer is disposed adjacent to the second pinned layer.

7. The TMR sensor device of claim 1 , wherein the first reference layer of the first TMR film comprises a Co/CoFe/Co multi-layer stack having a thickness of between about 20 Angstroms and about 30 Angstroms, and wherein the second reference layer of the second TMR film comprises a Co/CoFe/Co multi-layer stack having a thickness of between about 20 Angstroms and about 30 Angstroms.

8. A method of fabricating a TMR sensor device, comprising:

forming one or more bottom leads, wherein each of the one or more bottom leads is separated from adjacent bottom leads by a dielectric layer;

depositing a first TMR film over at least a first bottom lead, a second bottom lead, and the dielectric layer;

removing a first portion of the first TMR film disposed above the second bottom lead such that the first TMR film is disposed on the first bottom lead;

depositing a second TMR film over the first TMR film, the second bottom lead, and at least a portion of the dielectric layer, the second TMR film being different than the first TMR film; and

removing a first portion of the second TMR film disposed over the first TMR film such that the second TMR film is disposed on the second bottom lead.

9. The method of claim 8 , further comprising pattern formation of a first resistor, a second resistor, a third resistor, and a fourth resistor with designated geometries or shapes.

10. The method of claim 9 , further comprising:

forming first top leads over the first resistor and the fourth resistor comprising the first TMR film and second top leads over the second resistor and the fourth resistor comprising the second TMR film,

wherein the first resistor is adjacent to the second resistor and the third resistor, the second resistor is adjacent to the first resistor and the fourth resistor, the third resistor is adjacent to the first resistor and the fourth resistor, and the fourth resistor is adjacent to the second resistor and the third resistor.

11. The method of claim 10 , wherein the first TMR film comprises a synthetic anti-ferromagnetic pinned layer having a magnetization direction of a first reference layer orthogonal to a magnetization direction of a first free layer.

12. The method of claim 10 , wherein the second TMR film comprises a double synthetic anti-ferromagnetic pinned layer having magnetization directions orthogonal to a magnetization direction of a second free layer.

13. The method of claim 8 , wherein a reference layer of the first TMR film has a magnetization direction anti-parallel to a magnetization direction of a first pinned layer of the first TMR film, and wherein the second TMR film comprises a second reference layer, a second pinned layer, and a third pinned layer disposed between the second reference layer and the second pinned layer, the second reference layer having a magnetization direction parallel to a magnetization direction of the second pinned layer and anti-parallel to a magnetization direction of the third pinned layer.

14. A method of fabricating a TMR sensor device, comprising:

forming one or more bottom leads, wherein each of the one or more bottom leads is separated from adjacent bottom leads by a dielectric layer;

depositing a first TMR film over the one or more bottom leads and the dielectric layer, the first TMR film comprising a synthetic anti-ferromagnetic pinned layer having a magnetization direction of a first reference layer orthogonal to a magnetization direction of a first free layer;

depositing a first photoresist over a first portion of the first TMR film and at least a first bottom lead;

etching a second portion of the first TMR film to expose at least a second bottom lead such that the first TMR film is disposed on the first bottom lead;

removing the first photoresist;

depositing a second TMR film over the first TMR film, the second bottom lead, and the dielectric layer, the second TMR film comprising a double synthetic anti-ferromagnetic pinned layer having magnetization direction of a second reference layer orthogonal to a magnetization direction of a second free layer and opposite to the magnetization direction of the first reference layer of the first TMR film;

depositing a second photoresist over a first portion of the second TMR film and the second bottom lead;

etching a second portion of the second TMR film to expose the first TMR film such that the second TMR film is disposed on the second bottom lead; and

removing the second photoresist.

15. The method of claim 14 , further comprising pattern formation of a first resistor, a second resistor, a third resistor, and a fourth resistor with designated geometries or shapes.

16. The method of claim 15 , further comprising forming first top leads over the first resistor and the fourth resistor comprising the first TMR film and second top leads over the second resistor and the fourth resistor comprising the second TMR film.

17. The method of claim 15 , wherein each of the first, second, third, and fourth resistors is a TMR resistor or a TMR resistor array.

18. The method of claim 15 , wherein the first, second, third, and fourth resistors are disposed in a same plane.

19. The method of claim 15 , wherein the first resistor is adjacent to the second resistor and the third resistor, the second resistor is adjacent to the first resistor and the fourth resistor, the third resistor is adjacent to the first resistor and the fourth resistor, and the fourth resistor is adjacent to the second resistor and the third resistor.

20. The method of claim 14 , wherein the first portion of the first TMR film and the first portion of the second TMR film are equal in size.