TUNNEL TYPE MAGNETIC SENSOR HAVING FIXED MAGNETIC LAYER OF COMPOSITE STRUCTURE CONTAINING CoFeB FILM, AND METHOD FOR MANUFACTURING THE SAME
OwnerKazuaki Ikarashi, Eiji Umetsu +2inventors
InventorsKazuaki Ikarashi, Eiji Umetsu, Kenichi Tanaka, Kota Asatsuma
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Abstract
A second fixed magnetic layer is formed of a CoFeB layer of CoFeB and an interface layer of CoFe or Co provided in that order from the bottom. An insulating barrier layer composed of Al—O is formed on the second fixed magnetic layer. When a lamination structure composed of CoFeB/CoFe/Al—O is formed as described above, a low RA and a high rate of change in resistance (ΔR/R) can be simultaneously obtained. In addition, variations in RA and rate of change in resistance (ΔR/R) can be suppressed as compared to that in the past.
Claims25
A tunnel type magnetic sensor comprising:
- a lamination portion including a fixed magnetic layer that has a fixed magnetization direction;
- an insulating barrier layer;
- and a free magnetic layer that has a variable magnetization direction with respect to an external magnetic field, wherein the fixed magnetic layer, the insulating barrier layer and the free magnetic layer are laminated to each other in that order from the bottom,
- wherein the insulating barrier layer is formed of Al—O, and
- a barrier layer-side magnetic layer that forms at least a part of the fixed magnetic layer and that is in contact with the insulating barrier layer is formed to have a CoFeB region formed of CoFeB and an intervening region that is located between the CoFeB region and the insulating barrier layer and that is formed of CoFe or Co.
A tunnel type magnetic sensor comprising:
- a lamination portion including a fixed magnetic layer that has a fixed magnetization direction;
- an insulating barrier layer;
- and a free magnetic layer that has a variable magnetization direction with respect to an external magnetic field, wherein the fixed magnetic layer, the insulating barrier layer and the free magnetic layer are laminated to each other in that order from the bottom,
- wherein the insulating barrier layer is formed of Al—O,
- a barrier layer-side magnetic layer that forms at least a part of the fixed magnetic layer and that is in contact with the insulating barrier layer is formed of CoFeB, and
- in the barrier layer-side magnetic layer, a B concentration at an interface side in contact with the insulating barrier layer is lower than that at an opposite side opposite to the interface.
A tunnel type magnetic sensor comprising:
- a lamination portion including a fixed magnetic layer that has a fixed magnetization direction;
- an insulating barrier layer;
- and a free magnetic layer that has a variable magnetization direction with respect to an external magnetic field,
- the fixed magnetic layer, the insulating barrier layer and the free magnetic layer are laminated to each other in that order from the bottom,
- wherein the insulating barrier layer is formed of Al—O, and
- a barrier layer-side magnetic layer that forms at least a part of the fixed magnetic layer and that is in contact with the insulating barrier layer is formed to have a lamination structure including a CoFeB layer formed of CoFeB and an intervening layer that is located between the CoFeB layer and the insulating barrier layer and that is formed of CoFe or Co.
A method for manufacturing a tunnel type magnetic sensor having a lamination portion including a fixed magnetic layer that has a fixed magnetization direction, an insulating barrier layer, and a free magnetic layer that has a variable magnetization direction with respect to an external magnetic field, the fixed magnetic layer, the insulating layer and the free magnetic layer are laminated to each other in that order from the bottom, the method comprising:
- a) of laminating an interface layer composed of CoFe or Co on a CoFeB layer composed of CoFeB to form a barrier layer-side magnetic layer which forms at least a part of the fixed magnetic layer;
- (b) of forming the insulating barrier layer composed of Al—O on the barrier layer-side magnetic layer;
- and
- (c) of forming the free magnetic layer on the insulating barrier layer.
Dependencies are inferred from the claim text.