JP2005085821A - Magnetoresistive effect element and magnetic memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetoresistive effect device capable of restraining a variation from occurring in the switching magnetic field of a free layer, and to provide a magnetic memory using the same. <P>SOLUTION: The magnetoresistive effect device comprises: a magnetization-fixed layer containing a first ferromagnetic film whose direction of magnetization is substantially fixed in a certain direction; a non-magnetic layer deposited on the magnetization-fixed layer; a magnetization free layer containing a second ferromagnetic film whose direction of magnetization varies corresponding to an external magnetic field; and an amorphous conductive layer formed on the magnetization free layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetoresistive effect element and a magnetic memory, and more particularly to a magnetoresistive effect element having a ferromagnetic tunnel junction type or spin valve type structure and a magnetic memory using the same.

  A magnetoresistive element using a magnetic film is used for a magnetic head, a magnetic sensor, and the like, and has been proposed to be used for a solid magnetic memory (magnetoresistance effect memory: MRAM (Magnetic Random Access Memory)). .

  In a so-called spin-valve structure film in which one non-magnetic conductive layer is inserted between two magnetic metal layers, a current flows perpendicularly to the film surface, and a giant magneto-resistance effect (GMR) There has been proposed a magnetoresistive element capable of obtaining the above.

  In recent years, in a sandwich structure film in which a single dielectric is inserted between two magnetic metal layers, a so-called “ferromagnetic” element is used as a magnetoresistive effect element utilizing a tunnel current by flowing a current perpendicular to the film surface. A tunnel junction element (Tunneling Magneto-Resistance effect: TMR element) has been proposed. In the ferromagnetic tunnel junction element, since the magnetoresistance change rate of 20% or more can be obtained, the possibility of civilian application to MRAM has increased.

In this ferromagnetic tunnel junction device, a thin Al (aluminum) layer having a thickness of 0.6 nm to 2.0 nm is formed on a ferromagnetic electrode, and then the surface thereof is exposed to oxygen glow discharge or oxygen gas to thereby form Al _2. This can be realized by forming a tunnel barrier layer made of O ₃ .

  In addition, a ferromagnetic single tunnel junction having a structure in which an antiferromagnetic layer is provided on one ferromagnetic layer on one side of the ferromagnetic single tunnel junction and one side is a fixed magnetization layer has been proposed (for example, a patent) Reference 1).

  Further, a ferromagnetic tunnel junction via magnetic particles dispersed in a dielectric and a ferromagnetic double tunnel junction (continuous film) have been proposed.

  Also in these cases, the magnetoresistance change rate of 20 to 50% can be obtained, and the magnetoresistance change rate even if the voltage value applied to the ferromagnetic tunnel junction element is increased in order to obtain a desired output voltage value. Therefore, there is a possibility of application to MRAM.

The magnetic recording device using these ferromagnetic single tunnel junction or ferromagnetic double tunnel junction is nonvolatile, fast as 10 nanoseconds or less and write read time, have the potential that the number of times of rewriting even ¹⁰¹⁵ times or more. In particular, as described above, the magnetic recording element using the ferromagnetic double tunnel junction does not decrease the magnetoresistance change rate even if the voltage value applied to the ferromagnetic tunnel junction element is increased in order to obtain a desired output voltage value. Therefore, a large output voltage can be obtained, and preferable characteristics as a magnetic recording element can be obtained.

  However, regarding the memory cell size, when the 1Tr (transistor) -1TMR architecture is used, there is a problem that the size cannot be reduced below that of a semiconductor dynamic random access memory (DRAM).

  In order to solve this problem, a diode type architecture in which a TMR cell and a diode are connected in series between a bit line and a word line, or a TMR cell is simply arranged between a bit line and a word line. A matrix architecture has been proposed.

By the way, when a magnetic sensor, a magnetic head, or a magnetic memory using a magnetoresistive effect element such as a spin valve type or a tunnel junction type is manufactured, it is often necessary to provide a thick metal layer on the magnetoresistive effect element. For example, when these magnetoresistive elements are applied to MRAM, it is necessary to form a thick metal hard mask layer, metal vias, thick bit lines, etc. above the magnetoresistive elements (for example, Non-Patent Documents 1 and 2). reference)
Japanese Patent Laid-Open No. 10-4227 J. Appl. Phys. 79, 4724 (1996) J. Appl. Phys. 85, 5828 (1999)

  However, as a result of the study by the present inventors, when a magnetic sensor, a magnetic head, a magnetic memory, or the like is formed using a magnetoresistive effect element such as a spin valve type or a tunnel junction type, a magnetization free layer (“free layer”, It has been found that the switching magnetic field necessary for the magnetization reversal of the “easy magnetization layer” or the like tends to “vari” from a predetermined value. For example, when these magnetoresistive elements are applied to MRAM, the “variation” of the switching magnetic field at the time of writing is large, and malfunctions such as crosstalk are likely to occur. When the capacity is increased, the probability further increases and the yield increases. It turns out that there is a problem of getting worse.

  As a result of further studies by the present inventors, it has been found that one of the causes for causing such “variation” of the switching magnetic field is to form a thick conductive layer on the upper side of the magnetoresistive effect element. For example, if a thick metal hard mask layer, a metal via, a thick bit line, or the like is formed on the magnetoresistive effect element as described above, strain is easily introduced into the free layer. It was found to induce "variation".

  The present invention has been made based on recognition of such a problem, and an object thereof is to provide a magnetoresistive effect element capable of suppressing “variation” of a switching magnetic field of a free layer and a magnetic memory using the same. It is in.

  In order to solve the above-described problem, according to the present invention, a magnetization pinned layer including a first ferromagnetic film whose magnetization direction is substantially pinned in one direction and the magnetization pinned layer are provided. A nonmagnetic layer, a magnetization free layer provided on the nonmagnetic layer and including a second ferromagnetic film whose magnetization direction changes corresponding to an external magnetic field, and provided on the magnetization free layer There is provided a magnetoresistive effect element comprising an amorphous conductive layer.

  According to the present invention, there is provided a magnetic memory comprising the above-described magnetoresistive element and recording information by controlling the magnetization direction of the magnetization free layer.

  Alternatively, according to the present invention, the first wiring extending in the first direction, the above-described magnetoresistive effect element provided on the first wiring, and the magnetoresistive effect element, A second wiring extending in a direction crossing the first direction, and the magnetization of the magnetoresistive effect element by a magnetic field formed by flowing a current through each of the first and second wirings There is provided a magnetic memory characterized in that any of binary information is recorded by controlling the magnetization direction of the free layer.

  In the present specification, “non-crystalline” means not a single crystal state or a polycrystalline state but means an amorphous state (amorphous) or a state in which fine crystals are dispersed in an amorphous state. In a state where fine crystals are dispersed in an amorphous state, for example, a crystalline peak that is not substantially observed by X-ray diffraction can be referred to as “amorphous”.

  As described above in detail, according to the present invention, since the “variation” of the switching magnetic field in the free layer of the magnetoresistive effect element can be reduced, a large-capacity magnetic nonvolatile memory, a highly sensitive magnetic head, and the like can be realized. And there are significant industrial advantages.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view illustrating the cross-sectional structure of a magnetoresistive element according to an embodiment of the invention. That is, this specific example is a tunnel junction type magnetoresistive effect element. On the lower electrode LE, an antiferromagnetic layer AF, a pinned layer (magnetization pinned layer) PL, a tunnel barrier layer TL, a free layer (magnetization). The free layer (FL) has a structure in which the layers are stacked in this order.

  Furthermore, in the present embodiment, an amorphous conductive layer AL is laminated on the free layer FL. As will be described in detail later, the conductive layer AL is provided as a hard mask layer, a cap layer, a via layer, an upper electrode, or the like. The conductive layer AL is not a single crystal or a polycrystal, but has an amorphous structure or a structure in which fine crystals are dispersed in an amorphous state. By providing such a conductive layer AL, distortion is prevented from being introduced into the free layer FL, and “variation” of the switching magnetic field (magnetic field necessary for magnetization reversal) of the free layer FL due to magnetostriction is generated. Can be deterred.

  FIG. 2 shows a magnetoresistive effect element in which a crystalline conductive layer CL is stacked on a free layer FL as a comparative example. The thickness of each layer will be described. Usually, the thickness of the lower electrode LE is about 30 nanometers, and the total thickness from the antiferromagnetic layer AF to the free layer FL is about 30 nanometers. On the other hand, when the conductive layer CL is formed as a hard mask layer or a cap layer, the thickness is often 100 nanometers or more. Furthermore, when the conductive layer CL is provided as a via layer or an upper electrode, the thickness may be 300 nanometers or more.

  Thus, when the crystalline thick conductive layer CL is laminated on the free layer FL, strain is introduced into the free layer FL. This strain acts as a magnetostriction on the free layer FL made of a magnetic material, and changes the magnetic field at which the magnetization M of the free layer FL is reversed. That is, when the crystalline conductive layer CL is laminated, magnetostriction acts on the free layer FL, and the switching magnetic field changes. For this reason, when a magnetic sensor, a magnetic head, a magnetic memory, or the like is formed, there arises a problem that the sensitivity varies or the reversal magnetic field varies from one memory cell to another.

  On the other hand, the present inventor has laminated the amorphous conductive layer AL instead of the crystalline conductive layer CL on the free layer FL, so that the switching magnetic field of the free layer due to such strain is reduced. We found that the problem of "variation" can be solved. That is, when the conductive layer is formed in an amorphous rather than a crystalline state, the effect of relaxing the strain becomes remarkable. For this reason, by laminating the amorphous conductive layer AL, the strain applied from the upper bit line, hard mask, or via, which is formed to be extremely thick compared to the free layer FL, is effectively reduced. be able to. As a result, the occurrence of magnetostriction can be greatly reduced, and the “variation” of the switching magnetic field of the free layer FL can be suppressed.

As the material of the amorphous conductive layer AL, at least one element of (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W), (Pt, Pd, Ru, Rh, Ir, Os, An alloy containing at least one element of (Re, Au, Al) can be used.
Alternatively, the material of the conductive layer AL includes at least one element of (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) and at least one element of (Fe, Ni, Cr, Cu). An alloy can also be used.
Alternatively, as the material of the conductive layer AL, at least one element of (Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and (Pt, Pd, Ru, An alloy containing at least one element of Rh, Ir, Os, Re, Au, Al) can also be used.

  Alternatively, an oxide conductor such as an oxide of indium / titanium alloy (Indium-Titan-Oxide) or an oxide of indium zinc alloy (Indium-Zinc-Oxide) can be used as the material of the conductive layer AL. .

  When the above-described alloy or oxide conductor is used as the material of the conductive layer AL, the “variation” of the switching magnetic field is remarkably reduced. This is because in the case of the above-described alloy or oxide conductor, even when deposited on a layer made of a crystalline material (for example, the free layer FL), it is easy to form it in an amorphous state. Furthermore, even if these alloys and oxide conductors are annealed at 400 degrees Celsius for about 2 hours after film deposition, they remain in an amorphous state in terms of X-rays and do not recrystallize. Therefore, when these alloys and oxide conductors are used, an amorphous layer is uniformly maintained in the wafer even after a heating process such as sintering annealing, and good switching magnetic field characteristics can be obtained.

  When the planar shape aspect ratio of the tunnel junction type magnetoresistive effect element is (major axis / minor axis)> 3, since the shape magnetic anisotropy becomes large, the “variation” of the switching magnetic field of the free layer FL is To some extent. On the other hand, in the case of a low aspect that is essential for increasing the capacity of the magnetic memory (that is, when the planar shape aspect ratio of the tunnel junction type magnetoresistive effect element is (long axis / short axis) <3). By providing the amorphous conductive layer AL, the effect of suppressing the “variation” of the switching magnetic field can be remarkably obtained.

In these magnetoresistive elements, examples of the ferromagnetic material that can be used as the pinned layer PL and the free layer FL include Fe (iron), Co (cobalt), Ni (nickel), or alloys thereof, and (Co , Fe, Ni)-(Si, B) system or amorphous material such as Co- (Zr, Hf, Nb, Ta, Ti), (Fe, Co)-(B, Si, Hf, Zr, Sm, Ta, Metal-non-metallic nano _- granular films such as Al)-(F, O, N), magnetite with high spin polarizability, CrO ₂ , RXMnO _3-y (where R is rare earth, X is Ca (calcium), Ba ( Oxides such as barium) and Sr (strontium)), or NiMnSb (nickel, manganese, antimony), PtMnSb (platinum manganese, antimony) And Heusler alloys such as (CoFe) -Cr-Al (cobalt iron / chromium / aluminum).

  The pinned layer PL made of these materials desirably has unidirectional anisotropy. The free layer FL preferably has uniaxial anisotropy. Moreover, it is preferable to make those thickness into the range of 0.1 nanometer or more and 100 nanometer or less. Further, the thickness of the layer made of the ferromagnetic material needs to be a thickness that does not become superparamagnetic, and is more preferably 0.4 nanometers or more.

Further, it is desirable to add an antiferromagnetic layer AF to the ferromagnetic layer used as the pinned layer PL to fix the magnetization. As a material of such an antiferromagnetic layer AF, Fe (iron) -Mn (manganese), Pt (platinum) -Mn (manganese), Pt (platinum) -Cr (chromium) -Mn (manganese), Ni ( nickel) -Mn (manganese), Ir (iridium) -Mn (manganese), NiO (nickel oxide), _Fe 2 _{O 3} (iron oxide) and the like.

  These magnetic materials include Ag (silver), Cu (copper), Au (gold), Al (aluminum), Mg (magnesium), Si (silicon), Bi (bismuth), Ta (tantalum), B ( Boron), C (carbon), O (oxygen), N (nitrogen), Pd (palladium), Pt (platinum), Zr (zirconium), Ir (iridium), W (tungsten), Mo (molybdenum), Nb ( By adding a nonmagnetic element such as niobium or B (boron), the magnetic properties can be adjusted, and various physical properties such as crystallinity, mechanical properties, and chemical properties can be adjusted.

  On the other hand, a laminated film of a ferromagnetic layer and a nonmagnetic layer may be used as the pinned layer PL or the free layer FL. For example, a three-layer structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer or a multilayer film of three or more layers can be used. In this case, it is desirable that the interaction between the ferromagnetic or antiferromagnetic layers having weak interaction acts on the ferromagnetic layers on both sides via the nonmagnetic layer.

  More specifically, as a method for fixing the magnetic layer in one direction, Co (Co—Fe) / Ru (ruthenium) / Co (Co—Fe), Co (Co—Fe) / Ir (iridium) / Co ( Co-Fe), Co (Co-Fe) / Os (osmium) / Co (Co-Fe), Co (Co-Fe) / Re (rhenium) / Co (Co-Fe), Co-Fe-B, etc. Amorphous material layer / Amorphous material layer such as Ru (ruthenium) / Co—Fe—B, Amorphous material layer such as Co—Fe—B / Amorphous material layer such as Ir (iridium) / Co—Fe—B, Co—Fe -B or other amorphous material layer / Os (osmium) / Amorphous material layer such as Co-Fe-B, Co-Fe-B or other amorphous material layer / Re (rhenium) / Co-Fe- Amorphous material layer such as, can be used a three-layer structure laminate film of such.

When these laminated films are used as the pinned layer PL, it is desirable to further provide an antiferromagnetic layer adjacent thereto. As the antiferromagnetic layer in this case, Fe—Mn, Pt—Mn, Pt—Cr—Mn, Ni—Mn, Ir—Mn, NiO, Fe ₂ O ₃ or the like may be used as described above. it can. When this structure is used, the magnetization of the pinned layer PL is less affected by the current magnetic field from the bit line or word line of the magnetic memory, and the magnetization is firmly fixed. Further, the stray field from the pinned layer PL can be reduced (or adjusted), and the magnetic recording layer (free layer FL) can be changed by changing the film thickness of the two ferromagnetic layers forming the pinned layer PL. The magnetization shift can be adjusted.

  Furthermore, the thickness of the ferromagnetic layer needs to be a thickness that does not become superparamagnetic, and is more preferably 0.4 nanometers or more.

  Further, as the free layer FL, a two-layer structure of soft magnetic layer / ferromagnetic layer or a three-layer structure of ferromagnetic layer / soft magnetic layer / ferromagnetic layer may be used. As the free layer FL, a three-layer structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer and a five-layer structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer / nonmagnetic layer / ferromagnetic layer are used. By controlling the strength of the interaction between the layers, even when the cell width of the free layer (magnetic recording layer) FL, which is a memory cell, becomes submicron or less, the power consumption of the current magnetic field is not increased. A more favorable effect can be obtained. At this time, the type and film thickness of the ferromagnetic layer may be changed.

  Further, when these laminated structures are adopted as the free layer FL, Co—Fe, Co—Fe—Ni, Fe-rich Ni—Fe, or the like that increases MR is used for the ferromagnetic layer in contact with the tunnel barrier layer TL. It is more preferable to use Ni-rich Ni—Fe, Ni-rich Ni—Fe—Co or the like for the ferromagnetic layer that is not in contact with the tunnel barrier layer TL because the switching magnetic field can be reduced while maintaining a large MR.

  Nonmagnetic materials in these laminated structures include Ag (silver), Cu (copper), Au (gold), Al (aluminum), Ru (ruthenium), Os (osmium), Re (rhenium), Si (silicon), Bi (bismuth), Ta (tantalum), B (boron), C (carbon), Pd (palladium), Pt (platinum), Zr (zirconium), Ir (iridium), W (tungsten), Mo (molybdenum), Nb (niobium) or an alloy thereof can be used.

  Also in the ferromagnetic layer, the above-mentioned magnetic materials are Ag (silver), Cu (copper), Au (gold), Al (aluminum), Ru (ruthenium), Os (osmium), Re (rhenium), Mg. (Magnesium), Si (silicon), Bi (bismuth), Ta (tantalum), B (boron), C (carbon), O (oxygen), N (nitrogen), Pd (palladium), Pt (platinum), Zr (Zirconium), Ir (Iridium), W (Tungsten), Mo (Molybdenum), Nb (Niobium) and other non-magnetic elements are added to adjust the magnetic properties, and in addition, crystallinity, mechanical properties, chemistry Various physical properties such as physical properties can be adjusted.

On the other hand, the material of the tunnel barrier layer TL provided between the pinned layer PL and the free layer FL is Al ₂ O ₃ (aluminum oxide), SiO ₂ (silicon oxide), MgO (magnesium oxide), AlN (aluminum nitride). ), Bi ₂ O ₃ (bismuth oxide), MgF ₂ (magnesium fluoride), CaF ₂ (calcium fluoride), SrTiO ₂ (titanium oxide / strontium), AlLaO ₃ (lanthanum oxide / aluminum), Al—N—O Various insulators (dielectrics) such as (aluminum oxynitride) can be used.

  These compounds do not need to have a completely accurate composition in terms of stoichiometry, and may be deficient or excessive or deficient in oxygen, nitrogen, fluorine, or the like. Further, the thickness of the tunnel barrier layer TL is desirably thin enough to allow a tunnel current to flow, and in practice, desirably 10 nm or less.

Such a magnetoresistive element can be formed on a predetermined substrate by using various thin film forming means such as a sputtering method, a vapor deposition method, and a molecular beam epitaxial method. As the substrate in this case, for example, substrates made of various materials such as Si (silicon), SiO ₂ (silicon oxide), Al ₂ O ₃ (aluminum oxide), spinel, AlN (aluminum nitride) can be used.

  Moreover, Ta (tantalum), Ti (titanium), Pt (platinum), Pd (palladium), Au (gold), Ti (titanium) / Pt (as a base layer, a protective layer, a hard mask, etc. on the substrate. Platinum), Ta (tantalum) / Pt (platinum), Ti (titanium) / Pd (palladium), Ta (tantalum) / Pd (palladium), Cu (copper), Al (aluminum) -Cu (copper), Ru ( A layer made of ruthenium), Ir (iridium), Os (osmium), or the like may be provided.

The tunnel junction type magnetoresistive element material according to the embodiment of the present invention has been described above.
Next, a spin valve magnetoresistive element according to an embodiment of the present invention will be described.
FIG. 3 is a schematic view illustrating the cross-sectional structure of the magnetoresistive effect element according to the embodiment of the invention. That is, this example is a spin valve type magnetoresistive effect element, and on the lower electrode LE, an antiferromagnetic layer AF, a pinned layer (magnetization pinned layer) PL, a spacer layer SL, a free layer (magnetization free). Layer) FL is laminated in this order.

  Also in this embodiment, the amorphous conductive layer AL is laminated on the free layer FL. As described above with reference to FIG. 1, the conductive layer AL is provided as a hard mask layer, a cap layer, a via layer, an upper electrode, or the like. Also in this specific example, the conductive layer AL is not a single crystal or a polycrystal, but has an amorphous (amorphous) or a structure in which fine crystals are dispersed in an amorphous. By providing such a conductive layer AL, it is possible to prevent strain from being introduced into the free layer FL, and to suppress the occurrence of “variation” of the switching magnetic field of the free layer FL due to magnetostriction.

  In the case of a spin valve type element, a spacer layer SL for blocking these magnetic couplings is provided between the pinned layer PL and the free layer FL. The pinned layer PL has its magnetization M fixed in a predetermined direction. The free layer FL can change its magnetization M according to a magnetic field applied from the outside. The resistance to the sense current flowing through the element changes according to the relative directions of magnetization of the pinned layer PL and the free layer FL.

  Also in this specific example, the pinned layer PL and the free layer FL can have the same material and configuration as those described above with reference to FIG. On the other hand, the spacer layer SL is formed of a conductive nonmagnetic material. That is, as a material constituting the spacer layer SL, Ag (silver), Cu (copper), Au (gold), Al (aluminum), Ru (ruthenium), Os (osmium), Re (rhenium), Si (silicon) ), Bi (bismuth), Ta (tantalum), B (boron), C (carbon), Pd (palladium), Pt (platinum), Zr (zirconium), Ir (iridium), W (tungsten), Mo (molybdenum) ), Nb (niobium), or alloys thereof.

  Furthermore, the spacer layer SL may be nonmagnetic and have an insulating portion and a conductive portion. In other words, when a sense current is passed in a direction perpendicular to the film surface (current perpendicular to plane: CPP), the conductive portions locally formed in the spacer layer SL form the pinned layer PL and the free layer FL. It may function as a current path to be connected. Thus, in the CPP type spin valve magnetoresistive effect element, it becomes easy to appropriately increase the resistance value of the element and obtain a large magnetoresistance change.

  The tunnel junction type and spin valve type magnetoresistive elements to which the present invention is applied have been described above with reference to FIGS. 1 to 3.

  Next, a cell structure of a magnetic memory using these magnetoresistive effect elements will be described with a specific example.

  FIG. 4 is a schematic cross-sectional view showing the cell structure of the magnetic memory according to the embodiment of the present invention.

  That is, the figure shows the architecture of the memory when MOS transistors are used. In this specific example, the main electrode of the lower select transistor Tr is connected to the lower electrode LE of the magnetoresistive element 10. A buffer layer (underlayer) BF is provided on the lower electrode LE. A word line WL insulated from the magnetoresistive element 10 is wired below the magnetoresistive element 10. On the other hand, the upper electrode of the magnetoresistive effect element 10 is connected to a bit line BL wired substantially orthogonal to the word line WL. Then, an amorphous conductive layer AL is formed as a cap layer on the free layer FL of the magnetoresistive effect element 10, and is connected to the bit line BL via a hard mask or via XL formed thereon. ing.

  On the other hand, a magnetic coating layer SM made of a magnetic material is provided on the side surfaces of the word line WL and the bit line BL and on the opposite wall surface viewed from the magnetoresistive effect element 10. These magnetic coating layers SM magnetically shield the bit line BL and the word line WL, respectively, prevent leakage of the current magnetic field, and efficiently apply the current magnetic field to the free layer FL of the magnetoresistive effect element 10. Thus, it also has a role of “magnetic yoke”.

  Data reading is performed by turning on the lower selection transistor Tr and flowing a sense current to the bit line BL via the magnetoresistive element 10. On the other hand, in writing data, a write current is applied to each of the bit line BL and the word line WL which are substantially orthogonal to each other, and a combined magnetic field of these generated current magnetic fields is applied to the free layer FL of the magnetoresistive effect element 10 to magnetize it. Is performed by reversing.

According to the present invention, by providing the amorphous conductive layer AL on the free layer FL, it is possible to prevent distortion from being introduced into the free layer FL from the hard mask or via XL formed thereon. be able to. As a result, it is possible to prevent the occurrence of magnetostriction in the free layer FL and eliminate the “variation” of the switching magnetic field.
Although FIG. 4 shows an example in which the magnetic coating layer SM is provided on the bit line BL and the word line WL, the present invention is not limited to this, and the magnetic coating layer SM may not be provided.

  FIG. 5 is a schematic sectional view showing a second specific example of the cell structure of the magnetic memory according to the embodiment of the present invention. In the figure, the same elements as those described above with reference to FIGS. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted. That is, FIG. 5 also shows a memory architecture when MOS transistors are used.

In this specific example, the amorphous conductive layer AL provided on the free layer FL serves as a hard mask or a via. Then, a bit line BL is connected thereto. In the case of this specific example, the film thickness of the conductive layer AL may be 100 nanometers or more. By providing such a thick non-crystalline conductive layer AL on the free layer FL, strain is introduced into the free layer FL from the thick bit line BL (which may be 300 nanometers or more) formed thereon. Can be prevented. As a result, the magnetostriction in the free layer FL can be prevented and the “variation” of the switching magnetic field can be eliminated.
FIG. 6 is a schematic cross-sectional view showing a third specific example of the cell structure of the magnetic memory according to the embodiment of the present invention. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the case of this specific example, an amorphous first conductive layer AL1 and an amorphous second conductive layer AL2 are stacked on the free layer FL. These first and second conductive layers AL serve as hard masks or vias. On top of this, the bit line BL is connected.

As described above, by providing the amorphous conductive layers AL1 and AL2 between the free layer FL and the bit line BL, it is possible to prevent introduction of strain from the bit line BL to the free layer FL. As a result, the magnetostriction in the free layer FL can be prevented and the “variation” of the switching magnetic field can be eliminated.
Furthermore, by changing the materials of the first conductive layer AL1 and the second conductive layer AL2 as appropriate, it is possible to increase the degree of freedom of design and to facilitate the manufacturing process. For example, the first conductive layer AL is formed of a material that is difficult to be etched with respect to etching such as predetermined RIE (reactive ion etching), and the second conductive layer AL is etched with respect to the etching. It can be formed of a material that is easily processed. In this case, when patterning the second conductive layer AL2, the first conductive layer AL1 can be used as an etching stop layer or a mask layer.

  4 to 6 show specific examples using the read MOS transistor Tr, but the architecture of the memory cell of the present invention is not limited to these. That is, in addition to these, a simple cross matrix type, a 1 diode-1 MR element type with a diode added thereto, a writing transistor type in which writing is performed with one wiring using a selective writing MOS transistor, and writing by spin injection. In various architectures such as the spin-polarized current writing type, by providing an amorphous conductive layer on the free layer of the magnetoresistive effect element, the hard mask, via, wiring, etc. Strain can be prevented from being introduced into the free layer. As a result, generation of magnetostriction in the free layer can be prevented, and “variation” of the switching magnetic field can be prevented.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to examples.

  First, as a first embodiment of the present invention, an embodiment in which a magnetic memory having the architecture shown in FIG. 4 is manufactured will be described.

  The structure of this magnetic memory will be described as follows in accordance with its manufacturing procedure.

  That is, as shown in FIG. 7, a MOS transistor Tr, a via VW, and a word line WL are formed and a substrate embedded in the insulating layer IL is formed. On this substrate, first, the lower electrode LE / buffer layer BF / antiferromagnetic layer AF / pinned layer PL / tunnel barrier layer TL (or spacer layer SL) / free layer FL / conductive layer AL (cap layer) / Pt layer or Ru layer / metal hard mask HM is formed. In this example, the lower electrode LE was formed of tantalum (Ta). On top of that, Ta (5 nm) / Ru (3 nm) / Ir—Mn (10 nm) / CoFe (3 nm) / Ru (0.9 nm) / CoFe (3.25 nm) / AlOx (1) .4 nm) / CoNiFe (3 nm).

  That is, Ta (5 nm) / Ru (3 nm) is formed as the buffer layer BF, Ir—Mn (10 nm) is formed as the antiferromagnetic layer AF, and CoFe (3 nm) / Ru (0.9 nm) is formed as the pinned layer PL. / CoFe (3.25 nm) was formed, AlOx (1.4 nm) was formed as the tunnel barrier layer TL, and CoNiFe (3 nm) was formed as the free layer FL.

On top of that, an amorphous alloy made of Ta—Ir (tantalum-iridium) is formed to a thickness of 20 nm as the conductive layer AL, and then a Ru conductive layer is formed to a thickness of 10 nm. Further, tantalum (Ta) is formed as the hard mask HM. ) To a thickness of 120 nm. Here, the composition of the conductive layer AL was Ta ₆₅ Ir ₃₅ .

  Thereafter, annealing was performed in a magnetic field at 300 ° C. When X-ray diffraction was examined after annealing in a magnetic field, a diffraction peak of Ta-Ir constituting the conductive layer AL was not observed, and the conductive layer AL was amorphous or a microcrystal having a size equal to or smaller than the X-ray interference length ( It was confirmed that it was a microcrystal).

  Then, after applying a resist and performing a PEP (photo-engraving process), the hard mask HM made of Ta was RIE-etched with a chlorine-based gas, and stopped at the Ru metal layer therebelow.

  Thereafter, the resist was peeled off, and the ferromagnetic tunnel junction was separated by etching by ion milling to the Ir—Mn layer using the Ta hard mask HM as a mask. The planar shape of the tunnel junction was an ellipse with an aspect ratio of 1: 2.5. The size was set to 0.3 μm × 0.75 μm.

  Thereafter, a SiOx protective film was formed, a resist was applied, PEP was performed, and then the lower electrode LE was patterned by RIE etching. Thereafter, the resist was removed, and an interlayer insulating film made of SiOx was formed, and then etched back and planarized to expose the surface of the Ta hard mask HM.

  After that, after sputter etching, the bit line BL and the magnetic coating (magnetic yoke) layer SM are formed, and the resist coating, PEP, RIE, and resist removal processes are sequentially performed, so that the magnetic memory shown in FIG. Produced.

  The magnetic characteristics were measured by applying a magnetic field in the major axis direction of the CoNiFe free layer FL of the magnetic memory cell thus obtained.

  FIG. 8 is a graph showing the results of measuring the asteroid curve of 16 magnetic memory cells. From the figure, it can be seen that the asteroid curves of the free layer of these 16 memory cells overlap well, and the “variation” of the switching magnetic field is sufficiently small. That is, it can be seen that even when a large-capacity magnetic memory is formed, problems such as write errors and crosstalk can be suppressed.

  In the experiment conducted separately from this example, the material of the amorphous conductive layer AL formed on the free layer FL is TaPt, WPt, ZrPt, NbPt, MoPt, VPt, CrPt, TaRu, WRu, ZrRu, In any of the cases where NbRu, MoRu, VRu, CrRu, WIr, ZrAl, NbAl, MoAl, VAl and CrAl are used, similar to the result shown in FIG. It was.

  Next, as a second embodiment of the present invention, an embodiment in which a magnetic memory having the architecture shown in FIG. 5 is manufactured will be described. In this embodiment, a sample (sample 1) provided with an amorphous conductive layer AL as a hard mask, and a sample (sample) provided with an amorphous conductive layer AL as a wiring via embedded in an insulating layer. 2) and were created.

The structure of these magnetic memories will be described as follows along the manufacturing procedure.
That is, first, as in the first embodiment, a substrate in which the MOS transistor Tr, the via VW, the word line WL, and the like are embedded in the insulating layer IL is formed.

  Then, a lower electrode LE / TMR / Pt layer or Ru layer / conductive layer AL was formed on this substrate as “Sample 1”. As will be described later, the conductive layer AL is used as a “hard mask” for patterning the TMR.

  On the other hand, a lower electrode LE / TMR / Pt layer or Ru layer was formed on the substrate as “Sample 2” separately from this. That is, a sample without the amorphous conductive layer AL as a hard mask was prepared as “Sample 2”.

Here, the lower electrode LE has a stacked structure of Ta / Al / Ta in order from the lower side.
The TMR of “Sample 1” is Ta (5 nm) / Ru (3 nm) / Pt—Mn (15 nm) / CoFe (3 nm) / Ru (0.9 nm) / CoFe (3.25 nm) in order from the bottom. / AlOx (1.4 nm) / CoFeB (3 nm) / Ru (18 nm).

  That is, Ta (5 nm) / Ru (3 nm) is formed as the buffer layer BF, Pt—Mn (15 nm) is formed as the antiferromagnetic layer AF, and CoFe (3 nm) / Ru (0.9 nm) is formed as the pinned layer PL. / CoFe (3.25 nm) was formed, AlOx (1.4 nm) was formed as the tunnel barrier layer TL, and CoFeB (3 nm) was formed as the free layer FL.

  On the other hand, the TMR of “Sample 2” is Ta (5 nm) / Ru (3 nm) / Pt—Mn (15 nm) / CoFe (3 nm) / Ru (0.9 nm) / CoFe (3.25 nm) in order from the bottom. / AlOx (1.4 nm) / CoFeNi (3 nm) / Ru (18 nm).

In addition, as the conductive layer AL as a hard mask in “Sample 1”, a Ta—Al amorphous alloy was formed to a thickness of 120 nm. The composition of the conductive layer AL was Ta ₆₀ Al ₄₀ .

  Thereafter, annealing in a magnetic field was performed at 300 ° C. When X-ray diffraction was performed after annealing in a magnetic field, the diffraction peak of Ta—Al constituting the conductive layer AL in “Sample 1” was not observed, and it was confirmed to be amorphous or microcrystalline.

  Thereafter, in “Sample 1”, after applying a resist and performing PEP, the conductive layer AL (Ta—Al amorphous alloy) was RIE using a chlorine-based gas, and etching was stopped at the Ru layer below. Thereafter, the resist was peeled off, and etching was performed by ion milling to the PtMn layer constituting the TMR using the conductive layer AL as a hard mask, thereby separating and separating the ferromagnetic tunnel junction. The planar shape of the tunnel junction was an ellipse with an aspect ratio of 1: 2. The size was 0.3 μm × 0.6 μm in diameter. Thereafter, a SiOx protective film was formed, a resist was applied, PEP was performed, and the lower electrode LE was patterned by RIE. Thereafter, the resist was removed, and an SiOx interlayer insulating film was formed, followed by etch back to flatten the surface and expose the surface of the conductive layer AL (Ta-Al amorphous alloy hard mask layer).

  Thereafter, the upper wiring BL is formed after the sputter etching, and further, the magnetic coating (magnetic yoke) layer SM is formed on the side surface and the upper surface, and the resist coating, PEP, RIE, and resist removal steps are performed. A magnetic memory having the structure shown in FIG.

On the other hand, for “Sample 2”, the TMR laminated structure was formed on the substrate, and then the TMR was bonded and separated by patterning using a resist mask without forming the hard mask layer. Then, after removing the resist and forming a SiOx interlayer insulating film, PEP is performed to form a via hole in the SiOx layer using fluorine (F) gas, and the surface of the Ru layer on the upper side of the TMR laminated structure at the bottom Was exposed. Then, after sputter etching, a conductive layer AL made of a Ta—Al amorphous alloy is formed as a wiring via, an upper wiring BL is formed thereon, and a magnetic coating (magnetic yoke) layer SM is formed on the side and upper surfaces thereof. A magnetic memory having the structure shown in FIG. 5 was manufactured through the steps of resist coating, PEP, RIE, and resist removal. Again, the composition of the conductive layer AL was Ta ₆₀ Al ₄₀ .

  Thereafter, a magnetic field was applied in the major axis direction of the CoFeB layer (sample 1) and the CoFeNi layer (sample 2) immediately below the upper wiring BL by annealing in a magnetic field.

  9 and 10 are graphs showing the results of measuring the asteroid curves of 16 elements in samples 1 and 2, respectively. In any sample, it was found that the “variation” of the switching magnetic field was small, and desirable characteristics as a large-capacity magnetic memory were obtained.

  In the experiment conducted separately from this example, the material of the amorphous conductive layer AL formed as a hard mask or wiring via is PrPt, PrRu, PrIr, PrAl, PrAu, PrPd, NdPt, NdRu, NdIr, NdAl, In any case where NdAu, NdPd, GdPt, GdRu, GdIr, DyAl, DyAu, and ErPd were used, the “variation” of the switching magnetic field was small and good characteristics were obtained as in the result shown in FIG.

(Comparative example)
As a comparative example of the second embodiment, a magnetic memory using a hard mask (sample 3) made of crystalline Ta and a wiring via (sample 4) made of crystalline Ta will be described.

  The manufacturing method of the magnetic memory of this comparative example is the same as that of the second example except that the conductive layer AL (Ta—Al amorphous alloy) in Samples 1 and 2 is changed to a metal layer made of Ta. After the samples 3 and 4 were prepared, annealing was performed in a magnetic field, and a magnetic field was applied in the major axis direction of the CoFeB layer (sample 3) and the CoFeNi layer (sample 4) immediately below the upper wiring BL. When X-ray diffraction was examined after annealing in a magnetic field, Ta diffraction peaks were observed in the Ta hard mask (Sample 3) and Ta wiring via (Sample 4), respectively. It was found to consist of -Ta.

  11 and 12 are graphs showing the results of measuring the asteroid curves of 16 elements in samples 3 and 4, respectively. In any sample, the “variation” of the switching magnetic field is large, and when used as a large-capacity magnetic memory, it can be seen that there is room for improvement in that problems such as write errors and crosstalk are likely to occur.

  As a third embodiment of the present invention, an embodiment in which a magnetic memory having the two-layered conductive layers AL1 and AL2 shown in FIG. 6 will be described.

The structure of the magnetic memory of the present embodiment will be described as follows along the manufacturing procedure.
That is, first, as in the first embodiment, a substrate in which the MOS transistor Tr, the via VW, the word line WL, and the like are embedded in the insulating layer IL is formed. Next, the lower electrode LE / TMR / Pt layer or Ru layer / non-crystalline conductive layer (hard mask layer) AL2 was formed on this substrate.

  In this example, a stacked structure of Ta / Al / Ta was formed as the lower electrode LE in order from the lower side. TMR is Ta (5 nm) / Ru (3 nm) / Pt—Mn (15 nm) / CoFe (3 nm) / Ru (0.9 nm) / CoFe (3.25 nm) / AlOx (1. 4 nm) / CoFeNi (3 nm)) / Ta—Fe conductive layer AL1 (amorphous cap layer) (18 nm).

That is, Ta (5 nm) / Ru (3 nm) is formed as the buffer layer BF, Pt—Mn (15 nm) is formed as the antiferromagnetic layer AF, and CoFe (3 nm) / Ru (0.9 nm) is formed as the pinned layer PL. / CoFe (3.25 nm) was formed, AlOx (1.4 nm) was formed as the tunnel barrier layer TL, and CoNiFe (3 nm) was formed as the free layer FL. The composition of the conductive layer AL was Ta ₄₅ Fe ₅₅ .

  Then, a conductive layer AL2 made of a Ta—Al amorphous alloy was formed to a thickness of 120 nm as an amorphous hard mask layer thereon.

  Thereafter, annealing was performed in a magnetic field at 300 ° C. When X-ray diffraction is examined after annealing in a magnetic field, no diffraction peak is observed in the conductive layer AL1 (Ta—Fe amorphous alloy) and the conductive layer AL2 (Ta—Al amorphous alloy), and the layer is amorphous or microcrystalline. Was confirmed.

  Next, after applying a resist and performing PEP, the conductive layer AL2 (Ta-Al amorphous alloy) was RIE with a chlorine-based gas, and etching was stopped with the conductive layer AL1 (Ta-Fe amorphous alloy).

  Thereafter, the resist was peeled off, and etching was performed by ion milling to the PtMn layer of TMR using the conductive layer AL2 (Ta—Al amorphous alloy) as a hard mask, thereby separating and separating the ferromagnetic tunnel junction. The planar shape of the tunnel junction was an ellipse with an aspect ratio of 1: 2. The size was 0.3 μm × 0.6 μm in diameter.

  Next, a SiOx protective film was formed, a resist was applied, PEP was performed, and the lower electrode LE was formed by patterning using RIE. Then, after removing the resist and forming an SiOx interlayer insulating film, etch back was performed to flatten the surface of the interlayer insulating film and expose the surface of the conductive layer AL2 (Ta—Al amorphous alloy). Thereafter, after sputter etching, the upper wiring BL was formed, and the magnetic coating (magnetic yoke) layer SM was formed on the side surface and upper surface of the upper wiring BL, thereby producing the structure shown in FIG.

  Thereafter, annealing was performed in a magnetic field, and a magnetic field was applied in the major axis direction of the CoFeNi magnetic layer immediately below the upper wiring BL.

  FIG. 13 is a graph showing the results of measuring the asteroid curves of the 16 elements formed in this way.

  It was confirmed that the “variation” of the switching magnetic field was sufficiently small and desirable characteristics were obtained as a large-capacity magnetic memory.

  In this embodiment, the material of the first conductive layer AL1 that is difficult to be etched by RIE includes WFe, ZrFe, NbFe, MoFe, VFe, TaNi, WNi, ZrNi, NbNi, MoNi, Vni, TaCr, WCr, and ZrCu. , NbCu, MoCu, VCu TaPt, WPt, ZrPt, NbPt, MoPt, VPt, CrPt, TaRu, WRu, ZrRu, NbRu, MoRu, VRu, and CrRu, and the second conductive layer AL2 that is easily etched by RIE For example, any of WAl, ZrAl, NbAl, MoAl, VAl, and CrAl can be used.

  Next, as a fourth embodiment of the present invention, a specific example of a CPP type magnetoresistive effect element will be described.

  FIG. 14 and FIG. 15 are conceptual diagrams schematically showing the main configuration of the magnetoresistive effect element according to the exemplary embodiment of the present invention. That is, these drawings show the state in which the magnetoresistive effect element is incorporated in the magnetic head, and FIG. 14 shows the magnetoresistive in a direction substantially parallel to the medium facing surface P facing the magnetic recording medium (not shown). It is sectional drawing which cut | disconnected the effect element. FIG. 15 is a cross-sectional view of the magnetoresistive effect element cut in a direction perpendicular to the medium facing surface P.

  The magnetoresistive effect element illustrated in FIGS. 14 and 15 is an element having a hard abutted structure, and a lower electrode 12 and an upper electrode 20 are provided above and below the magnetoresistive film 14. In FIG. 14, a bias magnetic field application film 16 and an insulating film 18 are laminated on the side surfaces on both sides of the magnetoresistive film 14. Further, as illustrated in FIG. 15, a protective layer 30 is provided on the medium facing surface of the magnetoresistive film 4.

  The magnetoresistive film 4 has a tunnel junction type or spin valve type structure, and has the structure according to the embodiment of the present invention as described above with reference to FIGS. That is, an amorphous conductive layer is stacked on the free layer, and the introduction of strain from the hard mask and the upper electrode 20 formed thereon is suppressed. Alternatively, the upper electrode 20 may be formed as an amorphous conductive layer.

  The sense current for the magnetoresistive film 4 is energized in a direction substantially perpendicular to the film surface as indicated by the arrow A by the electrodes 12 and 20 disposed above and below the magnetoresistive film 4. A bias magnetic field is applied to the magnetoresistive effect film 14 by a pair of bias magnetic field application films 16, 16 provided on the left and right. This bias magnetic field controls the magnetic anisotropy of the free layer of the magnetoresistive effect film 14 to form a single magnetic domain, thereby stabilizing the magnetic domain structure and suppressing Barkhausen noise associated with the domain wall movement. be able to.

  According to the present invention, the generation of magnetostriction in the free layer can be suppressed by laminating the amorphous conductive layer on the free layer of the magnetoresistive film 14. As a result, it is possible to suppress the “variation” or decrease in sensitivity of the magnetoresistive effect element. For example, when applied to a magnetic head, magnetic reproduction with high sensitivity and good reproducibility is possible.

  Next, as a fifth embodiment of the present invention, a magnetic reproducing apparatus equipped with the magnetoresistive effect element of the present invention will be described. That is, the magnetoresistive effect element or magnetic head of the present invention described with reference to FIGS. 1 to 15 can be incorporated into a recording / reproducing integrated magnetic head assembly and mounted on a magnetic recording / reproducing apparatus, for example.

  FIG. 16 is a main part perspective view illustrating a schematic configuration of such a magnetic recording / reproducing apparatus. That is, the magnetic recording / reproducing apparatus 150 of the present invention is an apparatus using a rotary actuator. In the figure, a recording medium disk 200 is mounted on a spindle 152 and rotated in the direction of arrow A by a motor (not shown) that responds to a control signal from a drive device control unit (not shown). The magnetic recording / reproducing apparatus 150 of the present invention may include a plurality of medium disks 200.

  A head slider 153 that records and reproduces information stored in the medium disk 200 is attached to the tip of a thin-film suspension 154. Here, the head slider 153 has, for example, the magnetoresistive effect element or the magnetic head according to any one of the above-described embodiments mounted near the tip thereof.

  When the medium disk 200 rotates, the medium facing surface (ABS) of the head slider 153 is held with a predetermined flying height from the surface of the medium disk 200. Alternatively, a so-called “contact traveling type” in which the slider contacts the medium disk 200 may be used.

  The suspension 154 is connected to one end of an actuator arm 155 having a bobbin portion for holding a drive coil (not shown). A voice coil motor 156, which is a kind of linear motor, is provided at the other end of the actuator arm 155. The voice coil motor 156 is composed of a drive coil (not shown) wound around the bobbin portion of the actuator arm 155, and a magnetic circuit composed of a permanent magnet and a counter yoke arranged so as to sandwich the coil.

  The actuator arm 155 is held by ball bearings (not shown) provided at two positions above and below the spindle 157, and can be freely rotated and slid by a voice coil motor 156.

FIG. 17 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side. That is, the magnetic head assembly 160 includes an actuator arm 155 having, for example, a bobbin portion that holds a drive coil, and a suspension 154 is connected to one end of the actuator arm 155.
A head slider 153 including any one of the magnetoresistive elements or the magnetic head described above with reference to FIGS. 1 to 15 is attached to the tip of the suspension 154. The suspension 154 has a lead wire 164 for writing and reading signals, and the lead wire 164 and each electrode of the magnetic head incorporated in the head slider 153 are electrically connected. In the figure, reference numeral 165 denotes an electrode pad of the magnetic head assembly 160.

  According to the present invention, by providing the magnetoresistive effect element or magnetic head of the present invention as described above with reference to FIGS. 1 to 15, sensitivity variation and reduction can be suppressed, and the recording density can be higher than that of the prior art. The information magnetically recorded on the medium disk 200 can be read reliably.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, a person skilled in the art is concerned with specific materials, such as a ferromagnetic layer, an insulating layer, an antiferromagnetic layer, an intermediate layer, a nonmagnetic metal layer, and an electrode constituting a magnetoresistive effect element, as well as a film thickness, shape, and dimensions. The present invention can be implemented in the same manner by selecting as appropriate, and the same effects can be obtained within the scope of the present invention.

  Similarly, the structure, material, shape, and dimensions of each element constituting the magnetic memory of the present invention can be appropriately selected by those skilled in the art to implement the present invention in the same manner and obtain similar effects. It is included in the scope of the present invention.

  In addition, all magnetoresistive elements that can be implemented by those skilled in the art based on the magnetoresistive elements described above as embodiments of the present invention are also within the scope of the present invention.

It is a schematic diagram which illustrates the cross-section of the magnetoresistive effect element concerning embodiment of this invention. As a comparative example, a magnetoresistive effect element in which a crystalline metal layer CL is stacked on a free layer FL is shown. It is a schematic diagram which illustrates the cross-section of the magnetoresistive effect element concerning embodiment of this invention. It is a schematic cross section showing the cell structure of the magnetic memory concerning an embodiment of the invention. It is a schematic cross section showing the 2nd specific example of the cell structure of the magnetic memory concerning embodiment of this invention. It is a schematic cross section showing the 3rd example of the cell structure of the magnetic memory concerning embodiment of this invention. 1 is a schematic cross-sectional view showing a magnetic memory according to a first embodiment of the present invention. It is a graph showing the result of having measured the asteroid curve of 16 magnetic memory cells. It is a graph showing the result of having measured the asteroid curve of 16 elements in the sample 1. FIG. 6 is a graph showing the results of measuring asteroid curves of 16 elements in sample 2. FIG. 6 is a graph showing the results of measuring an asteroid curve of 16 elements in sample 3. FIG. 6 is a graph showing the results of measuring asteroid curves of 16 elements in sample 4. FIG. It is a graph showing the result of having measured the asteroid curve of 16 elements of the magnetic memory of 3rd Example of this invention. 1 is a cross-sectional view of a magnetoresistive effect element according to an embodiment of the present invention cut in a direction substantially parallel to a medium facing surface P facing a magnetic recording medium (not shown) of a magnetic head. . FIG. 15 is a cross-sectional view of the magnetoresistive effect element of FIG. 14 cut in a direction perpendicular to the medium facing surface P. 1 is a perspective view of a main part illustrating a schematic configuration of a magnetic recording / reproducing apparatus according to an embodiment of the invention. 5 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side. FIG.

Explanation of symbols

AF Antiferromagnetic layer BL Bit line FL Free layer LE Lower electrode WL Word line NM Nonmagnetic layer IL Insulating layer PL Pinned layer SM Magnetic coating layer SL Nonmagnetic intermediate layer Tr Select transistor TB Tunnel barrier layer UL Upper electrode

Claims (11)

A magnetization pinned layer including a first ferromagnetic film having a magnetization direction pinned substantially in one direction;
A nonmagnetic layer provided on the magnetization pinned layer;
A magnetization free layer including a second ferromagnetic film provided on the nonmagnetic layer and having a magnetization direction that changes in response to an external magnetic field;
An amorphous conductive layer provided on the magnetization free layer;
A magnetoresistive effect element comprising:   The conductive layer includes at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, and Pt, Pd, Ru, Rh, Ir, Os, Re, Au. 2. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is made of an alloy including at least one element selected from the group consisting of Al and Al.   The conductive layer is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, and at least selected from the group consisting of Fe, Ni, Cr and Cu. 2. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is made of an alloy containing one element.   The conductive layer includes at least one element selected from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and Pt, Pd, Ru, Rh. 2. The magnetoresistive effect element according to claim 1, wherein the magnetoresistive element is made of an alloy containing at least one element selected from the group consisting of Ir, Os, Re, Au, and Al.   The magnetoresistive element according to claim 1, wherein the conductive layer is made of an oxide conductor.   The magnetoresistive element according to claim 1, wherein the nonmagnetic layer is made of an insulator capable of tunneling current in a direction perpendicular to the film surface.   The magnetoresistive element according to claim 1, wherein the nonmagnetic layer has conductivity.   The magnetoresistive effect element according to claim 1, wherein a crystalline metal wiring is connected on the conductive layer. A magnetoresistive element according to any one of claims 1 to 8,
A magnetic memory, wherein information is recorded by controlling a magnetization direction of the magnetization free layer. A first wiring extending in a first direction;
The magnetoresistive effect element according to any one of claims 1 to 8, provided on the first wiring,
A second wiring extending in a direction crossing the first direction on the magnetoresistive element;
One of the binary information is recorded by controlling the magnetization direction of the magnetization free layer of the magnetoresistive effect element by a magnetic field formed by flowing current through the first and second wirings, respectively. A magnetic memory characterized by that. 11. The magnetic memory according to claim 10, wherein at least one of the first and second wirings has a coating layer made of a magnetic material on at least both side surfaces thereof.

Images