JP2008306169A - Magnetoresistive element, magnetoresistive element manufacturing method, and magnetic multilayer film creating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetoresistive element excellent in thermal stability and having a high MR ratio.
A magnetoresistive element includes an antiferromagnetic layer formed of a layer containing manganese, and a first magnetization fixed layer formed of a layer including a ferromagnetic material and a platinum group metal located on the antiferromagnetic layer side. A second magnetization pinned layer formed of a layer having a ferromagnetic material, and a laminated magnetization pinned layer having a first nonmagnetic intermediate layer positioned between the first magnetization pinned layer and the second magnetization pinned layer; A magnetization free layer formed of a layer having a magnetic material, and a second nonmagnetic intermediate layer positioned between the stacked magnetization fixed layer and the magnetization free layer.
[Selection] Figure 1

Description

  The present invention relates to a magnetoresistive element such as a tunnel magnetoresistive element and a giant magnetoresistive element, a method for manufacturing the same, and a magnetic multilayer film forming apparatus. The present invention relates to a magnetoresistive element such as a resistance element and a giant magnetoresistive element, a manufacturing method thereof, and a magnetic multilayer film forming apparatus.

  Giant magnetoresistive elements and tunnel magnetoresistive elements have been used for magnetic heads of conventional magnetic disk drive devices.

  A giant magnetoresistive element has an antiferromagnetic layer, a ferromagnetic pinned layer, a nonmagnetic conductive layer, and a ferromagnetic free layer, and a tunnel magnetoresistive element has an antiferromagnetic layer, a ferromagnetic pinned layer, a tunnel barrier layer, and a ferromagnetic free layer. Has a layer.

  In the giant magnetoresistive element and the tunnel magnetoresistive element, as a ferromagnetic material used for the ferromagnetic fixed layer, at least one element of Fe, Co, and Ni can be used. As the antiferromagnetic material used for the antiferromagnetic layer, a material obtained by adding a noble metal element to Mn such as PtMn or IrMn can be used.

  However, the conventional magnetoresistive element has poor heat stability. For example, when the magnetoresistive element is exposed to heating at a temperature of 300 ° C. or higher, its MR (magnetoresistive) ratio is significantly reduced. Existed.

In the magnetoresistive elements described in Patent Document 1, Patent Document 2, Patent Document 3 and Patent Document 4, although some improvement in thermal stability is observed, the MR ratio still sufficient for practical use is still Not achieved.
JP 2000-67418 A (US Pat. No. 6,052,263) JP 2003-258335 A Japanese Patent Laid-Open No. 2003-304012 JP 2005-203790 A

  According to the research and analysis by the present inventors, it has been found that the cause of the instability of the magnetoresistive element with respect to heat is as follows.

  For example, in the manufacturing process of the magnetic head, the tunnel magnetoresistive element magnetizes the PtMn layer, which is an antiferromagnetic layer, and therefore heat treatment at 250 to 300 ° C. in a strong magnetic field of several T (tesla) after film formation is performed. Time has gone. In addition, in the magnetic random access memory, in addition to the heat treatment in the strong magnetic field after the film formation, a heat treatment exceeding 300 ° C. is performed in a subsequent process. In such a heat treatment step, manganese (Mn) in the above-described antiferromagnetic layer is diffused to other layers, for example, the ferromagnetic fixed layer and the tunnel barrier layer, by the heat during the heat treatment. The magnetic characteristics of the magnetic pinned layer are deteriorated and the tunnel barrier effect of the tunnel barrier layer is deteriorated. As a result, the MR ratio of the magnetoresistive element is lowered.

  The ferromagnetic fixed layer and the tunnel barrier layer preferably have a crystal structure such as a microcrystal, a polycrystal, or a single crystal, and the crystalline ferromagnetic fixed layer or the crystalline tunnel barrier layer has been diffused. It is assumed that the MR ratio is lowered as a result of being adversely affected by (Mn).

  In particular, a crystalline first ferromagnetic pinned layer containing cobalt iron (CoFe) whose ferromagnetic pinned layer is located on the substrate side, a nonmagnetic intermediate layer such as ruthenium (Ru) thereon, and crystalline cobalt iron boron (CoFeB) In the case of using a ferromagnetic pinned layer of a SAF (Synthetic Anti-Ferromagnet) structure having three crystalline second ferromagnetic pinned layers containing), manganese ( Mn) was adversely affected by thermal diffusion, and as a result, the MR ratio as a magnetoresistive element was lowered.

  The above-mentioned thermal diffusion phenomenon occurs similarly in the giant magnetoresistive element.

  An object of the present invention is to provide a magnetoresistive element having excellent thermal stability and a high MR ratio, such as a tunnel magnetoresistive element and a giant magnetoresistive element, and a method for manufacturing the same.

  The magnetoresistive element, the magnetoresistive element manufacturing method, and the magnetic multilayer film creating apparatus according to the present invention that achieve the above object mainly have the following configurations.

The magnetoresistive element according to the present invention is
An antiferromagnetic layer formed of a layer containing manganese;
A first magnetization pinned layer formed by a layer having a ferromagnetic material and a platinum group metal, a second magnetization pinned layer formed by a layer having a ferromagnetic material, and the first magnetization pinned, located on the antiferromagnetic layer side A laminated magnetization fixed layer having a first nonmagnetic intermediate layer located between the layer and the second magnetization fixed layer;
A magnetization free layer formed of a layer having a ferromagnetic material;
A second nonmagnetic intermediate layer located between the stacked magnetization fixed layer and the magnetization free layer;
It is characterized by having.

In addition, a method for manufacturing a magnetoresistive element according to the present invention includes:
An antiferromagnetic layer,
A laminated magnetization fixed layer having a laminated structure having a first magnetization fixed layer, a first nonmagnetic intermediate layer, and a second magnetization fixed layer;
A second nonmagnetic intermediate layer;
A method of manufacturing a magnetoresistive element having a magnetization free layer,
A first step of forming the antiferromagnetic layer by a sputtering method using a target containing manganese (Mn);
After the first step, a second step of forming the first magnetization fixed layer by sputtering using a target containing a platinum group metal and a target containing a ferromagnetic material,
After the second step, a third step of forming the first nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the third step, a fourth step of forming the second magnetization fixed layer by sputtering using a target containing a ferromagnetic material;
After the fourth step, a fifth step of forming the second nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the fifth step, a sixth step of forming the magnetization free layer by sputtering using a target containing a ferromagnetic material;
After the sixth step, the antiferromagnetic layer, the first magnetization fixed layer, the first nonmagnetic intermediate layer, and the stacked magnetization fixed layer having a stacked structure including the second magnetization fixed layer, A seventh step including a step of performing a heat treatment in a heating furnace on the second nonmagnetic intermediate layer and the magnetization free layer;
It is characterized by having.

Alternatively, a method for manufacturing a magnetoresistive element according to the present invention includes:
An antiferromagnetic layer,
A laminated magnetization fixed layer having a laminated structure having a first magnetization fixed layer, a first nonmagnetic intermediate layer, and a second magnetization fixed layer;
A second nonmagnetic intermediate layer;
A method of manufacturing a magnetoresistive element having a magnetization free layer,
A first step of forming the antiferromagnetic layer by a sputtering method using a target containing manganese (Mn);
After the first step, a second step of forming the first magnetization fixed layer by sputtering using a target containing a platinum group metal and a ferromagnetic material;
After the second step, a third step of forming the first nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the third step, a fourth step of forming the second magnetization fixed layer by sputtering using a target containing a ferromagnetic material;
After the fourth step, a fifth step of forming the second nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the fifth step, a sixth step of forming the magnetization free layer by sputtering using a target containing a ferromagnetic material;
After the sixth step, the antiferromagnetic layer, the laminated ferromagnetic pinned layer having a laminated structure including the first magnetization pinned layer, the first nonmagnetic intermediate layer, and the second magnetization pinned layer; A seventh step including a step of heat-treating the second non-magnetic intermediate layer and the magnetization free layer in a heating furnace;
It is characterized by having.

Moreover, the magnetic multilayer film creating apparatus according to the present invention includes:
A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first deposition chamber for filming;
A platinum group metal was contained by sputtering using a ferromagnetic target containing a platinum group metal on the substrate that was connected to the transfer chamber via a gate valve and carried by the robot carrier. A second deposition chamber for depositing the first ferromagnetic pinned layer;
A second ferromagnetic pinned layer is formed by sputtering using a ferromagnetic target containing a ferromagnetic material on the substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A third deposition chamber for filming;
A fourth non-magnetic intermediate layer is formed by sputtering using a non-magnetic target on the substrate which is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A membrane chamber;
A fifth film forming chamber that is connected to the transfer chamber via a gate valve and forms a crystalline magnesium oxide layer on the substrate transferred by the robot transfer device;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a first nonmagnetic interlayer on the first ferromagnetic pinned layer, a second on the first nonmagnetic interlayer. A discharge mechanism for discharging the substrate on which the ferromagnetic pinned layer and the crystalline magnesium oxide layer are laminated;
It is characterized by having.

Alternatively, the magnetic multilayer film creating apparatus according to the present invention is
A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first deposition chamber for filming;
By the co-sputtering method using a platinum target containing a platinum group metal and a target containing a ferromagnetic material on the substrate transported by the robot transfer device, connected to the transfer chamber and a gate valve. A second deposition chamber for depositing a first ferromagnetic pinned layer containing a platinum group metal;
A second ferromagnetic pinned layer is formed by sputtering using a ferromagnetic target containing a ferromagnetic material on the substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A third deposition chamber for filming;
A fourth non-magnetic intermediate layer is formed by sputtering using a non-magnetic target on the substrate which is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A membrane chamber;
A fifth film forming chamber that is connected to the transfer chamber via a gate valve and forms a crystalline magnesium oxide layer on the substrate transferred by the robot transfer device;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a first nonmagnetic interlayer on the first ferromagnetic pinned layer, a second on the first nonmagnetic interlayer. A discharge mechanism for discharging the substrate on which the ferromagnetic pinned layer and the crystalline magnesium oxide layer are laminated;
It is characterized by having.

Moreover, the magnetic multilayer film creating apparatus according to the present invention includes:
A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first ferromagnetic pinned layer containing a platinum group metal was formed by co-sputtering using a platinum-containing target containing a platinum group metal and a ferromagnetic target containing a ferromagnetic material. Forming a nonmagnetic intermediate layer by sputtering using a nonmagnetic target, and forming a second ferromagnetic pinned layer by sputtering using a ferromagnetic target containing a ferromagnetic material A chamber;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a nonmagnetic interlayer on the first ferromagnetic pinned layer, and a second ferromagnetic pinned layer on the nonmagnetic interlayer. A discharge mechanism for discharging a substrate having a laminated magnetic multilayer film;
An apparatus for producing a magnetic multilayer film, comprising:

Moreover, the magnetic multilayer film creating apparatus according to the present invention includes:
A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first ferromagnetic pinned layer containing a platinum group metal was formed by co-sputtering using a platinum-containing target containing a platinum group metal and a ferromagnetic target containing a ferromagnetic material. First, a nonmagnetic intermediate layer is formed by sputtering using a nonmagnetic target, and a second ferromagnetic fixed layer is formed by sputtering using a ferromagnetic target containing a ferromagnetic material. A deposition chamber;
First, a magnesium oxide layer or a metal magnesium layer is formed by sputtering using a magnesium oxide target or a metal magnesium target on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. Two deposition chambers;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a nonmagnetic intermediate layer on the first ferromagnetic pinned layer, a second ferromagnetic pinned layer on the nonmagnetic intermediate layer, And a discharge mechanism for discharging a substrate having a magnetic multilayer film in which a magnesium oxide layer or a metal magnesium layer is laminated,
It is characterized by having.

  According to the present invention, it is possible to obtain a magnetoresistive element having high thermal stability and a higher MR ratio.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the constituent elements described in this embodiment are merely examples, and the technical scope of the present invention is determined by the scope of claims, and is limited by the following individual embodiments. is not.

  FIG. 1 is a sectional view of a tunnel magnetoresistive element according to the first embodiment of the present invention.

  The tunnel magnetoresistive element of this embodiment includes a lower electrode layer 11, an antiferromagnetic layer 12, a first ferromagnetic fixed layer (first magnetization fixed layer) 13, a first nonmagnetic intermediate layer 14, and a second ferromagnetic fixed layer. (Second magnetization fixed layer) 15, second nonmagnetic intermediate layer (tunnel barrier layer) 16, ferromagnetic free layer (magnetization free layer) 17, and upper electrode layer 18 are laminated in this order. The film formation is performed by, for example, a DC sputtering method. Here, the magnetic moment of the first ferromagnetic pinned layer 13 is pinned in one direction by exchange coupling with the antiferromagnetic layer 12. Further, the second ferromagnetic pinned layer 15 has a magnetic moment fixed in an antiparallel direction to the first ferromagnetic pinned layer 13 by antiferromagnetic exchange coupling via the first nonmagnetic intermediate layer 14. Such a laminated magnetization fixed layer including the first ferromagnetic fixed layer 13, the first nonmagnetic intermediate layer 14, and the second ferromagnetic fixed layer 15 forms the SAF structure.

  The ferromagnetic pinned layer according to the embodiment of the present invention is not limited to the three-layer configuration including the first ferromagnetic pinned layer 13, the first nonmagnetic intermediate layer 14, and the second ferromagnetic pinned layer 15. It may be composed of one ferromagnetic layer, or may be a laminated structure of four or more layers.

As a material of the antiferromagnetic layer 12 used in the present invention, platinum manganese (PtMn), iridium manganese (IrMn), or the like is used. The antiferromagnetic layer 12 is obtained by a film forming method using a sputtering method, a CVD (Chemical Vapor Deposition) method, an ion beam evaporation method, an epitaxy method, or the like.
As the first ferromagnetic fixed layer 13 used in the present invention, an alloy represented by the following general formula A containing at least one metal selected from the metal group consisting of Fe, Co, and Ni and a platinum group metal is used. be able to.

Formula A
_{(Fe a Co b Ni c)} d (M) e
(However, 0 ≦ a <100, 0 ≦ b <100, 0 ≦ c <100, a + b + c = 100, 95.5 ≦ d ≦ 50, 0.5 ≦ e ≦ 50, d + e = 100) M is a platinum group Indicates a system metal. )
The platinum group metal used in the present invention is at least one selected from platinum-based elements composed of platinum (Pt), iridium (Ir), osmium (Os), palladium (Pd), ruthenium (Rh) and rhodium (Ru). Metals of more than one kind of elements (including alloys of these elements) can be used. In particular, in the present invention, it is preferable to use platinum (Pt) as the platinum group metal.

  The addition amount of the platinum group metal in the alloy is 0.5 atomic% to 50 atomic%, preferably 10 atomic% to 40 atomic%.

  In the embodiment of the present invention, the first ferromagnetic fixed layer 13 using a CoFe-based alloy or a CoFeNi-based alloy is added with a metal composed of at least one element selected from the platinum group elements described above, whereby the above-mentioned Thermal diffusion of Mn in the antiferromagnetic layer 12 can be suppressed, and as a result, diffusion to the second ferromagnetic pinned layer 15 and the second nonmagnetic intermediate layer (tunnel barrier layer) 16 described below can be suppressed. .

  In the first ferromagnetic fixed layer 13 used in the present invention, boron (B) is contained in the alloy represented by the general formula A in an amount of 0.5 atomic% to 30 atomic%, preferably 5 atomic% to 25 atomic%. Can be contained.

  In the present invention, the alloy represented by the above general formula A or an alloy containing B (boron) in this alloy is formed by sputtering, CVD (Chemical Vapor Deposition), ion beam deposition, epitaxy, or the like. Is done. The formed first ferromagnetic pinned layer 13 can have an amorphous, microcrystalline, or polycrystalline non-single crystal structure or a single crystal structure. In particular, in the present invention, it is advantageous to increase the effect that the first ferromagnetic pinned layer 13 is formed of a polycrystalline ferromagnetic material. According to the present invention, by using a SAF (Synthetic antiferromagnet) structure for the first ferromagnetic pinned layer 13, the thermal stability of the tunnel magnetoresistive element can be improved.

  The second ferromagnetic pinned layer 15 used in the present invention preferably contains an alloy containing at least one metal selected from the metal group consisting of Fe, Co and Ni, or an alloy and boron (B). An alloy represented by the following general formula B can be used.

Formula B
_{(Fe x Co y Ni z)} m (B) n
(However, 0 ≦ x <100, 0 ≦ y <100, 0 ≦ z <100, x + y + z = 100, m + n = 100, 0 ≦ n <30, 70 <m ≦ 100)
The second ferromagnetic pinned layer 15 is made of platinum made of a platinum-based element such as platinum (Pt), iridium (Ir), osmium (Os), palladium (Pd), ruthenium (Rh), or rhodium (Ru). Group metals can be added and contained. At this time, the content of the platinum group metal in the alloy is 0.5 atomic% to 30 atomic%, preferably 5 atomic% to 25 atomic%. In particular, it is preferable to use platinum (Pt) among platinum group metals.

As the first nonmagnetic intermediate layer 14 used in the present invention, ruthenium (Ru), rhodium (Rh), chromium (Cr), iridium (Ir), or an alloy thereof can be used. In addition, a first layer formed from ruthenium (Ru), rhodium (Rh), chromium (Cr), iridium (Ir), or an alloy thereof and copper (Cu), silver (Ag), gold (Au), or aluminum A laminate composed of a second layer formed of (Al) or an alloy thereof can also be used. The first nonmagnetic intermediate layer 14 used in the present invention is obtained by a film forming method using a sputtering method, a CVD (Chemical Vapor Deposition) method, an ion beam evaporation method, an epitaxy method, or the like. In the tunnel magnetoresistive element of the present invention, the second nonmagnetic intermediate layer 16 functions as a tunnel barrier layer. As the tunnel barrier layer, amorphous, microcrystalline, polycrystalline, or other non-single crystal structure or single crystal structure magnesium oxide ((Mg) _f (O) _g : f + g = 100 40 <f <60 60 <g <40) Can be used. The tunnel barrier layer is obtained by a film forming method using a sputtering method, a CVD (Chemical Vapor Deposition) method, an ion beam evaporation method, an epitaxy method, or the like. The polycrystalline or single crystal magnesium oxide used in the tunnel barrier layer of the present invention is preferably formed of a (100) plane crystal parallel to the layer interface in the film thickness direction in the layer. .

  In the giant magnetoresistive element of the present invention, the second nonmagnetic intermediate layer 16 can be made of a nonmagnetic material such as copper (Cu).

  As the ferromagnetic free layer 17 used in the present invention, an alloy containing at least one element selected from the group consisting of iron (Fe), nickel (Ni) and cobalt (Co), for example, cobalt iron (CoFe ) Alloy, a sputtering method using a ferromagnetic target containing a cobalt iron nickel (CoFeNi) alloy, and the like.

  In the present invention, the ferromagnetic free layer 17 can contain boron (B), and the above-described platinum group metal can be added.

  FIG. 2 shows another aspect of the SAF structure in the first embodiment described above in the second embodiment of the present invention.

  The first ferromagnetic pinned layer 13 in the SAF structure shown in FIG. 2 is a laminated structure of a third ferromagnetic layer 21 and a fourth ferromagnetic layer 22, and the second ferromagnetic pinned layer 15 is a fifth ferromagnetic layer. This is a laminated structure of the layer 23 and the sixth ferromagnetic layer 24.

  For the third ferromagnetic layer 21, an alloy represented by the general formula A containing at least one metal selected from the metal group consisting of Fe, Co, and Ni and a platinum group metal can be used. The addition amount of the platinum group metal in this alloy is 0.5 atomic% to 50 atomic%, preferably 10 atomic% to 40 atomic%.

  In the second embodiment, the third ferromagnetic layer 21 using a CoFe-based alloy or a CoFeNi-based alloy is added with a metal composed of at least one element selected from the above platinum group elements, so that the antiferromagnetic layer is added. 12 can be suppressed, and as a result, diffusion to the second ferromagnetic pinned layer 15 and the second nonmagnetic intermediate layer 16 described below can be suppressed.

  In the third ferromagnetic layer 21 used in the present invention, boron (B) is contained in an alloy represented by the general formula A in an amount of 0.5 atomic% to 30 atomic%, preferably 5 atomic% to 25 atomic%. It can be included.

  In the second embodiment, the alloy represented by the above general formula A or an alloy containing B (boron) in this alloy is formed by using a sputtering method, a CVD (Chemical Vapor Deposition) method, an ion beam deposition method, an epitaxy method, or the like. A film is formed. The formed third ferromagnetic layer 21 can have an amorphous, microcrystalline, or polycrystalline non-single crystal structure or a single crystal structure. In particular, in the second embodiment, it is advantageous for enhancing the effect that the third ferromagnetic layer 21 is formed of a polycrystalline ferromagnetic material. The fourth ferromagnetic layer 22, the fifth ferromagnetic layer 23, and the sixth ferromagnetic layer 24 used in the second embodiment are preferably at least one selected from the metal group consisting of Fe, Co, and Ni. An alloy containing a metal or an alloy represented by the general formula B containing an alloy and boron (B) can be used.

  In the second embodiment, platinum (Pt) in at least one of the fourth ferromagnetic layer 22, the fifth ferromagnetic layer 23, and the sixth ferromagnetic layer 24, preferably in all layers, A platinum group metal composed of a platinum-based element such as iridium (Ir), osmium (Os), palladium (Pd), ruthenium (Rh), or rhodium (Ru) can be added. At this time, the content of the platinum group metal in the alloy is 0.5 atomic% to 30 atomic%, preferably 5 atomic% to 25 atomic%. In particular, it is preferable to use platinum (Pt) among platinum group metals.

  Next, with reference to FIG. 3, an apparatus and a manufacturing method for manufacturing the tunnel magnetoresistive element having the above laminated structure will be described. FIG. 3 is a schematic plan view of an apparatus for manufacturing a tunnel magnetoresistive element. This apparatus is an apparatus capable of producing a multilayer film including a plurality of magnetic films, and is a sputtering film forming apparatus for mass production. is there.

  The magnetic multilayer film manufacturing apparatus 30 shown in FIG. 3 is a cluster type apparatus, and includes a plurality of film forming chambers based on a sputtering method. In the magnetic multilayer film manufacturing apparatus 30, a transfer chamber 32 including a robot transfer apparatus (not shown) is installed at the center position. In the transfer chamber 32 of the magnetic multilayer film manufacturing apparatus 30, two load / unload chambers 35 and 36 are provided, and a substrate (silicon substrate) 31 is loaded / unloaded by each. By alternately using these load and unload chambers 35 and 36, a multilayer film can be produced with high productivity.

  In the magnetic multilayer film manufacturing apparatus 30 described above, for example, three film forming chambers 37A, 37B, and 37C, one etching chamber 38, and one oxidation chamber 39 are provided around the transfer chamber 32. In the etching chamber 38, the required surface of the tunnel magnetoresistive element is etched. In the oxidation chamber 39, the metal film is oxidized to form a tunnel barrier layer of the oxide film. Between each chamber (37A, 37B, 37C, 38, 39) and the transfer chamber 32, each chamber (37A, 37B, 37C, 38, 39) is isolated and can be opened and closed as necessary. Is provided. Each chamber is provided with a vacuum exhaust mechanism, a gas introduction mechanism, a power supply mechanism and the like (not shown).

In each of the film forming chambers 37A, 37B, and 37C of the magnetic multilayer film manufacturing apparatus 30, the above-described magnetic films are sequentially deposited on the substrate 31 from below by sputtering. For example, four or five targets (tantalum (Ta) 41, copper (Cu) 42, cobalt iron boron) arranged on a suitable circumference are respectively provided on the ceiling portions of the film forming chambers 37A, 37B, and 37C. (CoFeB) 43, nickel iron (NiFe) 44, cobalt iron (C ₉₀ Fe ₁₀ ) 45), (platinum manganese (PtMn) 51, cobalt iron platinum (CoFePt) 52, ruthenium (Ru) 53, cobalt iron (C ₉₀₎ Fe ₁₀ ) 54, cobalt iron (C ₇₀ Fe ₃₀ ) 55), (magnesium oxide (MgO) 61, nickel iron chromium (NiFeCr) 62, magnesium (Mg) 63, aluminum (Al) 64) are arranged. Furthermore, the substrate 31 is disposed on a substrate holder located coaxially with the circumference.

In the above, the targets (41, 42, 43, 44, 45), (51, 52, 53, 54, 55) and (61, 62, 63, 64) are selected according to the material of the layer to be deposited. Is done. The target 52 of the first ferromagnetic fixed layer 13 may be, for example, a cobalt iron platinum (CoFePt) target, the target 52 is a platinum (Pt) target, and the target 55 is cobalt iron (Co ₇₀ Fe ₃₀ ). A co-sputtering method using a target or a co-sputtering method using the target 52 as a platinum (Pt) target and the target 54 as a cobalt iron (Co ₉₀ Fe ₁₀ ) target may be used.

  Further, the material of the target 41 may be “Ta” for the base electrode layer and the upper electrode layer, and the material of the target 43 may be “CoFeB” for the second ferromagnetic fixed layer 15. The material of the target 51 may also be a “PtMn” target for the antiferromagnetic layer 12. Further, the material of the target 53 may be a “Ru” target for the first nonmagnetic intermediate layer 14. Further, the material of the target 61 may be an “MgO” target for the second nonmagnetic intermediate layer 16 to be a tunnel barrier layer. Further, the targets 63 and 64 may be “Mg” and “Al” targets for a metal layer that is a precursor when forming a tunnel barrier layer by oxidation treatment.

  In order to deposit a magnetic film having an appropriate composition with good efficiency, the plurality of targets are preferably provided so as to be inclined toward each substrate, but may be provided in a state parallel to the substrate surface. . Further, the plurality of targets and the substrate are arranged based on a configuration that rotates relatively. In the magnetic multilayer film manufacturing apparatus 30 having the above-described configuration, the magnetic multilayer film shown in FIG. 1 is sequentially formed on the substrate 31 by the sputtering method using the film forming chambers 37A, 37B, and 37C. The

  In the embodiment described above, the tunnel magnetoresistive element has been described. However, the present invention can be realized by changing the above-described tunnel barrier layer to a nonmagnetic conductive layer such as copper (Cu) as the second nonmagnetic intermediate layer 16. A magnetoresistive element can be constructed.

  The tunnel magnetoresistive element that has been laminated by performing the sputtering film formation in each of the film formation chambers 37A, 37B, and 37C is subjected to an annealing process in a heat treatment furnace. At this time, the annealing temperature is, for example, about 200 ° C. to 400 ° C., and the annealing process is performed, for example, for 4 hours in a magnetic field of 8 kOe (64 KA / m), for example. Thereby, required magnetization is given to PtMn which is a diamagnetic layer of the tunnel magnetoresistive element.

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

Example 1
FIG. 4 is a cross-sectional view showing the configuration of Example 1 of the tunnel magnetoresistive element of the present invention. The tunnel magnetoresistive element of the present embodiment is a bottom type tunnel magnetoresistive element and corresponds to the configuration shown in FIG.

In FIG. 4, the Ta layer 71-1 (using the target 41), the CuN layer 71-2 (using the target 42), and the Ta layer 71-3 (using the target 41) constitute the lower electrode layer, and the thickness is These are 5 nm, 20 nm, and 3 nm, respectively. The PtMn layer 72 (using the target 51) is an antiferromagnetic layer and has a thickness of 15 nm. The (Co ₇₀ Fe ₃₀ ) _100-X Pt _X layer 73 (using a co-sputtering target of the target 52 and the target 55) is a first ferromagnetic pinned layer and has a thickness of 2.5 nm. The Ru layer 74 (using the target 53) is a nonmagnetic layer (nonmagnetic intermediate layer) and has a thickness of 0.85 nm. The Co ₇₀ Fe ₃₀ layer 75 (using the target 55) is a second ferromagnetic pinned layer and has a thickness of 2.5 nm. The AlO _X layer 76 (using the target 64) is a second nonmagnetic intermediate layer (tunnel barrier layer) and has a thickness of 1.2 nm. The (Co ₇₀ Fe ₃₀ ) ₈₀ B ₂₀ layer 77 (using the target 43) is a ferromagnetic free layer and has a thickness of 3 nm. The Ta layer 78-1 (using the target 41) and the Ru layer 78-2 (using the target 53) constitute the upper electrode layer, and have a thickness of 10 nm and 7 nm, respectively. In this example, platinum (Pt) was added to the first ferromagnetic pinned layer in the addition amount (atomic%) shown in Table 1 below.

The AlO _x layer 76 is subjected to oxidation treatment in the oxidation chamber 39 shown in FIG. 3 after forming the Al layer.

Instead of the AlO _x layer 76, a tunnel barrier layer 76 of magnesium oxide (MgO) may be used. At this time, the target 64 can be a magnesium oxide (MgO) target or a metal magnesium target. When the metal magnesium target is used, an oxidation process is performed in the oxidation chamber 39 in order to oxidize the metal magnesium layer.

  Next, the obtained tunnel magnetoresistive element was transferred to an annealing chamber, where annealing treatments of 270 ° C., 300 ° C., and 330 ° C. were performed, and MR (%) at each temperature was measured. The results are shown in Table 1 below.

  According to Table 1, when platinum (Pt) was not added, MR (%) decreased as the annealing temperature increased. It can be seen that the reduction rate of the MR ratio is reduced by adding Pt. And especially the temperature dependence of MR (%) was improved by adding platinum (Pt). In particular, when the amount of platinum (PT) added exceeds 18 atomic%, the reduction rate of MR (%) could be greatly reduced. The upper limit of the amount of platinum (Pt) added is not particularly limited, but 50 atomic% is preferably the upper limit.

(Example 2)
A similar tunnel magnetoresistive element is formed using iridium (Ir), Os (osmium), palladium (Pd), Rh (rhodium), and Ru (ruthenium) in place of platinum (Pt) used in Example 1. Then, the same temperature dependence test as in Example 1 was performed. As a result, as in Example 1, the temperature dependency was improved.

(Example 3)
A tunnel magnetoresistive element was prepared in the same manner as in Example 1 except that the Co ₇₀ Fe ₃₀ layer 75 which is the second ferromagnetic fixed layer used in Example 1 was changed to a Co ₆₀ Fe ₂₀ Pt ₁₀ layer. The temperature dependency was tested in the same manner as in Example 1. The results are shown in Table 2 below.

(Comparative Example 1)
Similar to Example 3 except that the (Co ₇₀ Fe ₃₀ ) _100-X Pt _X layer 73, which is the first ferromagnetic pinned layer used in Example 3, was replaced with a Co ₇₀ Fe ₃₀ layer containing no platinum. Then, a tunnel magnetoresistive element was prepared, and the temperature dependency similar to that of Example 1 was tested. The results are shown in Table 3 below.

Example 4
FIG. 5 is a cross-sectional view showing the configuration of an embodiment of the giant magnetoresistive element of the present invention. The giant magnetoresistive element of the present embodiment is a giant magnetoresistive element having a bottom type structure.

In FIG. 5, a nickel iron chromium (NiFeCr) layer 501 (using a target 62) is a lower electrode layer and has a thickness of 4 nm. The platinum manganese (PtMn) layer 502 (using the target 51) is an antiferromagnetic layer and has a thickness of 12 nm. Cobalt iron platinum (Co ₉₀ Fe ₁₀ ) _100-X Pt _X layer 503 (using a co-sputtering target of target 52 (CoFePt) and target 54) is a first ferromagnetic pinned layer with a thickness of 1.8 nm. is there. The ruthenium (Ru) layer 504 (using the target 53) is the first nonmagnetic intermediate layer and has a thickness of 0.9 nm. Cobalt iron (Co ₉₀ Fe ₁₀ layer) 505 (using the target 54) is the second ferromagnetic pinned layer and has a thickness of 2.2 nm. The copper (Cu) layer 506 (using the target 42) is a second nonmagnetic intermediate layer, and has a thickness of 2 nm. Cobalt iron (Co ₉₀ Fe ₁₀ layer) 507 (using the target 45) is a ferromagnetic free layer having a thickness of 1.3 nm. Nickel iron (Ni ₈₃ Fe ₁₇ layer) 508-1 (using target 44), copper (Cu) layer 508-2 (using target 42), tantalum (Ta layer) 508-3 (using target 41) are the top An electrode layer is formed, and the thicknesses are 2.5 nm, 6 nm, and 3 nm, respectively. In this example, platinum (Pt) was added to the first ferromagnetic fixed layer. This element was annealed at a temperature of 300 ° C., and MR (%) at this time was measured. The result is shown in FIG.

  FIG. 6 shows the MR (%) of a giant magnetoresistive element subjected to heat treatment (300 ° C.) for 4 hours in a high magnetic field of 0.8 T after film formation, and platinum ( It is a figure which shows the relationship with Pt) addition amount. The MR (%) increases as platinum (Pt) is added, and an MR (%) of about 16.0% is obtained at 8 atomic%. An MR (%) of about 16.3% was obtained when the platinum (Pt) content was in the vicinity of 12 to 24 atomic%. This is an increase of about 0.8% from MR% (15.5%) without adding platinum (Pt). The upper limit of the amount of platinum (Pt) added is defined within a preferable range for the ferromagnetic layer, but the upper limit is approximately 50 at%. Therefore, the platinum (Pt) Pt addition amount exceeds 0 atomic% and is 50 atomic% or less, preferably 8 atomic% or more and 50 atomic% or less, more preferably 12 atomic% or more and 24 atomic% or less.

  The tunnel magnetoresistive element and giant magnetoresistive element of the present invention can be used for a magnetic head and a magnetic random access memory of a magnetic disk drive.

It is sectional drawing of the tunnel magnetoresistive element concerning embodiment of this invention. It is sectional drawing of the tunnel magnetoresistive element concerning another embodiment of this invention. It is a figure which shows schematic structure of the manufacturing apparatus of the magnetoresistive element of this invention. 1 is a cross-sectional view of a tunnel magnetoresistive element according to Example 1. FIG. It is sectional drawing of the giant magnetoresistive element of this invention. It is a figure which shows the characteristic which shows the temperature dependence of the element of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Lower electrode layer 12 Antiferromagnetic layer 13 First ferromagnetic fixed layer 14 Nonmagnetic intermediate layer 15 Second ferromagnetic solid layer 16 Tunnel barrier layer 17 Ferromagnetic free layer 18 Upper electrode 21 Third ferromagnetic layer 22 Fourth strong Magnetic layer 23 Fifth ferromagnetic layer 24 Sixth ferromagnetic layer 30 Magnetic multilayer film manufacturing apparatus

Claims (18)

An antiferromagnetic layer formed of a layer containing manganese;
A first magnetization pinned layer formed by a layer having a ferromagnetic material and a platinum group metal, a second magnetization pinned layer formed by a layer having a ferromagnetic material, and the first magnetization pinned, located on the antiferromagnetic layer side A laminated magnetization fixed layer having a first nonmagnetic intermediate layer located between the layer and the second magnetization fixed layer;
A magnetization free layer formed of a layer having a ferromagnetic material;
A second nonmagnetic intermediate layer located between the stacked magnetization fixed layer and the magnetization free layer;
The magnetoresistive element characterized by having.   The platinum group metal is at least one metal selected from the group consisting of platinum (Pt), iridium (Ir), Os (osmium), palladium (Pd), Rh (rhodium), and Ru (ruthenium). The magnetoresistive element according to claim 1.   The magnetoresistive element according to claim 1, wherein the platinum group metal is platinum (Pt).   The magnetoresistive element according to claim 1, wherein the first magnetization fixed layer and the second magnetization fixed layer have a ferromagnetic material having a crystal structure.   The magnetoresistive element according to claim 4, wherein the crystal structure is microcrystal, polycrystal, or single crystal.   The magnetoresistive element according to claim 1, wherein the second nonmagnetic intermediate layer includes magnesium oxide having a crystal structure.   The magnetoresistive element according to claim 6, wherein the crystal structure is microcrystal, polycrystal, or single crystal.   The magnetoresistive element according to claim 6, wherein the second magnetization fixed layer contains a platinum group metal.   The magnetoresistive element according to claim 1, wherein the magnetization free layer contains a platinum group metal.   The magnetoresistive element according to claim 1, wherein the second nonmagnetic intermediate layer includes aluminum oxide.   The magnetoresistive element according to claim 1, wherein the first magnetization fixed layer contains the platinum group metal in a range of 0.5 atomic% to 50 atomic%.   The magnetoresistive element according to claim 1, wherein the first magnetization fixed layer contains the platinum group metal in a range of 10 atomic% to 40 atomic%. An antiferromagnetic layer,
A laminated magnetization fixed layer having a laminated structure having a first magnetization fixed layer, a first nonmagnetic intermediate layer, and a second magnetization fixed layer;
A second nonmagnetic intermediate layer;
A method of manufacturing a magnetoresistive element having a magnetization free layer,
A first step of forming the antiferromagnetic layer by a sputtering method using a target containing manganese (Mn);
After the first step, a second step of forming the first magnetization fixed layer by sputtering using a target containing a platinum group metal and a target containing a ferromagnetic material,
After the second step, a third step of forming the first nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the third step, a fourth step of forming the second magnetization fixed layer by sputtering using a target containing a ferromagnetic material;
After the fourth step, a fifth step of forming the second nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the fifth step, a sixth step of forming the magnetization free layer by sputtering using a target containing a ferromagnetic material;
After the sixth step, the antiferromagnetic layer, the first magnetization fixed layer, the first nonmagnetic intermediate layer, and the stacked magnetization fixed layer having a stacked structure including the second magnetization fixed layer, A seventh step including a step of performing a heat treatment in a heating furnace on the second nonmagnetic intermediate layer and the magnetization free layer;
A method of manufacturing a magnetoresistive element, comprising: An antiferromagnetic layer,
A laminated magnetization fixed layer having a laminated structure having a first magnetization fixed layer, a first nonmagnetic intermediate layer, and a second magnetization fixed layer;
A second nonmagnetic intermediate layer;
A method of manufacturing a magnetoresistive element having a magnetization free layer,
A first step of forming the antiferromagnetic layer by a sputtering method using a target containing manganese (Mn);
After the first step, a second step of forming the first magnetization fixed layer by sputtering using a target containing a platinum group metal and a ferromagnetic material;
After the second step, a third step of forming the first nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the third step, a fourth step of forming the second magnetization fixed layer by sputtering using a target containing a ferromagnetic material;
After the fourth step, a fifth step of forming the second nonmagnetic intermediate layer by a sputtering method using a target containing a nonmagnetic material,
After the fifth step, a sixth step of forming the magnetization free layer by sputtering using a target containing a ferromagnetic material;
After the sixth step, the antiferromagnetic layer, the laminated ferromagnetic pinned layer having a laminated structure including the first magnetization pinned layer, the first nonmagnetic intermediate layer, and the second magnetization pinned layer, A seventh step including a step of performing a heat treatment in a heating furnace on the second nonmagnetic intermediate layer and the magnetization free layer;
A method of manufacturing a magnetoresistive element, comprising: A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first deposition chamber for filming;
A platinum group metal was contained by sputtering using a ferromagnetic target containing a platinum group metal on the substrate that was connected to the transfer chamber via a gate valve and carried by the robot carrier. A second deposition chamber for depositing the first ferromagnetic pinned layer;
A second ferromagnetic pinned layer is formed by sputtering using a ferromagnetic target containing a ferromagnetic material on the substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A third deposition chamber for filming;
A fourth non-magnetic intermediate layer is formed by sputtering using a non-magnetic target on the substrate which is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A membrane chamber;
A fifth film forming chamber that is connected to the transfer chamber via a gate valve and forms a crystalline magnesium oxide layer on the substrate transferred by the robot transfer device;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a first nonmagnetic interlayer on the first ferromagnetic pinned layer, on the first nonmagnetic interlayer A discharge mechanism for discharging the substrate on which the second ferromagnetic pinned layer and the crystalline magnesium oxide layer are stacked;
An apparatus for producing a magnetic multilayer film, comprising: A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first deposition chamber for filming;
By the co-sputtering method using a platinum target containing a platinum group metal and a target containing a ferromagnetic material on the substrate transported by the robot transfer device, connected to the transfer chamber and a gate valve. A second deposition chamber for depositing a first ferromagnetic pinned layer containing a platinum group metal;
A second ferromagnetic pinned layer is formed by sputtering using a ferromagnetic target containing a ferromagnetic material on the substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A third deposition chamber for filming;
A fourth non-magnetic intermediate layer is formed by sputtering using a non-magnetic target on the substrate which is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A membrane chamber;
A fifth film forming chamber that is connected to the transfer chamber via a gate valve and forms a crystalline magnesium oxide layer on the substrate transferred by the robot transfer device;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a first nonmagnetic interlayer on the first ferromagnetic pinned layer, on the first nonmagnetic interlayer A discharge mechanism for discharging the substrate on which the second ferromagnetic pinned layer and the crystalline magnesium oxide layer are stacked;
An apparatus for producing a magnetic multilayer film, comprising: A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first ferromagnetic pinned layer containing a platinum group metal was formed by co-sputtering using a platinum-containing target containing a platinum group metal and a ferromagnetic target containing a ferromagnetic material. Forming a nonmagnetic intermediate layer by sputtering using a nonmagnetic target, and forming a second ferromagnetic pinned layer by sputtering using a ferromagnetic target containing a ferromagnetic material A chamber;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a nonmagnetic interlayer on the first ferromagnetic pinned layer, and a second ferromagnetic pinned on the nonmagnetic interlayer A discharge mechanism for discharging a substrate having a magnetic multilayer film in which layers are laminated;
An apparatus for producing a magnetic multilayer film, comprising: A transfer chamber equipped with a robot transfer device;
A loading mechanism for loading a substrate for forming a magnetic multilayer film into the transfer chamber;
An antiferromagnetic layer is formed by sputtering using an antiferromagnetic target containing manganese (Mn) on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. A first ferromagnetic pinned layer containing a platinum group metal was formed by co-sputtering using a platinum-containing target containing a platinum group metal and a ferromagnetic target containing a ferromagnetic material. First, a nonmagnetic intermediate layer is formed by sputtering using a nonmagnetic target, and a second ferromagnetic fixed layer is formed by sputtering using a ferromagnetic target containing a ferromagnetic material. A deposition chamber;
First, a magnesium oxide layer or a metal magnesium layer is formed by sputtering using a magnesium oxide target or a metal magnesium target on a substrate that is connected to the transfer chamber via a gate valve and transferred by the robot transfer device. Two deposition chambers;
The antiferromagnetic layer, a first ferromagnetic pinned layer on the antiferromagnetic layer, a nonmagnetic intermediate layer on the first ferromagnetic pinned layer, a second ferromagnetic pinned on the nonmagnetic intermediate layer A discharge mechanism for discharging a substrate having a magnetic multilayer film in which a layer and a magnesium oxide layer or a metal magnesium layer are laminated;
An apparatus for producing a magnetic multilayer film, comprising:

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