JP2005109201A - Ferromagnetic tunnel junction element, magnetic memory cell, and magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve thin layers of an element without sharply deteriorating magnetic characteristics in a ferromagnetic tunnel junction element, a magnetic memory cell, and a magnetic head. <P>SOLUTION: At least a pinned layer 3 in a ferromagnetic tunnel junction element having a lamination structure consisting of a foundation layer 1/a 0 to 5 nm-thick antiferromagnetic layer 2/the pinned layer 3/an insulating layer 4/a free layer 5 is shaped so that magnetic anisotropy arises more than that in the shape of the free layer 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a ferromagnetic tunnel junction device, a magnetic memory cell, and a magnetic head, and more particularly to a ferromagnetic tunnel junction device, a magnetic memory cell, and a magnetic tunnel junction device characterized by a structure for thinning the ferromagnetic tunnel junction device. The present invention relates to a magnetic head.

  A ferromagnetic tunnel junction (MTJ) element is used as a magnetic sensor unit constituting a reproducing magnetic head, or as an information storage unit of a magnetic random access memory device (MRAM; Magnetic Random Access Memory). (For example, refer to Patent Document 1 or Patent Document 2).

See FIG.
FIG. 13 is a conceptual configuration diagram of a ferromagnetic tunnel junction device, which includes a pinning layer 81 made of an antiferromagnetic layer, a pinned layer 82 made of a ferromagnetic layer, a tunnel insulating film 83 such as Al—O, and a ferromagnetic layer. It has a structure in which free layers 84 composed of layers are sequentially stacked, and is configured such that current flows in the film thickness direction.

  In this ferromagnetic tunnel junction device, when the magnetization direction of the free layer 84 is parallel to the magnetization direction of the pinned layer 82, the tunnel current easily flows, so that the resistance state is low. A high resistance state is entered, and magnetic information written on the magnetic recording medium is read or information of “0” or “1” is stored due to the difference in resistance state.

See FIG.
FIG. 14 is a laminate of NiFe (24 nm) / Co ₇₄ Fe ₂₆ (10 nm) / Al—O (1.6 nm) / Co ₇₄ Fe ₂₆ (10 nm) / IrMn (50 nm) / Al (10 nm), 150 μm × 2 is a magnetoresistance curve of a ferromagnetic tunnel junction element having a size of 150 μm.

See FIG.
FIG. 15 is a schematic cross-sectional view of the 1Tr-1MTJ type MRAM. One electrode of the ferromagnetic tunnel junction device 100 that manages memory, that is, the capping layer 106 is connected to the bit line 98, and the other electrode, that is, The base layer 101 is connected to the source region 91 or the drain region 92 of the transistor 90.
Here, the drain region 92 is connected.

  A lead layer 97 is provided on a write word line 95 orthogonal to the bit line 98 via an interlayer insulating film 96, on which a base layer 101, an antiferromagnetic layer 102, a pinned layer 103, a tunnel insulating layer are provided. 104, a free layer 105, and a capping layer 106 are sequentially formed, and a bit line 98 is connected to the capping layer 106.

See FIG.
FIG. 16 is an equivalent circuit diagram of a memory cell constituting such an MRAM. An MTJ element 100 is disposed at an intersection between a write word line 95 and a bit line 98, and a source wiring layer 94 is grounded to a plate line 99. Connected to.

Recording in this MRAM is performed by reversing the magnetization of the free layer 105 by a synthetic magnetic field generated by passing a current through the bit line 98 and the write word line 95 orthogonal to each other.
On the other hand, reading is performed by applying a voltage to the word line 93 provided at the gate of the transistor 90 and conducting between the source region 91 and the drain region 92, thereby causing a current to flow through the ferromagnetic tunnel junction device 100. It is determined whether the state is “0” or “1”.

A major problem in such an MRAM is that when the size of the ferromagnetic tunnel junction element (MTJ element) is reduced for higher density, the magnetic field for writing becomes smaller.
That is, since the upper limit of the current density for preventing migration is determined, current cannot flow through a thin wire having a small cross-sectional area.

See FIG.
FIG. 17 shows the generated magnetic field when the line width of 0.5 μm × 0.5 μm is shrunk to the line width of 0.1 μm × 0.1 μm when the upper limit of the current density is 8 × 10 ⁶ A / cm ^2. The generated magnetic field is about 1/5 with respect to the shrinkage of 1/5 geometrically.

  In order to improve the problem of reducing the strength of the generated magnetic field due to shrink, a method of providing a magnetic yoke made of NiFe or the like around the wiring has been devised.

See FIG.
FIG. 18 is a diagram simulating the intensity H _x of the generated magnetic field at a position 10 nm away from two types of wiring of a cross section of 0.1 μm × 0.1 μm and a cross section of 0.07 μm × 0.07 μm. The case where the yoke is provided and the case where the yoke is not provided are shown. As shown in the figure, the magnetic field generated is increased 3 to 4 times by providing the magnetic yoke.

However, since the generated magnetic field H _x varies depending on the distance from the wiring and decreases as the distance from the wiring increases, this situation will be described with reference to FIG.
See FIG.
FIG. 19 shows the distance dependence of the generated magnetic field H _x from the surface of the wiring in the wiring having a cross section of 0.1 μm × 0.1 μm, and about 1 [Oe / nm when the magnetic yoke is provided. ] At a reduction rate of].

Therefore, how to place the MTJ element close to the wiring, that is, the write word line is an important problem.
JP 2003-031776 A JP 2002-299484 A

  In order to bring the free layer and the write word line close to each other, each layer interposed between them, in particular, the pinning layer having the maximum film thickness may be thinned. However, the pinning layer made of an antiferromagnetic layer such as PtMn may be used. In order to develop the pinning effect, a film thickness of 10 nm to 20 nm is required at least, which is a limiting requirement for proximity.

  If the difference in coercive force between the pinned layer and the free layer is used, the magnetization direction of the pinned layer can be fixed under operating conditions, but the applied magnetic field strength is limited and stable operation cannot be expected. There is a problem.

  On the other hand, since the recording density in the magnetic recording medium is regulated by the film thickness of the MTJ element constituting the reproducing head, it is necessary to reduce the thickness of the MTJ element in order to increase the recording density. The presence of the thickest antiferromagnetic layer becomes a problem.

  Accordingly, an object of the present invention is to realize the thinning of elements required in a magnetic memory device or a magnetic head without significantly deteriorating magnetic characteristics.

FIG. 1 is a diagram illustrating the basic configuration of the present invention. Means for solving the problems in the present invention will be described with reference to FIG.
In order to solve the above-mentioned problem, the present invention has a strong structure having a laminated structure comprising an underlayer 1 / an antiferromagnetic layer 2 having a thickness of 0 to 5 nm / a pinned layer 3 / an insulating layer 4 / a free layer 5. In the magnetic tunnel junction element, at least the pinned layer 3 has a shape in which magnetic anisotropy appears from the shape of the free layer 5.
In this case, since the direction of the write magnetic field caused by the current passed through the bit line is normally the longitudinal direction of the pinned layer 3, it is preferable to have shape anisotropy in the longitudinal direction of the pinned layer 3.

  As described above, by increasing the shape anisotropy of the pinned layer 3, the magnetization direction of the pinned layer 3 can be stably fixed even if the antiferromagnetic layer 2 is thinned or eliminated. The ferromagnetic tunnel junction device can be made thin.

  Alternatively, instead of giving magnetic anisotropy to the shape, the magnetization of the pinned layer 3 may be magnetically fixed using a magnetostrictive effect generated by the difference in stress between the underlayer 1 and the pinned layer 3.

  In this case, since the magnetic anisotropy is represented by the product of the magnetostriction constant and the stress, in order to give the magnetic anisotropy in the longitudinal direction of the pinned layer 3, the thermal expansion coefficient of the underlayer 1 is the pinned layer 3. When the thermal expansion coefficient is smaller than that, tensile stress acts in the longitudinal direction of the pinned layer 3, so that the magnetostriction constant of the pinned layer 3 needs to be positive.

  On the other hand, when the thermal expansion coefficient of the underlayer 1 is larger than the thermal expansion coefficient of the pinned layer 3, a compressive stress acts in the longitudinal direction of the pinned layer 3, so that the magnetostriction constant of the pinned layer 3 needs to be negative. .

  In the above configuration, the ferromagnetic tunnel junction element can be made the thinnest by setting the thickness of the antiferromagnetic layer 2 to zero.

  Further, the antiferromagnetic layer 2 cannot exhibit a sufficient pinning effect in the range of 0 to 5 μm, but has a maximum coercive force in the range of 2.5 to 5 nm. Thus, the magnetization direction of the pinned layer 3 can be stably fixed, and further stabilization can be achieved by combining the shape anisotropy and / or the magnetic anisotropy of the pinned layer 3.

  Further, since the space between the free layer 5 and the write word line can be made closer by using the ferromagnetic tunnel junction element having the above configuration as the memory holding unit, the line width of the wiring such as the write word line Narrow and fine magnetic memory cells can be constructed, and a highly integrated magnetic memory device can be constructed by arranging a plurality of magnetic memory cells.

  Further, by using the ferromagnetic tunnel junction element having the above configuration as a magnetic sensor unit for reproduction, it is possible to configure a fine magnetic head, thereby realizing a high recording density magnetic recording apparatus. .

  According to the present invention, by thinning the ferromagnetic tunnel junction device, the free layer in the MRAM can be brought close to the write word line, and the magnetic field intensity generated from the word line can be increased, so that the current in writing can be increased. Can be reduced.

  Further, in the magnetic head, the magnetic sensor part constituting the reproducing head can be made thin, whereby the recording bits can be miniaturized, so that the magnetic recording apparatus can be increased in density.

  In the present invention, the ferromagnetic tunnel junction device is thinned by thinning the antiferromagnetic layer so that a sufficient pinning effect does not appear or eliminating the antiferromagnetic layer. The disappearance of the pinning effect due to the increase in the coercive force of the antiferromagnetic layer or the shape anisotropy and / or the magnetic anisotropy of the pinned layer is compensated.

Here, with reference to FIG. 2 thru | or FIG. 9, the manufacturing process of Example 1 of this invention is demonstrated.
See Figure 2
First, a p-type well region 12 is formed in a predetermined region of the n-type silicon substrate 11, and an element isolation oxide film 13 is formed by selectively oxidizing the n-type silicon substrate 11. Then, a gate insulating film 14 is formed in the element formation region. Then, a gate electrode 15 made of WSi serving as a read word line is formed, and As ions are implanted using the gate electrode 15 as a mask, thereby forming an n ⁻ type LDD region 16.

Next, a SiO ₂ film is deposited on the entire surface, and anisotropic etching is performed to form the sidewalls 17. Then, As ions are implanted again to form the n ⁺ -type drain region 18 and the n ⁺ -type source region 19. Then, after forming a thick first interlayer insulating film 20 made of an O ₃ -TEOS-SiO ₂ film, contact holes reaching the n ⁺ type drain region 18 and the n ⁺ type source region 19 are formed. Are plugged with W to form W plugs 21 and 22.
The O ₃ -TEOS-SiO ₂ film is deposited at 400 ° C. by the CVD method using TEOS + O ₃ as a source gas, and the same applies to the following steps.

See Figure 3
Next, after depositing TiN / Al / TiN on the entire surface using a sputtering method and patterning, the connection conductor 23 and the source wiring layer 24 are formed, and then the O ₃ -TEOS-SiO ₂ film is formed again. A two-layer insulating film 25 is formed, then a contact hole reaching the connection conductor 23 is formed, and this contact hole is filled with W to form a W plug 26.
The source wiring layer 24 is finally connected to a grounded plate line.

See Figure 4
Next, Ti / TiN / Al / Ti / TiN is again deposited on the entire surface and then patterned to form the connection conductor 27 and the write word line 28, and then again, a thin SiO ₂ film such as a TEOS-NSG film. A third interlayer insulating film 29 made of a film or the like is formed, then a contact hole reaching the connection conductor 27 is formed, and this contact hole is filled with W through Ti / TiN to form a W plug 30.

See Figure 5
Next, the lower electrode 31 connected to the connection conductor 27 is formed by depositing Ta with a thickness of, for example, 20 nm on the entire surface by sputtering, and then patterning. Then, again, the O ₃ -TEOS is formed. A thin fourth interlayer insulating film 32 made of a SiO ₂ film is deposited, and then flattened by CMP until the lower electrode 31 is exposed.

See FIG.
Next, using a sputtering method, a Co ₇₄ Fe ₂₆ layer 33 with a thickness of, for example, 1.4 nm and a Ru layer 34 with a thickness of, for example, 0.75 nm in a state where the substrate temperature is, for example, 100 ° C. Then, a Co ₇₄ Fe ₂₆ layer 35 having a thickness of, for example, 2.2 nm is sequentially deposited to form a pinned layer 36 having a ferri-spin structure.
In this case, since the Ru layer 34 is optimized to be about 1 nm or less, the Co ₇₄ Fe ₂₆ layer 33 and the Co ₇₄ Fe ₂₆ layer 35 on both sides thereof are strongly antiferromagnetically coupled, so that one magnetic film as a whole is obtained. Behave like

Subsequently, after depositing Al having a thickness of, for example, 0.9 nm, the tunnel insulating film 37 made of Al-O is formed by oxidation, and then the thickness is again increased under similar sputtering conditions. A Co ₇₄ Fe ₂₆ layer 38 having a thickness of 1 nm, a NiFe layer 39 having a thickness of, for example, 6 nm, and a cap layer 41 having a thickness of, for example, 20 nm are sequentially deposited.
The Co ₇₄ Fe ₂₆ layer 38 and the NiFe layer 39 constitute a free layer 40.

See FIG.
Next, by performing ion milling using the resist pattern 42 as a mask, for example, the cap layer 41 to the pinned layer 36 are etched into a 1.5: 1 rectangular shape in which the longitudinal direction of the lower electrode 31 becomes longer.

See FIG.
Next, after removing the resist pattern 42, the cap layer 41 to the free layer 40 are etched into a 1: 1 square shape by using a new resist pattern 43, so that the pinned layer having a larger magnetic anisotropy than the free layer 40 is obtained. An MTJ element 44 including the layer 36 is formed.

See FIG.
Next, after removing the resist pattern 43, a fifth interlayer insulating film 45 made of an O ₃ —TEOS—SiO ₂ film is deposited on the entire surface, and then the surface of the cap layer 41 is exposed by CMP. Polishing to flatten the whole surface.

  Next, after depositing a p-SiN film 46 having a thickness of, for example, 100 nm using a plasma CVD method, a contact hole for the MTJ element 44 is provided, and then a thickness is formed on the entire surface using a sputtering method. For example, after depositing a TiN layer having a TiN / Al / TiN structure by sequentially depositing a TiN layer having a thickness of 100 nm, an Al layer having a thickness of, for example, 800 nm, and a TiN layer having a thickness of, for example, 100 nm. The bit line 47 is formed by patterning so as to extend in a direction orthogonal to the write word line 28, thereby completing the basic structure of the MRAM.

  In Example 1, since the magnetic anisotropy of the pinned layer 36 is made larger than the magnetic anisotropy of the free layer 40 due to the shape effect, the magnetization direction of the pinned layer 36 is used without using an antiferromagnetic layer. Can be fixed stably.

  Since the antiferromagnetic layer is omitted, the thickness of the MTJ element 44 can be drastically reduced, and thereby the distance between the free layer 40 and the write word line 28 can be made closer. Therefore, even when the current flowing through the write word line 28 is reduced, the free layer 40 can be positioned at a position where a sufficient magnetic field strength is generated, and the MRAM can be highly integrated.

Next, a magnetic head according to a second embodiment of the present invention will be described with reference to FIGS.
See FIG.
FIG. 10 is a schematic cross-sectional view of the main part of the magnetic head according to the second embodiment of the present invention. First, the thickness is formed on the Al ₂ O ₃ —TiC substrate 51 through the Al ₂ O ₃ film 52 by plating. However, after forming the lower magnetic shield layer 53 made of, for example, 300 nm of NiFe, the lower electrode 54 made of, for example, Ta having a thickness of, for example, 10 nm is formed by vapor deposition.

Next, using a sputtering method, with the substrate temperature set at, for example, 100 ° C., the thickness is, for example, an underlayer 55 made of NiFe having a thickness of 25 nm, and the thickness is 2.5 to 5 nm, for example, 3.3 nm. A FeMn layer 56, a Co ₇₄ Fe ₂₆ layer 57 having a thickness of 1.4 nm, a Ru layer 58 having a thickness of, for example, 0.75 nm, and a Co ₇₄ Fe ₂₆ layer 59 having a thickness of, for example, 2.2 nm are sequentially deposited. Thus, a pinned layer 60 having a ferri-spin structure is obtained.

Subsequently, after depositing Al having a thickness of, for example, 0.9 nm, the tunnel insulating film 61 made of Al—O is formed by oxidation, and then the thickness is again increased under similar sputtering conditions. A 1 nm thick Co ₇₄ Fe ₂₆ layer 62, a 6 nm thick NiFe layer 63, for example, and a 20 nm thick cap layer 65, for example, are sequentially deposited. The Co ₇₄ Fe ₂₆ layer 62 and the NiFe layer 63 constitute a free layer 64.

  Next, by performing ion milling using a resist pattern (not shown) as a mask, the cap layer 65 to the pinned layer 60 are patterned to form the magnetic sensor portion 66.

Next, using the resist pattern as it is as a lift-off mask, a SiO ₂ film 67 and a magnetic domain control film 68 made of CoCrPt are sequentially deposited by sputtering, and then the resist pattern is removed.

Next, an SiO ₂ planarizing film 69 is provided on the entire surface, and after planarizing, a contact hole reaching the cap layer 65 is formed. Next, a Ta film is deposited on the entire surface, and then the upper electrode 70 is formed by patterning. Form.

Next, the upper magnetic shield layer 71 made of NiFe having a thickness of, for example, 1 μm is formed by selective plating.
Thereafter, a composite type magnetic head in which a conventional inductive write head is formed on the upper magnetic shield layer 71 and an MTJ element having an antiferromagnetic layer made extremely thin by performing slider processing or the like is used as a magnetic sensor unit 66 will be described. can get.

See FIG.
Figure 11 is an explanatory diagram of film thickness dependency of H _ua of the antiferromagnetic a layer FeMn, contributes magnetic field strength H _ua pinning of the pinned layer until the thickness of the FeMn is approximately 6nm Not expressed.
The figure shows the measurement results for a sample having a structure of Ta (10 nm) / NiFe (25 nm) / FeMn (xnm) / Ta (10 nm).

See FIG.
FIG. 12 is an explanatory diagram of the film thickness dependence of the coercive force H _c in the same sample as FIG. 11, showing a maximum value at about 3.3 nm, and thereafter abruptly attenuates as the film thickness increases.

Therefore, in Example 2, although the FeMn layer 56 that is an antiferromagnetic layer does not exhibit the pinning effect, it has a very large coercive force H _c , and therefore uses this large coercive force. The magnetization direction of the pinned layer 60 can be stably fixed.

  As described above, in Example 2, since the antiferromagnetic layer is remarkably thin compared with the conventional MTJ element, the thickness of the MTJ element itself can be significantly reduced. Recording density can be increased.

As mentioned above, although each Example of this invention was described, this invention is not restricted to the structure and conditions described in each Example, A various change is possible.
For example, the above numerical values such as film thickness are merely examples, and may be changed as appropriate according to the times and needs.

  In each of the above embodiments, the antiferromagnetically coupled ferri-spin structure film having a CoFe / Ru / CoFe structure is used as the pinned layer, but a single layer of CoFe may be used.

  In the above embodiment, a CoFe / NiFe laminated film is used as the free layer. However, the invention is not limited to the laminated film, and a single layer film may be used.

In each of the above embodiments, the Al-O film is formed by oxidizing Al with a tunnel insulating film formed thereon, but is not limited to the Al-O film, and Al ₂ O ₃ The film itself may be formed, and another nonmagnetic insulator such as a SiN film may be used.

  In the first embodiment, an antiferromagnetic layer is not provided at all, but the film thickness in the vicinity where the coercive force of 5 nm or less takes a maximum value, for example, a film within the range of the half width around the maximum value. A thick antiferromagnetic layer may be provided, whereby the magnetization direction of the pinned layer can be more stably fixed.

  In Example 1 described above, the pinned layer has a 1.5: 1 rectangular shape. However, the pinned layer is not limited to 1.5: 1, and the shape anisotropy increases with an elongated shape. This ratio is arbitrary, and the shape of the free layer may be made rectangular as long as it does not exceed the shape anisotropy of the pinned layer.

In Example 1 described above, the magnetization direction of the pinned layer is stably fixed using shape anisotropy, but the stress applied to the pinned layer due to the difference in thermal expansion coefficient with the underlayer. May be used.
That is, since the magnetic anisotropy is represented by the product of the magnetostriction constant and the stress, the magnetic anisotropy can be increased by increasing the stress.

For example, since Ta has a smaller thermal expansion coefficient than CoFe, when Ta is used as an underlayer, tensile stress is applied in the longitudinal direction of the CoFe pinned layer.
CoFe has a magnetostriction constant of 0 in Co ₉₀ Fe ₁₀ , and the magnetostriction constant at which the Fe composition ratio is larger is positive, and is negative when it is small.
Therefore, since Co ₇₄ Fe ₂₆ has a positive magnetostriction constant, a large magnetic anisotropy appears in the longitudinal direction of the pinned layer.

On the other hand, when the thermal expansion coefficient of the underlayer is larger than the thermal expansion coefficient of the pinned layer, a compressive stress is applied in the longitudinal direction of the pinned layer. In this case, a negative layer such as Co ₉₅ Fe ₅ is used as the pinned layer. By using a ferromagnetic material having a magnetostriction constant of 2 as the pinned layer, a large magnetic anisotropy can be exhibited in the longitudinal direction of the pinned layer.

  As described above, when magnetic anisotropy is actively used, that is, when the difference in the thermal expansion coefficient between the underlayer and the pinned layer is increased so that the magnetic anisotropy appears greatly, The shape of the layer and the free layer may be the same shape.

  Further, in Example 2 above, the planar shapes of the pinned layer and the free layer in the MTJ element are substantially the same. The pinned layer may have a rectangular shape so as to obtain a directivity, whereby the magnetization direction of the pinned layer can be more stably fixed.

In Example 2 described above, FeMn is used as the antiferromagnetic layer. However, the antiferromagnetic layer is not limited to FeMn, and other antiferromagnetic layers such as IrMn or PdPtMn may be used.
In this case, the value at which the coercive force becomes a maximum value is strictly different from that of FeMn, but the film thickness of the antiferromagnetic layer may be in the range of the half value width around the maximum value.

  In the second embodiment, the composite thin-film magnetic head is described as being integrated with the write head.

The detailed features of the present invention will be described again with reference to FIG. 1 again.
Again see Figure 1
(Additional remark 1) In the ferromagnetic tunnel junction element which has the laminated structure consisting of the underlayer 1 / antiferromagnetic layer 2 / pinned layer 3 / insulating layer / free layer 5 having a thickness of 0 to 5 nm, at least the pinned layer 3 A ferromagnetic tunnel junction element characterized by having a shape in which magnetic anisotropy appears from the shape of the free layer 5.
(Supplementary note 2) The ferromagnetic tunnel junction device according to supplementary note 1, wherein shape anisotropy is provided in a longitudinal direction of the pinned layer 3.
(Supplementary Note 3) In a ferromagnetic tunnel junction device having a laminated structure composed of an underlayer 1 / an antiferromagnetic layer 2 having a thickness of 0 to 5 nm / a pinned layer 3 / an insulating layer 4 / a free layer 5; A ferromagnetic tunnel junction element characterized in that the magnetization of the pinned layer 3 is magnetically fixed by using a magnetostrictive effect generated by a difference in stress of the pinned layer 3.
(Additional remark 4) The ferromagnetic tunnel junction of Additional remark 3 characterized by making the thermal expansion coefficient of the said foundation | substrate layer 1 smaller than the thermal expansion coefficient of the said pinned layer 3, and making the magnetostriction constant of the said pinned layer 3 positive. element.
(Supplementary note 5) The ferromagnetic tunnel junction according to supplementary note 3, wherein the thermal expansion coefficient of the underlayer 1 is made larger than the thermal expansion coefficient of the pinned layer 3 and the magnetostriction constant of the pinned layer 3 is made negative. element.
(Supplementary note 6) The ferromagnetic tunnel junction device according to any one of supplementary notes 1 to 5, wherein the antiferromagnetic layer 2 has a thickness of zero.
(Additional remark 7) In the ferromagnetic tunnel junction element which has the laminated structure which consists of the underlayer 1 / antiferromagnetic layer 2 / pinned layer 3 / insulating layer 4 / free layer 5 having a thickness of 0 to 5 nm, the antiferromagnetic layer 2. A ferromagnetic tunnel junction device having a thickness of 2 in a range of 2.5 nm to 5 nm.
(Supplementary note 8) A magnetic memory cell using the ferromagnetic tunnel junction device according to any one of supplementary notes 1 to 7 as a memory holding unit.
(Supplementary Note 9) A magnetic memory device in which a plurality of magnetic memory cells according to Supplementary Note 8 are arranged.
(Supplementary Note 10) A magnetic head using the ferromagnetic tunnel junction device according to any one of Supplementary Notes 1 to 7 as a magnetic sensor unit for reproduction.

  As an application example of the present invention, MRAM is typical, and can be applied as a nonvolatile storage device of information equipment. Further, it is not used as MRAM, but a magnetic sensor of a reproducing head constituting a thin film magnetic head. It may be used as.

It is explanatory drawing of the fundamental structure of this invention. It is explanatory drawing of the manufacturing process to the middle of MRAM of Example 1 of this invention. It is explanatory drawing of the manufacturing process to the middle after FIG. 2 of MRAM of Example 1 of this invention. It is explanatory drawing of the manufacturing process to the middle after FIG. 3 of MRAM of Example 1 of this invention. It is explanatory drawing of the manufacturing process to the middle after FIG. 4 of MRAM of Example 1 of this invention. It is explanatory drawing of the manufacturing process to the middle after FIG. 5 of MRAM of Example 1 of this invention. It is explanatory drawing of the manufacturing process to the middle after FIG. 6 of MRAM of Example 1 of this invention. It is explanatory drawing of the manufacturing process to the middle after FIG. 7 of MRAM of Example 1 of this invention. It is explanatory drawing of the manufacturing process after FIG. 8 of MRAM of Example 1 of this invention. It is a schematic principal part sectional drawing of the magnetic head of Example 2 of this invention. It is an explanatory view of a film thickness dependency of H _ua in FeMn. It is an explanatory view of a film thickness dependency of the coercive force H _c of FeMn. It is a conceptual block diagram of a ferromagnetic tunnel junction element. It is a magnetoresistive curve of a ferromagnetic tunnel junction element. It is a schematic sectional drawing of 1Tr-1MTJ type | mold MRAM. It is an equivalent circuit diagram of the memory cell which comprises MRAM. It is explanatory drawing of the current density dependence of the generated magnetic field. It is explanatory drawing of the effect of a magnetic yoke. It is an illustration of the distance dependence of the wiring of the generated magnetic field H _x.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Underlayer 2 Antiferromagnetic layer 3 Pinned layer 4 Insulating layer 5 Free layer 11 n-type silicon substrate 12 p-type well region 13 Element isolation oxide film 14 Gate insulating film 15 Gate electrode 16 n ⁻ type LDD region 17 Side wall 18 n ⁺ Type drain region 19 n ⁺ type source region 20 first interlayer insulating film 21 W plug 22 W plug 23 connecting conductor 24 source wiring layer 25 second interlayer insulating film 26 W plug 27 connecting conductor 28 writing word line 29 third layer Insulating film 30 W plug 31 Lower electrode 32 Fourth interlayer insulating film 33 Co ₇₄ Fe ₂₆ layer 34 Ru layer 35 Co ₇₄ Fe ₂₆ layer 36 Pinned layer 37 Tunnel insulating film 38 Co ₇₄ Fe ₂₆ layer 39 NiFe layer 40 Free layer 41 Cap Layer 42 resist pattern 43 resist pattern 44 MTJ element 45 fifth interlayer insulating film 46 p-SiN film 47 bit 51 Al ₂ O ₃ -TiC substrate 52 Al ₂ O ₃ film 53 lower magnetic shield layer 54 lower electrode 55 base layer 56 FeMn layer 57 Co ₇₄ Fe ₂₆ layer 58 Ru layer 59 Co ₇₄ Fe ₂₆ layer 60 pinned layer 61 tunnel insulating film 62 Co ₇₄ Fe ₂₆ layer 63 NiFe layer 64 Free layer 65 Cap layer 66 Magnetic sensor part 67 SiO ₂ film 68 Magnetic domain control film 69 SiO ₂ planarizing film 70 Upper electrode 71 Upper magnetic shield layer 81 Pinning layer 82 Pinned layer 83 Tunnel insulation Film 84 Free layer 90 Transistor 91 Source region 92 Drain region 93 Word line 94 Source wiring layer 95 Write word line 96 Interlayer insulating film 97 Lead layer 98 Bit line 99 Plate line 100 Ferromagnetic tunnel junction element 101 Underlayer 102 Antiferromagnetic Layer 103 Pinned layer 104 Tunnel insulating layer 105 Free Layer 106 capping layer

Claims (5)

In a ferromagnetic tunnel junction device having a laminated structure consisting of an underlayer / an antiferromagnetic layer having a thickness of 0 to 5 nm / pinned layer / insulating layer / free layer, at least the shape of the pinned layer is more magnetic than the shape of the free layer. A ferromagnetic tunnel junction device characterized by having a shape in which anisotropy appears. In a ferromagnetic tunnel junction device having a laminated structure comprising an underlayer / antiferromagnetic layer / thickness of 0 to 5 nm / pinned layer / insulating layer / free layer, it is generated due to a difference in stress between the underlayer and the pinned layer. A ferromagnetic tunnel junction device, wherein the magnetization of a pinned layer is magnetically fixed using a magnetostrictive effect. In a ferromagnetic tunnel junction device having a laminated structure consisting of an underlayer / antiferromagnetic layer / pinned layer / insulating layer / free layer having a thickness of 0 to 5 nm, the antiferromagnetic layer has a thickness of 2.5 nm to 5 nm. A ferromagnetic tunnel junction device characterized by that. 4. A magnetic memory cell using the ferromagnetic tunnel junction device according to claim 1 as a memory holding unit. 4. A magnetic head comprising the ferromagnetic tunnel junction element according to claim 1 as a reproducing magnetic sensor unit.

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