JP2001291914A - Structure of magnetoresistance(mr) element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an element largely exhibiting tunnel magnetoresistance(TMR) effect by precisely controlling thickness, width and length of a cluster layer and properly selecting material. SOLUTION: A magnetoresistance element constituted of a ferromagnetic electrode (A component), a forced layer (F component) or a sensitized layer (D component) and the cluster layer (K component) is formed on an upper surface of an insulating substrate (B component) which is formed of nonmagnetic material by combining MBE method, lithography method, ion etching method, strong external magnetic field and heat treatment. As a result, a magnetoresistance element, whose magnetoresistance(MR) is largely decreased by applying a small external magnetic field is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an MBE method, a MOCVD method, a sputtering method, or another film forming method, a lithography method, an ion etching method, a combination of application of a strong external magnetic field and heat treatment. When the length or thickness of the magnetic electrode layer-ferromagnetic electrode layer, that is, the length or thickness of the cluster layer is precisely controlled, and a weak magnetic field H such as a magnetic medium is not applied, a state having a large electric resistance value is obtained. However, when a weak magnetic field H such as a magnetic medium is applied, a spin-dependent tunnel effect appears, causing a large decrease in electric resistance. A spin-dependent tunneling magneto-resistance (TMR) element configuration and a method of manufacturing the same About.

[0002]

2. Description of the Related Art Conventionally, Cu-Fe, Cu-Co, Ag
A multilayer thin film is formed by a MBE method using a combination of -Co or Ag-Fe, or a ferromagnetic cluster such as Fe or Co is formed in a Cu or Ag matrix by an ionization cluster beam (ICB) method. Formed in a dispersed state or embedded in an oxide insulator matrix (eg,
S. Barzilai et al. Phys. Rev. B23, 1809 (1981)
). According to such a method, the effect of spin-dependent scattering of electrons at the interface between the ferromagnetic material and the nonmagnetic good conductor at the multilayer thin film, the effect of spin-dependent scattering of electrons at the interface between the ferromagnetic material cluster and the matrix of the nonmagnetic good conductor, Alternatively, spin-dependent tunneling between ferromagnetic clusters in a non-magnetic insulator matrix was responsible for the creation of the magnetoresistance (Magnetoresistance) effect. An element in which thin films of a ferromagnetic material (for example, Co or Fe) and a semiconductor or an insulator (for example, Ge or Al ₂ O ₃ ) having non-magnetic characteristics are alternately stacked exhibits a tunnel magnetoresistance effect. (Eg, S. Maekawa et al, IEEE Trans. Magn. MAG-18, N
o.2, 707 (1982)).

A magnetic head for reading is manufactured by using such a magnetoresistive element, and a current is constantly applied to the magnetic head for reading.
When placed close to the magnetic medium, information recorded as a change in the weak magnetic field of the magnetic medium can be read out as a change in voltage of the magnetic head.

[0004]

The conventional magnetoresistive effect is caused by the scattering phenomenon of electrons at a hetero-phase interface between a magnetic material and a good conductor, or the appearance of a spin-dependent tunneling effect in a laminated thin film of a ferromagnetic material and an insulator. There was a drawback that control was difficult and the resistance change could not be increased because the effect of changing by the magnetic field was used.

According to the present invention, the thickness of the cluster layer, or
By precisely controlling the length, in the presence of a weak magnetic field such as a magnetic medium, to produce an element that can effectively control the appearance of the spin-dependent tunneling effect, that is, the spin-dependent tunneling magnetoresistance The purpose is to manufacture an element having a large change.

[0006]

Means for Solving the Problems In order to achieve the above object, according to the present invention, a first, second and third insulating layers, a compulsory layer, and a non-magnetic insulating substrate are provided.
The cluster layer is formed by MBE (or MOCVD, sputtering, etc.), lithography, ion etching,
By using a strong external magnetic field and heat treatment, a spin-dependent tunneling magneto-resistance (TMR) element is finally manufactured in which the increase / decrease of the tunneling magneto-resistance can be controlled by a weak magnetic field.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, first, the distance between ferromagnetic electrodes, that is, the thickness, width, and length of the cluster layer is precisely controlled. In addition, precise control of the distance between clusters is important for controlling the increase and decrease of the spin-dependent tunnel magnetoresistance. Thus, a spin-dependent tunneling magneto-resistance (TMR) element that converts a small change in an external magnetic field into a large change in electric resistance can be manufactured.

In the device structure according to the first, second, third and fourth aspects, the spin of the ferromagnetic cluster in the cluster layer has superparamagnetic characteristics due to the small size of the cluster, and has a random characteristic. In a different direction. Therefore, when no external magnetic field is applied, the electric resistance between the ferromagnetic electrodes is large, but when a weak external magnetic field H such as a magnetic medium is applied, the spin directions of the ferromagnetic electrodes and the clusters match. , Electrical resistance decreases. That is, a spin-dependent magnetoresistance effect is developed. In the element structure described in claim 2 (FIGS. 3 and 4) and claim 4 (FIG. 7), the forcing layer made of the K component adjusts the spin direction of the cluster in the cluster layer to a weak external direction such as a magnetic medium. It is weakly regulated in a direction rotated by 90 degrees with respect to the spin direction of the magnetic field. In the device structure described in claim 4 (FIG. 8), the sensitizing layer composed of the D component acts to enhance the action of the external magnetic field when a weak external magnetic field is applied.

According to the first, second, third and fourth aspects, the direction of the spin of each ferromagnetic electrode is made to coincide with the direction of a weak external magnetic field such as a magnetic medium, that is, (a) in the vertical direction of the plan view. To increase the thickness, the thickness of the cluster layer (FIGS. 1, 2, 3, and 4) or the thickness (FIGS. 5, 6,
FIGS. 7 and 8) show the antiferromagnetic coupling (antiferromagneti).
ferromagnetic co, not c coupling
upling). The K component composing the forcing layer is a hard ferromagnetic material having characteristics equivalent to those of a permanent magnet,
Alternatively, at the time of fabrication, a strong external magnetic field is also applied in the horizontal direction in the plan view, and the spin direction of the forcing layer is set in the horizontal direction. At this time, the spin direction of each ferromagnetic electrode does not change due to the shape effect and remains in the longitudinal direction. Therefore, the direction of the spin of the cluster in the cluster layer is set parallel to the direction of the spin of the forced layer. Under such a spin setting, a weak external magnetic field such as a magnetic medium acts upward from the bottom of the side view to obtain [0008]
The magnetoresistance change described in (1) appears. First ferromagnetic electrode 8
6, 2 and 3, when a constant current is always passed between the second ferromagnetic electrodes 87, FIG.
When a weak external magnetic field such as a magnetic medium is applied from the bottom to the top in the side view of FIG. 7C, a voltage drop corresponding to the application of the magnetic field occurs between the ferromagnetic electrodes.

[0010]

Examples Table 1 shows Example numbers, element structures, A, B,
The materials for the C, D, F and K components and the results are shown. "Good" described in the results is 233K-38.
5% to 10% at 3K, "Excellent" is 10% at 233K to 383K
~ 20% and "best" is 2 at 233K-383K
It represents a rate of change in magnetoresistance of 0 to 30%.

[0011]

[Table 1]

[0012]

As described above, according to the present invention, since the thickness, width and length of the cluster layer are precisely controlled to produce a magnetoresistive element, an extremely small magnetic field corresponding to a magnetic medium is produced. As a result, a large resistance decrease based on the spin-dependent tunneling effect was observed.

[Brief description of the drawings]

FIG. 1 shows a spin-dependent magnetoresistive element structure including a ferromagnetic electrode and a cluster layer including a cluster having superparamagnetic characteristics. (A) is a plan view, (b) is an end view, and
(C) is a side view.

FIG. 2 shows a spin-dependent magnetoresistive element structure in which a certain thickness of a ferromagnetic electrode differs from that of FIG. (A) is a plan view, (b) is an end view, and (c) is a side view.

FIG. 3 shows a spin-dependent magnetoresistive element structure including a ferromagnetic electrode, a cluster layer including a cluster having superparamagnetic characteristics, and a forcing layer. (A) is a plan view, (b) is an end view,
And (c) is a side view.

FIG. 4 shows a spin-dependent magnetoresistive element structure in which the thickness of a ferromagnetic electrode is different from that of FIG. (A) is a plan view, (b) is an end view, and (c)
Is a side view.

FIG. 5 shows a first ferromagnetic electrode laminated on an insulating substrate;
When the cluster layer and the second ferromagnetic electrode are arranged,
1 shows a spin-dependent magnetoresistive element structure. (A) is a plan view,
(B) is an end view, and (c) is a side view.

FIG. 6 shows a first ferromagnetic electrode laminated on an insulating substrate,
When the cluster layer and the second ferromagnetic electrode are arranged,
1 shows a spin-dependent magnetoresistive element structure. (A) is a plan view,
(B) is an end view, and (c) is a side view.

7A shows a spin-dependent magnetoresistive element structure in which, in addition to the element structure shown in FIG. 6, (a) a forcing layer having a longitudinal direction is incorporated in the vertical direction of the plan view. (A) is a plan view, (b) is an end view, and (c) is a side view.

8 shows a spin-dependent magnetoresistive element structure in the case where the forcing layer is replaced with a sensitizing layer in the element structure of FIG. (A)
Is a plan view, (b) is an end view, and (c) is a side view.

FIG. 9C is a side view of the element in which the magnetoresistive element is incorporated in the shielding layer 101 so that a magnetoresistance change rate is exhibited when a weak external magnetic field such as a magnetic medium is applied upward. The form is shown. (A) is a plan view, (b) is an end view, and (c) is a side view.

[Explanation of symbols]

 11: Forced layer 31: Sensitizing layer 41: First insulating layer 42: Second insulating layer 43: Third insulating layer 86: First ferromagnetic electrode 87: Second ferromagnetic electrode 91: Insulating substrate 101: Shielding layer 111 : Cluster layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 10/16 H01L 43/12 41/18 G01R 15/02 A H01L 43/12 33/06 R

Claims (5)

[Claims] As shown in FIG. 1, a first ferromagnetic electrode 86 (A component) and a second ferromagnetic electrode 86 (A component) are vertically arranged on an insulating substrate 91 (B component) in a plan view (a). A component), and a non-magnetic first insulating layer 4 is formed between them from below.
1 (C component: thickness T2 = 2 to 500 nm), on which
Cluster layer 111 (K component: thickness T1 = 2 to 50 nm:
Width W4 = 2-500 nm: Length W3 = 10-400 n
m) (In this case, by forming a film in an oxygen or air atmosphere, a spherical metal or alloy cluster having a diameter D (D = 1 to 30 nm) can be easily tunneled into the insulating oxide film. Is naturally formed at the distance where
Adjacent to this, a third insulating layer 43 (C component) having the same thickness as the cluster layer, and a second insulating layer 42 (C component: thickness T3 = 2 to 500 nm) are formed thereon. It is a structure to be formed, comprising the components described in claim 5,
Molecular beam epitaxy (Molecular-Beam
Epitaxial Method: MBE method, Metal Organic Chemical Vapor Deposition method (Metal-Or)
ganic Chemical Vapor Deposition Method: MOCVD
Method, sputtering, other film forming methods, lithography, ion etching, application of a strong external magnetic field and heat treatment, and a tunnel magnetoresistance (TM) based on the principle of spin-dependent tunnel effect.
R) Form of element and method for producing the element. FIG. 2 shows a structure in which the principle is the same as that of the structure shown in FIG. 1, and the shapes of the first and second ferromagnetic electrodes are thinned to facilitate manufacture. Each dimension in FIG. 2 conforms to the dimension in FIG. Shielding layer 101 (D component)
FIG. 9 shows an element configuration in which is incorporated. 2. FIGS. 3 and 4 show a structure in which a forced layer 11 (F component: width W5 = 2 to 2) made of a ferromagnetic material or an antiferromagnetic material is added to the structure of FIG. 1 (FIGS. 1 and 2). 400n
m: length W3 = 10 to 400 nm), which is composed of the components described in claim 5, and is formed by MBE (or sputtering, or another film forming method), lithography, ion A tunnel magnetoresistive (TMR) element based on the principle of spin-dependent tunneling, which is manufactured by etching, application of a strong external magnetic field, and heat treatment, and a method for manufacturing the same.
The dimensions of FIGS. 3 and 4 not described in the claims are
According to the dimensions of FIG. 1 and FIG. An element configuration incorporating the shielding layer 101 (D component) is shown in FIG. 3. As shown in FIG. 5, the insulating substrate 91 (B
Component), in the (a) plan view, the non-magnetic first insulating layer 41 (C component: thickness T4 = 6 to 1050 n)
m) and the second insulating layer 42 (C component: thickness T4 = 6 to 105)
0 nm), and a first ferromagnetic electrode 86 (A component: width W3 = 2 to 500 nm: thickness T2) is formed from below.
= 2-500 nm), and the cluster layer 111 (K
Component: thickness T1 = 2 to 50 nm: width W4 = 2 to 500 n
m: length W3 = 20 to 400 nm) (in this case, oxygen,
Alternatively, by forming a film in an air atmosphere, the diameter D
(D = 1-30 nm) spherical metal or alloy clusters are spontaneously formed in the insulating oxide film at a distance at which a tunnel effect easily appears.), Adjacent thereto, the same thickness as the cluster layer And a width equal to the length of the cluster layer,
A third insulating layer 43 (C component) is formed, and a second ferromagnetic electrode 87 (A component: width W3 = 2 to 50) is formed thereon.
0 nm: thickness T3 = 2 to 500 nm), and is composed of the components described in claim 5 and is composed of MBE.
Method, MOCVD method, sputtering method, other film forming methods,
It is characterized by being manufactured by lithography, ion etching, application of a strong external magnetic field and heat treatment.
A form of a tunnel magnetoresistive (TMR) element based on the principle of spin-dependent tunneling and a method for manufacturing the same. FIG.
Has the same principle as that of the structure shown in FIG. 5, and has a structure in which the shapes of the first insulating layer and the second insulating layer are thinned to facilitate manufacture. Each dimension (T1, T2, T3, W3 and W4) is
According to the dimensions of FIG. An element configuration incorporating the shielding layer 101 (D component) is shown in FIG. FIG. 7 shows the width G (G = G) of the non-magnetic third insulating layer 43 in addition to the structure of FIG. 3 (FIGS. 5 and 6).
0.5 to 100 nm) apart and have insulator properties.
Forced layer 11 made of ferromagnetic material or antiferromagnetic material (F component: width W3 = 2-500 nm: length L3 = 100-10
000 nm), comprising the components described in claim 5, MBE (or sputtering, MOCVD, or other film forming methods), lithography, ion etching, strong A form of a tunnel magnetoresistive (TMR) element based on the principle of a spin-dependent tunneling effect, which is manufactured by applying an external magnetic field and heat treatment, and a manufacturing method thereof. FIG.
It has the same shape as the structure shown in FIG.
Sensitizing layer 31 (D component: width W3 = 2 to 500 nm: length L
3 = 100 to 10000 nm). Each dimension other than the dimension described in claim 4 conforms to each dimension of the structure of claim 3 (FIG. 6). Shielding layer 101 (D
FIG. 9 shows an element configuration incorporating the (component). 5. A first ferromagnetic electrode 86 and a second ferromagnetic
As an A component having a large polarizability constituting the ionic electrode 87,
Metals having ferromagnetic properties such as Fe and Co, and CoP
Ferromagnetic properties of t, NiFe, CoFe, NiFeCo, etc.
B component constituting the insulating substrate 91 using an alloy having
And the first insulating layer 46, the second insulating layer 47, and the third
Has non-magnetic properties as a C component constituting the insulating layer 48
Alumina (Al_TwoO_Three) And SiO_TwoUse each etc.
I do. Soft ferromagn with excellent high frequency characteristics
sensitizing layer 31 having the property of etic material), and
As a D component constituting the shielding layer 101, an FeSi alloy,
Amorphous alloys (FeNiMoSiB, FeCoSi
B, CoMnB, CoHfB, FeCoNbSiB and
And FeNiPB) or cubic spinel ferrite
Light (MeFe _TwoO_FourWhere Me is Mn, Fe,
Co, Ni, Cu, Zn, Mg and Cd, or
MnZn, NiZn, L composed of these combinations
iZn, MgZn, MnMg, MnCu and LiNi
And NiCuCoMnAl ferrite
And yttrium-iron-garnet-based mixed acids
Use a compound. As the F component constituting the compulsory layer 11,
Hard magnet with the same characteristics as a permanent magnet
BaF, a hard ferromagnetic material
e₁₂O₁₉, SrFe₁₂O₁₉And PbFe₁₂O₁₉Each Fe
Light, SmCo magnet material, and antiferromagnetic material
FeMn, NiMn, NiO, PtMn, PdP
Use tMn, RhMn, MnIr alloy, etc.
You. Configure a cluster layer containing ferromagnetic clusters,
Co-Al-O, Ni-Si-O, Co
-Si-O, Fe-Mg-O, Fe-Hf-O (above
Represents Co-Al, Ni- in oxygen or air atmosphere.
Si, Co-Si, Fe-Mg, Fe-Hf alloy
Film formation by BE method, sputtering method or other methods
And the use of Fe-Mg-F alloys
Magnetic based on the principle of spin-dependent tunneling
Resistance (TMR) element form and manufacturing method.