JPS58213485A - Manufacture of magnetoresistance effect element - Google Patents

Abstract

PURPOSE:To enhance the magnetoresistance effect as well as to increase the detection output without changing or deteriorating the coersive force, saturated magnetization, anisotropy and the like by a method wherein an ion is implanted on the magnetic film which constitutes the magnetoresistance effect element. CONSTITUTION:Magnetoresistance effect DELTArho/rho is increased by implanting an ion such as H<+>2 ion, Ne<+> ion and the like, 1X10<16>ion/cm<2> or thereabout for H<+> ion and 2X10<14>/cm<2> or thereabout for Ne<+> ion, on the magnetic film of 3,500Angstrom in thickness consisting of Ni-Fe alloy of composition 81wt% and 19wt% respectively, which constitutes the magnetoresistance effect element. Thus, the ion- implanted magnetoresistance effect element can be used for the detector of magnetic thin film memory, a tip-appearing detector for VTR tape and the like.

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a magnetoresistive element.

As is well known, magnetoresistive elements that utilize the magnetoresistive effect include magnetic thin film memory detectors, magnetic field sensors, magnetic heads, magnetic bubble detectors, Magnescale detectors,
Many types of VTR tape cue detectors have been proposed.

For example, detection of bubble magnetic domains using the magnetoresistive effect uses the change in resistance value that occurs when the axis of easy magnetization, which is set in the same direction as the current, is rotated in a direction perpendicular to the current due to the stray magnetic field from the bubble magnetic domain. This is what I did.

In general, in the above-mentioned various elements that utilize the magnetoresistive effect, the detection voltage v8 is applied to the terminal as -R-I (ΔR=resistance value change,
= current) is generated, and if the length, width, and thickness of the element are t, w, and t, respectively, the terminal voltage v8 becomes -Vs=Δρ fist□·r=(Δρ/ρ)·IIIW. Here, Δρ is the resistivity change.

It can be seen that in order to obtain a large detection voltage, when the element permissible current is kept constant, it is better to use a material with a large change in resistivity, increase the element length t, and decrease the element width W1 and the element film thickness t.

In the case of magnetic bubble 2 detection, the effective element length t is the bubble diameter d, but it has become possible to overcome this restriction by using a clever method called bubble stretching. but,
Regarding the element width W, there are restrictions on reducing it because it is necessary to take into account the effects of demagnetizing fields, etc. In actual detection, the element operates in a non-saturation region.

Specific magnetoresistive detection elements that have already been announced can be roughly divided into thin film types and thick film types in terms of film thickness, and those that use stretch as a detection method and those that do not.

The thin film type has a thickness of 200 to 50 mm for the detection element only.
On the other hand, in the thick film type, a part of the transfer element is also used for detection, so the film thickness is 1000 to 5000. Comparing the detection voltages of both under the same conditions, it is clear from the above equation that the thin film type is superior. However, in the thin film type,
Since the size of the film in the thickness direction is limited, the surface scattering effect of conduction electrons becomes large and the resistivity ρ increases, so the 7 magnetoresistive effect Δρ/ρ becomes small, and in reality it becomes large. Detection voltage is not obtained.

Conventional methods for obtaining a large magnetoresistive effect Δρ/ρ using conventionally known thin-film and thick-film magnetoresistive elements include the following.

Medium The magnetoresistive effect Δρ/ρ can be reduced by alloying or compounding the magnetic film.

(11) Heat treatment is used to reduce the resistivity ρ and increase the magnetoresistive effect Δρ/ρ.

However, in these conventional methods, in the fire method described below, Δρ/ρ is determined by material properties and element dimensional design, and when a magnetic film is formed by a known method such as vapor deposition or sputtering, the magnetoresistive effect Δρ/ρ ρ tends to be saturated.

The method (11) has practical limitations because properties outside the magnetoresistive effect Δρ/ρV (for example, coercive force, saturation magnetization, anisotropy, etc.) change or deteriorate. In addition, in order to obtain a large detection voltage by a method other than the above-mentioned method, it is necessary to increase the detection current It from the above equation, but this causes fatal drawbacks such as heat generation of the element and shortening of the life span. Therefore, it is difficult to put it into practical use.

An object of the present invention is to solve the above-mentioned conventional problems and to easily manufacture a magnetoresistive element with a large detection voltage.
An object of the present invention is to provide a method for manufacturing a magnetoresistive element.

In order to achieve the above object, Kineimeisha increases the magnetoresistive effect Δρ/ρ by implanting ions into the magnetic film constituting the magnetoresistive element, thereby increasing the detection voltage.

The present invention will be explained in detail below.

Figure 1 shows the detection output (-MR
This figure shows the magnetic field dependence of (Δρ/ρ)). 1st
In the figure, the curve Ham b+c shows the result of measuring the magnetoresistive effect by successively decreasing the element width of an element with constant element length/element width. It can be seen that a large magnetic field is required. For example, since the effective stray magnetic field from the pull magnetic domain in a magnetic bubble element is 100 G, the element is considered to be operating in a non-saturation region during actual detection.

Fig. 2 Magnetoresistive effect Δρ/ in H1Ni-Fe alloy
This figure shows the dependence of ρ on Ni content. Detection output (Δρ/
As is clear from song #i11, ρ) is Ni=86w
t% reaches approximately 4.5%.

On the other hand, in the non-saturation region used for actual detection, as is clear from curve 2, the detection output (Δρ/ρ) of the magnetic field 650e is about 3.5% at maximum;
As shown in the second section, in actual detection, most elements are generally used in the non-saturation region, so Δρ/ρ of the conventional magnetoresistive element under the permissible detection current is 3.
, about 5%.

Figure 3 shows the magnetoresistive effect Δρ/ in Ni-Co alloy.
This shows the magnetic field dependence of ρ.

In Ni-Co alloy, unlike Ni-Fe alloy, the magnetoresistive effect is as large as about 6%. However, since the minimum magnetic field required for saturation operation is more than twice as strong as that of the N1-pe gold alloy, it has the disadvantage that its applicability as an element is limited.

FIG. 4 shows an example in which the magnetoresistive effect Δρ/ρ is increased by alloying Ni-Fe alloy with CO. As shown in Figure 4, at CO content aowt%, magnetoresistive effect Δρ/
ρ shows the maximum value and is approximately twice as high as that without CO addition. However, even with this conventional method using alloying, the magnetoresistive effect Δρ/ρ tends to be saturated.

Figure 5 shows that the Ni-P e
An example of increasing the magnetoresistive effect Δρ/ρ of the alloy film is shown below.
Since the resistivity ρ decreases at ~400C, it increases rapidly. FIG. 6 shows the dependence of the coercive force Ha of this Ni-Fe alloy on the heat treatment temperature, and the coercive force Hc also increases rapidly at 300 to 400 C, at which point the growth of crystal grains begins. In this way, the magnetoresistive effect Δρ/
Increasing ρ has the disadvantage that other properties change or deteriorate.

7 and 8 show an embodiment of the invention, with a thickness of 3
An example is shown in which the magnetoresistive effect Δρ/ρ of a N1-Fe alloy with a composition of 81 wt% to 19 wt% is increased by ion implantation. In Figure 7, the curve 3.4 H22
and N e+ at 75 KeV and 130 Ke, respectively.
Curve 5.6 in Figure 8 shows the case of implantation with Hl
. and N e+ as I x 10” and 2, respectively.
This shows the case where the N i -p e
The magnetoresistive effect Δρ/ρ of the alloy film increases as the amount of hydrogen ions implanted increases, and the magnetoresistive effect Δρ/ρ of the alloy film increases as the implanted amount of hydrogen ions increases, and the
i 0n /crn'', which showed a maximum value of 4.6%, which was approximately 30% increased compared to before ion implantation. Regarding the ion implantation depth, in the case of a thickness of 3500A, the magnetoresistive effect Δ
In light hydrogen ion implantation, ρ/ρ shows a maximum value of 4.6% at an accelerating voltage of 75 KeV, as shown in curve 5 in Figure 8, and even in heavy Ne4 ion implantation, it shows a maximum value of 4.6%, as shown in curve 6 in Figure 8. As is clear, there was a tendency to increase at accelerating voltages of 130 KeV or higher. FIG. 9 shows the above N i −F
The dependence of the coercive force He on the implantation voltage when ion implantation is performed on e-alloy is shown, and the curve 7゜8 shows the dependence of the coercive force He on the implantation voltage, respectively.
The results are shown when /e- is inserted. As is clear from FIG. 9, the coercive force He after ion implantation shows almost the same value as before ion implantation. As described above, according to the present invention, unlike increasing the magnetoresistive effect Δρ/ρ by the well-known heat treatment method, it is possible to increase the magnetoresistive effect Δρ/ρ by changing other properties.
can be increased. Such magnetoresistive effect Δ according to the present invention
The increase in ρ/ρ does not depend on the composition of the Ni-Fe alloy. For example, when the Ni content is 66 wt%, the increase in Δρ/ρ
from 4.5% to 6%, and Ni content from 70 to 90%.
In the case of Ni-Co alloys, I increases from 6% to 7.8%.

FIG. 10 shows the dependence of the magnetoresistive effect Δρ/ρ on the film thickness when ions are implanted into the N1-Fe alloy. In Fig. 1θ, the curves [9°9', 9'' are the characteristics of the untreated N1-pe deposited film, and the curves @10, 10', 10''
is this film KHt" at 75KeV I x 10'"
/ctrt". As is clear from songs @9" and 10", the resistivity change Δ
ρ does not change even after ion implantation, and the magnetoresistive effect Δρ/ρ increases as shown in track #J9-10 due to the decrease in resistivity ρ due to ion implantation. The rate of increase of the magnetoresistive effect Δρ/ρ is constant regardless of the film thickness h1, and in a thin film permutation film with a thickness of 500 people, even by ion implantation! Approximately 30% from 112.1% to 2.8%
increase Also, since the bulk resistivity of the pJi-Fe alloy is about 14 μΩ-saw, for a film thickness of 3000 Å or more, the resistivity ρ is ion? It was observed that the value close to the bulk value was obtained by including J.

Figure 11 shows a heat-treated Ni
This is an example showing the effect obtained when ions are implanted into a -Fe alloy deposited film. In FIG. 11, symbol 11.
11' is an untreated deposited film, symbol 12.1. ．． 2' aH
,” 0.7X10” at 125KeV and 80KeV
The characteristics obtained after a 0.7 x 10" 7 cm" implant are shown. After heat treatment, as is clear from the straight line 11, the magnetoresistive effect Δρ/ρti is 4.2 at 400C.
%. However, the magnetoresistive effect Δρ/ρ of the ion-implanted film increased to 4.6% regardless of the heat treatment temperature, as is clear from the direct 1R12. Furthermore, as shown in curve 11', the coercive force He increases from 0.50e to 1808 by heat treatment at 400C;
When ion implantation is performed according to the present invention, song 1Iia1
2', the increase was only 0.70 e. In other words, in thin-film MR heads, etc., the magnetoresistive effect Δρ/ρ and the coercive force H are temporarily reduced by heat treatment.
After increasing a, it is also possible to perform ion implantation to restore only the coercive force He.

- Observing the size of crystal grains at points a, b, c, and d of the power cylinder 11, each of ~150 people.

They were 200, 700 and 700 people. That is, by heat treatment from (Xiang point to (C7 point), 150 people →
700 grain growth occurs, which decreases the resistivity ρ and increases the magnetoresistive effect Δρ/ρ, but at points (a) and (b), although there is no difference in the grains. The magnetoresistive effect Δρ/ρ increased. From this, it is clear that the mechanisms of the conventional heat treatment method and the increase in the magnetoresistive effect due to ion implantation according to the present invention are completely different.

FIG. 12 is an example showing the dependence of the magnetoresistive effect and coercive force on the heat treatment temperature when the magnetoresistive effect Δρ/ρ is increased by ion implantation into the N1-pe alloy film.

In Figure 12, curves 13.13'U, N1-p'e
The alloy film alone, the straight line 14.14' is coated with a film on this film, and the Hll is I x 1016 at 75 KeV'.
/lyn” implantation results. When light hydrogen ions are implanted, the magnetoresistive effect Δρ/ρ decreases as shown in curve 13 because hydrogen is released to the outside at a temperature of 200C or higher. On the other hand, in a film that is heat-treated after forming a laminated film, the ion implantation effect can be maintained below the temperature at which crystal grain growth begins in the case of Ni-pe alloy, as shown by the straight line 14. can.

As described above, according to the present invention, Δρ/
ρ to about 4.6% under the allowable detection current, and thin film MR
Even in heads, etc., Δρ/ρ is t'i? 1!
'Can be increased by 30%.

Furthermore, according to the present invention, without being limited to ion species, if ions other than hydrogen or neon, such as helium and lithium, are distributed in the magnetic film up to atoms io' in the periodic table, magnetoresistance can be improved. The effect Δρ/ρ can be increased. The more uniform this ion distribution is, the more reproducibly the increase in the magnetoresistive effect Δρ/ρ can be achieved. To achieve this, for example, multiple ion implantation is performed as shown in FIG. This is also valid.

In addition, in order to improve the reliability of magnetoresistive elements,
After ion implantation, it is effective to perform heat treatment to stabilize the implanted ions, but in this case, estimate the release of implanted ions due to thermal diffusion and use a dose larger than the maximum value of Δρ/ρ. It is also effective to implant ions in advance and then perform heat treatment to obtain the maximum Δρ/ρ.

According to the present invention, the detection output of the magnetoresistive element can be significantly increased compared to the conventional one, and in terms of heat generation and lifespan,
An extremely reliable element can be formed.

[Brief explanation of drawings]

Fig. 1 is a curve diagram showing the dependence of the magnetoresistive effect Δρ/ρ on an externally applied magnetic field in a conventional magnetoresistive element, and Fig. 2 is a curve diagram showing the dependence of the magnetoresistive effect Δρ/ρ in a Ni-pe alloy.
Figure 3 is a curve diagram showing the dependence of the magnetoresistive effect Δρ/ρ on the externally applied magnetic field in a Ni-Co alloy. Figure 4 is a curve diagram showing the dependence of the magnetoresistive effect Δρ/ρ on the externally applied magnetic field in a Ni-Co alloy.
Figures 5 and 6 are curve diagrams showing the CO composition dependence of the magnetoresistive effect Δρ/ρ in the e-Co alloy. Curve diagrams showing heating temperature dependence, FIGS. 7 to 12 are curve diagrams for explaining different embodiments of the present invention, respectively. Agent Patent attorney Toshiyuki Usuda χ 1 Fig. 2 Fig. ηl+A/λt (wt7p) Fig. 3 Stone blade pa (reσe) fJ 4 Fig. Ca (wt Chestnut 5th mold! Cultivation temperature (7) ’f76 Figure heat kIL ball/L('C) fJ 7 Figure) 41' (X /I /#N /l-rify, f(
y<ta"ier/1wIsu'v18 Figure J■ih force O speed 41B-(ktv) fu(,ycn]t),5a tllll 151
1 2eaJ13zsami m4'lJ-cxev>
a 4yσMmo4 rjn calculation 11 on the diagram

Claims (1)

[Claims] 1. A method for manufacturing a magnetoresistive element, comprising the step of implanting ions into a magnetic film to increase the magnetoresistive effect of the magnetic film.