JPS63288004A - Manufacture of film with magnetical anisotropy prependicular to film surface - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a magnetically anisotropic film perpendicular to the film plane.

BACKGROUND OF THE INVENTION When attempting to utilize a conventional magnetic material as a thin film magnetic recording material, it is often convenient for the magnetization to be perpendicular to the film surface. This is because perpendicular magnetic recording has a higher recording density than longitudinal magnetic recording, and magneto-optical recording allows polar Kerl+Song to be used. In a ferromagnetic thin film, the condition that the magnetization is perpendicular to the film surface is Kl>2πMs' (Reference Reference Kuchiki Applied Materials J!
[! Academic journal 1017 (1986)). Here, Kl is perpendicular magnetic anisotropy energy and Ms is saturation magnetization. Things that improve this are shape anisotropy due to the columnar structure unique to thin films, stress-induced magnetic anisotropy through magnetostriction, and directional ordination due to the directional order of atomic pairs.
er% gas anisotropy, etc. are considered. However, the magnetic material in question has significant perpendicular magnetic anisotropy, which is not +J. The most common magnetic materials are iron and giant err.
PtMnSb alloys and the like that have a rotation angle usually do not have perpendicular magnetic anisotropy. For this reason, it has been difficult to fabricate thin films with magnetization in the perpendicular direction using these materials.

The problem to be solved by the invention is that, for example, a PtMnSb alloy can grow a medium phase orientation film on a M (Join) base plate.

At this time, if the single crystal substrate surface is selected as the (ioo) plane, Fe
, for PtMnSb, Qo, C0Fe2O4 (100)
An alignment film is obtained. Of these, Fe and p t M n 3
In b, the (100) axis is perpendicular (the easy axis of magnetization is small) due to the small magnetocrystalline anisotropy of the material itself.

The present invention aims at obtaining a perpendicular magnetic anisotropy film in the cylinder by enhancing the effect of shape magnetic anisotropy in magnetic materials such as these, which have originally small magnetocrystalline anisotropy and making it difficult to form a perpendicular magnetic film. It is an object of the present invention to provide a method for manufacturing a film with perpendicular magnetic anisotropy.

Means for Solving the Problems In order to solve the above problems, Komei Komei used a substrate with a series of fine protrusions on its surface, and grew minute magnetic atoms on the (1111 protrusions). .

In particular, a 1t1 crystal is used as a substrate, and crystal columns with oriented crystal axes are grown on m-thin protrusions while being magnetically insulated from the surroundings. Furthermore, it is desirable that the diameter of the micro-11 protrusions is 10 μm or less and the height is 0.5 μm or more so as to sufficiently enhance the effect of shape magnetic anisotropy.

Effect With the above configuration, taking a PtMnSb alloy as an example, MCJ can be etched using an etching solution mainly containing hydrofluoric acid.
Pt and Mn were fabricated by arranging fine protrusions on a crystal substrate in O and controlling the substrate temperature.

sb is simultaneously sputtered to grow the C1b crystal phase of PtMnSb in one bitaxial manner. At this time, due to the random intrusion direction of the sputtered atoms and the projection effect of the yIi fine protrusions, the growth of the protrusions in the height direction is promoted, and the columnar structure becomes more and more prominent. Moreover, even if the deposition of atoms in the crystal pillars formed at this time has progressed considerably, sputtered atoms are difficult to penetrate into the areas between the protrusions, and the crystal pillars are magnetically insulated from the surrounding crystal pillars. For this reason, each crystal column has strong shape magnetic anisotropy, and the thin film as a whole has a large I.
Direct magnetic anisotropy begins to appear. Such an effect is
The GL protrusion of the single crystal substrate is 10 μm or less, and the height is 0.5 μm.
This becomes especially noticeable when the value is greater than m, and even if it deviates from this range, there is still some effect. In this way, it was confirmed that even ``e'' and PtMnSb alloys, which do not have a perpendicular magnetization component when used as a normal magnetic material of 1fflF2, have significant perpendicular magnetic anisotropy.

Example Hereinafter, one embodiment of Komei Ki will be explained based on the drawings.

In one embodiment of the present invention, an example using a PtMnSb alloy will be described in detail. First, the concentration ratio is water:&rl acid:
The MSO single crystal substrate was immersed in an etching solution of hydrofluoric acid = 30:1:1 at room temperature for 48 hours. By this process, a diameter of 0.5 μm was formed on the fvlol plate 1 shown in FIG.
1 A forest of fine protrusions 2 with a height of about 1 μm were formed. 8r
When sputter etching is performed in a mixed gas of Freon gas and Freon gas, edges are similarly produced, but the effect is relatively weak. In this way (using the Mg0u plate 3 on which the Il+ protrusions 2 are formed), a film is formed using a ternary DC sputtering device.

Fig. 2 shows a ternary DC sputtering apparatus used for the above film formation. In Fig. 2, 6 is an Mgo
7 is a metal target of Pt, Mn, or Sb; 8 is a power source for driving the metal target 7; 9 is a heater that heats the substrate 3;
is a sputtering gas, and 10 is an exhaust gas. In this device, three metal targets 7 are sputtered at the same time, so
By changing the target power consumption of each power source 8, the composition of the alloy film can be easily changed.

Furthermore, since there is no need to rotate the substrate holder (not shown), the optimum substrate temperature for epitaxial growth can be selected using the heater 6. According to previous research, pt,
If the sputtering rate of Mn and sb is approximately 1=1:1 and the substrate temperature is maintained at 500°C, PtMnS
Since it is already known that only the C1b crystal phase b is epitaxially grown on the Mg0W plate 3, the substrate humidity is similarly set to 500° C. and the sputtering rate is 1:1:1 in FIG. 2 as well.

In FIG. 1, sputtered atoms 4 of three classes come flying onto the surface of the substrate 3 as described above, but the sputtered atoms 4 of the sputtering gas 9
Since they collide with r atoms and are scattered, the directions become random, and the number of sputtered atoms 4 obliquely incident on the surface of the substrate 3 increases. Those +J? ? ? ' is obstructed by the fine protrusions 2 and becomes difficult to penetrate into the shadow part, that is, the part between the protrusions 2. As a result, only the top portion of the hesitation microprotrusion 2 becomes easier to grow, and a forest of PtMnSb crystal pillars 5 isolated from the surroundings are formed.

Film formation was carried out for about 10 minutes, and the average film thickness was about 10 minutes.
It is estimated that there were about 00 people. The film produced in this way turns gray due to diffused reflection of light on the surface and J3
The dark blue color is completely different from the dark blue color of It and films using MgO substrates without surface treatment. The electrical resistivity in the plane t'j is 40
It is abnormally large compared to PtMnSbg of the same thickness, which is about 0 μΩ・α. When the surface is observed using an optical microscope, crystal columns with a diameter of about 0.5 μIrL can be observed. Looking at the Xa diffraction pattern of this thin film, it can be seen that the C1 phase of PtMnSb has grown despite the difference in electrical resistivity and surface color.

The magnetization curve thus obtained is shown in Figure 3 (a).For comparison, a PT fabricated using an MqO substrate without surface treatment
Figures 3(b) and 3(c) show the aging curves of the lyln3b film. That is, FIG. 3(a) shows the magnetization curve in the direction perpendicular to the film surface of the ptMn3b film when a substrate whose surface has been processed by the present invention is used, and FIG.
FIG. 3(C) shows the magnetization curve in the direction perpendicular to the film surface in the same case as FIG. 3(b).

As is clear from Fig. 3(C), Mg without surface addition T
When a xi plate is used, there is a finite magnetic anisotropy perpendicular to the film surface, but the magnetic anisotropy perpendicular to the film surface is weak. In the p t M n 3 b film obtained in the present invention, the structure shown in Fig. 3 (a
), the perpendicular magnetic anisotropy is greatly improved. In Fig. 3(a), 1e (coercive force) = 220 (Oe) Mr (residual magnetization) = 200 (eIIu /cc) IK (anisotropic magnetic field) = 4 kOe Ms (U magnetization) = 450 enu / cc. This is shown in Figure 3 (
Compared to C) discipline, Mr is about 5 times more, He is about 1.5 times more,
In No. 11, it is about half that, and the face-1 orthogonal anisotropy has increased significantly. This is thought to be because the effect of shape magnetic anisotropy v1 plays a major role since it is insensitive to the orientation of the magnetic field, resulting in a large perpendicular magnetic orientation in the thin film as a whole. A similar effect can be obtained as a magnetic material.
e.

It was also observed in J3 in ferrites such as Co and CoFe2O4.

Moreover, this effect is obtained when Si is used as a single crystal substrate.

NaC1, Ti, W, Safj Iyer, CaF2゜Bed
, SrT rao3 , LiTaO3 and other single crystals.

fK In the above embodiment, the sputtering method was explained, but it is also possible to use other a film forming methods such as vapor deposition method.

Effects of the Invention As described above, according to the present invention, even magnetic materials that do not have perpendicular magnetic anisotropy in normal thinning can be formed into perpendicularly magnetized films by the effect of shape magnetic anisotropy using a relatively accurate process. This greatly contributes to the application of perpendicular magnetic recording media jJ and magneto-optical memories.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of the epitaxy cell growth process showing one embodiment of the present invention, Fig. 2 is a cross-sectional view showing the schematic configuration of the sputtering equipment used in Kikomei, and Figs. 3 (a) to (C). are P when formed by the method of one embodiment of the present invention, respectively.
Magnetization curve diagram in the direction perpendicular to the film surface of the tMnSb film and P t M rr S using an MQO substrate without surface processing
3(b) is a magnetization curve diagram in the in-plane direction of the film, and a magnetization curve diagram in the perpendicular direction to the film surface in the same case as FIG. 3(b). 1... MqO substrate, 2... Fine protrusions, 3... V&
M (110 substrate, 4... sputtered atoms, 5... crystal column, 7... metal target, 8...
...Power supply, 9...Sputter gas. Agent Moriki I Hiroshi Figure 1/ --- M2O 耘 2-・Chest 3- Chokeki 6 end power Kai Niri 4 table 4-, u with 4 faces 5- axis spinning

Claims (1)

[Claims] 1. A method for manufacturing a perpendicular magnetic anisotropic film, using a substrate having a series of fine protrusions on its surface, and depositing magnetic atoms on the fine protrusions. 2. A method for manufacturing a perpendicular magnetic anisotropic film according to claim 1, wherein a single crystal is used as a substrate and magnetic atoms are deposited on minute protrusions to obtain an oriented film. 3. The method for manufacturing a perpendicular magnetic anisotropic film according to claim 2, wherein the size of the microprotrusions on the single crystal substrate is 10 μm or less in diameter and 0.5 μm or more in height.