JPS60229291A - Forming method of magnetic bubble transfer path - Google Patents

Abstract

PURPOSE:To form a magnetic bubble transfer path having a sufficiently large difference (DELTAHk) between anisotropic magnetic fields of non-implantation area and an implantation area and an excellent temperature characteristic by implanting ions and again implanting them after annealing at a prescribed temperature. CONSTITUTION:After a mask for shielding the ion implantation is formed on a magnetic garnet monocrystal film, ions are implanted for forming a magnetic bubble transfer path. When the path is annealed at 600 deg.C or above, the lattice distortion caused by the ion implantation returns to a small value, while Curie temperature returns to an approximately original temperature. On the other hand a magnetic anisotropic constant value will not return to its original value but becomes smaller. When a small amount of ions are implanted under this condition on the outer circumference of the transfer path to the extent where the difference is produced in the inner surface direction of anisotropy, the magnetic bubble transfer path can be formed which has a slight decrease in the Curie temperature, a sufficiently large DELTAHk and excellent transfer and temperature characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magnetic bubble element, particularly an ion-implanted Kx
! The present invention relates to a method for forming a transfer path for a magnetic bubble element, which provides a transfer path for magnetic bubbles.

(Prior art and its problems) In recent years, the development of ion-implanted magnetic bubble elements has been progressing as an all-in-one file memory with high-density storage capacity.

The characteristics required for the drive NtK of the ion-implanted magnetic bubble element are that the uniaxial magnetic anisotropy constant value in the layer is negative so that the magnetization in the layer can be tilted in-plane, and the non-implanted region below The difference ΔHk between the anisotropic magnetic fields is sufficiently large.

Conventionally, in this device, k is obtained by utilizing the grinding strain effect from the lattice strain caused by ion implantation.

Conventionally, as shown in Fig. 1, a mask pattern 1 for shielding implanted ions having a typical bead shape was formed on a magnetic garnet single crystal thin layer grown on a non-magnetic garnet substrate as a magnetic bubble transfer path. By implanting ions from above, an ion-implanted layer 2 is formed, and a magnetic bubble transfer path is formed in which magnetic bubbles are transferred along the Il+ field outside the bead-shaped non-implanted region 3.

In this ion implantation process, the implanted ions are hydrogen, helium, and neon ions.In order to obtain Δ)(k, which is mainly studied but has a sufficiently large negative value, if the implantation i is a hydrogen ion, 'lX 10”/Cl11 to 4×10’6/
On the other hand, when using helium or ViAt ion, the amount of cd implanted varies from 4×1O's/C1d to 5×1
0”/c11, and 2x from l x IQ '4/ad
lQ14/c++! is necessary.

In the case of hydrogen injection, the amount of injection is large, so the manufacturing cost is high.

In either case, the ion implantation process results in an ion implantation layer (
The Curie temperature of the drive layer (hereinafter referred to as the drive layer) decreases according to the amount of #1 strain, and as the amount of implantation increases, the strain increases, and the change in magnetic anisotropy increases When implanted at the dose necessary to cause a change in magnetic anisotropy for good device operation,
There was a problem in that the Curie temperature decreased by about 100° C. and the device temperature characteristics deteriorated.

(Object of the Invention) The present invention has been made in view of the above points, and the object thereof is to provide a method for forming a magnetic bubble transfer path having a sufficiently large ΔHk content and good temperature characteristics.

(Structure of the Invention) That is, in the method of forming a magnetic bubble transfer path formed by ion implantation into a Fia garnet single crystal thin film according to the present invention, bead-shaped beads are placed on the magnetic zomenet single crystal thin film to shield implanted ions. S keno() is characterized in that it includes a step of forming a mask pattern, implanting ions, annealing at a temperature of 600° C. or higher, and then implanting ions again.

This is a method for forming a transfer path.

(Summary of the present invention) In the present invention, in order to obtain the negative uniaxial anisotropy required for the drive layer in order to suppress the drop in the Curie temperature of the drive layer of the ion-implanted magnetic bubble element, As shown in FIG. 2, this is achieved by suppressing the positive growth-induced magnetic anisotropy that the magnetic garnet film has, although it is largely due to the strain-induced abrasive anisotropy caused by ion implantation.

That is, after forming a mask for forming a transfer path, ions are implanted in order to suppress positive growth induced magnetic anisotropy, and then annealing is performed at a temperature of at least 600°C to remove lattice strain caused by this ion implantation process. By returning the amount fO to a small amount, the Curie temperature returns to the Curie temperature before injection, or to a temperature close to it. However, only the magnetic anisotropy does not return to its original state even after annealing, and the magnetic anisotropy constant value decreases. This is because the growth-induced magnetic anisotropy was suppressed as a result of the injection disturbing the lattice within the injection layer.

After this step, ion implantation is performed again. This is due to the fact that the magnetic anisotropy has been reduced in the previous process, and the amount required is sufficient to cause a difference in the magnetic anisotropy in the in-plane direction l (L) on the outer periphery of the magnetic bubble transfer path. Since the degree of decrease in temperature is smaller than in the past, the element temperature characteristics can be improved.

(Example) The present invention will be explained in more detail below with reference to Examples.

i with negative magnetostriction constant grown by liquid phase method on GGG substrate
YSmLuCaBi s (Fe
te) sO□ (film thickness 1.27 Am, characteristic length 1=0.
12ttm, p sum magnetic flux density 6soGauss, Ku
46000 erg/d.

λ+l+1 =>2. Plasma CV
After forming DK using 1 μm thick Sin, neon ions were accelerated at 200 KeV and at a dose of 5.
x 10"/i and acceleration energy 80KeV dose 1.33 /
ml and acceleration energy at a dose of 40 KeV 1. OX
After injecting 10/7, it was annealed in air at 300° C. for 1 hour to form a magnetic bubble transfer path.

In this embodiment, 5iO- was used as the mask for forming the transfer path, but the effects of the present invention will remain the same if it is a material with a high melting point such as alumina.

As a comparative example, a transfer path forming mask was formed using gold with a thickness of 5000A on a basic garnet film having the same characteristics as the example, and then helium and ions were accelerated at an energy of 100K.
eV, dose 47 × 10”/cI.

and acceleration energy 40KcV, dose amount 2.2X
After implantation at IO'/cd, it was annealed in air at 300° C. for 1 hour to form a bubble transfer path.

The magnetic bubble transfer characteristics according to this example are comparable to those of a transfer path (comparative example) formed by a known magnetic bubble transfer path formation method at room temperature, and △H
k is 26,000eT in the comparative example, whereas this example is 26,000eT.
9000e was obtained. Moreover, the Curie temperature of the drive layer of the comparative example was 145°C, whereas the Curie temperature of the drive island of the example of the present invention was as high as 168°C.

The annealing process after the neon implantation process was performed at 1000°C as in the example.
As a result of conducting the annealing process at other temperatures, the effect of increasing Δ)lk was found even when the annealing temperature was low, which was greater than in the case of 1000° C. annealing. Curie temperature is slightly lower, but higher than the comparative example.

However, if the temperature was lower than 600° C., the crystallinity sometimes deteriorated. (Even above 100°C, the effect of increasing △I-1k can be seen, and the Curie temperature becomes -Jl, a temperature higher than M6 cases, exceeding 180°C.

At 1050° C. or higher, the bubble film properties change, but in this case, there is no problem if the original bubble film is used, taking into account the change in bubble film properties due to annealing.

Moreover, the acceleration energy of this example is 200Ke V and 80
Instead of KeV neon injection process, ■ Acceleration x Ne/L
/Gee 2ooKeV, dose 9 x 10"/d and acceleration energy 80 K, eV, dose, 3.
A step of implanting 8×to14/d nitrogen ions was performed to form a magnetic bubble transfer path.

Also, ■ acceleration energy 70KeV, dose amount, 1 x
In 17/crI and acceleration energy 35KeV,
A magnetic bubble transfer path was formed by implanting hydrogen molecule ions at a dose of 4.5 x 10''/d.

In this way, even in the transfer path formation method in which the neon implantation step is replaced with nitrogen and hydrogen ion implantation, ΔHk
[A value similar to that obtained with neon injection was obtained, and the decrease in Curie temperature was also similar to that obtained with neon injection.

In this way, the effect is the same regardless of the ionic species, such as neon, hydrogen, nitrogen, helium, and phoron.

Furthermore, it is clear that the effects of the present invention can be obtained even if a hydrogen injection process or a neon injection process is performed instead of the helium injection process of this embodiment.

As described above, the present invention can provide a magnetic bubble transfer path which has a high Curie temperature and good temperature characteristics, a large Hk and a good transfer characteristic, and has great advantages in manufacturing magnetic bubble elements. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing the shape of a magnetic bubble transfer path. l Implantation mask pattern 2 Ion implantation drive layer 3 Non-implantation region 71 Drawing procedure amendment (voluntary) 59.11. 〜5 Showa year, S commendation, Japan Patent Office Commissioner 1, Indication of matter 1985 Chair review, Application No. 085251 2, Name of Rirou, Magnetic bubble transfer path formation method 3, Relationship with the case of the person making the amendment Applicant: 5-33-1-4 Shiba, Minato-ku, Tokyo, Agent 5, Detailed explanation of the invention claimed in the specification subject to amendment, column 64, Statement of contents of amendment, page 9, lines 5 to 7 ``Also, it is clear that the effects of the present invention can be obtained even if a hydrogen injection step or a neon injection step is performed instead of the helium injection step of this embodiment.'' Instead of the helium implantation step, for example, hydrogen ions can be accelerated with an energy of 80 keVl, 3
X 101/d and acceleration energy 40 keys. A similar effect can be obtained by replacing the helium implantation step with the 6×10”/7 implantation step.In this way, instead of the helium implantation step in this embodiment, other ion implantation steps, such as a hydrogen ion implantation step or a neon implantation step, are performed. It is clear that the effects of the present invention can be obtained even if

Claims (1)

[Claims] In the method for forming a magnetic bubble transfer path formed by ion implantation onto a thin expanded magnetic garnet single crystal, a mask pattern is formed on the magnetic garnet single crystal thin film to shield implanted ions, and then the ions are implanted at 600°C. A method for forming a magnetic bubble transfer path comprising the step of annealing at a temperature above and then implanting ions again.