JPS59193595A - Formation of magnetic bubble transfer line - Google Patents

Abstract

PURPOSE:To obtain a bubble transfer line for a magnetic bubble element which has a large area for a bubble drive enable magnetic field by forming a metallic pattern with a inclined side face and implanting an ion to a thin film with the pattern to be used as a mask. CONSTITUTION:An ion is implanted to a magnetic garnet single crystal thin film 2 using the mask pattern 1 having the inclined side face. As a result, the ion implanted area also includes the area near the outer circumference of the area masked by the mask pattern. Thus it is possible to obtain a bead-shaped transfer line having the effective construction width of about 0.8mum. The ion irradiated to the sloping part of the pattern 1 pierces partially through the pattern 1 and is implanted mainly to the area near the surface of the area of a garnet layer 2 which is masked with the mask pattern. The boundary line 3 of an ion implanted area 4 in the film thickness direction is approximate to a straight line vertical to the surface of the film 2. Under such conditions, the stability can be improved for a magnetized wall which is generated at the area near the boundary of the ion implanted area.

Description

[Detailed Description of the Invention] The present invention creates magnetic bubble domains (hereinafter referred to as puzzles) by implanting ions into a magnetic garnet single crystal thin film.
The present invention relates to a magnetic bubble element having a structure in which a transfer path is formed.

The target magnetic bubble element has a mask pattern formed using a metal such as gold or molybdenum or a resist material on the surface of a magnetic garnet single crystal thin film that has a negative magnetostriction constant and uniaxial magnetic anisotropy perpendicular to the film surface. Furthermore, by implanting ions, a bubble is driven by a magnetized domain wall generated at the outer edge of a non-implanted region shielded by a pattern mask.

Conventionally, the shape of a mask pattern formed of gold or the like has been formed so that its side surfaces are not inclined with respect to the surface of the magnetic garnet film.

However, in a bubble transfer path formed by ion implantation after forming such a mask pattern, the lower limit of the bias magnetic field region that allows bubble transfer increases due to malfunction due to jump to an adjacent bubble transfer path. have.

This malfunction of jumping to the adjacent bubble transfer path is caused by, for example,
It is known that this can be improved by narrowing the width of the constriction of the beaded transfer path (see Figure 6, Japanese Society of Applied Magnetics, Abstracts of Academic Lectures (November 1982), p. 78, 15).
P D -1, K, Mizun.

and H, Urai). In the summary, the diameter is 1μ.
It is described that the best transferable bias magnetic field region is obtained when the constriction width of the bead-shaped transfer path in a micron (m) bubble is set to 0.8 μm. Diameter 1μ
In a 4 Mbit/chip (megabit/chip) magnetic bubble element using m bubbles, the chip size is approximately 1 crrL x 1 crn, and the narrow width of all bubble transfer paths in such a large area is formed. The limit for producing a mask pattern for ion implantation with good reproducibility is approximately 1 μm using normal optical exposure methods, and it is said that it is extremely difficult to form a transfer path with a constriction width of 0.8 μm. There are drawbacks.

An object of the present invention is to provide a method for forming magnetic bubble transfer paths that eliminates the above-mentioned drawbacks.

The formation method of the present invention involves epitaxially growing a magnetic garnet single crystal thin film on a non-magnetic garnet single crystal substrate, forming a metal butter on the thin film, and implanting ions into the thin film using the pattern as a mask. In a method for forming a magnetic bubble transfer path for a magnetic bubble element in which magnetic bubbles are transferred around the outer periphery of an ion-implanted region, the side surfaces of the metal pattern are formed at an angle, and ions are implanted into the thin film using the pattern as a mask.

Next, the present invention will be explained in detail with reference to the drawings.

In the present invention, a mask pattern with inclined sides is used for ion implantation into a magnetic garnet single crystal thin film.

That is, although the minimum width of the mask pattern is about 1 μm, by making the side surfaces of the pattern slope, the ion implantation region includes the region near the outer periphery of the region shielded by the mask pattern. , effectively, 0.
A bead-shaped transfer path having a constriction width of about 8 μm can be formed.

Moreover, in the case of the conventional mask pattern 1 whose side surfaces are not inclined as shown in FIG. .

The deep boundary of the magnetic garnet ion-implanted layer extends to the region shielded by the mask pattern, and the boundary line of the implanted region in the film thickness direction becomes curved.

On the other hand, in the case of the present invention, as shown in FIG. Analysis of the scattering process of the implanted ions shows that the implanted ions are implanted near the surface, and the boundary line 3 of the implanted region 4 in the film thickness direction is close to a direct line perpendicular to the surface of the magnetic garnet film.

When the boundary of the ion implantation region 4 is close to a straight line perpendicular to the surface of the magnetic garnet film, the stability of the magnetized domain wall generated near the boundary of the ion implantation region can be improved.

Next, embodiments of the present invention will be described in detail.

Film thickness 1.28 on gadolinium gallium garnet
μm, saturation magnetic flux density 667 Gauss, % magnetic length 10.119
μm(Y8mLnBiCa)3(1”eGe)
A magnetic garnet film of Bon is grown by liquid phase epitaxial growth, and a chromium/full double layer film with a thickness of 100A and 15000A is deposited on this film, and an AZ13 film with a thickness of 5500A is deposited on top of this film.
50J (trademark; Sibley, USA) resist pattern is formed. Next, the chromium/full bilayer film is ion-milled by irradiating the entire surface with argon ions with an acceleration energy of 500 eV. Peel off the resist pattern,
After forming a mask pattern with a side surface inclination angle of 60°, helium ions were applied at 100 kV, 4.25×10
” pcs/ad and 40kV, 2.OXl, 0 pcs/
A bubble transfer path is formed by conditionally injecting crA. Third
The black circles in the figure indicate the magnetic field region in which bubbles can be driven in the bubble transfer path formed in this manner.

On the magnetic garnet film, a film (Yf9mL
A magnetic garnet film of uBica) 3 (FeGe) 6012 is formed, and a chromium/gold pattern with a thickness of 5000A is ion-milled using a resist pattern with a thickness of 100OOA on this film to create a mask pattern with no sloped sides. After the formation, helium ions are implanted under the same implantation conditions as in the example. The bubble driveable magnetic field region of the bubble transfer path formed in this manner is indicated by a white circle in FIG.

As is clear from FIG. 3, the present invention has the advantage that it is possible to obtain a bubble transfer path with a larger bubble driveable magnetic field area than the conventional one.

In addition, the angle of inclination of the side surface of the mask pattern is 6 in this example.
It is not limited to 0°, and some of the ions irradiated to the inclined part penetrate the mask pattern, are implanted near the surface of the magnetic garnet that is shielded by the mask pattern, and are implanted into areas where there is no mask pattern. In addition to the effect that ions are implanted into the region shielded by the mask pattern due to scattering, the ion implantation region covers the entire ion implantation layer from the surface to the deep part, and a part of the outer periphery of the region shielded by the mask pattern. An angle that extends to the middle is sufficient.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional mask pattern, FIG. 2 is a sectional view showing a mask pattern used in the present invention, and FIG. 3 is a bubble driveable magnetic field region of a bubble transfer path according to the present invention and a conventional forming method. FIG. 4 is a diagram illustrating a comparison between the bubble transfer path and the bubble driveable magnetic field region according to the present invention. In the figure, 1...Mask pattern 7.2...
... Magnetic garnet film, 3 ... Ion implantation region boundary line, 4 ... Ion implantation region, 5 ...
...Non-ion implanted region. ! Figure / Gofu? figure

Claims (1)

[Claims] After epitaxially growing a magnetic garnet single-crystal thin film on a non-magnetic garnet single-crystal substrate, a metal pattern is formed on the thin film, and the pattern is used as a 7-layer film to implant ions into the thin film. A method for forming a magnetic bubble transfer path for a magnetic bubble element in which magnetic bubbles are transferred around the periphery of the magnetic bubble transfer, characterized in that the side surfaces of the metal pattern are formed at an angle, and ions are implanted into the thin film using the pattern as a mask. Tract formation method.