JPH0366756B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic bubble generator suitable for an ion implantation magnetic bubble element and a method for manufacturing a magnetic bubble generator. More specifically, the present invention relates to a magnetic bubble generator that improves generator characteristics and a method for manufacturing the same.

[Conventional technology]

A magnetic bubble element that uses magnetic bubbles existing in a magnetic crystal thin film with anisotropy perpendicular to the film plane as an information substance is well known. The basic function of a magnetic bubble device is the transfer and generation of magnetic bubbles. With the increase in storage density of magnetic bubble devices in recent years, the method of manufacturing magnetic bubble transfer paths has become more common, such as by ion implantation, which is suitable for higher densities.

Transfer path formation by ion implantation is described in the document published by Nelson et al. in 1980, The Bell System Technical Journal, Vol. 59, No. 229-257.
Page 1 (BSTJ, vol.59 (No.2), 229 (1980))
As shown in the figure, this is carried out by masking only the magnetic bubble transfer path pattern portion and implanting ions into the other regions. Furthermore, a hard bubble suppression (HBS) ion-implanted layer for suppressing hard bubbles that inhibit high-speed transfer of bubbles has generally been formed, including on the above-mentioned non-ion-implanted pattern portion. A magnetic bubble element having such a magnetic bubble transfer path pattern is called an ion-implanted magnetic bubble element.

On the other hand, a magnetic bubble generator in an ion-implanted magnetic bubble element is generally constructed by providing a hairpin-like conductor pattern at the cusp portion of a transfer path pattern, as shown in FIG. 13 of the same document. To actually generate magnetic bubbles, a current pulse is applied to the hairpin-shaped conductor, and the resulting current magnetic field from the airpin conductor is locally applied to the transfer path pattern cusp to generate nucleation, which causes magnetization reversal in that area. Use the law.

[Problem that the invention seeks to solve]

Figures 2A and B show the magnetic bubble generation and transfer characteristics of the ion-implanted magnetic bubble device, which is the conventional technique described above.
Shown below. (YSmLnCaBi) ₃ for 1μm diameter bubble
(FeGe) ₅ O ₁₂ A magnetic bubble transfer path 2 consisting of a non-ion-implanted pattern is formed in the magnetic bubble material 1 which is a magnetic crystal thin film, and a hairpin conductor pattern 4 for generating magnetic bubbles is provided at the cusp of the transfer path pattern. It is being Hard bubble suppression (HBS) ion implantation is performed on the entire surface, and HBS 10 is also present on the non-implanted pattern. When the in-plane rotating magnetic field Hr is applied in the direction of the arrow 5, a current pulse (pulse width W=0.2 μs) is applied to the hairpin conductor 4. The magnetic bubble generation current pulse amplitude Ig and the bias magnetic field margin at that time are shown in FIG. 2A. When the current pulse amplitude Ig exceeds 160 mA, the lower limit of the bias magnetic field margin rapidly increases due to the generation of unnecessary magnetic bubbles, and the operating bias margin suddenly decreases. For this reason, it has been found that the conventional element has the drawback that the current amplitude margin necessary for stable magnetic bubble generation operation is extremely limited.

It has been found that the HBS layer, which is ion-implanted throughout the entire surface, has a significant effect on the phenomenon of unwanted magnetic bubbles. By applying the in-plane magnetic field Hr, the magnetization of the HBS layer by ion implantation across the entire surface is directed in the direction of Hr as shown by arrow 10. The magnetization of the ion-implanted layer for driving a magnetic bubble has a large component that is forcibly directed in the direction of the magnetization of the HBS layer due to the exchange force caused by the magnetization of the HBS layer. Therefore, the magnetization 11 of the driving ion-implanted layer causes a strong magnetic charge distribution at the boundary of the non-implanted pattern forming the magnetic bubble transfer pattern, and the nucleated magnetic bubbles are shown as 40 along the pattern boundary. Stretch it out like that. Since a magnetic field component in the magnetic bubble extinction direction is generated outside the hairpin conductor 4, the stretched magnetic bubble is cut into a plurality of pieces, and some of them end up flowing out as unnecessary magnetic bubbles.

An object of the present invention is to suppress the generation of the above-mentioned unnecessary magnetic bubbles and provide a magnetic bubble generator with excellent operating characteristics.

[Means for solving problems]

As a means for solving the problems of the magnetic bubble generator in the conventional ion-implanted magnetic bubble element as described above, the magnetic bubble generator according to the present invention has the following features. That is, it has a magnetic bubble transfer path pattern formed by ion implantation, and a hard bubble non-suppressing closed region including a cusp portion of the transfer path pattern and tape portions on both sides thereof is provided, and magnetic bubbles are caused to flow by an in-plane rotating magnetic field. It is characterized in that a hairpin-shaped conductor pattern having a common area with the cusp part is provided in the area.

Furthermore, the present invention provides a method of manufacturing such a magnetic bubble generator, and in particular, the process of manufacturing the hard bubble non-suppression closed region has the following characteristics. That is, when performing full-surface ion implantation for HBS, there is a manufacturing method in which the area where the closed region is to be formed is masked with an implanted ion-shielding material, and the thickness of the ion-implanted shielding mask for forming the magnetic bubble transfer path pattern is controlled by the closed region. When HBS ions are implanted by thickening only in the region, HBS is added to the transfer pattern part in the closed region.
A manufacturing method that prevents ions from reaching, and
In this manufacturing method, after performing ion implantation on the entire surface for HBS, the HBS ion implanted layer only in the closed region is removed by etching.

[Effect]

The operating principle of the present invention will be explained using FIG. 1 showing a first embodiment of the present invention. FIG. 1A is a plan view of a portion of a magnetic bubble generator according to the present invention. The magnetic bubble transfer path pattern 2 is formed by ion implantation into the outside thereof. The non-implanted closed region 3 during HBS ion implantation is the cusp portion 20 of the transfer path pattern and the tape portions 21 and 2 on both sides thereof.
1'. A hairpin-shaped conductor pattern 4 is provided on the cusp portion 20.

When a magnetic bubble is generated, an in-plane magnetic field is applied in the direction shown by arrow 5. In the HBS ion non-implanted closed region 3, no in-plane magnetization layer exists on the magnetic bubble transfer path pattern 2. Therefore, the in-plane magnetization 11 of the ion-implanted layer for driving magnetic bubbles is generated along the pattern boundary based on the anisotropic relaxation of the ion implantation strain generated around the pattern 2 in the direction perpendicular to the pattern boundary. Due to the magnetic anisotropy in the longitudinal direction, magnetic charges are generated that are concentrated in the direction of the cusp portion and concentrated on the cusp portion 20 . At this time, when a current pulse for generating magnetic bubbles is applied to the hairpin-shaped conductor pattern 4, the magnetic bubbles are nucleated only in the cusp portion 20 due to the concentrated magnetic charge, and unnecessary magnetic bubbles are prevented from springing out. I can do it.

FIG. 1B shows a cross-sectional view along a straight line a-a' including a part of the magnetic bubble transfer path pattern. It is shown that the HBS ion implantation layer 10 does not exist in the magnetic bubble transfer pattern 2 portion. The hairpin conductor pattern 4 is provided on the bubble material 1 with a suitable space therebetween.

〔Example〕

FIG. 3 shows a second embodiment of the invention. In this embodiment, the corners of the non-injection closed region 3 are chamfered 31 so as not to have acute angles. As will be explained later, this serves to prevent unnecessary magnetic charge from being concentrated due to the step difference in the in-plane magnetization layer at the boundary of the closed region, which occurs when a closed region is created by removing the HBS layer by etching. It is something.

FIG. 4 shows a third embodiment of the invention. In this embodiment, the boundary of the non-injected closed region 3 has a convex corner 32 at the gap between the hairpin conductors 4 . When an in-plane magnetic field is applied in the direction shown by the arrow 5, the magnetization 1 of the HBS layer outside the closed region is reduced at the convex corner 32.
0 is distributed along the closed region boundary, corner part 3
2, a magnetic charge of opposite polarity is generated. Due to this magnetic charge of opposite polarity, the magnetic bubble is suppressed from unnecessarily extending within the hairpin gap after nucleation occurs, and more stable operating characteristics are obtained.

Next, a method for manufacturing a non-ion implanted closed region related to the method for manufacturing a magnetic bubble generator of the present invention will be described. FIG. 5 shows a first embodiment of the first manufacturing method using a sectional view. As shown in FIG. 5A, a mask pattern 6 is formed on the magnetic bubble material 1 at a position where a non-implanted closed region 3 for HBS ion implantation is provided, for example, using a photoresist, a metal film, or an ion-shielding material such as an oxide. It is formed using optical exposure or the like. Next, ion implantation 60 for HBS is performed. this is,
Normally 40KV accelerated Ne ⁺ is used. The mask pattern thickness is 1μ for AZ-1350J series photoresist.
m, 0.3 μm for Au film, 0.5 μm for SiO ₂ film
It is sufficient if it is not less than m. When implantation is performed under these conditions, the HBS ion implantation layer 10 is formed on the magnetic bubble material except for the closed region. The mask pattern 6 that is no longer needed is removed by etching.

Next, as shown in FIG. 5B, in order to form a magnetic bubble transfer path pattern 2, a mask pattern 7 is provided and He ⁺ or Hi ⁺ ion implantation 70 is performed. The mask pattern can be used for a 0.6μm thick Au film or a 1μm thick Au film.
Any SiO ₂ film may be used. The ion implantation acceleration voltage is preferably about 110 KV for He ⁺ and about 60 KV for H ₂ ⁺ . In this way, a configuration is realized in which there is no HBS layer on the transfer pattern of the closed area, and the HBS layer is provided in other parts, and the manufacturing method of the present invention is realized.

A second embodiment of the first magnetic bubble generator manufacturing method according to the present invention is shown in FIGS. 6A and 6B. In this embodiment, contrary to the previous embodiment, ion implantation is first performed to form the magnetic bubble transfer path pattern 2. After forming the transfer path pattern, the mask pattern 7 is removed. Thereafter, a mask pattern 6 for forming a non-implanted closed region for HBS ion implantation is formed, and HBS ion implantation is performed. At this time, the injection may be performed through the thin insulating film 61. Even with this method, the transfer path pattern without the HBS ion-implanted layer according to the present invention is formed in the closed region.

Next, a first embodiment of the second magnetic bubble generator manufacturing method according to the present invention will be described using FIGS. 7A and 7B. As shown in FIG. 7A, a mask pattern 6 is provided on the magnetic bubble material 1 in the closed region where the HBS ions are not implanted. Next, an ion implantation mask layer 71 for forming a transfer pattern is provided using the same mask material. Then, a transfer path pattern is formed using a resist pattern, and a transfer path pattern forming mask pattern 7 is formed by an etching method as shown in FIG. By doing this, the transfer path pattern forming mask pattern 7' in the closed area can be made thicker than in other parts. When performing ion implantation for transfer pattern formation, the acceleration energy is passed through a thin mask pattern to a certain extent.
Choose a thick mask pattern so that ions do not pass through. For example, when applying He ⁺ ions to 150 KV for SiO ₂ with a thickness of 1 μm, some of the He ⁺ ions pass through the mask pattern and a substantial HBS layer 10 is formed. At this time, if the thickness of the thick mask pattern 7' is selected to be 1.5 μm with SiO ₂ , He ⁺ ions cannot pass through this, and no HBS layer exists in that portion. That is, according to the present invention
A structure corresponding to the HBS ion-implanted region is realized.

The second embodiment of the second manufacturing method of the present invention is described in the eighth embodiment.
Shown in Figures A and B. In this embodiment, first, as shown in FIG. 1A, an ion implantation mask pattern 7 for forming a magnetic bubble transfer path pattern is formed. Next, a resist pattern 73 is formed in the non-implanted closed region for HBS ions, and etching 8 is performed. Resist pattern 7
The transfer pattern forming mask pattern covered by 3 is not etched, and the other patterns are etched and thinned. When the resist pattern is then peeled off, a transfer path pattern forming mask pattern 7 and a thicker mask pattern 7' than the transfer path pattern forming mask pattern 7 are formed as shown in FIG. Thereafter, ions are implanted in the same manner as in the previous embodiment, and the desired structure is realized.

That is, the feature of this manufacturing method is that the thickness of the ion implantation shielding mask for forming a transfer pattern is increased only within the intended closed region.

Finally, the third manufacturing method of the present invention is shown in FIGS. 9A and 9B.
Explain using. First, as shown in FIG. 9A, the entire surface ion implantation layer 10 for HBS and the transfer path pattern 20 are formed by ion implantation using the usual method. Next, a mask pattern 65 is formed excluding the closed area portion.

Next, etching 8 is performed by ion milling or the like to remove only the upper layer of the ion-implanted layer, that is, the HBS layer. As a result, as shown in Figure B, within the closed region, the HBS layer is removed as shown at 66,
No in-plane magnetization layer exists on the transfer path pattern 2 in that region. That is, the configuration of the present invention requires
A closed region without an HBS layer is formed.

In the present invention, a magnetic garnet film of (YSmLuBiCa) ₂ (FeGe) ₅ O ₁₂ for 1 μm diameter magnetic bubbles is used as a bubble material, a magnetic bubble transfer path pattern is formed by 60 KV H ₂ ⁺ injection, and in-plane rotation is performed at a frequency of 100 KHz. FIG. 10 shows the operating characteristics of the generated current bias magnetic field when applied to a magnetic bubble generator in which magnetic bubbles are driven by a magnetic field. H ₂ ⁺ in Figure 10
The characteristics represented by are the effects of applying the present invention,
It can be seen that the generator current amplitude characteristics are greatly improved compared to the conventional example shown by He ⁺ +HBS.

〔Effect of the invention〕

As described above, by using the present invention, the magnetic bubble generation characteristics are improved.

[Brief explanation of drawings]

Fig. 1 shows a first embodiment showing the principle of the present invention, Fig. 2 shows a conventional example, Figs. 3 and 4 show other embodiments of the invention, and Figs. 5 to 9 show a conventional example. FIG. 10, which is a diagram showing an example of the manufacturing method of the present invention, is a diagram showing the effects of the present invention. In the figure, 1 is a magnetic bubble material, 2 is a transfer path pattern, 3 is a closed region where hard bubble suppressing ions are not implanted, 4 is a hairpin conductor, 5 is an in-plane magnetic field application direction, 6 is a closed region forming mask pattern, 7 and 7' are transfer path forming mask patterns, and 8 is an etching method. 10 is a hard bubble suppressing ion-implanted layer and its magnetization direction, 11 is a magnetization direction of a magnetic bubble driving layer, 13 and 14 are directions of magnetic anisotropy in the magnetic bubble material, 20 is a cusp portion, and 21 and 21' are tapes. 31 and 32 are closed region boundaries, 60 is HBS ion implantation, 61 is a spacer, 65 is a mask pattern, 66 is an HBS living area, and 70 is transfer pattern forming ion implantation.

Claims (1)

[Scope of Claims] 1. In a magnetic bubble element that has a magnetic bubble transfer path pattern formed by ion implantation and transfers magnetic bubbles along the transfer path pattern using an in-plane rotating magnetic field, the magnetic bubble transfer A magnetic bubble generation method characterized by providing a hard bubble non-suppression closed region including a cusp portion of a path pattern and tape portions at both ends thereof, and providing a hairpin-shaped conductor pattern having a common area with the cusp portion within the region. vessel. 2. In a method for manufacturing a magnetic bubble element having a magnetic bubble transfer path pattern formed by an ion implantation method and transferring magnetic bubbles along the transfer path pattern using an in-plane rotating magnetic field, the magnetic bubble transfer path pattern is A mask pattern is provided using an ion-shielding material in a closed region including the cusp portion and the tape portions on both sides thereof, and then hard bubble suppressing ion implantation is performed. A method for manufacturing a magnetic bubble generator, comprising forming a hairpin-like conductor pattern on a transfer pattern cusp within the closed region after peeling off the mask pattern. 3. In a method for manufacturing a magnetic bubble element having a magnetic bubble transfer path pattern formed by an ion implantation method and transferring magnetic bubbles along the transfer path pattern by an in-plane rotating magnetic field, forming the magnetic bubble transfer path pattern. Only a portion of the ion implantation mask pattern including the cusp portion and the tape portions on both sides thereof is formed thicker than the other portions, and then the thick film region contains acceleration energy that does not pass through the mask pattern but other portions contain acceleration energy that passes through the mask pattern. A method for manufacturing a magnetic bubble generator, comprising performing ion implantation under ion implantation conditions, and forming a hairpin conductor pattern on the cusp portion after peeling off the mask pattern. 4. In a method for manufacturing a magnetic bubble element having a magnetic bubble transfer path formed by an ion implantation method and transferring magnetic bubbles along the transfer path pattern using an in-plane rotating magnetic field, the method includes ion implantation for forming the transfer path pattern. Then, ion implantation is performed on the entire surface to suppress hard bubbles, and then the closed region including the cusp portion of the transfer path pattern and the tap portions at both ends thereof is covered with an etching-resistant mask material, and only the hard bubble suppressing layer in the region is removed by etching. and then forming a hairpin conductor pattern on the cusp portion of the transfer path pattern.