JPS607682A - magnetic bubble memory element - Google Patents

Abstract

PURPOSE:To pass magnetic bubbles easily through the border between an ion injection area and non-injection area by smoothing the profile of ion injection to the border. CONSTITUTION:When ions are injected to a magnetic bubble crystal 10 by using a metallic film formed by etching so as to be a mask having a prescribed shape as a mask 14, the ions loss acceleration energy in accordance with the thickness of the mask 14 and a distortion area of an ion injection layer 16 is made gentle at the border (a) between the ion injection area and the non-injection area. The potential distribution is also moderately changed. In the magnetic bubble memory element having a bubble transfer passage due to the ion injection and a ''Permalloy '' transfer passage, magnetic bubbles pass through the border of these areas easily and an excellent gate operation is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a magnetic bubble memory 7' high speed which is a combination of an ion implantation bubble device and a TOI bubble device.

Background of the Technology Recently, in magnetic bubble memories, a method has been used in which bubble transfer paths are formed by ion implantation to improve the fA density. However, the bubble transfer path using this ion implantation method has the disadvantage that the driving force of its driving pattern is smaller than that of the conventional permalloy pattern, and it is relatively strong1.
A funkushi that requires driving power and even strong full trapping power. In particular, the design of the replicate gate was difficult. For this reason, it has been considered to use a permalloy pattern in such locations, and a magnetic bubble memory device that is a combination of an ion-implanted bubble device and a permalloy bubble device has been developed.

Prior Art and Problems FIG. 1 is a diagram for explaining a function gate portion of a magnetic bubble memory device which is a combination of a conventional ion implantation bubble device and a permalloy bubble device. In the figure, the hatched area 1 is the ion implanted region, 2 is the non-ion implanted region, 3 is the boundary thereof, 4 is the minor loop formed in the ion implanted region, and 5 is the permalloy pattern in the non-ion implanted region. The formed major line, 6 indicates a permaloid pattern constituting a gate portion, and 7 indicates a gate conductor.

Conventionally, such a magnetic bubble memory device has an ion implantation region 1 between the major gate part and the minor transfer path.
There is a boundary 6 that separates the non-ion implanted region 2 from the ion-implanted region 2, and the bubble operated in the gate part always passes through this boundary once. However, at this boundary, due to the unique potential shown in Figure 2, the bubble becomes a tiger at the boundary.
It has the disadvantage that the original gate operation is hindered because it is easy to be pushed (due to @ pull) or difficult to exceed (due to repulsion).

Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides a magnetic bubble memory device in which an ion-implanted bubble device and a permalloy bubble device are combined, so that bubbles can easily pass through the boundary between an ion-implanted region and a non-ion-implanted region. The object is to provide a magnetic bubble memory element.

According to the present invention, in a magnetic bubble memory element having a bubble transfer path formed by an ion implantation method and a bubble transfer path formed by a permalloy pattern, the boundary between an ion implanted region and a non-ion implanted region is This is achieved by providing a magnetic bubble memory element characterized by a gentle ion implantation profile only in some narrow range that is sufficient for the bubble to pass through.

Zero curtain of invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 6 is a diagram for explaining the magnetic bubble memory confectionery according to the present invention, in which α shows a metal mask for projection exposure;
Section α shows the state of the photoresist after exposure and development, section b shows the state of the metal vapor deposited film (mask for ion implantation) after etching, and section C shows the state after ion implantation. In the figure, 10 is a bubble crystal, 11 is a metal vapor deposited film, 12 is a photoresist, and 16 is a metal mask.

The metal mask 15 has a triangular protrusion 13a as shown in the diagram α, and its dimensions on i #l are such that the base W of the triangle is larger than the bubble diameter, and the height H is smaller than the resolution of the exposure device, which is the pattern ΦM. The portion is at least as large as the bubble diameter.

Using this metal mask 13, a photoresist 1 is deposited on the metal film 11 deposited on the bubble crystal 10, as shown in figure a'.
When 2 is exposed, the portions below the light resolution of the protruding portions of triangles 1 and α are exposed with so-called blur because the light wraps around them.

As a result, an extremely tapered triangular portion 12α is formed in the photoresist 12.

When the metal vapor deposited film 11 is ion-etched in this state,
As shown in FIG. 6, a tapered triangular pattern 11α similar to the triangular portion of the photoresist is formed. When ion implantation 15 is performed using this pattern of gold 11 as a mask 14, the amount of ions blocked varies depending on the thickness of the mask 14 as shown in Figure 0 (more precisely, ions implanted with a certain acceleration energy The ions lose their acceleration energy depending on the thickness of the mask 14 (1. As a result, the projected range of ions in the crystal under a portion of the taper changes with a certain slope).The projected range of ions has a distribution. As a result, the region of strain in the ion-implanted layer 16 is located at its boundary (α
part) changes smoothly.

When the strain distribution in the ion-implanted layer is step-like, the potential distribution is as shown in Figure 2 above, but when it changes gradually, the potential is 17 as shown in Figure 4.
The distribution also changes gradually.

Therefore, the potential wall 18 that puff /l/ must overcome when it makes a 3f correction at the boundary is a gradual change of fl.
It is lower when changing in Z than when changing in a step-like manner.
As a result, the margin of bubble boundary crossing becomes wider.

As a method of intentionally blurring a part of the boundary between the ion-implanted region and the non-ion-implanted region, it is also possible to use a pattern having the following shape. Fig. 5 shows a pattern in which a triangular protrusion is provided. Instead, four triangular parts 22 are provided at the boundary 21 between the ion-implanted region 19 and the non-ion-implanted region 20, and in FIG. The effect of the embodiment shown in FIGS. 5 and 6 is as follows.
This is similar to the embodiment shown in the figure.

Effects of the Invention As explained in detail above, the magnetic bubble memory element of the present invention has a 6-bore area only where the bubble passes through the boundary separating the ion-implanted region and the non-ion-implanted region.
It is possible to gently change the strain profile in that part, which has a great effect of lowering the potential wall and making it easier for bubbles to pass through.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining the function gate part of a magnetic bubble memory device that is a combination of an ion-implanted bubble device and a permalloy device, and Figure 2 is a diagram showing the potential at the boundary between the ion-implanted region and the non-ion-implanted region. , FIG. 3 is a diagram for explaining the magnetic bubble memory device according to the present invention, FIG. 4 is a diagram showing the potential at the boundary between the ion-implanted region and the non-ion-implanted region, and FIGS. 5 and 6 are other diagrams. It is a figure for explaining an example. In the drawing, 10 is a bubble crystal, 11 is gold 1. '＋(
12 shows a deposited film, 12 shows a photoresist, and 13 shows a metal mask. Figure 2 Distance (c)

Claims (1)

[Claims] 1. In a magnetic bubble memory element having a bubble transfer path formed by an ion implantation method and a bubble transfer path formed by a permalloy pattern, the boundary between the ion implanted region and the non-ion implanted region is defined by the boundary between the ion implanted region and the non-ion implanted region. A magnetic bubble memory element characterized in that the profile of ion implantation is made gentle only in a sufficiently narrow range. 2. As a means to achieve the above conditions, the part of the mask for forming the ion implantation transfer path corresponding to the boundary part where the bubble passes as described in item 1 above is made into a convex or concave shape, and a part of the mask is made into a convex or concave shape, and a part of the mask is made into a convex shape. 2. The magnetic bubble memory element according to claim 1, wherein the magnetic bubble memory element has a shape that is less than the resolution. 3. Similarly, as a means for realizing the above condition, a plurality of island-like patterns having a resolution lower than the resolution of light exposure are provided adjacent to the boundary in the corresponding part of the mask according to the above-mentioned item 2. The magnetic bubble memory device according to item 1.