JPH03260989A - magnetic bubble memory device - 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 magnetic bubble memory device equipped with an ion implantation transfer path, and in particular improves the pattern shape of a minor loop transfer path that stores magnetic bubbles as recorded information. The present invention relates to magnetic bubble memory devices.

[Prior Art] It is known that an ion implantation type transfer path pattern is used instead of the conventional permalloy transfer path pattern as a magnetic bubble transfer path, which is a basic component of a magnetic bubble memory device, and this has improved the high performance of the memory device. It is expected that integration will be possible. The ion implantation transfer path has a structure as illustrated in FIG. In the figure, 1 is a magnetic bubble medium that can generate magnetic bubbles. This is, for example, a magnetic film such as a magnetic garnet film, in which magnetic bubbles B exist.

By selectively implanting ions such as H21) He", Ne+, etc. into the surface of the magnetic film 1, a bubble (hereinafter, magnetic bubble is simply referred to as bubble) transfer path]0 is formed.

1(l) external region 2 is the region into which ions are implanted.

By applying a bias magnetic field HB from the outside in a direction perpendicular to this film, the magnetic bubbles B are made to exist stably. Transfer of the magnetic bubble is performed by applying a rotating magnetic field I (R) that rotates within the plane of this film from the outside.

The rotating magnetic field I (R magnetizes the ion implantation region I2 and generates a bubble attracting magnetic pole at the boundary of the bubble transfer path 10, thereby transferring bubbles along the boundary of the transfer path 10. When rotating circularly, the direction of bubble transfer is in the direction of arrow P.

In a magnetic bubble memory device, a large number of bubble transfer paths 10 in FIG. 4 are formed in parallel and used as a minor loop m for storing information. In an actual device, in addition to the minor loop m, a major line M forming an information input/output path is formed in a direction orthogonal to the minor loop m, as shown schematically in FIG. 5. Note that E in the figure indicates the outer corner of the minor loop m.

In FIG. 4, the bubble magnetic film 1 further has an axially symmetrical crystal axis orientation, and the bubble transfer direction 4i [11A of the minor loop m is conventionally made to match the stripe easy axis direction [112]. It has been.

[■■21] in the stripe easy axis direction is a symbol that collectively refers to the crystal orientations [1121, [121], and [211] of the magnetic film.

Note that this type of ion implantation transfer path, for example,
EEE Transaction on Magnetics, MAGE [IE3Trans, Mag
n,, MAG-13, No, 6 (1,977) P,
It is known as 1744-1.7641.

[Problems to be Solved by the Invention] In order to realize such a magnetic bubble memory device, it is essential to realize a minor loop m and a major line M that can stably transfer magnetic bubbles. For this reason, various studies have been made in the past by changing the process conditions for ion implantation and the shape of the transfer path pattern.

As a result, the stripe difficult axis direction [
At the outer corner that turns from 112 m to [■■2] in the easy axis direction, the lower limit side of the operating bias magnetic field margin is narrower (25°C) than the straight transfer path, as shown in Figure 7.
Furthermore, the transfer characteristics become extremely poor at low temperatures (-40'C to 0C), making it impossible to obtain stable transfer characteristics necessary for practical use. 6 is an enlarged view of the outer corner E shown in FIG. 5, and FIG. 7 is a characteristic diagram of the operating bias magnetic field margin.

According to the studies of the present inventors, this reduction in the operating bias magnetic field margin at the outer corner is a problem specific to the ion implantation transfer path, and will be explained in more detail with reference to FIG. 6. The bubble transfer direction is as shown by the arrow P, and there is no problem in the straight section P3) of the transfer path, but at the corner section P2) P3, the characteristics deteriorate significantly and the bubble transfer stops. , there were problems such as jumping to other adjacent loops.

Therefore, an object of the present invention is to solve the problem that the operating bias magnetic field margin at the outer corner of the conventional minor loop m is narrow, and to provide an improved minor loop m that can obtain stable transfer characteristics over a wide temperature range. An object of the present invention is to provide a magnetic bubble memory device with the following features.

[Means for Solving the Problems] The objects of the present invention are as follows: (1) In a magnetic bubble memory device equipped with an ion implantation transfer path, the stripe difficult axis direction [11
By using a magnetic bubble memory device, the pattern shape of the outer transfer path corner of the minor loop that is folded back from [2] to the easy axis direction [2] is tilted at an inclination angle O with respect to the main straight transfer path portion of the transfer path. And, preferably, (2) in the magnetic bubble memory device equipped with an ion implantation transfer path, the stripe difficulty axis direction [11
The pattern shape of the outer transfer path corner of the minor loop that folds back from 2] to the easy axis direction [■■2] is such that the transfer path for at least 3 bits is tilted at an inclination angle of 0 = 10° to the main straight transfer path portion of the transfer path. (3) in a magnetic bubble memory device provided with an ion implantation transfer path, from the stripe difficult axis direction [112]; The pattern shape of the outer transfer path corner of the minor loop which is folded back to the easy axis direction [■■21] is distantly related to the magnetic bubble memory device which is formed into a ■-shape.

[Action costripe hard axis direction [1, 121 to easy axis direction [1
At the outer corner of the minor loop m that turns back to [12], the P2 side where the bubble enters from the straight transfer path P□,
At least 3 bits on the side going out from P3 to the linear transfer path P4 are tilted with respect to the linear transfer path P□, P4, and the inclination angle 0 is O'< O <90', preferably 10° ≦ for practical purposes. O≦45°, more preferably 15°≦0≦3
Set it to 0°. This gradually increases the distance between the outer corners of adjacent minor loops and softens sudden changes in magnetization, thereby preventing errors such as bubbles jumping between adjacent loops at the lower limit of the operating bias magnetic field margin and trap errors. Ru.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a plan view of an outer corner pattern of a minor loop m showing an example of an embodiment according to the present invention, in which the stripe direction is from the difficult axis direction [:1.12] to the easy axis direction [112].
The side where the bubble at the outer corner that turns back to P2 enters from the straight transfer path P□ and from the corner P3 to the straight transfer path P4
0 (=10°,
15°, 20°, 30″′, 40°) is an inclined V-shaped outer corner.In the conventional outer corner, the distance between adjacent minor loops is close, so bubbles tend to jump to the next loop and the margin However, since the distance between the V-shaped outer corner of this embodiment and the adjacent loop gradually increases, the bubble jump error to the adjacent loop can be reduced.
The influence from adjacent loops is reduced and trap errors are reduced.
Each can be prevented.

Figure 2 compares the operating bias magnetic field margins of the conventional outer corner (0 = 90°) and the V-shaped outer corner of the present invention (P2) with the straight transfer path portion (p t, P4). Show the results. Particularly preferred θ=20° in this embodiment
According to , the lower limit of Ha at the outer corner has the same characteristics as that of the straight transfer path.

Example 2.

FIG. 3 is a plan view of an outer corner pattern of a minor loop m showing an example of another embodiment according to the present invention, where θ=
It is a trapezoidal outer corner with an inclination of 18 degrees. In this example, the distance between adjacent minor loops m at the corners is gradually increased, and the corner portions are cut, so that the chip area can be made smaller than in the embodiment shown in FIG. In this case as well, H. It was possible to almost eliminate the amount of loss in margin for the straight transfer path at the lower limit.

[Effects] According to the present invention, the bubble at the outer corner of the minor loop that folds back from the stripe difficult axis direction [112] to the easy axis direction [112:] is formed on the side where the bubble enters from the straight transfer path and the side where it exits to the straight transfer path. By tilting at least one of the transfer paths at an angle of θ with respect to the straight transfer path, the distance from the adjacent loop gradually increases, which has the effect of preventing jump errors and trap errors.

[Brief explanation of drawings]

FIG. 1 and FIG. 3 are pattern plan views of the minor loop outer corner portion showing different embodiments of the present invention, and FIG.
The figure is a bias magnetic field margin characteristic diagram comparing the characteristics of a conventional pattern and that of the present invention regarding the bias magnetic field margin characteristics of the outer corner portion. Figure 4 is a partial cross section showing the transfer path structure of the ion implantation method. A perspective view of the main parts, a diagram showing the transfer characteristics in the conventional outer circumference, FIGS. 5 and 6 are schematic diagrams of the transfer path showing the conventional outer corner pattern and the bubble transfer direction, respectively, and FIG. 7 is the conventional bias magnetic field margin. FIG. Explanation of symbols> 10...Ion implantation method Bubble transfer path 2...Ion implantation region B...Magnetic bubble P...Bubble transfer direction HR...Rotating magnetic field HF3...Bias magnetic field O...・Inclination angle.

Claims (1)

[Claims] 1) In a magnetic bubble memory device equipped with an ion implantation transfer path, the pattern shape of the outer transfer path corner of the minor loop that folds back from the stripe difficult axis direction [11■] to the easy axis direction [■■2] , a magnetic bubble memory device in which a main linear transfer path portion of a transfer path is inclined at an inclination angle θ. 2) In a magnetic bubble memory device equipped with an ion implantation transfer path, the pattern shape of the outer transfer path corner of the minor loop that folds back from the stripe difficult axis direction [11■] to the easy axis direction [■■2] is the main straight line of the transfer path. A magnetic bubble memory device comprising a transfer path for at least 3 bits inclined at an inclination angle θ=10° to 45° with respect to a shaped transfer path portion. 3) In a magnetic bubble memory device equipped with ion implantation and a transfer path, the pattern shape of the outer transfer path corner of the minor loop that folds back from the stripe difficult axis direction [11■] to the easy axis direction [■■2] is V-shaped. Consists of a magnetic bubble memory device.