JPS58179985A - Transfer pattern of ion implantation bubble device - Google Patents

Abstract

PURPOSE:To ensure a sufficient bias margin even at the bad track side, by giving a prescribed form to a magnetic bubble transfer path which is formed by the ion implantation. CONSTITUTION:A sawtooth-shaped transfer pattern 6 having a cusp 7 for each bit is formed at the bad track side with the ion implantation. The side ab where the magnetic bubble is drawn out of the cusp 7 is set vertical to the stripe facilitating direction K1 of a magnetic bubble crystal, and an excessively small opening angle is avoided for the cusp 7 with the side cd where the cusp 7 is drawn in. Furthermore the repressed part bc of the cusp 7 is set in parallel to the transfer direction P of the magnetic bubble in order to improve the pass- through of a pattern during its production. Owing to such a form, the bias margin of the bad track side is sufficiently increased in comparison with a roof- top pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION (IJ, Technical Field of the Invention) The present invention relates to a bubble transfer path for a magnetic bubble memory device fabricated by ion implantation.

(2), Technology background: Information accumulation using magnetic bubbles, l! The magnetic bubble utilization device that performs 1liI physical performance etc. has a high non-volatile storage density, low power consumption, etc., and also has a mechanical
! Since it is a solid-state device that does not contain any additives, it has extremely high reliability. Recently, the amount of information on such magnetic bubble memory devices has also increased.

There is a demand for increased storage density due to demands for smaller devices. For this reason, a method has recently been developed to improve storage density by forming bubble transfer paths by ion implantation.This method uses gadolinium as shown in the plan view of FIG. A thin film 2t of magnetic garnet that will become a bubble crystal is formed on a gallium garnet substrate 1 by liquid phase epitaxial growth, and ions of hydrogen, neon, helium, etc. are applied to a portion 4 of the magnetic thin film 2 other than the pattern 3. Inject it. In the device in which the entire pattern 3 is formed in this way, the direction of the easy axis of magnetization of the ion-implanted part 4 coincides with the in-plane direction as shown by arrow a, and the direction of the easy axis of magnetization of pattern part 3 is the same as the original direction as shown by arrow a. 111 in the in-plane direction and perpendicular I. Therefore, the bubble 5 is transferred along the periphery of the pattern 3 as shown by the arrow C by the rotating magnetic field. This pattern has a shape in which circles and hexagons are arranged in a row so that some of the shapes are l, and unlike the conventional permalloy pattern, the nine-point dimension does not require a gap, and the index of the ninth dimension may be loose, so the pattern can be made smaller and higher density is expected.

A pattern is formed by this ion implantation method, and the fCC injection thin film is easily striped out as shown in Figure 3.
is in three directions lυ, 1ffJ, [jJIJK l 2
0' (D11a exists without a granary, and depending on which direction the connected disk pattern 3 runs in a row with respect to the easy direction of the stripes that are spaced at 120 degrees, the super track field, pad track b, and hard track・Three paths for bubble movement in track g are created. Here, the relationship between the super track line, the #2 magnetic thin film bubble crystal direction, and the traveling direction of the transfer path is shown in Figure 3, and the station transmission line This transfer path is generally said to have a large bias margin, and is the path through which bubbles are easily transferred.Pad track b is a transfer path that is said to have the smallest bias margin due to the relationship shown in Figure 3. The path on the opposite side of the super track chain is the pad track g, which is the path where the bubble is transferred.・It becomes a track b.In the case of the magnetic thin film bubble crystal, any path of the continuous image disk pattern in the direction rL becomes a quad O track g.

This is because the specificity of bubble transfer is lost due to the magnetocrystalline anisotropy of the magnetic thin film bubble crystal.

(3) Prior art and problems In a magnetic bubble device using such an ion implantation method, conventionally the fourth transfer path on the pad/track side was used.
The tire mold type shown in figure a and this after improvement 41
There was a root 7 top type shown in 8b, but eventually the T body 1
Although it does not depend on the direction of rotation of the 1J magnetic field, there are 9 drawbacks in that a sufficient margin cannot be maintained.

(4)9 Purpose of the Invention In view of the above-mentioned conventional drawbacks, it is an object of the present invention to provide a transfer pattern with sufficient margin on the pad-track side of an ion implantation bubble device.〇(5)0 According to the present invention, there is provided a bubble transfer path in an ion implantation puzzle device in which a bubble transfer path is formed in an FFI bubble crystal by an ion implantation method,
Each pit has a roughly serrated shape with a cusp, and the side that pulls out the bubble from the cusp is perpendicular to one of the stripe directions of the magnetic bubble crystal. Transfer pattern t for an ion implantation bubble device, characterized in that the corners are not too narrow and are smoothly connected to the sides of adjacent bits, and the most concave part of the cusp has a side parallel to the bubble transfer direction. -Achieved by providing

(6) 1 Embodiments of the Invention Embodiments of the Invention The embodiments of the invention will be described in detail in the t-i plane below.FIG. 5 is a diagram showing a transfer pattern for an ion implantation bubble device according to the present invention.

In the 6-line transfer pattern, 7 indicates the cusp, 2 indicates the easy stripe direction of the magnetic thin film bubble crystal, and HIL indicates the driving magnetic field.

This embodiment FLL is formed on the pad/track side, and the bubble transfer direction is in the direction of arrow P, and has a roughly sawtooth shape with cusp 7 on each bit. The side ab that is drawn out is perpendicular to any one direction of the stripe easy direction of the magnetic bubble crystal. In addition, the edge cd that draws the bubble into the cusp 7 is formed into a trap so that the opening angle of the cusp 7 does not become too narrow (which would cause the gap 6 and margin to deteriorate) and to connect smoothly with the edge of the 114v pit. has been done. Furthermore, the most concave part of the cusp 7 is the side bCY7 parallel to the bubble transfer direction to improve the pattern punching during manufacturing. In the transfer pattern of the present invention formed in this way, when the driving magnetic field HR rotates counterclockwise and faces in the A direction, the bubble is located in the transfer pattern 6.

When the driving magnetic field HR is directed in the B direction, the bubble is drawn into the cusp 7 of the transfer pattern and located at 1 n B'. Furthermore, while the driving magnetic field HR is directed toward C and D, the bubble stays at the cusp, and when the driving magnetic field HR rotates from D to A, it is pulled out to the position of the casp yoke E.

In this way, the bubble is transferred one bit per revolution of the driving magnetic field.

FIG. 6 is a diagram showing a transfer pattern according to the present invention when the driving magnetic field is clockwise. This embodiment is an inversion of the pattern of the previous embodiment, and its operation is exactly the same as that of the @embodiment.

FIG. 7 shows the operating characteristics of the pattern of the present invention (frequency I Hz
Bias-driving magnetic field margin)? FIG. 3 is a diagram showing a comparison between the margin of a rooftop pattern and the margin of a hypertrack pattern.

9. In the quadruple, the vertical axis is the bias magnetic field HB, and the horizontal axis is the drive magnetic field HR'. The margin of the pattern according to the present invention is made by self-edge A and 2. The margin of the super track pattern is made by 11B and B'. The margins of the rooftop pattern are shown by sC, respectively.From the figure, the pattern of the present invention has a narrower margin at low driving magnetic fields than the super top pattern (compared to the turn pattern, but it is much smaller than the top pattern). Good margin”fr
It can be seen that it has °. The diamond-shaped pad track at this time had no margin.

(7) The effects of the invention will be explained in detail in 6 (1) The transfer pattern for an ion implantation bubble device of the present invention has a sufficient margin as a transfer path on the pad track side. It has a great effect of improving reliability0

[Brief explanation of the drawing]

Figure 1 is a plan view of a magnetic bubble memory element formed by ion implantation, Figure 2 is a Wr plane view at the n-r1 proboscis of the first layer, and Figure 3 is the crystal direction and transfer path of the magnetic thin film bubble crystal. FIG. 4 shows the conventional transfer pattern on the pad tube track side; FIG. 5 and FIG. 6 show the transfer pattern for the ion implantation bubble device of the present invention. FIG. 7 is a characteristic diagram showing the operating characteristics of the transfer pattern of the present invention in comparison with a rooftop pattern and a super track pattern. In garden sales, 6 indicates a transfer pattern, and 7 indicates cusp 7. Patent applicant Fujitsu Limited Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Yukio Enda Akira Yamaguchi

Claims (1)

[Claims] ■Bubble transfer path in an ion-implanted puzzle device in which a bubble transfer path is formed in a magnetic bubble crystal by ion implantation.It has a roughly sawtooth shape with a cusp on each bit, and the side that pulls out the bubble from the cusp is a magnetic bubble. Crystal stripes can be easily aligned in any one direction and perpendicular! t-
fkL - On the side that draws the bubble into the cusp, the opening angle of the cusp is not too narrow and it is smoothly connected to the side of the adjacent pit, and the most curved part of the cusp has a side t parallel to the bubble transfer direction. - Provided vi - A transfer pattern for an ion implantation bubble device characterized by: