JPS5829192A - Replicate transfer gate for magnetic bubble memory - Google Patents

Abstract

PURPOSE:To simplify the manufacture process, by eliminating the need for a conductor pattern for bubble cut, through the provision of a conductor pattern for bubble stretching hold current application and a bubble cut pattern between the major and minor loops. CONSTITUTION:A magnetic bubble memory element is formed by forming a bubble drive layer with ion injection or a bubble drive layer having inter-surface anisotropy such as YIG on a magnetic bubble crystal substrate. As a replicate transfer gate for such as element, a conductor pattern 14 for current application to stretch and hold bubbles over a major 12 and a minor 13 loop, and a pattern 15 to cut stretched bubbles are provided between the major and minor loops 12 and 13, allowing to provide both functions of a replicate gate and a transfer gate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the modification of the replicate gate of a magnetic bubble memory device having a bubble driving layer by ion implantation or YIG. Bubble-based devices have numerous features such as non-volatility, high storage density, and low power consumption, and are also extremely reliable because they are solid-state devices that do not contain any mechanical elements.

Such magnetic bubble memory devices are also required to have an increased storage density due to the recent increase in the amount of information and the need to make the devices smaller. However, in the elements used in conventional magnetic bubble memories, the bubble transfer pattern is formed by photo-etching permalloy deposited on a magnetic thin film.
Its dimensional accuracy is limited by the accuracy of visible light exposure, making it difficult to reduce the pattern size and increase storage density.Recently, ion implantation or YI
A method of forming a transfer pattern using a G (yttrium iron garnet) thin film has been developed. To explain the ion implantation method as a representative example, as shown in the plan view of FIG. 1 and the cross-sectional view of FIG. Gallium Garnet (
GGG) A thin film 2 of magnetic garnet, which will become a bubble crystal, is formed on the substrate l by liquid phase epitaxial growth, and ions of hydrogen, neon, helium, etc. are implanted into the part 4 other than the pattern 3 of this a-type thin film 2. Pattern 3 is then formed. In the device in which the pattern 3 is formed in this way, the easy magnetization axis direction of the ion-implanted portion 4 coincides with the in-plane direction as shown by the arrow a, and the easy magnetization axis direction of the pattern portion 3 is the same as the original direction as shown by the arrow a. It is the same in-plane direction and straight. Therefore, the bubble 5 is transferred along the periphery of the pattern 30 as shown by the arrow C by the rotating magnetic field. This pattern 3 has a shape of connected circles and squares, and does not require gaps like the conventional permalloy pattern, even if the rounding dimension precision is loose, so the pattern can be made small and high density can be achieved. Major magnetic bubble memory elements such as
In the i-inner configuration, the replicate gate has a third
The structure shown in the figure is used. To explain the figure, numeral 6 is a major line, 7 is a minor loop, 8 is a hairpin-shaped conductor pattern spanning the major line and the conductor pattern, and 9 is a conductor pattern for cutting bubbles or a groove with a low extinction and demagnetizing field. The effect of this replicate gate is that when the bubble reaches the tip 4 of the minor loose, current is applied to conductor pattern 8 to extend the bubble, and then current is applied to conductor pattern 9 in the direction of collapsing the bubble, causing the bubble to disappear. It is divided into two parts, one is absorbed into the major 2-in-6, and the other is absorbed into the minor loop 7. Further, if grooves are used instead of the conductor pattern 9, the puzzle is divided by the grooves when the current is stopped after the conductor pattern stretches the shiver pull.

If the table replicate gate has conductor pattern 9, then other conductor patterns 8 and 0
(2-layer structure) The manufacturing process is complicated. Further, if a groove is used instead of the conductor pattern, processing such as etching or ion milling is required, and the manufacturing process thereof becomes complicated like the conductor pattern. In addition, a bubble memory using a replicate gate that cannot be divided into blocks due to its shape has a configuration as shown in Figure 4. The information string from inner loops 7-1 to 7-1 is transferred out to the main 4 and jar line 6 and arranged in chronological order!
Especially, non-volatility is achieved by replicating the information in the columns by the replicate gate 10, detecting one of the information columns by the detector IIK, and returning the other information column to the minor loop 7-8 to 74. Yes. Therefore, the readout time is longer than the conventional bubble memory block replication method using permalloy patterns.Also, in the event of a power outage, the information at the beginning position disappears, so it is necessary to check it when restarting. There was. This actual line was devised to solve these problems.

For this reason, the truth! In ji, in the replicate transfer gate of a magnetic bubble memory element, a bubble driving layer by ion implantation or a bubble driving layer having in-plane anisotropy such as WIQ is formed on a crystal substrate for 8-air bubbles. It is equipped with a conductor pattern for applying current to extend and hold the bubble across the minor K, and a putter Y that cuts the puzzle extended between the major and minor, and has the functions of both a replicate gate and a transfer gate. It is characterized by this.

Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings.

In FIG. 5, an example is shown. In FIG. 5, 12 is a major line, 13 is a minor loop, 14 is a U-shaped conductor pattern for expanding bubbles, and 15 is a chevron shape in which ions are not implanted. This is a pattern for cutting bubbles. And in this example, minor loop 13
The tip A of the major line 12 faces the cusp B of the conductor pattern 14 along the line connecting these two points.
A pattern 15 is formed near the middle between the major line 12 and the minor loop 13. The role of this pattern 15 is to form a diamond-shaped non-implanted pattern 16, as shown in FIG. If this occurs, a charged wall is generated in the downward direction that repulses and cuts the bubble. Therefore, as shown in Figure 5, when parts KA and B are in the phase of the rotating magnetic field of attraction. A charged wall of repulsion occurs in the ridge and 9 parts of the pattern 15 and plays the role of cutting the bubble.In addition, in the part near the tip of the minor loop 130 of the conductor pattern 14, there is a wall in two directions along the pattern of the minor loop 13. Incisions 14m and 14b are formed in order to widen the phase margin.

Next, the replication operation of this embodiment will be explained using FIG. Kj17. First, as shown in (a), the rotating magnetic field 11IR is indicated by arrow 1.
70 direction and when the bubble 1B approaches the tip of the ma4f-loop, a pulse current is applied to the conductor putter:/14. As a result, the bubble is stretched as shown in FIG. 1B and reaches the cusp of the major line 12. Then (
e) When the rotating magnetic field comes in the direction of arrow 180 as shown in the figure, the current in the conductor pattern 14 is turned off. When this happens, a charged wall of suction is generated at the cusp of major line 12 and the tip of minor loop 13, and a charged wall of repulsion occurs at the top and bottom of pattern 15, and the bubble is divided into 18 m and 18 b (
d) As shown in the figure, the bubble of the major line 120 and the tip of the minor loop 13 are respectively attracted. In this way, the bubble of the minor loop 13 is replicated to the major line 12.

Further, this embodiment can also be used as a transfer gate. The transfer-out operation of this embodiment will be explained using FIG. 8. First, as shown in the figure (a), when the rotating magnetic field HR is in the direction of the arrow 19 and the bubble 20 approaches the tip of the minor loop, the current flowing through the conductor pattern 14 is turned on.

As a result, the shivapur is stretched as shown in (b) and reaches the cubs of the major twin 12. In this state, the current is turned off when the rotating magnetic field moves in the direction of the arrow 21 as shown in the (@) diagram and as shown in the (d) diagram. In this case, a charged wall of attraction is generated only at the cusp of the major twin 12, and the bubble 20 is attracted to the cusp of the major fin 12 as shown in the figure. In this way, the minor loose bubble is transferred to the major line.

Figure 9 shows the operating margin of this embodiment, where the horizontal axis represents the driving field and the vertical axis represents the bias magnetic field. m'(
point ll) showed a trans 7-a-out operation.

The H2O diagram shows a replica/transfer gate of a pulsing board constructed by connecting the components of this embodiment, and its formation is easy.

FIG. 11 shows another embodiment, which is different from the embodiment shown in FIG. 5 and has a melting conductor pattern 14! The incision 14b formed along the tip of the inner loop 13 is made in one direction only. Note that the operation and effects of this embodiment are similar to those of the previous embodiment.

As explained above, the replicate transformer 7 agate of the present invention does not require a conductor pattern or groove for cutting bubbles, and the pattern for cutting bubbles can be formed at the same time as the major minor loose pattern, so the manufacturing process is conventional. It is significantly simpler than . Furthermore, the present invention can easily configure a block replicate gate, so that it is possible to realize a high-density bubble mesh with quick access and easy control.

[Brief explanation of the drawing]

! Figure IE1 is a plan view of a magnetic puzzle memory element formed by ion implantation; Figure E2 is a sectional view taken along the line 1-■ of Figure 1; Figure 3 is a plan view of a magnetic bubble memory element formed by ion implantation. Top view of the replicate gate,
Figure 4 is an explanatory diagram of an example of a major-minor configuration using ion implantation, Figure 5 is a plan view of a replicate transfer gate according to an embodiment of the present invention, and Figure 6 is the operating principle of the bubble cutting pattern. Explanatory diagram explaining the seventh
WJ is an explanatory diagram illustrating the replicate operation of the replicate transfer gate according to the embodiment of the present invention, No. 8.
The figure is also an explanatory diagram explaining the transfer operation, No. 9
The figure is an operating margin characteristic diagram, and Figure 1O is a plan view of a block replicate gate constructed by the replicate transfer gate according to the embodiment of the present invention.
gl1 diagram shows replicates of other embodiments of the present invention.
FIG. 3 is a plan view of a transfer gate. 12... Major line, 13... Minor loose, 14... Conductor pattern, 1K... Bubble cutting pattern. Patent applicant: Fujitsu Limited Patent agent: Akira Saneki, patent attorney: Kazuyuki Nishidate, patent attorney: Yukio Uchida, patent attorney: Akira Yamaguchi Figure 3

Claims (1)

[Claims] L Bubble driving layer by ion implantation on the magnetic bubble crystal substrate or YIG (yttrium iron garnet)
In a replicate transfer gate of a magnetic bubble memory element in which a bubble driving layer having in-plane anisotropy such as
A replicate transfer 9 gate characterized in that it has a pattern for cutting a bubble extended between major and minor, and has both the functions of a replicate gate and a transfer gate.