JPS6120955B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a bubble memory device that uses an ion-implanted layer as a bubble driving layer, in which a groove is provided between adjacent loops to remove the ion-implanted layer, thereby reducing interaction between each loop. It is related to the element.

Recently, in connection with increasing the density of bubble memories, a new method of forming transfer circuit patterns using ion implantation technology has been proposed. That is, FIG. 1A is an example of a conventionally frequently used transfer circuit pattern, in which a plurality of half-disk-shaped transfer patterns made of permalloy or the like are arranged on a crystal substrate for magnetic bubbles. In this case, the minimum limited dimension W by lithography technology is W = 2/3 d for the magnetic bubble diameter d, and therefore the illustrated pattern ends and intervals are limited by this dimension W, and the minimum magnetic bubble diameter is 1.5
It's double that. On the other hand, FIG. 1B shows an example of a pattern forming method using ion implantation. That is, ion implantation is performed by covering a disk pattern in the form of connected circles with a metal mask, and forming an ion implantation layer on the surface of the crystal substrate other than this pattern. When the magnetic bubbles are driven with such a configuration by applying a bias and a rotating magnetic field, the magnetic bubbles are transferred along the outer periphery of the connected disk pattern. In this case, the relationship between the minimum limit dimension of the pattern and the magnetic bubble diameter d is W
= 2d, and for example, the diameter of the magnetic bubble can be reduced to about half of the dimension W of the end of the connected disk pattern shown in the figure. Therefore, the magnetic bubble can be miniaturized, and the density of the bubble memory can be increased. It becomes possible.

When a transfer loop is formed using such a concatenated disk pattern, the distance between each adjacent loop is approximately 2
Interaction was eliminated by providing a bit interval, but even with this interval, bubbles often streaked out between loops at the lower limit of the bias margin, causing malfunctions.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bubble memory device that prevents malfunctions due to the interaction between loops.

In order to achieve the above object, the bubble memory device of the present invention includes a magnetic bubble crystal substrate, in which an ion implantation layer is formed on the entire surface of the crystal substrate except for the connected disk pattern area, and the bubble memory device is used as a bubble driving layer. , a groove from which the ion implantation layer is removed is provided between the bubble transfer paths formed by the connected disk pattern regions.

The present invention will be described in detail below with reference to examples.

FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention. In the figure, loops 2 and 3 consisting of connected disk patterns are formed at a predetermined interval on a liquid phase epitaxial (LPE) layer formed on, for example, a GGG crystal substrate surface of a magnetic bubble crystal substrate 1 as a magnetic bubble transfer pattern. It is assumed that they are separated and formed in parallel. This articulated disk pattern
A pattern is formed using a metal film such as gold (Au) on the LPE layer of the GGG crystal substrate 1, and using this pattern as a mask, ions are implanted into further crystal substrates to form an ion implantation layer 4. The metal pattern was then removed. When transferring magnetic bubbles to which a rotating magnetic field and a bias magnetic field are applied to the loops 2 and 3 of the connected disk pattern, if the interval is small, the adjacent patterns will affect them and cause malfunctions. In order to eliminate this, it is necessary to separate them by 2 bits or more, but this does not allow for high density. In the present invention, a groove 5 in which the ion implantation layer 4 is removed is located between the parallel loops 2 and 3.
By providing , it was possible to effectively eliminate interaction even if the interval was reduced to 2 bits or less. To form this groove 5, a step is added in which the ion implantation layer 4 is masked with a resist to form a groove pattern and removed by ion milling or chemical etching using, for example, H ₃ PO ₄ .

As explained above, according to the present invention, by removing the ion-implanted layer between parallel loops and forming grooves, the influence of interaction can be reduced even if the loop interval is reduced to 2 bits or less. , not only to prevent malfunctions. This enables higher density and is useful for realizing large-capacity bubble memories.

[Brief explanation of the drawing]

1A and 1B are general explanatory diagrams of the transfer pattern of a bubble memory element, and FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention. In the figure, 1 is a crystal substrate for magnetic bubbles, 2, 3 4 indicates a connected disk pattern, 4 indicates an ion-implanted layer, and 5 indicates a groove.

Claims (1)

[Claims] 1. In a bubble memory element that is used as a bubble driving layer by forming an ion implantation layer on the entire surface of a magnetic bubble crystal substrate except for the connected disk pattern area, the bubble transfer path consisting of the connected disk pattern area is A bubble memory element characterized in that a groove is provided between which the ion-implanted layer is removed.