JPH06196768A - Magnetic coupling type circuit - Google Patents

Abstract

PURPOSE:To provide a small-sized and high-speed magnetic coupling type circuit. CONSTITUTION:A first control wiring 5 is arranged on the earthing surface 1 through a firs insulating layer 7, a superconducting loop 4 consisting of a strip line including the Josephson junctions 2, 3 is arranged on a first control wiring 5 through a second insulating layer 8 and a second control wiring 6 is arranged on this superconducting loop 4 through a third insulating layer 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field coupling type circuit having a plurality of magnetically coupled control wirings, and particularly to a Josephson coupling, a superconducting loop, a superconducting quantum interferometer and the like. The present invention relates to a control wiring magnetically coupled to a circuit element.

[0002]

2. Description of the Related Art A magnetic field coupling type circuit having a plurality of magnetically coupled control wirings includes, for example, a superconducting quantum interferometer (S
There is a (QUID) gate. FIG. 3A is a schematic perspective view of a device structure having a conventional structure of a superconducting quantum interferometer (SQUID) gate. FIG. 3B shows A- in FIG.
It is a cross-sectional schematic diagram between B. A superconducting loop 4 composed of a strip line including Josephson junctions 2 and 3 is arranged on the ground plane 1 via an insulating layer, and two control wirings 5 are formed on the superconducting loop 4 via an insulating layer. , 6 are arranged in parallel. With this configuration, the two control wirings 5 and 6 are magnetically coupled to the superconducting loop 4 with a constant mutual inductance.

[0003]

However, in the structure of the magnetic coupling type circuit according to the conventional technique, the plurality of control wirings are magnetically coupled to the superconducting loops, which are circuit elements, with substantially equal mutual inductance values. As the number of control wirings increases, the line width of the superconducting loop arranged under the control wirings increases and the area of the circuit element itself increases. Further, since the line width of each control wiring cannot be increased, the inductance of the control wiring cannot be reduced, resulting in a problem that the operation speed becomes slow.

An object of the present invention is to eliminate such problems of the conventional magnetic field coupling type circuit and to provide a magnetic field coupling type circuit capable of downsizing and speeding up the circuit.

[0005]

According to the present invention, there are provided a circuit element whose operating characteristics change when a magnetic field is applied, and at least two or more elements arranged so as to be magnetically coupled to the circuit element. In a magnetic field coupling type circuit composed of a control wiring and a ground plane, a magnetic coupling portion of the circuit element and the at least two or more control wirings are laminated in a direction perpendicular to the ground plane through respective insulating layers. It is characterized by being configured.

[0006]

By laminating the circuit element and the plurality of control wirings in the direction perpendicular to the ground plane, the area can be first reduced. Secondly, since the line width per control wiring can be increased, the inductance of the control wiring can be reduced and the element can operate at high speed. Thirdly, since the mutual inductances that represent the magnitude of the degree of magnetic coupling between each control wiring and the circuit element are different, it is possible to take an optimum configuration according to the use of the plurality of control wirings. For example, in addition to the signal current due to the high speed operation of the element,
A current that does not depend on the operating speed, for example, a direct current for adjusting the operating point of the element or a current related to the reset operation may be injected. In such a case, a signal current resulting from high-speed operation of the element is injected into the control wiring with the largest mutual inductance, and a DC current is passed through the control wiring with the smallest mutual inductance, thereby reducing the size of the circuit and at the same time. It is possible to enable high-speed operation of the entire circuit. This is because the switching operation of the circuit element can be performed by applying a constant magnetic field Φ to the circuit element by the control wiring, and if the current value I flowing in the control line and the mutual inductance between the control line and the circuit element are M, From the relationship of Φ = M × I, the current I can be reduced by increasing the mutual inductance M. As a result, the operating time of the circuit element at the preceding stage that drives this circuit element can be estimated by approximately L / R = L × I / V, where L is the inductance of the control wiring. As can be seen from this, the current I
Reducing the value makes the circuit element in the preceding stage faster, and speeds up the overall operation when a large number of such circuit elements are integrated.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention for a superconducting quantum interferometer (SQUID) gate will be described below with reference to the drawings as an example of a magnetic field coupling type circuit having a plurality of magnetically coupling control wirings.

Example 1 FIG. 1A is a schematic perspective view of an element structure for explaining Example 1 of the present invention. FIG. 1B is a schematic cross-sectional view taken along the line AB of FIG. The first control wiring 5 is arranged on the ground plane 1 via the first insulating layer 7, and the Josephson junctions 2 and 3 are arranged on the first control wiring 5 via the second insulating layer 8. Superconducting loop 4 consisting of including stripline
On top of this superconducting loop 4 and a third insulating layer 9
The second control wiring 6 is arranged via the. The first control wiring 5, the superconducting loop 4, and the second control wiring 6 are laminated in a direction perpendicular to the ground plane 1 with an insulating layer 7 interposed therebetween. First control wiring 5, superconducting loop 4 and second
The line width W of the control wiring 6 is equal to the film thickness D, the film thickness of the first insulating layer 7 is H1, the film thickness of the second insulating layer 8 is H2, and the film thickness of the third insulating layer 9 is H3. By thus laminating the circuit element and the two control wirings in the direction perpendicular to the ground plane, the area can be reduced as compared with the configuration of the conventional technique. Further, since the line width per control wiring can be increased, there is an effect that the inductance of the control wiring can be reduced and the element can operate at high speed.
Further, the mutual inductance M1 between the first control wiring 5 and the superconducting loop 4 and the mutual inductance M2 between the second control wiring 6 and the superconducting loop 4 can be approximately expressed as follows.

[0009]

[Equation 1]

Therefore, the mutual inductance M2 becomes larger than M1. For example, a signal current caused by high-speed operation of the element is passed through the second control wiring 6 having a large mutual inductance, and the first control wiring 5 having a small mutual inductance is supplied.
Is advantageous in that a direct current for adjusting the operating point of the device can be passed to reduce the size of the circuit and simultaneously enable high-speed operation of the entire circuit.

Here, a superconducting quantum interferometer (SQUID)
Although the gate is taken as an example, the same effect can be obtained in addition to the Josephson junction itself or the superconducting loop of the superconducting memory circuit.

Second Embodiment FIG. 2A is a schematic perspective view of an element structure for explaining a second embodiment of the present invention. 2B is a schematic cross-sectional view taken along the line AB of FIG. The first control wiring 5 is arranged on the ground plane 1 via the first insulating layer 7, and the second control wiring 6 is arranged on the first control wiring 5 via the second insulating layer 8. The superconducting loop 4 formed of a strip line including the Josephson junctions 2 and 3 is arranged on the second control wiring 6 via the third insulating layer 9. The first control wiring 5, the second control wiring 6, and the superconducting loop 4 are
Each is laminated in a direction perpendicular to the ground plane 1 with an insulating layer interposed therebetween.

By arranging the two control wirings 5 and 6 below the superconducting loop 4 in this way, in addition to the effect of the first embodiment, the inductance of the control wiring is further reduced to achieve high-speed operation of the circuit. It has the effect of enabling it.

[0014]

As described above, according to the present invention, the circuit element and the plurality of control wirings are laminated in the direction perpendicular to the ground plane, whereby the circuit can be downsized and the speed can be increased. A circuit can be realized.

[Brief description of drawings]

FIG. 1 is a schematic perspective view and a sectional view of an element structure for explaining an embodiment of a magnetic field coupling circuit according to the present invention.

FIG. 2 is a schematic perspective view and a sectional view of an element structure for explaining another embodiment of the magnetic field coupling circuit according to the present invention.

FIG. 3 is a schematic perspective view and a sectional view of an element structure for explaining a magnetic field coupling type circuit according to a conventional technique.

[Explanation of symbols]

 1 ground plane 2,3 Josephson junction 4 superconducting loop 5,6 control wiring 7,8,9 insulating layer

Claims (5)

[Claims] 1. A circuit element whose operating characteristics change when a magnetic field is applied, at least two or more control wirings arranged to be magnetically coupled to the circuit element, and a ground plane. In a magnetic field coupling type circuit configured, the magnetic coupling part of the circuit element and the at least two or more control wirings are laminated in a direction perpendicular to a ground plane via insulating layers, respectively. Magnetic coupling circuit. 2. The magnetic field coupling circuit according to claim 1, wherein the two or more control wirings are laminated on both sides of the circuit element in the vertical direction. 3. The magnetic field coupling circuit according to claim 1, wherein the two or more control wirings are laminated on one side of the circuit element in the vertical direction and on the ground plane side. 4. The magnetic field coupling circuit according to claim 1, wherein the control lines and the circuit elements have the same line width and the same film thickness. 5. The magnetic field coupling circuit according to claim 1, wherein the circuit element is a superconducting loop formed of a strip line including a Josephson junction.