JPS5889876A - Magnetic coupling type josephson quantum interferometer - Google Patents

Abstract

PURPOSE:To obtain the magnetic field coupling type Josephson quantum interferometer, whose manufacturing processes are simplified and a manufacturing yield rate and reliability can be improvided, by forming a signal line on the upper part of an inductance part which is continued to a lower electrode at the same layer as an upper electrode of a Josephson junction, without stacking the signal line on the Josephson junction. CONSTITUTION:A ground plane 202 and an insulating film 203 are provided on an Si substrate 201. The lower electrode 204 is manufactured on the film by a lift off method. An interferometer inductance 205 is simultaneously manufactured together with the lower electrode. The Josephson junction 208 is manufactured by an insulating film 206 and the upper electrode 207. The signal line 209 is simultaneously arranged with the upper electrode 207 only on the interferometer inductance 205. Thus the magnetic field coupling type Josephson quantum interferometer is manufactured. A signal current is supplied to the signal line 2 at the same level as the upper electrode layer, and a threshold value characteristic of the magnetic coupling type Josephson quantum interferometer is measured. As a result, approximately the same curve as that of the conventional interferometer is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Josephson device.7. The present invention relates to a magnetic field coupling type Josephson quantum interference needle suitable for simplifying the manufacturing process to %.

In a conventional magnetic field coupling board Josephson traverse meter, the input signal, that is, the signal current supply line (hereinafter referred to as the signal line) for generating the magnetic field, is connected to the lower electrode that constitutes the Josephson junction, and the upper electrode ≧ is separately connected to the lower electrode. A superconducting thin film, which is the same as the electrode, is provided further above the laminated structure of an upper electrode layer and a lower electrode layer with an insulating film interposed therebetween.

An example is shown in FIG. A ground plane 102 is placed on the Bi substrate 01. An insulating layer 103 is applied, and a lower electrode 104 is applied.
．． A Josephson junction 105 and an upper electrode 106 are manufactured. The inductance 107 of the interference needle is the lower electrode 10
Prepare at the same time as 4.

The signal line 109 is placed on the inductance 107 of the interference needle via the insulation #l 1108.

In this way, after the Josephson junction is fabricated, the subsequent process of fabricating the signal line becomes a very long process.

For this reason, there are disadvantages in that the yield rate for device fabrication is poor and reliability is low.

An object of the present invention is to provide a magnetically coupled Josephson quantum interference needle that can simplify the manufacturing process and improve reliability by 9 degrees per manufacturing yield.

The feature of the present invention is that the signal line in a magnetically coupled Josephson quantum interference needle is formed on the upper part of the inductance connected to the lower electrode in the same manner as the upper electrode of the junction, without stacking it on the Josephson junction. That's the point. With this configuration, the process of forming an insulating film between the upper electrode and the signal line and the formation of a superconducting layer thereon can be performed more easily than in the conventional configuration, and the manufacturing yield p, l'l! It also helps improve reliability. It was also confirmed that even if the signal current was passed only to the top of the inductance of the interferometer and not to the top of the junction, almost the same operation as a conventional interference needle could be obtained.

An embodiment of the present invention will be explained below with reference to FIG. A-B line sectional view, (C
) is an equivalent circuit diagram.

Ground plane 202° insulation film 2 on Bi substrate 201
03 was applied, and a lower electrode 204 was formed thereon by a lift-off method. The inductance 205 of the Josephson wave interference needle is fabricated at the same time as the lower electrode, and the Josephson junction 20-8. 9.

At the same time as the upper electrode 207, a signal line 209 was placed only on the inductance 205 of the interferometer to produce a magnetically coupled Josephson quantum interference needle.

A signal current was supplied to the signal line 209 in the same layer as this upper electrode layer, and the threshold characteristics of the magnetically coupled Josephson quantum interference needle were measured, and as a result, a curve almost similar to that of the conventional interference needle was obtained.

In addition, a load resistor is connected to the interference needle shown in Fig. 2, and an input signal current is input based on the threshold curve described above in the nine cycles. As a result of conducting principle experiments, it was found that the needle operated in the same way as a conventional interference needle.

As described above, the Josephson quantum interference needle of this embodiment has almost the same performance as the conventional one, and the manufacturing process of the needle 1 can be simplified.

According to the invention, a Josephson junction bottom electrode is provided.

In addition, the magnetic field coupling type Josephson quantum interference needle can be provided in the process of manufacturing the upper electrode, which simplifies the process compared to the conventional Sengaisha Seisaku process, and improves the yield rate of device manufacturing. , which has the effect of improving reliability.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional magnetically coupled Josephson quantum interference needle, Figure 2 is a plan view of an embodiment of the present invention, Figure 2(b) is a sectional view, Figure 2(C) is an equivalent circuit diagram. 204... Lower electrode, 205... Inductance. 206... Insulating film, 207... Upper electrode, 208...
...Josephson junction, 209...signal line. Agent Patent Attorney Toshiyuki Usuda'VJl Figure

Claims (1)

[Claims] 1. A lower electrode consisting of a superconducting layer; and 9. A superconducting layer laminated on a portion of the lower electrode with an insulating layer interposed therebetween. an upper electrode forming a small number of Josephson junctions (both at two locations) between the lower electrode and a signal line formed of the same layer as the upper electrode and magnetically coupled to the lower electrode;
Contains a magnetically coupled Josephson quantum interference needle.