CN116643087A - Circuit connection method, measurement circuit and application thereof - Google Patents
Circuit connection method, measurement circuit and application thereof Download PDFInfo
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- CN116643087A CN116643087A CN202310528267.7A CN202310528267A CN116643087A CN 116643087 A CN116643087 A CN 116643087A CN 202310528267 A CN202310528267 A CN 202310528267A CN 116643087 A CN116643087 A CN 116643087A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/02—General constructional details
- G01R1/04—Housings; Supporting members; Arrangements of terminals
- G01R1/0408—Test fixtures or contact fields; Connectors or connecting adaptors; Test clips; Test sockets
- G01R1/0416—Connectors, terminals
Abstract
The application discloses a circuit connection method, a measurement circuit and application thereof, and belongs to the field of quantum computing. The measuring circuit comprises a first circuit and a second circuit which are respectively separated to form two connecting parts, a grounding circuit for grounding the connecting parts and a bridging circuit for bridging the two opposite connecting parts. The measuring circuit can properly ground two electrodes of the Josephson junction, thereby avoiding static electricity generated during line connection passing through the Josephson junction, further realizing protection of the Josephson junction from static electricity damage, and realizing more accurate resistance measurement in view of using a Kelvin four-terminal wiring method to reflect the real resistance condition of the Josephson junction.
Description
Technical Field
The application belongs to the field of quantum information, in particular to the field of quantum computation, and particularly relates to a circuit connection method, a measuring circuit and application thereof.
Background
Josephson junctions are key components of the core device, the superconducting qubit, that implements superconducting quantum computers. The performance of the superconducting quantum computer is directly related to whether the superconducting quantum computer can realize effective quantum computation. The josephson junctions were measured at the time of fabrication of the quantum chip in order to evaluate the fabrication process and the quality thereof. Whereas the measurement of which will typically involve the ambient resistance of the josephson junction and from which its critical current can be obtained.
Therefore, it is an advantage to accurately measure the room temperature resistance of the josephson junction.
Disclosure of Invention
Examples of the application provide a circuit connection method, a measurement circuit and applications thereof. The scheme can avoid damage to the Sirtzion junction in the measuring process, and can realize more accurate measurement of the resistance of the Sirtzion junction.
The exemplary embodiment of the present application is implemented as follows.
In a first aspect, examples of the application propose a measurement circuit for measuring the resistance of a josephson junction based on the kelvin four-terminal wiring method.
Wherein the josephson junction has a first superconducting layer and a second superconducting layer, and the measurement circuit comprises:
a first circuit having one end configured to be connected to the first superconducting layer and the other end having two first connection portions separated;
a second circuit having one end configured to be connected to the second superconducting layer and the other end having two separated second connection portions;
a grounding circuit for grounding any one of the two first connection portions and the two second connection portions; and
a jumper circuit for connecting one first connection portion and one second connection portion;
wherein four ends are provided by two first connecting portions and two second connecting portions.
The measuring circuit has two first connections and two second connections, so that four ports (which may be described as four ports, for example) for external device, circuit connections can be provided by the two first connections and the two second connections. Therefore, the measuring circuit can be used for measuring the resistance of the Josephson junction based on the Kelvin four-terminal wiring method; and it allows to perform a circuit measurement of a measurement object with a lower resistance (in the example josephson junction) than with a voltammetric measurement circuit, with a higher precision/accuracy.
Meanwhile, in the measurement circuit described above, a ground circuit connecting the connection portion to the ground, and a connection (first connection portion and second connection portion) jumper circuit are also provided. The measurement circuit thus enables both the first and second superconducting layers of the josephson junction to be connected to ground. Then, when the two first and second connections are connected to the test instrument, static electricity generated during the connection can be conducted to ground without passing through the josephson junction, thereby protecting the josephson junction from static electricity during the connection. Because the Josephson junction is free from electrostatic damage in the wiring process, the resistance measurement result of the Josephson junction is more accurate, and the manufactured Josephson junction like the resistance situation can be reflected more truly.
According to some examples of the application, the measurement circuit further comprises:
the voltage measuring wire is configured to be connected to the voltmeter, and two ends of the voltage measuring wire are respectively connected with a first connecting part and a second connecting part;
the current measuring wire is connected to the ammeter, and two ends of the current measuring wire are respectively connected with the remaining first connecting part and the remaining second connecting part.
According to some examples of the application, two or more of the connection portions in the group consisting of the two first connection portions and the two second connection portions are grounded;
or the measuring circuit is provided with four grounding circuits, the two first connecting parts and the two second connecting parts form four connecting parts together, and the four grounding circuits are connected with the four connecting parts in a one-to-one mode.
According to some examples of the application, the measurement circuit has more than two crossover circuits;
and/or the measurement circuit comprises a same polarity jumper circuit connecting the two first connections to each other or the two second connections to each other.
In a second aspect, an example of the application proposes the use of a measurement circuit as described above for testing the resistance of a josephson junction.
According to some examples of the application, the measurement circuit is used to reduce the risk of electrostatic damage to the josephson junction when the measurement device in the measurement process is in a wire-connection operation with the josephson junction; .
In a third aspect, examples of the application provide a circuit connection method in measuring the resistance of a josephson junction.
The circuit connection method comprises the following steps:
a step of implementing electrostatic control by configuring the aforementioned measurement circuit; and
and connecting the two first connection parts and the two second connection parts to the measuring instrument.
According to some examples of the application, after the step of connecting the measuring instrument to the two first connection portions and the two second connection portions, the circuit connection method further includes: a step of breaking a ground circuit and a jumper circuit in the measurement circuit;
and/or, in the step of configuring the measurement circuit to achieve electrostatic control, the ground circuit is formed first and the crossover circuit is formed later.
In a fourth aspect, an example of the application proposes a method of measuring josephson junction resistance.
The measuring method comprises the following steps:
providing a Josephson junction to be tested, wherein the Josephson junction is provided with a first electrode and a second electrode, the first electrode is connected with a first line, the second electrode is connected with a second line, the tail end of the first line is separated into two first wiring ports, and the tail end of the second line is separated into two second wiring ports;
grounding a ground port provided by the at least one first wiring port or the at least one second wiring port and then bridging from the ground port to the other port, wherein the ground port is selected from one of the first wiring port and the second wiring port and the other port is selected from the other of the first wiring port and the second wiring port;
the two first wiring ports and the two second wiring ports are connected into a measuring instrument according to the Kelvin four-terminal wiring method; and
disconnecting the ground port from ground, and disconnecting the ground port from another port.
According to some examples of the application, the first and second wires are formed during fabrication of the josephson junction by a micro-nano process.
According to some examples of the application, the first electrode and the first line are connected by a meandering first elongate wire.
According to some examples of the application, the second electrode and the second wire are connected by a meandering second extension wire.
According to some examples of the application, grounding the ground port is accomplished by: wires are connected from ground to the ground port.
The beneficial effects are that:
the scheme in the example of the application uses kelvin four-terminal wiring to make circuit measurements of josephson junctions, and can route and contact resistance, providing higher measurement accuracy, than voltammetric resistance (otherwise known as voltammetry, amperometric). Meanwhile, the electrode of the Josephson junction is grounded through the measuring circuit, so that static electricity is prevented from passing through the Josephson junction when the measuring instrument is connected, the damage of the static electricity to the Josephson junction is avoided, and the measuring accuracy is correspondingly improved.
Drawings
For a clearer description, the drawings that are required to be used in the description will be briefly introduced below.
FIG. 1 is a circuit diagram of a circuit connection of a voltammetric measurement resistor in the related art;
FIG. 2 is a circuit connection diagram of Kelvin resistance measurement in an example of the application;
FIG. 3 is a circuit diagram of a first measurement circuit in an example of the application;
FIG. 4 is a circuit diagram of a second measurement circuit in an example of the application;
FIG. 5 is a circuit diagram of a third measurement circuit in an example of the application;
FIG. 6 is a circuit diagram of a fourth measurement circuit in an example of the application;
FIG. 7 is a circuit diagram of a fifth measurement circuit in an example of the application;
FIG. 8 is a circuit diagram of a sixth measurement circuit in an example of the application;
FIG. 9 is a circuit diagram of a seventh measurement circuit in an example of the application;
FIG. 10 shows a circuit diagram of a seventh exemplary measurement circuit of the present application connected to a voltmeter and an ammeter;
FIG. 11 is a flow chart illustrating a configuration sequence of a ground circuit and a jumper circuit of a first measurement circuit of an example of the present application;
fig. 12 is a flow chart showing a configuration of a ground circuit in the first measurement circuit according to the example of the present application.
Reference numerals illustrate: 100-measuring circuit; 100 a-a measurement circuit; 100 b-a measurement circuit; 100 c-a measurement circuit; 100 d-measuring circuit; 100 e-measuring circuitry; 100 f-measuring circuit; 101-a first circuit; 1011-a first connection; 102-a second circuit; 1021-a second connection; 103-a ground circuit; 104-a jumper circuit.
Detailed Description
Josephson junctions are nonlinear elements capable of forming non-uniform energy level structures and of constructing superconducting qubits based thereon. Josephson junctions are special devices formed from two superconductors in between and isolated by a thin layer of insulator between the two superconductors. The thickness of the non-superconductive layer/insulator is typically on the order of nanometers. Josephson junctions exhibit properties different from those of a typical superconductor and a typical insulator due to the tunneling effect of the cooper pair.
In the practice of superconducting quantum chips, a typical josephson junction is the structure of an Al-AlOx-Al heterojunction. The josephson junction is a three-layered sandwich structure in which superconductors located on both sides of the insulator can be generally described as two superconductor layers of the josephson junction and for ease of discussion as a first superconducting layer and a second superconducting layer, or as a first electrode and a second electrode, or as an upper electrode and a lower electrode, or as a bottom electrode and a top electrode.
Taking an aluminum-based josephson junction as an example, in a superconducting quantum chip, an aluminum film is fabricated on the surface of a substrate, a window exposing the substrate is formed by patterning it, and a multi-layered structure of josephson junctions is fabricated in the region of the window. For example, one or more materials, such as superconductors, dielectrics, and/or metals, are deposited. Depending on the materials selected, these materials may be deposited using deposition processes such as chemical vapor deposition, physical vapor deposition (e.g., evaporation or sputtering), or epitaxial techniques, among other deposition processes.
Exemplary methods include Ion Beam Assisted Deposition (IBAD), vacuum Evaporation plating (evapration), molecular Beam Epitaxy (MBE), pulsed Laser Deposition (PLD), chemical Vapor Deposition (CVD), sol-gel (sol-gel), and Magnetron Sputtering (Magnetron 25 Sputtering), among others.
It is also possible to remove one or more materials from the device during the manufacturing process. The removal process may include, for example, a wet etching technique, a dry etching technique, or a lift-off (lift-off) process, depending on the material to be removed. The materials forming the circuit elements described herein may be patterned using known exposure (lithographic) techniques, such as photolithography or electron beam exposure.
Josephson junctions are an important component of superconducting qubits, and the success or failure of their fabrication will directly be related to whether or not efficient quantum computation using superconducting qubits can be performed. To determine the quality of a josephson junction, it is often necessary to determine its resistance. If the resistance deviates from the design requirements, there is a problem that superconducting qubits based on the josephson junction cannot be used normally.
In general, the measured resistance can be measured by voltammetry, which has a wired measurement as shown in fig. 1. This scheme can be generally described as a two-terminal approach. Such a measurement method can also accept measurement results when the resistance of the measured object is relatively large. However, when the resistance value of the resistance of the measurement object is small, the measurement result that can be obtained by this measurement method will hardly satisfy the requirement.
This is because, due to the various connection lines and the contact positions of the measuring instrument with the lines, resistances, such as wire resistance and contact resistance, are present, respectively. And such resistances cannot be ignored already in the case of small resistances of the measurement object.
Therefore, in order to overcome the influence of the wire resistance of the line and the contact resistance of the measuring instrument (voltmeter, ammeter) and the line contact on the measuring structure, a four-terminal method is selected. In other parts or in some examples, the measurement may also be described as a four-terminal detection method, a four-wire detection method, or a four-point probe method, a four-wire resistance method, or a Kelvin resistance method, or the like.
The four-terminal method is used for carrying out the line configuration of a measuring system by a Kelvin four-terminal wiring method, and the measuring method has a wiring measuring mode shown in fig. 2. The wiring of the output current is separated from the lead wires for reading the voltage values at the two ends of the resistor to be measured, so that the measuring system is provided with separated current and voltage electrodes, and the impedance of the wiring and the contact resistance of the probe is eliminated. The method for measuring resistance can measure resistance with small resistance value, and can significantly reduce measurement error (compared with the two-end method), thereby obtaining high-precision measurement result.
From the above discussion, it will be appreciated that the above Kelvin resistance method may be considered for measuring the resistance of the Josephson junction. However, in practice, when the resistance measurement of the josephson junction is performed by adopting the method, the stability of the measurement result of the actual reflected multiple measurements needs to be improved, and there is also a problem that the resistance of the josephson junction cannot be accurately measured, or the expected resistance deviation of the junction with the same batch or the same process and structure design is large.
Through research, the inventors believe that this may be relevant in the way the line connection at the josephson junction is measured. Through practice, the inventor realizes that static electricity generated by connection operation in the measuring process can damage the Josephson junction, so that the measuring structure is distorted and the accuracy is reduced.
For example, given the small size (e.g. micron scale) of josephson junctions, and the vulnerability of structure and performance, the wire bonding operation during measurement can be achieved, for example, using ultrasonic welding. Ultrasonic welding refers to the transmission of ultrasonic waves to the surfaces of two objects to be welded by using high-frequency vibration waves, and under the condition of pressurization, the surfaces of the two objects are rubbed, deformed and heated to form a connection. However, as previously mentioned, the inventors have found that static electricity is generated during ultrasonic welding, which may cause the josephson junction to be destroyed and to fail.
Therefore, if the static influence can be eliminated in the process of measuring the resistance of the Josephson junction, positive significance can be brought to more accurate measurement of the resistance of the Josephson junction. In other words, even with kelvin resistance measurements, ideal josephson junction resistance measurements may not be obtained without overcoming the adverse effects of static problems.
Accordingly, the inventors believe that overcoming the static electricity problem can be achieved by preventing the generation of static electricity, or by avoiding static electricity generated during ultrasonic welding from passing through the josephson junction. In the examples of the present application, from the foregoing analysis, it is known that the inventors have chosen to overcome the static problem of avoiding that static electricity generated during ultrasonic welding passes through the josephson junction. Wherein the described "pass-through" means that static electricity is conducted from one of the two superconductor layers of the josephson junction to the other of the two superconductor layers.
As an exemplary option, for example, in the example of the application, a discharge path/path of static electricity is established in the resistance measurement system of the josephson junction, for example a discharge path to ground. In connection with the above discussion using the Kelvin four terminal connection method, it is contemplated that any one or more of the four terminals may be grounded.
Further, since two superconducting layers of the josephson junction need to be connected into the measurement system when specific circuit measurement is performed, static electricity may also pass through the josephson junction at the four ends, and then the grounding mode and sequence may need to be considered so as to avoid adverse effects of static electricity as much as possible.
The following detailed description of the present application is provided in connection with the accompanying drawings so that those skilled in the art can more clearly understand and practice the present application.
In some examples, the inventors propose a measurement circuit 100 for measuring the resistance of a josephson junction based on the kelvin four-terminal wiring method.
Wherein for convenience of explanation and understanding two superconductors in the three-layer structure of the superconductor-insulator-superconductor, which defines a josephson junction, are a first superconducting layer and a second superconducting layer, respectively. And therefore the josephson junction is mainly accessed into the measurement circuit 100 through the first and second superconducting layers for subsequent corresponding test operations according to the test requirements.
In an example, the measurement circuit 100 includes a first circuit 101 and a second circuit 102.
Wherein one end of the first circuit 101 is configured to be connected to the first superconducting layer of the josephson junction and the other end has two first connections 1011 separated. The two first connection portions 1011 constitute two ends in the kelvin four-terminal wiring method.
Similarly, one end of the second circuit 102 is configured to be connected to the second superconducting layer of the josephson junction and the other end has two second connections 1021 separated. The two second connection portions 1021 constitute the other two ends in the kelvin four-terminal wiring method. Therefore, it can be understood that four ends in the four-end wiring method are commonly provided by the two first connection portions 1011 and the two second connection portions 1021 described above.
In view of the size of the wiring and the convenience of connection, pads may be disposed at the ends of the respective first connection portions 1011, and pads may be disposed at the ends of the respective second connection portions 1021.
Further, the measurement circuit 100 further includes a grounding circuit 103 for grounding any one of the two first connection portions 1011 and the two second connection portions 1021; and a jumper circuit 104 for connecting one first connection portion 1011 and one second connection portion 1021. Fig. 3,4, 5, 6 and 7 show an example of a configuration of the ground circuit 103 and the jumper circuit 104 in the measurement circuit 100, respectively.
For convenience of distinction, four ends (pads) in the two first connection portions 1011 and the two second connection portions 1021 are numbered 1, 2, 3, and 4 in order from left to right in fig. 3 to 7.
Thus, in fig. 3, no. 1 configures the ground circuit 103, while No. 2 and No. 3 configure the jumper circuit 104.
In the measurement circuit 100a of fig. 4, the ground circuit 103 is configured No. 2, and the jumper circuits 104 are configured No. 2 and 3.
In the measurement circuit 100b of fig. 5, the ground circuit 103 is configured No. 2, and the jumper circuits 104 are configured No. 2 and 4.
In the measurement circuit 100c of fig. 6, the ground circuit 103 is configured No. 2, and the jumper circuits 104 are configured No. 2 and 3, and the ground circuit 103 is configured No. 4.
In the measurement circuit 100d of fig. 7, no. 1 and No. 3 are provided with the jumper circuit 104; the configuration ground circuit 103,4 No. 2 configures the ground circuit 103, and the jumper circuits 104,2 No. 1 and 3 configure the jumper circuit 104 No. 3.
It should be noted that in other examples of the present application, other ground circuits 103 and jumper circuits 104 may be configured, not limited to fig. 3-7. For example, two or more connection parts in the group consisting of the two first connection parts 1011 and the two second connection parts 1021 are grounded; therefore, other connection parts can be additionally arranged to carry out grounding on the basis of fig. 6 and 7.
Alternatively, the measurement circuit 100 has four ground circuits 103, and the two first connection portions 1011 and the two second connection portions 1021 together constitute four connection portions, and the four ground circuits 103 and the four connection portions are connected in a one-to-one manner. For example, in the measurement circuit 100e of fig. 8, the configuration ground circuit 103 No. 1, the configuration ground circuit 103 No. 2, the configuration ground circuits 103 No. 3, and the configuration ground circuits 103,2 No. 4, 103,3 No. 3, and the configuration jumper circuit 104 No. 4.
It will be appreciated that in fig. 7 and 8, the measurement circuit 100 has two (more than 3 in other examples) jumper circuits 104. In fig. 3,4, 5 and 6, a jumper circuit 104 that connects the first connection portion 1011 and the second connection portion 1021 across is shown. In fig. 7, a jumper circuit 104 is shown that connects the first connection portion 1011 and the second connection portion 1021 in a jumper manner. Fig. 8 shows that in the measurement circuit 100, a jumper circuit 104 connecting two second connection sections 1021 to each other will be included. In other examples, it is also possible to connect the two first connection portions 1011 to each other.
Further, since the first connection portion 1011 and the second connection portion 1021 connect two poles (described as a positive pole and a negative pole, for example) of the meter, respectively, in some examples, the crossover between the two first connection portions 1011 may also be referred to as a crossover of the same polarity; and the crossover between the first connection portion 1011 and the second connection portion 1021 may also be referred to as a crossover of different polarities.
Further to facilitate connection with a measuring instrument/meter, the measuring circuit 100 further comprises, according to the kelvin four-terminal measurement method: a voltage measurement line and a current measurement line.
And as the name suggests, the voltage measuring line is configured to be connected to the voltmeter, and both ends of the voltage measuring line are connected to one first connection portion 1011 and one second connection portion 1021, respectively. Further, the current measuring wire is configured to be connected to the ammeter, and both ends of the current measuring wire are connected to the remaining one first connection portion 1011 and the remaining one second connection portion 1021, respectively.
Fig. 9 is an example of configuring a voltage measurement line and a current measurement line on the basis of fig. 8. And in order to avoid clutter and ambiguity of the lines, in the measurement circuit 100f of fig. 9, the voltage measurement line and the current measurement line are not connected with the respective connection portions.
The structure of the measurement circuit 100 in the present application has been fully described so far. As before, the measurement circuit 100 can be used to test the resistance of the josephson junction. Thus, in the present application, the inventors have also proposed the use of this measurement circuit 100 for testing the resistance of a josephson junction.
And it is known that this application can be used to effect measurements of the resistance of the josephson junction with less electrostatic damage to the josephson junction. For example, measurement circuit 100 may be used to reduce the risk of electrostatic damage to josephson junctions when the measurement equipment in the measurement process (such as voltmeters and ammeters used in the aforementioned kelvin four-terminal measurement process) is in line connection with the josephson junctions.
For example, in the example illustrated schemes of fig. 3-9, both ends of the josephson junction have been connected to ground by measurement circuit 100. Thus, static electricity generated during the wiring process can be conducted to ground through the measurement circuit 100 when the measuring instrument is connected, and not through the josephson junction.
Thus, as an application example, in part, the inventors have also proposed a circuit connection method in measuring the resistance of a josephson junction.
The circuit connection method comprises the following steps:
a step of implementing electrostatic control by configuring the measurement circuit 100; and
and a step of connecting the two first connection portions 1011 and the two second connection portions 1021 to the measuring instrument.
Since the measurement circuit 100 grounds the two superconductor layers of the josephson junction, power-on measurements are made. The circuit connection method further includes, before the step of connecting the measuring instrument to the two first connection portions 1011 and the two second connection portions 1021, the step of breaking the ground circuit 103 and the jumper circuit 104 in the measuring circuit 100 before the step of conducting the test. And an exemplary scenario is shown in fig. 10.
Considering that if static electricity may also be present during the connection of measurement circuit 100 to the josephson junction, this static electricity may also potentially cause electrostatic damage to the josephson junction, it may also be considered that the order of connection of measurement circuit 100 to the josephson junction is controlled so as to reduce or avoid the adverse effect of the "potential static electricity" on the junction. In the step of configuring the measurement circuit 100 to achieve electrostatic control, the ground circuit 103 is formed first, and the crossover circuit 104 is formed later.
For example, taking the measurement circuit 100 shown in fig. 3 as an example, fig. 11 shows a flow of configuring the ground circuit 103 and then connecting the jumper circuit 104. In other words, consider that if static electricity may also be present during the connection of measurement circuit 100 to the josephson junction, this static electricity may also potentially cause electrostatic damage to the josephson junction, and control of the connection sequence of measurement circuit 100 to the josephson junction may also be considered to reduce or avoid the adverse effects of the "potential static electricity" junction.
Further, when the ground circuit 103 is configured in fig. 11, the adverse effect of static electricity can also be facilitated to be controlled by configuring the ground. For example, the first scheme: the ground circuit 103 is connected to the ground first and then to the first connection portion 1011, as shown in fig. 12. Alternatively, the second scheme: the ground circuit 103 is connected to the first connection portion 1011 and then to ground. Wherein it is advantageous to choose to configure the measurement circuit 100 based on the first scheme.
In order to make it easier for a person skilled in the art to implement the exemplary embodiment of the application, a method for measuring the resistance of a josephson junction is given in the examples.
The measuring method comprises the following steps:
step S1, providing a josephson junction to be tested, wherein the josephson junction has a first electrode and a second electrode, and the first electrode is connected with a first line, and the second electrode is connected with a second line, wherein the end of the first line is separated into two first connection ports, and the end of the second line is separated into two second connection ports.
In this step, the first and second lines are formed during the fabrication of the josephson junctions by a micro-nano process. Such as by using deposition, photolithography, etching, etc., alone and in combination. This approach can avoid the trouble of reconnecting the lines after the josephson junction is completed.
As previously mentioned, in some examples, the ground circuit 103 and the crossover circuit 104 are followed by ultrasonic welding, and thus, in some examples it is contemplated that the connection between the first electrode and the first line may be made by a meandering first extension wire. The distance between the first electrode and the first line can be increased, so that ultrasonic waves are prevented from directly acting on the Josephson junction, mechanical damage of the Josephson junction caused by the ultrasonic waves is avoided, and thermal damage of the Josephson junction caused by thermal effects generated by the ultrasonic waves is avoided. And similarly, the second electrode and the second wire are also connected by a meandering second extension wire. The first extension wire and the second extension wire are not shown in the drawing.
Step S2, then, grounding the ground port provided by the at least one first or the at least one second wiring port, and then bridging from the ground port to the other port, wherein the ground port is selected from one of the first and second wiring ports and the other port is selected from the other of the first and second wiring ports.
Wherein the wiring sequence of the grounding circuit 103 can be controlled to improve the electrostatic protection of the pair of junctions. For example, grounding the ground port is accomplished by: the conductors are connected from ground to the ground port, see fig. 12. In fig. 12, "two" indicates ground.
S3, connecting the two first wiring ports and the two second wiring ports into a measuring instrument according to a Kelvin four-terminal wiring method; and
step S4, disconnecting the ground port from the ground, and disconnecting the ground port from the other port.
After the above steps are implemented, the power-on test can be performed, and the method can also comprise a step S5 and a power-on measurement step.
The embodiments described above by referring to the drawings are exemplary only for explaining the present application and are not to be construed as limiting the present application.
For purposes of clarity, technical solutions, and advantages of embodiments of the present application, one or more embodiments have been described above with reference to the accompanying drawings. Wherein like reference numerals are used to refer to like elements throughout. In the description above, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that one or more embodiments may be practiced without these specific details, and that such embodiments may be incorporated by reference herein without departing from the scope of the claims.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
While the foregoing is directed to embodiments of the present application, other and further embodiments of the application may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims (10)
1. A measurement circuit for measuring the resistance of a josephson junction based on the kelvin four-terminal wiring method, the josephson junction having a first superconducting layer and a second superconducting layer, the measurement circuit comprising:
a first circuit having one end configured to be connected to the first superconducting layer and the other end having two first connection portions separated;
a second circuit having one end configured to be connected to the second superconducting layer and the other end having two separated second connection portions;
a grounding circuit for grounding any one of the two first connection portions and the two second connection portions; and
a jumper circuit for connecting one first connection portion and one second connection portion;
the four ends are provided by two first connecting portions and two second connecting portions together.
2. The measurement circuit of claim 1, wherein the measurement circuit further comprises:
the voltage measuring wire is configured to be connected to the voltmeter, and two ends of the voltage measuring wire are respectively connected with a first connecting part and a second connecting part; and
the current measuring wire is connected to the ammeter, and two ends of the current measuring wire are respectively connected with the remaining first connecting part and the remaining second connecting part.
3. The measurement circuit of claim 1, wherein more than two of the group of two first connections and two second connections are grounded;
or the measuring circuit is provided with four grounding circuits, the two first connecting parts and the two second connecting parts form four connecting parts together, and the four grounding circuits are connected with the four connecting parts in a one-to-one mode.
4. A measurement circuit according to claim 1, 2 or 3, wherein the measurement circuit has more than two crossover circuits;
and/or the measurement circuit comprises a same polarity jumper circuit connecting the two first connections to each other or the two second connections to each other.
5. Use of the measurement circuit of any one of claims 1 to 4 for testing the resistance of a josephson junction.
6. The use of the measurement circuit of claim 5 for testing the resistance of a josephson junction, wherein the measurement circuit is used to reduce the risk of electrostatic damage to the josephson junction when the measurement device is in wire-connection operation with the josephson junction during measurement.
7. A circuit connection method in measuring the resistance of a josephson junction, the circuit connection method comprising:
a step of implementing electrostatic control by configuring the measurement circuit according to any one of claims 1 to 4; and
and connecting the two first connection parts and the two second connection parts to the measuring instrument.
8. The circuit connection method in measuring the resistance of the josephson junction according to claim 7, characterized in that it further comprises the step of breaking the ground and crossover circuits in the measurement circuit after the step of connecting the measurement instrument to the two first and second connections;
and/or, in the step of configuring the measurement circuit to achieve electrostatic control, the ground circuit is formed first and the crossover circuit is formed later.
9. A method of measuring josephson junction resistance, the method comprising:
providing a josephson junction to be tested, wherein the josephson junction is provided with a first electrode and a second electrode, the first electrode is connected with a first line, the second electrode is connected with a second line, the tail end of the first line is separated into two first wiring ports, and the tail end of the second line is separated into two second wiring ports;
grounding a ground port provided by at least one first or at least one second wiring port and then bridging from the ground port to another port, wherein the ground port is selected from one of the first and second wiring ports and the other port is selected from the other of the first and second wiring ports;
the two first wiring ports and the two second wiring ports are connected into a measuring instrument according to the Kelvin four-terminal wiring method; and
disconnecting the ground port from ground, and disconnecting the ground port from another port.
10. The method of measurement of josephson junction resistance according to claim 9, characterized in that the method of measurement comprises one or more of the following definitions;
first definition: the first and second lines are formed during fabrication of a josephson junction by a micro-nano process;
a second definition: the first electrode is connected with the first circuit through a first zigzag extension wire;
third definition: the second electrode is connected with the second circuit through a second zigzag extension wire;
fourth definition: grounding the ground port is achieved by: wires are connected from ground to the ground port.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310528267.7A CN116643087A (en) | 2023-05-10 | 2023-05-10 | Circuit connection method, measurement circuit and application thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310528267.7A CN116643087A (en) | 2023-05-10 | 2023-05-10 | Circuit connection method, measurement circuit and application thereof |
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| CN116643087A true CN116643087A (en) | 2023-08-25 |
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| CN202310528267.7A Pending CN116643087A (en) | 2023-05-10 | 2023-05-10 | Circuit connection method, measurement circuit and application thereof |
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| CN (1) | CN116643087A (en) |
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