Technological processes for the fabrication of low- and high-Tc Josephson junctions, aimed for certain applications, are described. On the one hand, the integration of low-Tc superconductor digital electronics with superconducting sensor arrays enables input signal processing with quantum limited resolution at millikelvin temperatures. We describe this mixed signal superconductor technology for analogue sensor readout and signal multiplexing for operating temperatures down to 300 mK. On the other hand, by making use of modern high-Tc Josephson junction technology, sensitive magnetometers, which require a modest cooling power, can be developed. Examples of the application of the mentioned processes are shown.
Technological processes for the fabrication of low- and high-Tc Josephson junctions, aimed for certain applications, are described. On the one hand, the integration of low-Tc superconductor digital electronics with superconducting sensor arrays enables input signal processing with quantum limited resolution at millikelvin temperatures. We describe this mixed signal superconductor technology for analogue sensor readout and signal multiplexing for operating temperatures down to 300 mK. On the other hand, by making use of modern high-Tc Josephson junction technology, sensitive magnetometers, which require a modest cooling power, can be developed. Examples of the application of the mentioned processes are shown.
The integration of superconductor digital electronics together with superconducting sensors can enable smart multi-channel sensor arrays. Applications of such sensors range from basic astrophysical research to advanced security screening devices. The main advantage of superconducting sensor interfaces is the very low power consumption in combination with a very low noise level; both are required in order to keep the excellent superconducting sensor performance without distortions. The FLUXONICS Foundry technology has been optimized with respect to electronic interfaces circuits for analogue sensor readout and signal multiplexing. In this work, we describe this new interface technology and present a comparison with our standard RSFQ technology.
An overview of semiconductor-based and superconductor-based low-temperature electronics is presented. The general issues of reliability and thermal expansion mismatch are discussed. The discussion of semiconductor electronics starts with a description of a cryogenic supercomputer, the ETA, and then covers devices and materials, noise and applications to signal processing for sensors. Superconductor electronics is then discussed, including signal processing, digital systems, and oscillating junctions. The success of electronics with small numbers of Josephson junctions and the outlook for higher-temperature operation are addressed. Hybrid applications, combining semiconductor and superconductor technologies at the device, circuit, or system level, are examined, highlighting the problems of electrical interfacing and interconnections. >
An overview of semiconductor-based and superconductor-based low-temperature electronics is presented. The general issues of reliability and thermal expansion mismatch are discussed. The discussion of semiconductor electronics starts with a description of a cryogenic supercomputer, the ETA, and then covers devices and materials, noise and applications to signal processing for sensors. Superconductor electronics is then discussed, including signal processing, digital systems, and oscillating junctions. The success of electronics with small numbers of Josephson junctions and the outlook for higher-temperature operation are addressed. Hybrid applications, combining semiconductor and superconductor technologies at the device, circuit, or system level, are examined, highlighting the problems of electrical interfacing and interconnections.>
Quantum computers represent a prominent example of technology harnessing quantum phenomena for practical applications. Implementations based on superconducting solid-state qubits play a leading role. These have facilitated the implementation of the first commercially viable quantum computers through the use of well-established and scalable fabrication technologies. As the number of qubits in these systems is continuously increasing, there is an urgent need to advance wiring and integration methods. Specifically, the demand for high-frequency control and readout lines within the millikelvin coolers introduces unwanted heat load. As a scalable alternative, superconducting digital electronics has been proposed as a promising candidate for direct interfacing with superconducting quantum circuits. We, therefore, advanced our well-established cross-type, sub-micrometer-sized Nb-based Josephson junction technology for analog circuits to allow for the implementation of digital circuits. Thus, an advanced mixed signal process CJ2 hosts both, analog and digital circuits, on a single chip, using Josephson junctions of a wide critical current range. We discuss the technology and the realization of first circuits as well as results of basic logic gate and dc-SQUID operations. This advanced technology CJ2 enables the development of digital interfaces for quantum circuits by academic and industrial partners in the framework of the European FLUXONICS foundry.
The pioneers of superconducting electronics are accumulating an impressive record of achievement. For example, they have now gained the high-performance lead in the important field of digital electronics. Logic delays of 13 picoseconds and switching times of 9 picoseconds have been experimentally demonstrated. The same basic devices, Josephson junctions, also make the most sensitive microwave detectors, the most sensitive magnetometers (or current sensors) and the most stable voltage sources. Although each of these developments is an important independent accomplishment, the combination of these developments in a single technology merits special attention.
It has been nearly 110 years since the discovery of superconductors, and more than 30 years since the discovery of high temperature superconductors (HTS). Great progress has been made in the application of superconducting electronics in the last two decades. HTS microwave devices have shown much higher perfomance than the traditional ones and have found their ways to the industry applications in mobile communication, radar, and special communication applications. Owing to the ultrahigh sensitivity to magnetic fields and currents, superconducting quantum interference devices (SQUIDs) have been used as the irresplacible sensors in geological surveying, magnetic resonanc imaging, biomagnetic imaging, and other areas. The sensitivity of superconducting radiation detectors such as superconducting SIS mixer, superconducting hot electron bolometer, superconducting transition edge sensor, superconducting nanowire single photon detector, and superconducting microwave kinetic inductance detector are near the quantum limitation. They are now key technology in geophysics, astrophysics, quantum information science, biomedicine, and so on. Superconducting Josephson parametric amplifier has become a key element for superconducting quantum computing. Superconducting integrated circuit has been included in the international roadmap for devices and systems, and shows that having the potential to become one of the mainstreams for post-Moore information processing technology. In metrology, superconducting Josephson effect and Josephson junction array devices have been widely used in the redefinition of quantum voltage reference and basic units of the International system of Units. Superconducting electronics plays an important role in the current quantum information technology boom, which in turn promotes the development of superconducting electronics. This review will brief introduce the research and application of superconducting electronics in China in recent years.