Standard microelectronic fabrication techniques have been utilized to produce batch quantities of superconducting quantum electronic devices and circuits. The overall goal is a fabrication technology yielding circuits that are rugged and stable and capable of being fabricated controllably and reproducibly in sizeable quantities. Our progress toward this goal is presented, with primary emphasis on the most recent work, which includes the use of electron-beam lithography and techniques of hybrid microelectronics. Several prototype microcircuits have been successfully fabricated. These microcircuits are formed in a thin-film parent material consisting of layers of superconducting and normal metals, and use proximity-effect structures as the active circuit elements.
Standard microelectronic fabrication techniques have been utilized to produce batch quantities of superconducting quantum electronic devices and circuits. The overall goal is a fabrication technology yielding circuits that are rugged and stable and capable of being fabricated controllably and reproducibly in sizeable quantities. Our progress toward this goal is presented, with primary emphasis on the most recent work, which includes the use of electron-beam lithography and techniques of hybrid microelectronics. Several prototype microcircuits have been successfully fabricated. These microcircuits are formed in a thin-film parent material consisting of layers of superconducting and normal metals, and use proximity-effect structures as the active circuit elements.
Techniques have been developed with which it is possible to fabricate superconducting thin-film structures with a wide variety of electrical and superconducting parameters which show Josephson-like phenomena. These bridges-based on the proximity effect-are made in layered thin-film ``substrates'' using a large variety of superconducting and nonsuperconducting materials. In this paper we detail the fabrication techniques and the electrical and superconducting characteristics for these proximity effect bridges including a simple low-frequency (<10 GHz) equivalent circuit based on analysis and experiment which closely describes the quantum phase coherence operation of the bridges in their voltage sustaining state. Extension of these fabrication techniques to entire thin-film electrical circuits including resistors, capacitors, and inductors with these bridges and leading to an entire superconducting microcircuit technology is discussed.
Quantum computing is rapidly evolving from theoretical frameworks to functional hardware, with physical qubits now being realized across multiple experimental platforms. Precision nanofabrication has enabled the development of low-loss, high-coherence quantum devices. Among the various approaches, superconducting circuits and trapped-ion systems have emerged as the most advanced and experimentally successful platforms for realizing controllable and scalable qubits. This review presents an overview of nanoscale fabrication techniques employed in these two architectures. We first outline the operating principles that define qubit behavior, followed by a discussion of representative device designs and fabrication workflows. In superconducting circuits, we examine processes such as thin-film deposition, lithographic patterning, and Josephson-junction fabrication that determine key parameters including qubit frequency, anharmonicity, and coherence. For trapped-ion systems, we describe the transition from bulk electrode assemblies to microfabricated surface traps produced using photolithography, metal deposition, and dielectric layering, where electrode geometry and surface treatment directly influence ion confinement and motional heating. We further discuss fabrication-related challenges, including dielectric loss, surface contamination, and material defects that limit coherence and reproducibility, along with emerging mitigation strategies such as advanced cleaning, low-loss materials, and improved surface engineering. By drawing parallels between these two leading platforms, this review highlights that continued progress in nanofabrication remains central to realizing scalable, high-fidelity quantum processors.
Quantum device fabrication and integration represent a critical frontier in the advancement of next-generation computing and communication technologies. This chapter provides an overview of the fundamental principles and processes involved in the fabrication of quantum devices, including superconducting qubits, semiconductor quantum dots, and spin-based devices. Key fabrication techniques such as advanced lithography, thin-film deposition, etching, and material characterization are discussed, with emphasis on the stringent requirements for precision, material purity, and defect control. The chapter also addresses challenges associated with integrating quantum devices with classical CMOS electronics, including cryogenic operation, interconnect design, scalability, and noise mitigation. By examining current fabrication approaches and integration strategies, this chapter highlights the technological barriers and emerging solutions shaping scalable quantum systems. The discussion offers readers a foundational understanding of how quantum devices are realized and integrated, bridging the gap between quantum physics and practical hardware implementation.
Quantum device fabrication and integration represent a critical frontier in the advancement of next-generation computing and communication technologies. This chapter provides an overview of the fundamental principles and processes involved in the fabrication of quantum devices, including superconducting qubits, semiconductor quantum dots, and spin-based devices. Key fabrication techniques such as advanced lithography, thin-film deposition, etching, and material characterization are discussed, with emphasis on the stringent requirements for precision, material purity, and defect control. The chapter also addresses challenges associated with integrating quantum devices with classical CMOS electronics, including cryogenic operation, interconnect design, scalability, and noise mitigation. By examining current fabrication approaches and integration strategies, this chapter highlights the technological barriers and emerging solutions shaping scalable quantum systems. The discussion offers readers a foundational understanding of how quantum devices are realized and integrated, bridging the gap between quantum physics and practical hardware implementation.
Superconducting circuits are a promising platform for implementing fault-tolerant quantum computers, quantum limited amplifiers, ultra-low power superconducting electronics, and sensors with ultimate sensitivity. Typically, circuit fabrication is realized by standard nanolithography, generally associated with a high level of control over defects and contaminants. Additive approaches have not been used so far since they are expected to be inferior in terms of superconducting properties or quantum coherence. This work shows that liquid-metal based micro-pipette printing is suited for fabricating superconducting lumped-element resonators with high internal quality factors. The applicability of our technique for low-loss superconducting device fabrication and the possibility to locally add metal structures, without affecting any preexisting circuit elements, is a further advantage. Our results open up new avenues in the hardware implementation of scaled-up superconducting quantum computers.
This article reviews recent progress in superconducting nanodevices, with particular emphasis on fabrication methods developed for superconducting nanowires and nanoscale Josephson junctions based on different barrier materials. It evaluates the future potential of superconducting nanodevices, including nano-superconducting quantum interference devices (nanoSQUIDs), in light of improvements in nanoscale fabrication and manipulation techniques, along with their likely impacts on future quantum technology and measurement. The article first considers efforts to realize devices at the physical scale of 100 nm and below before discussing different types of Josephson junction such as trilayer junctions. It also describes the use of focused ion beam milling and electron beam lithography techniques for junction fabrication at the nanoscale and the improved energy sensitivity detectable with a nanoSQUID. Finally, it looks at a range of applications for nanoSQUIDs, superconducting single photon detectors, and other superconducting nanodevices.