Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Applied Physics Letters

Superconducting InGaAs junction field-effect transistors with Nb electrodes

Alan W. Kleinsasser, Thomas Nelson Jackson, David T. McInturff, F. Rammo, George D. Pettit, J. M. Woodall

Published Oct 30, 1989• 71 citations
Publisher

Abstract

We describe the design, fabrication, and characterization of superconducting In0.47Ga0.53As junction field-effect transistors (JFETs) with Nb source and drain electrodes. In0.47Ga0.53As has the advantage of combining large coherence length and high Schottky barrier transmission, making it a very attractive material on which to base superconducting FETs. At large voltages these devices behave as normal FETs in either enhancement or depletion modes, while at small voltages they act as Josephson junctions or super-Schottky diodes. Both normal and super- currents are controlled by the gate.

DOI
10.1063/1.102166

Related papers

Semiconductor heterostructure weak links for Josephson and superconducting FET applications

Alan W. Kleinsasser, Thomas Nelson Jackson, George D. Pettit +3 more

Superconductor-normal-superconductor (SNS) weak links using a semiconductor as the normal region are of interest for applications in high frequency Josephson devices and in superconducting field effect transistors. Recently, there has been a revival of interest in materials such as InAs which, in principle, allow true SNS structures without tunneling (Schottky) barriers at the electrodes, In this paper we discuss the requirements for semiconductor SNS Josephson and FET devices and describe the fabrication and characterization of planar SNS weak links in which the normal region is InAs, which is part of a heterostructure consisting of a thin (100 nm) layer of n-InAs grown on undoped GaAs. Nb electrodes defined by electron beam lithography have been made with spacings as small as 260 nm. Preliminary measurements indicate that the devices have good electrical behavior which is well explained by SNS weak link theory, using coherence lengths calculated from measured material parameters. These weak links can be the basis for superconducting FET devices, and have the significant advantage of allowing simple device isolation compared with bulk InAs, which was used in earlier work.

IEEE Transactions on Magnetics•Mar 1, 1987•11 citations

Silicon-coupled Josephson junctions and super-Schottky diodes with coplanar electrodes

Rich Ruby, T. Van Duzer

Superconducting devices with coplanar electrodes have been fabricated using electron-beam lithography to define the smallest feature. The devices each consist of two Pb-In alloy electrodes, 20 µm wide, deposited on a clean, degenerately doped silicon substrate. The two electrodes are separated by a thin (100-300-nm) gap. Electron-beam lithography is used to define the gap, and sputter etching to remove the underlying alloy film. Depending on the width of the gap and the condition of the metal-semiconductor interface, these devices displayed either Josephson or super-Schottky diode behavior. The Josephson devices show a high degree of robustness and hadI_{c}Rproducts in the range 200-800 µV at 4.2 K. The super-Schottky diodes had current sensitivities S in the range 1000-1300 V-1when measured at 4.2 K.

IEEE Transactions on Electron Devices•Nov 1, 1981•39 citations

On-chip Hybrid Superconducting-Semiconducting Quantum Circuit

Kaveh Delfanazari, Michael Joseph Kelly, Charles G. Smith +8 more

In this paper, we experimentally demonstrate a hybrid superconducting-semiconducting circuit consisting of eight planar and ballistic Nb-In0.75Ga0.25As-Nb Josephson junctions. E-beam lithography was used to fabricate the Josephson junctions on an InGaAs chip. In contrast to our previous studies on long junctions that were fabricated by photolithography, in this study, we observe the induced superconductivity in an In0.75Ga0.25As quantum well at higher temperatures, between T = 0.3 and 1 K (3He cryostat temperature range). The induced superconducting gap of Δind= 0.65 meV was measured at lowest base temperature T = 300 mK. The effect of temperature and magnetic fields B on the induced superconductivity are presented. Our results suggest that our In0.75Ga0.25As heterostructure is a promising scalable material system for quantum processing and computing applications.

IEEE Transactions on Applied Superconductivity•Mar 6, 2018•18 citations

SPICE models and applications of superconducting FETs and higher-voltage Josephson gates

Uttam Ghoshal, T. Van Duzer, Harry Kroger

The authors describe the development of circuit models, applications of superconducting field effect transistors (SFETs), and higher-voltage Josephson junction (HVJJ) circuits which are important for the feasibility of several novel hybrid superconducting-semiconducting circuits. They also discuss the delay optimization involved in designing and embedding interface circuits in a hybrid superconductor-semiconductor technology. It is noted that, with the advances made in semiconductor technologies, interfaces between the two technologies are practical now and the advantages of hybrid circuits in various applications should be realizable in practice. In the case of interfacing typical Nb-based Josephson junction circuits to 0.5 mu m CMOS technologies, it was estimated that the minimum delay through the interface is approximately 110 ps and the optimum number of junctions in each branch of the HVJJ circuits is 10.>

Technical digest - International Electron Devices Meeting/Technical digest•Dec 9, 2002•6 citations

On-chip hybrid Superconducting-Semiconducting Circuit

Kaveh Delfanazari, Reuben K. Puddy, Ma, P +8 more

In this paper, we experimentally demonstrate a hybrid superconducting-semiconducting (S-Sm) circuit consisting of eight planar and ballistic Nb-In0.75Ga0.25As-Nb Josephson junctions. E-beam lithography was used to fabricate the Josephson junctions on an InGaAs chip. In contrast to our previous studies on long junctions that were fabricated by photolithography, in this study, we observe the induced superconductivity in an In0.75Ga0.25As quantum well at higher temperatures, between T= 0.3 and 1.4 K (3He cryostat temperature range). The induced superconducting gap of & #x0394;ind= 0.65 meV was measured at lowest base temperature T= 300 mK. The effect of temperature and magnetic fields B on the induced superconductivity are presented. Our results suggest that our In0.75Ga0.25As heterojunctions is a promising scalable material system for quantum processing and computing applications.

•Mar 6, 2018•0 citations

Epitaxial superconductor-semiconductor two-dimensional systems for superconducting quantum circuits

Joseph O’Connell Yuan, Kaushini S. Wickramasinghe, William M. Strickland +4 more

Qubits on solid state devices could potentially provide the rapid control necessary for developing scalable quantum information processors. Materials innovation and design breakthroughs have increased functionality and coherence of qubits substantially over the past two decades. Here, we show by improving interface between InAs as a semiconductor and Al as a superconductor, one can reliably fabricate voltage-controlled Josephson junction field effect transistor (JJ-FET) that can be used as tunable qubits, resonators, and coupler switches. We find that bandgap engineering is crucial in realizing a two-dimensional electron gas near the surface. In addition, we show how the coupling between the semiconductor layer and the superconducting contacts can affect qubit properties. We present the anharmonicity and coupling strengths from one and two-photon absorption in a quantum two level system fabricated with a JJ-FET.

arXiv:2104.01159•Journal of Vacuum Science & Technology A Vacuum Surfaces and Films•Mar 23, 2021•26 citations
We describe the design, fabrication, and characterization of superconducting In0.47Ga0.53As junction field-effect transistors (JFETs) with Nb source and drain electrodes. In0.47Ga0.53As has the advantage of combining large coherence length and high Schottky barrier transmission, making it a very attractive material on which to base superconducting FETs. At large voltages these devices behave as normal FETs in either enhancement or depletion modes, while at small voltages they act as Josephson junctions or super-Schottky diodes. Both normal and super- currents are controlled by the gate.
Superconductor-normal-superconductor (SNS) weak links using a semiconductor as the normal region are of interest for applications in high frequency Josephson devices and in superconducting field effect transistors. Recently, there has been a revival of interest in materials such as InAs which, in principle, allow true SNS structures without tunneling (Schottky) barriers at the electrodes, In this paper we discuss the requirements for semiconductor SNS Josephson and FET devices and describe the fabrication and characterization of planar SNS weak links in which the normal region is InAs, which is part of a heterostructure consisting of a thin (100 nm) layer of n-InAs grown on undoped GaAs. Nb electrodes defined by electron beam lithography have been made with spacings as small as 260 nm. Preliminary measurements indicate that the devices have good electrical behavior which is well explained by SNS weak link theory, using coherence lengths calculated from measured material parameters. These weak links can be the basis for superconducting FET devices, and have the significant advantage of allowing simple device isolation compared with bulk InAs, which was used in earlier work.
Superconducting devices with coplanar electrodes have been fabricated using electron-beam lithography to define the smallest feature. The devices each consist of two Pb-In alloy electrodes, 20 µm wide, deposited on a clean, degenerately doped silicon substrate. The two electrodes are separated by a thin (100-300-nm) gap. Electron-beam lithography is used to define the gap, and sputter etching to remove the underlying alloy film. Depending on the width of the gap and the condition of the metal-semiconductor interface, these devices displayed either Josephson or super-Schottky diode behavior. The Josephson devices show a high degree of robustness and hadI_{c}Rproducts in the range 200-800 µV at 4.2 K. The super-Schottky diodes had current sensitivities S in the range 1000-1300 V-1when measured at 4.2 K.
In this paper, we experimentally demonstrate a hybrid superconducting-semiconducting circuit consisting of eight planar and ballistic Nb-In0.75Ga0.25As-Nb Josephson junctions. E-beam lithography was used to fabricate the Josephson junctions on an InGaAs chip. In contrast to our previous studies on long junctions that were fabricated by photolithography, in this study, we observe the induced superconductivity in an In0.75Ga0.25As quantum well at higher temperatures, between T = 0.3 and 1 K (3He cryostat temperature range). The induced superconducting gap of Δind= 0.65 meV was measured at lowest base temperature T = 300 mK. The effect of temperature and magnetic fields B on the induced superconductivity are presented. Our results suggest that our In0.75Ga0.25As heterostructure is a promising scalable material system for quantum processing and computing applications.
The authors describe the development of circuit models, applications of superconducting field effect transistors (SFETs), and higher-voltage Josephson junction (HVJJ) circuits which are important for the feasibility of several novel hybrid superconducting-semiconducting circuits. They also discuss the delay optimization involved in designing and embedding interface circuits in a hybrid superconductor-semiconductor technology. It is noted that, with the advances made in semiconductor technologies, interfaces between the two technologies are practical now and the advantages of hybrid circuits in various applications should be realizable in practice. In the case of interfacing typical Nb-based Josephson junction circuits to 0.5 mu m CMOS technologies, it was estimated that the minimum delay through the interface is approximately 110 ps and the optimum number of junctions in each branch of the HVJJ circuits is 10.>
In this paper, we experimentally demonstrate a hybrid superconducting-semiconducting (S-Sm) circuit consisting of eight planar and ballistic Nb-In0.75Ga0.25As-Nb Josephson junctions. E-beam lithography was used to fabricate the Josephson junctions on an InGaAs chip. In contrast to our previous studies on long junctions that were fabricated by photolithography, in this study, we observe the induced superconductivity in an In0.75Ga0.25As quantum well at higher temperatures, between T= 0.3 and 1.4 K (3He cryostat temperature range). The induced superconducting gap of & #x0394;ind= 0.65 meV was measured at lowest base temperature T= 300 mK. The effect of temperature and magnetic fields B on the induced superconductivity are presented. Our results suggest that our In0.75Ga0.25As heterojunctions is a promising scalable material system for quantum processing and computing applications.
Qubits on solid state devices could potentially provide the rapid control necessary for developing scalable quantum information processors. Materials innovation and design breakthroughs have increased functionality and coherence of qubits substantially over the past two decades. Here, we show by improving interface between InAs as a semiconductor and Al as a superconductor, one can reliably fabricate voltage-controlled Josephson junction field effect transistor (JJ-FET) that can be used as tunable qubits, resonators, and coupler switches. We find that bandgap engineering is crucial in realizing a two-dimensional electron gas near the surface. In addition, we show how the coupling between the semiconductor layer and the superconducting contacts can affect qubit properties. We present the anharmonicity and coupling strengths from one and two-photon absorption in a quantum two level system fabricated with a JJ-FET.