We implemented, optimized, and fully tested a superconducting Josephson junction fabrication process over multiple runs tailored for integrated digital circuits that are used for control and readout of superconducting qubits operating at millikelvin temperatures. This process was optimized for highly energy efficient rapid single flux quantum (ERSFQ) circuits with critical currents reduced by a factor of ∼10 as compared to those operated at 4.2 K. Specifically, it implemented Josephson junctions with 10 μA unit critical current fabricated with 10 μA/μm2 critical current density. In order to circumvent the substantial size increase in the SFQ circuit inductors, we employed an NbN high kinetic inductance layer with 8.5 pH/sq sheet inductance. Similarly, to maintain the small size of junction resistive shunts, we used a non-superconducting PdAu alloy with 4.0 Ω/sq sheet resistance. For integration with quantum circuits in a multi-chip module, 5 and 10 μm height bump processes were also optimized. To keep the fabrication process in check, we developed and thoroughly tested a comprehensive process control monitor chip set.
Skip Nav Destination
Article navigation
22 May 2023
Research Article|
May 22 2023
High density fabrication process for single flux quantum circuits
Special Collection:
Advances in Superconducting Logic
D. Yohannes
;
D. Yohannes
(Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Supervision, Validation, Writing – original draft, Writing – review & editing)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
M. Renzullo
;
M. Renzullo
(Investigation, Methodology, Writing – original draft, Writing – review & editing)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
J. Vivalda;
J. Vivalda
(Investigation)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
A. C. Jacobs
;
A. C. Jacobs
(Investigation, Resources)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
M. Yu;
M. Yu
(Investigation)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
J. Walter;
J. Walter
(Data curation, Formal analysis, Investigation, Visualization, Writing – review & editing)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
A. F. Kirichenko
;
A. F. Kirichenko
(Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Validation, Writing – review & editing)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
I. V. Vernik;
I. V. Vernik
(Data curation, Formal analysis, Investigation, Methodology, Supervision, Validation, Writing – original draft, Writing – review & editing)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
Search for other works by this author on:
O. A. Mukhanov
O. A. Mukhanov
a)
(Conceptualization, Data curation, Formal analysis, Funding acquisition, Methodology, Project administration, Resources, Supervision, Validation, Writing – original draft, Writing – review & editing)
SEEQC, Inc
., 150 Clearbrook Road, Elmsford, New York 10523, USA
a)Author to whom correspondence should be addressed: [email protected]
Search for other works by this author on:
a)Author to whom correspondence should be addressed: [email protected]
Note: This paper is part of the APL Special Collection on Advances in Superconducting Logic.
Appl. Phys. Lett. 122, 212601 (2023)
Article history
Received:
March 30 2023
Accepted:
May 11 2023
Citation
D. Yohannes, M. Renzullo, J. Vivalda, A. C. Jacobs, M. Yu, J. Walter, A. F. Kirichenko, I. V. Vernik, O. A. Mukhanov; High density fabrication process for single flux quantum circuits. Appl. Phys. Lett. 22 May 2023; 122 (21): 212601. https://doi.org/10.1063/5.0152552
Download citation file:
Pay-Per-View Access
$40.00
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Citing articles via
Roadmap on photonic metasurfaces
Sebastian A. Schulz, Rupert. F. Oulton, et al.
Sputter epitaxy of ScAlN films on GaN high electron mobility transistor structures
Tomoya Okuda, Shunsuke Ota, et al.
Era of entropy: Synthesis, structure, properties, and applications of high-entropy materials
Christina M. Rost, Alessandro R. Mazza, et al.
Related Content
Ferromagnetic Josephson switching device with high characteristic voltage
Appl. Phys. Lett. (May 2012)
Superconductor digital electronics: Scalability and energy efficiency issues (Review Article)
Low Temp. Phys. (May 2016)
Single-flux-quantum signal processors monolithically integrated with a superconducting nanostrip single-photon detector array
Appl. Phys. Lett. (May 2023)
Superconducting pulse conserving logic and Josephson-SRAM
Appl. Phys. Lett. (May 2023)
Systematic method to evaluate energy dissipation in adiabatic quantum-flux-parametron logic
J. Appl. Phys. (November 2019)