Wafer-scale uniformity of Dolan-bridge and bridgeless Manhattan-style Josephson junctions for superconducting quantum processors

Journal Article (2024)
Author(s)

N. Muthusubramanian (TU Delft - QN/Kavli Nanolab Delft)

M. Finkel (TU Delft - QCD/DiCarlo Lab)

W.J. Duivestein (TU Delft - QN/Groeblacher Lab)

C. Zachariadis (TU Delft - QN/Kavli Nanolab Delft)

S. L.M. van der Meer (TU Delft - QCD/DiCarlo Lab)

H.M. Veen (TU Delft - QCD/DiCarlo Lab)

M. Beekman (TNO, TU Delft - BUS/TNO STAFF)

T. Stavenga (TU Delft - QCD/DiCarlo Lab)

Alessandro Bruno (TU Delft - QN/Kavli Nanolab Delft)

L. Di Carlo (TU Delft - QN/DiCarlo Lab, TU Delft - QCD/DiCarlo Lab)

Research Group
QN/Kavli Nanolab Delft
Copyright
© 2024 N. Muthusubramanian, M. Finkel, W.J. Duivestein, C. Zachariadis, S.L.M. van der Meer, H.M. Veen, M.C. Beekman, T. Stavenga, A. Bruno, L. DiCarlo
DOI related publication
https://doi.org/10.1088/2058-9565/ad199c
More Info
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Publication Year
2024
Language
English
Copyright
© 2024 N. Muthusubramanian, M. Finkel, W.J. Duivestein, C. Zachariadis, S.L.M. van der Meer, H.M. Veen, M.C. Beekman, T. Stavenga, A. Bruno, L. DiCarlo
Research Group
QN/Kavli Nanolab Delft
Issue number
2
Volume number
9
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Abstract

We investigate die-level and wafer-scale uniformity of Dolan-bridge and bridgeless Manhattan-style Josephson junctions, using multiple substrates with and without through-silicon vias (TSVs). Dolan junctions fabricated on planar substrates have the highest yield and lowest room-temperature conductance spread, equivalent to ∼ 100 M H z in transmon frequency. In TSV-integrated substrates, Dolan junctions suffer most in both yield and disorder, making Manhattan junctions preferable. Manhattan junctions show pronounced conductance decrease from wafer center to edge, which we qualitatively capture using a geometric model of spatially-dependent resist shadowing during junction electrode evaporation. Analysis of actual junction overlap areas using scanning electron micrographs supports the model, and further points to a remnant spatial dependence possibly due to contact resistance.