Improving Josephson junction reproducibility for superconducting quantum circuits: shadow evaporation and oxidation

• URL: http://arxiv.org/abs/2212.06692v1
• Date: Tue, 13 Dec 2022 16:05:43 GMT
• Title: Improving Josephson junction reproducibility for superconducting quantum circuits: shadow evaporation and oxidation
• Authors: D.O. Moskalev, E.V. Zikiy, A.A. Pishchimova, D.A. Ezenkova, N.S. Smirnov, A.I. Ivanov, N.D. Korshakov, and I.A. Rodionov
• Abstract summary: We report on a robust chip scale $Al/AlO_x/Al$ fabrication method due to comprehensive study of shadow evaporation and oxidation steps. We fabricate three $5times10$ $mm2$ chips with 18 transmon qubits showing less than 1.9% frequency variation between qubit on different chips.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The most commonly used physical realization of superconducting qubits for quantum circuits is a transmon. There are a number of superconducting quantum circuits applications, where Josephson junction critical current reproducibility over a chip is crucial. Here, we report on a robust chip scale $Al/AlO_x/Al$ junctions fabrication method due to comprehensive study of shadow evaporation and oxidation steps. We experimentally demonstrate the evidence of optimal Josephson junction electrodes thickness, deposition rate and deposition angle, which ensure minimal electrode surface and line edge roughness. The influence of oxidation method, pressure and time on critical current reproducibility is determined. With the proposed method we demonstrate $Al/AlO_x/Al$ junction fabrication with the critical current variation ($\sigma/I_c$) less than 3.9% (from $150\times200$ to $150\times600$ $nm^2$ area) and 7.7% (for $100\times100$ $nm^2$ area) over $20\times20$ $mm^2$ chip. Finally, we fabricate separately three $5\times10$ $mm^2$ chips with 18 transmon qubits (near 4.3 GHz frequency) showing less than 1.9% frequency variation between qubit on different chips. The proposed approach and optimization criteria can be utilized for a robust wafer-scale superconducting qubit circuits fabrication.

Related papers

• Quantum dynamics of frustrated Josephson junction arrays embedded in a transmission line: an effective XX spin chain with long-range interaction [0.0]
  We study theoretically a variety of collective quantum phases occurring in frustrated saw-tooth chains of Josephson junctions embedded in a dissipationless transmission line. The direct embedding of $pi$-Josephson junctions in a transmission line allows to establish a short/long-range interaction between (anti)vortices of well separated cells.
  arXiv  Detail & Related papers  (2024-07-04T13:40:08Z)
• Integer Fluxonium Qubit [0.0]
  We describe a superconducting qubit derived from operating a fluxonium circuit in a zero magnetic field. The Ramsey coherence time exceeds 100 us, and the average fidelity of Clifford gates is benchmarked to $mathcalF > 0.999$. Our work establishes a ready-to-use partially protected" superconducting qubit with an error rate comparable to the best transmons.
  arXiv  Detail & Related papers  (2024-03-25T13:55:20Z)
• Towards large-scale quantum optimization solvers with few qubits [59.63282173947468]
  We introduce a variational quantum solver for optimizations over $m=mathcalO(nk)$ binary variables using only $n$ qubits, with tunable $k>1$. We analytically prove that the specific qubit-efficient encoding brings in a super-polynomial mitigation of barren plateaus as a built-in feature.
  arXiv  Detail & Related papers  (2024-01-17T18:59:38Z)
• Improving Josephson junction reproducibility for superconducting quantum circuits: junction area fluctuation [0.0]
  Josephson superconducting qubits and parametric amplifiers are prominent examples of superconducting quantum circuits. critical current $I_c$ variation of the Josephson junction, as the most important electrical parameter, needs to be minimized. We optimized Josephson junctions fabrication process and demonstrate resistance variation of $9.8-4.4%$ and $4.8-2.3%$ across $22times22$ $mm2$ and $5times10$ $mm2$ chip areas.
  arXiv  Detail & Related papers  (2022-10-27T10:00:24Z)
• Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields [62.997667081978825]
  We show that qubit coherence can be improved by tuning defects away from the qubit resonance using an applied DC-electric field. We also discuss how local gate electrodes can be implemented in superconducting quantum processors to enable simultaneous in-situ coherence optimization of individual qubits.
  arXiv  Detail & Related papers  (2022-08-02T16:18:30Z)
• Compact superconducting microwave resonators based on Al-AlOx-Al capacitor [56.00511651498414]
  resonators based on aluminum oxide -- aluminum ($mathrmAl/AlO_x/Al$) parallel-plate capacitors. The size of the resonators is only 0.04$mathrmmm2$, which is more than one order smaller than the typical size of coplanar resonators.
  arXiv  Detail & Related papers  (2022-03-17T20:11:53Z)
• Rapid generation of all-optical $^{39}$K Bose-Einstein condensates using a low-field Feshbach resonance [58.720142291102135]
  We investigate the production of all-optical $39$K Bose-Einstein condensates with different scattering lengths using a Feshbach resonance near $33$ G. We are able to produce fully condensed ensembles with $5.8times104$ atoms within $850$ ms evaporation time at a scattering length of $232. Based on our findings we describe routes towards high-flux sources of ultra-cold potassium for inertial sensing.
  arXiv  Detail & Related papers  (2022-01-12T16:39:32Z)
• Algorithmic Ground-state Cooling of Weakly-Coupled Oscillators using Quantum Logic [52.77024349608834]
  We introduce a novel algorithmic cooling protocol for transferring phonons from poorly- to efficiently-cooled modes. We demonstrate it experimentally by simultaneously bringing two motional modes of a Be$+$-Ar$13+$ mixed Coulomb crystal close to their zero-point energies. We reach the lowest temperature reported for a highly charged ion, with a residual temperature of only $Tlesssim200mathrmmu K$ in each of the two modes.
  arXiv  Detail & Related papers  (2021-02-24T17:46:15Z)
• Simplified Josephson-junction fabrication process for reproducibly high-performance superconducting qubits [0.0]
  Current shadow-evaporation techniques for aluminum-based Josephson junctions require a separate lithography step to deposit a patch. We use one lithography step and one vacuum cycle to evaporate both the junction electrodes and the patch. Such high frequency predictability is a requirement for scaling-up the number of qubits in a quantum computer.
  arXiv  Detail & Related papers  (2020-11-10T16:42:50Z)
• Optimal coupling of HoW$_{10}$ molecular magnets to superconducting circuits near spin clock transitions [85.83811987257297]
  We study the coupling of pure and magnetically diluted crystals of HoW$_10$ magnetic clusters to microwave superconducting coplanar waveguides. Results show that engineering spin-clock states of molecular systems offers a promising strategy to combine sizeable spin-photon interactions with a sufficient isolation from unwanted magnetic noise sources.
  arXiv  Detail & Related papers  (2019-11-18T11:03:06Z)
• Implementation of a transmon qubit using superconducting granular aluminum [0.0]
  grAl may provide a robust source of non-linearity for strongly driven quantum circuits. In intrinsic qubit linewidth $gamma = 2 pi times 10,mathrmkHz$, corresponding to a lifetime of $16,mathrmmu s$. This linewidth remains below $2 pi times 150,mathrmkHz$ for in-plane magnetic fields up to $sim70,mathrmmT$.
  arXiv  Detail & Related papers  (2019-11-06T12:18:43Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.