Overlap junctions for high coherence superconducting qubits

Abstract

Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These junctions are made in two separate lithography steps with normal-angle evaporation. Most significantly, this work demonstrates that it is possible to achieve high coherence with junctions formed on aluminum surfaces cleaned in situ with Ar milling before the junction oxidation. This method eliminates the angle-dependent shadow masks typically used for small junctions. Therefore, this is conducive to the implementation of typical methods for improving margins and yield using conventional CMOS processing. The current method uses electron-beam lithography and an additive process to define the top and bottom electrodes. Extension of this work to optical lithography and subtractive processes is discussed.

4 pages, 3 figures

References in corpus (15)

• Observation of high coherence in Josephson junction qubits measured in a three-dimensional circuit QED architecture
• Superconducting qubit in waveguide cavity with coherence time approaching 0.1ms
• Qubit architecture with high coherence and fast tunable coupling
• Procedure for systematically tuning up crosstalk in the cross resonance gate
• A simple all-microwave entangling gate for fixed-frequency superconducting qubits
• Improved superconducting qubit coherence using titanium nitride
• State tomography of capacitively shunted phase qubits with high fidelity
• Fast adiabatic qubit gates using only ${\sigma }_z$ control
• Low Loss Superconducting Titanium Nitride Coplanar Waveguide Resonators
• Bulk and surface loss in superconducting transmon qubits
• Concentric transmon qubit featuring fast tunability and an anisotropic magnetic dipole moment
• Electromagnetically induced transparency in circuit QED with nested polariton states
• Multi-photon dressing of an anharmonic superconducting many-level quantum circuit
• Coherence in a transmon qubit with epitaxial tunnel junctions
• Suspending superconducting qubits by silicon micromachining

Cited by in corpus (32)

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• The 2021 Quantum Materials Roadmap
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• Electromagnetically induced transparency in circuit QED with nested polariton states
• High-coherence superconducting qubits made using industry-standard, advanced semiconductor manufacturing
• Resolving the positions of defects in superconducting quantum bits
• Non-degenerate parametric amplifiers based on dispersion engineered Josephson junction arrays
• Path toward manufacturable superconducting qubits with relaxation times exceeding 0.1 ms
• Inductively shunted transmon qubit with tunable transverse and longitudinal coupling
• Merged-element transmon
• Side-wall spacer passivated sub-um Josephson junction fabrication process
• Probing defect densities at the edges and inside Josephson junctions of superconducting qubits
• Amplitude and frequency sensing of microwave fields with a superconducting transmon qudit
• In-situ bandaged Josephson junctions for superconducting quantum processors
• Magnetic-field resilience of 3D transmons with thin-film Al/AlO${}_x$/Al Josephson junctions approaching 1 T
• Coherent superconducting qubits from a subtractive junction fabrication process
• Transmon Qubit in a Magnetic Field: Evolution of Coherence and Transition Frequency
• An argon ion beam milling process for native ${\text{AlO}}_{\text{x}}$ layers enabling coherent superconducting contacts
• Native approach to controlled-Z gates in inductively coupled fluxonium qubits
• Implementing two-qubit gates at the quantum speed limit
• Effects of surface treatments on flux tunable transmon qubits
• High coherence fluxonium manufactured with a wafer-scale uniformity process
• Argon milling induced decoherence mechanisms in superconducting quantum circuits
• Development of transmon qubits solely from optical lithography on 300mm wafers
• Towards merged-element transmons using silicon fins: the FinMET
• A universal quantum gate set for transmon qubits with strong ZZ interactions
• Overlap junctions for superconducting quantum electronics and amplifiers
• Material matters in superconducting qubits
• A practical guide for building superconducting quantum devices
• Synthetic-lattice Bloch wave dynamics in a single-mode microwave resonator
• Review of Superconducting Qubit Devices and Their Large-Scale Integration
• Design of an inductively shunted transmon qubit with tunable transverse and longitudinal coupling