Optical Direct Write of Dolan--Niemeyer-Bridge Junctions for Transmon Qubits

Abstract

We characterize highly coherent transmon qubits fabricated with a direct-write photolithography system. Multi-layer evaporation and oxidation allows us to change the critical current density by reducing the effective tunneling area and increasing the barrier thickness. Surface treatments before resist application and again before evaporation result in high coherence devices. With optimized surface treatments we achieve energy relaxation $T_1$ times in excess of $80\mu$s for three dimensional transmon qubits with Josephson junction lithographic areas of 2 $\mu {\mathrm{m}}^2$.

arXiv comment7 pages, 3 figures

References in corpus (41)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Charge insensitive qubit design derived from the Cooper pair box
• Superconducting Qubits: Current State of Play
• Observation of high coherence in Josephson junction qubits measured in a three-dimensional circuit QED architecture
• Coherent Josephson qubit suitable for scalable quantum integrated circuits
• New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds
• Towards understanding two-level-systems in amorphous solids -- Insights from quantum circuits
• Quantum Approximate Optimization of Non-Planar Graph Problems on a Planar Superconducting Processor
• Experimental evidence for a surface distribution of two-level systems in superconducting lithographed microwave resonators
• Fluctuations of Energy-Relaxation Times in Superconducting Qubits
• Decoherence benchmarking of superconducting qubits
• Microwave Dielectric Loss at Single Photon Energies and milliKelvin Temperatures
• Materials loss measurements using superconducting microwave resonators
• Loss and decoherence due to stray infrared light in superconducting quantum circuits
• Measurement and Control of Quasiparticle Dynamics in a Superconducting Qubit
• Unsupervised Machine Learning on a Hybrid Quantum Computer
• Demonstrating a Driven Reset Protocol of a Superconducting Qubit
• Correlating decoherence in transmon qubits: Low frequency noise by single fluctuators
• Protecting superconducting qubits from external sources of loss and heat
• Microwave response of vortices in superconducting thin films of Re and Al
• Electric field spectroscopy of material defects in transmon qubits
• Photon Shot Noise Dephasing in the Strong-Dispersive Limit of Circuit QED
• Minimal resonator loss for circuit quantum electrodynamics
• Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle Excitations
• Characterization and Reduction of Capacitive Loss Induced by Sub-Micron Josephson Junction Fabrication in Superconducting Qubits
• Improving wafer-scale Josephson junction resistance variation in superconducting quantum coherent circuits
• Cavity Attenuators for Superconducting Qubits
• Trapping a single vortex and reducing quasiparticles in a superconducting resonator
• Direct Dispersive Monitoring of Charge Parity in Offset-Charge-Sensitive Transmons
• Decoherence of superconducting qubits caused by quasiparticle tunneling
• Improving the Quality Factor of Microwave Compact Resonators by Optimizing their Geometrical Parameters
• Simplified Josephson-junction fabrication process for reproducibly high-performance superconducting qubits
• Merged-Element Transmons: Design and Qubit Performance
• Tunneling Spectroscopy of Two-level Systems Inside Josephson Junction
• Merged-element transmon
• Geometric Scaling of Two-Level-System Loss in Superconducting Resonators
• A Josephson junction defect spectrometer for measuring two-level systems
• An argon ion beam milling process for native ${\text{AlO}}_{\text{x}}$ layers enabling coherent superconducting contacts
• Development of transmon qubits solely from optical lithography on 300mm wafers
• Localization and reduction of superconducting quantum coherent circuit losses
• High Quality Stepped-Impedance Resonators Suitable for Circuit-QED Measurement of Superconducting Artificial Atoms

Cited by in corpus (2)

• Fabrication and surface treatment of electron-beam evaporated niobium for low-loss coplanar waveguide resonators
• An engineering guide to superconducting quantum circuit shielding