In-situ bandaged Josephson junctions for superconducting quantum processors

Abstract

Shadow evaporation is commonly used to micro-fabricate the key element of superconducting qubits - the Josephson junction. However, in conventional two-angle deposition circuit topology, unwanted stray Josephson junctions are created which contribute to dielectric loss. So far, this could be avoided by shorting the stray junctions with a so-called bandage layer deposited in an additional lithography step, which may further contaminate the chip surface. Here, we present an improved shadow evaporation technique allowing one to fabricate sub-micrometer-sized Josephson junctions together with bandage layers in a single lithography step. We also show that junction aging is significantly reduced when junction electrodes are oxidized in an oxygen atmosphere directly after deposition.

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Cited by in corpus (9)

• Path toward manufacturable superconducting qubits with relaxation times exceeding 0.1 ms
• TOF-SIMS Analysis of Decoherence Sources in Nb Superconducting Resonators
• Probing defect densities at the edges and inside Josephson junctions of superconducting qubits
• Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields
• Tunable coupling of widely separated superconducting qubits: A possible application towards a modular quantum device
• Fermion-Parity-Based Computation and its Majorana-Zero-Mode Implementation
• Strain-spectroscopy of strongly interacting defects in superconducting qubits
• Material matters in superconducting qubits
• A practical guide for building superconducting quantum devices