Related papers: Development of transmon qubits solely from optical…
We investigate a photolithography-only fabrication process for transmon Josephson junctions using a modified double-oblique evaporation geometry. Using a bilayer resist process and Al shadow evaporation, we fabricate junction structures and…
We introduce a simplified fabrication technique for Josephson junctions and demonstrate superconducting Xmon qubits with $T_1$ relaxation times averaging above 50$~\mu$s ($Q>$1.5$\times$ 10$^6$). Current shadow-evaporation techniques for…
Improvements in circuit design and more recently in materials and surface cleaning have contributed to a rapid development of coherent superconducting qubits. However, organic resists commonly used for shadow evaporation of Josephson…
We present the results of an industry-grade fabrication of superconducting qubits on 200 mm wafers utilizing CMOS-established processing methods. By automated waferprober resistance measurements at room temperature, we demonstrate a…
The development of superconducting qubit technology has shown great potential for the construction of practical quantum computers. As the complexity of quantum processors continues to grow, the need for stringent fabrication tolerances…
Superconducting qubits are among the most promising platforms for realizing practical quantum computers. One requirement to create a quantum processor is nonlinearity, which in superconducting circuits is typically achieved by sandwiching a…
Quantum bits, or qubits, are an example of coherent circuits envisioned for next-generation computers and detectors. A robust superconducting qubit with a coherent lifetime of $O$(100 $\mu$s) is the transmon: a Josephson junction…
Reducing materials and processing-induced decoherence is critical to the development of utility-scale quantum processors based on superconducting qubits. Here we report on the impact of two fluorine-based wet etches, which we use to treat…
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…
We present the fabrication and characterization of transmon qubits formed from aluminum Josephson junctions on two different silicon-based substrates: (i) high-resistivity silicon (Si) and (ii) silicon-on-insulator (SOI). Key to the qubit…
As the superconducting qubit platform matures towards ever-larger scales in the race towards a practical quantum computer, limitations due to qubit inhomogeneity through lack of process control become apparent. To benefit from the advanced…
State-of-the-art transmon qubits rely on large capacitors which systematically improves their coherence due to reduced surface loss participation. However, this approach increases both the footprint and the parasitic cross-coupling and is…
Quantum processors using superconducting qubits suffer from dielectric loss leading to noise and dissipation. Qubits are usually designed as large capacitor pads connected to a non-linear Josephson junction (or SQUID) by a superconducting…
Transmon qubits are ubiquitous in the pursuit of quantum computing using superconducting circuits. However, they have some drawbacks that still need to be addressed. Most importantly, the scalability of transmons is limited by the large…
By using the dry etching process of tantalum (Ta) film, we had obtained transmon qubit with the best lifetime (T1) 503 us, suggesting that the dry etching process can be adopted in the following multi-qubit fabrication with Ta film. We also…
Despite the fact that the resolution of conventional contact/proximity lithography can reach feature sizes down to ~0.5-0.6 micrometers, the accurate control of the linewidth and uniformity becomes already very challenging for gratings with…
The reproducibility of qubit parameters is a challenge for scaling up superconducting quantum processors. Signal crosstalk imposes constraints on the frequency separation between neighboring qubits. The frequency uncertainty of transmon…
Despite mounting evidence that materials imperfections are a major obstacle to practical applications of superconducting qubits, connections between microscopic material properties and qubit coherence are poorly understood. Here, we perform…
Scalability in the fabrication and operation of quantum computers is key to move beyond the NISQ era. So far, superconducting transmon qubits based on aluminum Josephson tunnel junctions have demonstrated the most advanced results, though…
We report a comparative study on transmon qubit control using (i) conventional attenuated coaxial microwave line and (ii) an optical control system using modulated laser light delivered over telecommunications optical fiber to a photodiode…