Advancements in Low-Loss Capacitors for Quantum Computing Applications

Recent advancements in superconducting quantum information technology have been bolstered by the development of low-loss parallel plate capacitors. A research paper titled "Fabrication and characterization of low-loss Al/Si/Al parallel plate capacitors for superconducting quantum information applications" by Anthony McFadden and colleagues presents significant findings in this area.

The study focuses on the fabrication of high aspect ratio silicon fins, which are used to create capacitors with widths below 300 nm and a total height of approximately 3 μm. These capacitors are made using anisotropic wet etching of Si(110) substrates followed by aluminum metallization. The research indicates that these single-crystal silicon capacitors can be integrated into lumped element resonators and transmon qubits, enhancing their performance.

Key results from the microwave characterization of these devices show that they achieve a low power internal quality factor greater than 500,000 for lumped element resonators. Additionally, the qubit $T_1$ times exceed 25 μs, suggesting that these capacitors are suitable for applications requiring low loss and compact designs with minimal stray capacitance.

The implications of these findings are substantial for the future of superconducting circuits, as they may lead to more efficient and compact quantum computing components. The research highlights the potential of Si-Fins technology in advancing the capabilities of superconducting quantum information systems.

For further details, the full paper can be accessed at arXiv:2408.01369.