第一列
Many challenges remain to improve qubit performance due to material and interface issues. This project will tackle the most challenging issues in superconducting qubits, which include the growth of high-quality superconducting thin films, high-quality oxide barriers, and related heterostructures, the superconducting measurements, and the fabrication/analysis of the Josephson junctions, the resonators, the high impedance circuits, and the qubits. The perfection of material growth, device fabrication, and measurements are the keys to realizing high-quality superconducting qubit devices.
High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of cross-sectional views of the MBE-grown epi-Al/sapphire heterostructure (bottom left) and the in situ deposited Al2O3/epi-Al heterostructure (top left). In this study, the superconducting microwave oscillators fabricated using various materials and processes achieved a quality factor of over one million at low power (right).
-
Co-PI
-
Minghwei Hong (National Taiwan University)
-
Juhn-Jong Lin (National Yang Ming Chiao Tung University)
High-Quality Superconducting Material Growth and Device Fabrication
- This technology aims to solve the following problems:
To address the issue of energy dissipation caused by materials and interface imperfection in superconducting qubits, which leads to a reduction in quantum coherence time.
- Importance/Breakthrough:
In this research, high-quality superconducting thin films and protective layers are grown using molecular beam epitaxy within an ultra-high vacuum chamber. Device processing techniques are developed, enabling microwave oscillator devices made from various materials to achieve a quality factor of over one million.
- Relevance to the future research directions of the project:
The quality factor of microwave oscillator devices is directly related to the coherence time of the constructed superconducting qubits. Using the materials and processing techniques from this technology can produce superconducting qubits with high coherence times, which can directly reduce error rates and improve performance.
High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of cross-sectional views of the MBE-grown epi-Al/sapphire heterostructure (left) and the in situ deposited Al2O3/epi-Al heterostructure (right). A schematic representation of the heterostructure (center) shows the orientations of the epi-Al film and the sapphire substrate. This demonstrates the high quality of the materials and interfaces for our superconducting qubit devices.