Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2023
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866909329720868864 |
|---|---|
| author | Biznárová, Janka Osman, Amr Rehnman, Emil Chayanun, Lert Križan, Christian Malmberg, Per Rommel, Marcus Warren, Christopher Delsing, Per Yurgens, August Bylander, Jonas Roudsari, Anita Fadavi |
| author_facet | Biznárová, Janka Osman, Amr Rehnman, Emil Chayanun, Lert Križan, Christian Malmberg, Per Rommel, Marcus Warren, Christopher Delsing, Per Yurgens, August Bylander, Jonas Roudsari, Anita Fadavi |
| contents | We demonstrate aluminum-on-silicon planar transmon qubits with time-averaged ${T_1}$ energy relaxation times of up to ${270\,μs}$, corresponding to Q = 5 million, and a highest observed value of ${501\,μs}$. We use materials analysis techniques and numerical simulations to investigate the dominant sources of energy loss, and devise and demonstrate a strategy towards mitigating them. The mitigation of loss is achieved by reducing the presence of oxide, a known host of defects, near the substrate-metal interface, by growing aluminum films thicker than 300 nm. A loss analysis of coplanar-waveguide resonators shows that the improvement is owing to a reduction of dielectric loss due to two-level system defects. We perform time-of-flight secondary ion mass spectrometry and observe a reduced presence of oxygen at the substrate-metal interface for the thicker films. The correlation between the enhanced performance and the film thickness is due to the tendency of aluminum to grow in columnar structures of parallel grain boundaries, where the size of the grain depends on the film thickness: transmission electron microscopy imaging shows that the thicker film has larger grains and consequently fewer grain boundaries containing oxide near this interface. These conclusions are supported by numerical simulations of the different loss contributions in the device. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_06797 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits Biznárová, Janka Osman, Amr Rehnman, Emil Chayanun, Lert Križan, Christian Malmberg, Per Rommel, Marcus Warren, Christopher Delsing, Per Yurgens, August Bylander, Jonas Roudsari, Anita Fadavi Quantum Physics Superconductivity We demonstrate aluminum-on-silicon planar transmon qubits with time-averaged ${T_1}$ energy relaxation times of up to ${270\,μs}$, corresponding to Q = 5 million, and a highest observed value of ${501\,μs}$. We use materials analysis techniques and numerical simulations to investigate the dominant sources of energy loss, and devise and demonstrate a strategy towards mitigating them. The mitigation of loss is achieved by reducing the presence of oxide, a known host of defects, near the substrate-metal interface, by growing aluminum films thicker than 300 nm. A loss analysis of coplanar-waveguide resonators shows that the improvement is owing to a reduction of dielectric loss due to two-level system defects. We perform time-of-flight secondary ion mass spectrometry and observe a reduced presence of oxygen at the substrate-metal interface for the thicker films. The correlation between the enhanced performance and the film thickness is due to the tendency of aluminum to grow in columnar structures of parallel grain boundaries, where the size of the grain depends on the film thickness: transmission electron microscopy imaging shows that the thicker film has larger grains and consequently fewer grain boundaries containing oxide near this interface. These conclusions are supported by numerical simulations of the different loss contributions in the device. |
| title | Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits |
| topic | Quantum Physics Superconductivity |
| url | https://arxiv.org/abs/2310.06797 |