2014 Fiscal Year Research-status Report
全窒化物誘電体材料と基板を用いたエピタキシャル超伝導量子ビットの作製
| Project/Area Number |
25420352
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| Research Institution | National Institute of Information and Communications Technology |
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Principal Investigator |
丘 偉 独立行政法人情報通信研究機構, 未来ICT研究所 ナノICT研究室, 研究員 (90535189)
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Keywords | Superconducting / TiN / Al / CPW / quality factor / dielectri loss |
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| Outline of Annual Research Achievements |
We studied the dielectric losses of superconducting microwave resonator by developing aluminum (Al) thin-film coplanar waveguide resonator fabricated by sputtering and thermal evaporation methods. And it only shows limited improvement of the dielectric loss compare to the previously studied NbN resonator. TiN (200) thin-film resonators fabricated on Si substrate with the heated substrate temperature show the quality factor obtained was high as 5.0x10+5 at the temperature of 300 mK.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Thin-film superconducting CPW resonators have been developed by using both Al- and TiN-based superconducting materials. Al-based resonators were fabricated by both dc-sputtering and thermal evaporation methods and only show limited improvement of dielectric loss compare to NbN-based resonator. TiN (200) thin-film resonator grown on hydrogen-terminated Si substrate show a significant loss improvement from 1x10-3 of NbN-based resonator to 2x10-6 measured at the temperature of 300mK.
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| Strategy for Future Research Activity |
Although the dielectric loss of TiN-based thin-film resonator is very low, it is very difficult to obtain high quality TiN/AlN/TiN Josephson junctions, thus full qubit circuit based on the current available fabrication process of TiN. Future study will be focused on development of trilayer structure process for Josephson junction circuit while maintain the low dielectric loss contribution from base-layer superconducting and substrate materials.
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| Causes of Carryover |
The incurred amount from last fiscal year was due to the cancellation of a scheduled international conference due to the longer than expected visa issue.
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| Expenditure Plan for Carryover Budget |
The incurred amount will be used to cover the extra cost of the international conference in Europe due to the weakness of yen.
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Research Products
(5 results)
