Presentation Information

2:30 PM - 2:45 PM JST(5:30 AM - 5:45 AM UTC)

[9p-N304-5]Superconducting Transmon Qubits with Sidewall Spacer Passivated Fully Epitaxial NbN/AlN/NbN Junctions

〇(M2)Koki Honda¹, Daiki Kurihara¹, Tokunoshin Uchida¹, Hiroki Kutsuma¹, Hirotaka Terai², Taro Yamashita¹ (1.Tohoku Univ., 2.NICT)

Keywords:

superconducting qubit,sidewall spacer structure,NbN/AlN/NbN Josephson junction

In the NbN/AlN/NbN junctions, TLS-induced decoherence is expected to be reduced by utilizing a crystallized aluminum nitride (AlN) tunnel barrier. On the other hand, it has been pointed out that their complex fabrication process may have suppressed their coherence properties. To resolve this issue, in this work we focused on the sidewall spacer structure, which was recently used for the Nb-based qubits with improved coherence properties. We fabricated superconducting transmon qubits with sidewall spacer passivated NbN/AlN/NbN junctions. We will discuss the details of the fabrication process and the measurement results of transmon qubits with these junctions.

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