Photolithography-Only Fabrication of Transmons Using Double-Oblique Evaporation

• URL: http://arxiv.org/abs/2605.19590v1
• Date: Tue, 19 May 2026 09:31:29 GMT
• Title: Photolithography-Only Fabrication of Transmons Using Double-Oblique Evaporation
• Abstract summary: We fabricate transmon Josephson junctions using a modified double-oblique evaporation geometry.<n>Results demonstrate the feasibility of realizing functional transmon devices in a photolithography-only process.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We investigate a photolithography-only fabrication process for transmon Josephson junctions using a modified double-oblique evaporation geometry. Using a bilayer resist process and Al shadow evaporation, we fabricate junction structures and confirm by optical and scanning electron microscopy that the resulting narrowed crossing region reaches a geometrical area on the order of $10^4~\mathrm{nm}^2$, which lies in the size range relevant to qubit junction fabrication. Room-temperature resistance screening shows that the junction resistance falls within the target range for the present transmon design over a usable process window and exhibits a clear design dependence. We further implement fabricated junctions in transmon devices and evaluate them in a three-dimensional Al cavity at $20 \, \mathrm{mK}$, where we observe basic transmon qubit operation with $f_{01}$=4.865 GHz, $T_1 \sim 9 \, μ\mathrm{s}$, and $T_2^* \sim 0.4 \, μ\mathrm{s}$. These results demonstrate the feasibility of realizing functional transmon devices in a photolithography-only process using double-oblique evaporation.

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