Optical direct write of Dolan–Niemeyer-bridge junctions for transmon qubits

We characterize highly coherent transmon qubits fabricated with a direct-write photolithography system. Multi-layer evaporation and oxidation allows us to change the critical current density by reducing effective tunneling area increasing barrier thickness. Surface treatments before resist application again result in high coherence devices. With optimized surface we achieve energy relaxation $T_1$ times excess of $80\ \mu$s for three dimensional Josephson junction lithographic areas 2 $\mu\mathrm{m}^2$.