J. Brewster

Optical Direct Write of Dolan-Bridge Junctions for Transmon Qubits

  1. J. T. Monroe,
  2. D. Kowsari,
  3. K. Zheng,
  4. J. Brewster,
  5. D. S. Wisbey,
  6. and K. W. Murch
We characterize highly coherent transmon qubits fabricated with a direct-write photolithography system. Multi-layer evaporation and oxidation allows us to tune the Josephson energy
by reducing the effective tunneling area and increasing the barrier thickness. Surface treatments before resist application and again before evaporation reduce the occurrence of strongly-coupled two-level system fluctuators, resulting in high coherence devices. With optimized surface treatments we achieve energy relaxation T1 times in excess of 80 μs for three dimensional transmon qubits with Josephson junction lithographic areas of 2 μm2.
arxiv pdf