Implementation of scalable suspended superinductors

  1. Christian Jünger,
  2. Trevor Chistolini,
  3. Long B. Nguyen,
  4. Hyunseong Kim,
  5. Larry Chen,
  6. Thomas Ersevim,
  7. William Livingston,
  8. Gerwin Koolstra,
  9. David I. Santiago,
  10. and Irfan Siddiqi
Superinductors have become a crucial component in the superconducting circuit toolbox, playing a key role in the development of more robust qubits. Enhancing the performance of these
devices can be achieved by suspending the superinductors from the substrate, thereby reducing stray capacitance. Here, we present a fabrication framework for constructing superconducting circuits with suspended superinductors in planar architectures. To validate the effectiveness of this process, we systematically characterize both resonators and qubits with suspended arrays of Josephson junctions, ultimately confirming the high quality of the superinductive elements. In addition, this process is broadly compatible with other types of superinductors and circuit designs. Our results not only pave the way for scalable novel superconducting architectures but also provide the primitive for future investigation of loss mechanisms associated with the device substrate.