Fabrication of Superconducting Resonators on hBN Thin Films

Student’s name: River Chen Home Institution: University of Illinois at Urbana-Champaign NNCI Site: CNF @ Cornell University REU Principal Investigator: Professor Zhiting Tian REU Mentor: Joyce Christiansen-Salameh Abstract: 2D materials have attracted much attention due to their unique physical and chemical properties. Here we investigate the integration of a thin film grown of one of these 2D materials, hexagonal Boron Nitride (hBN), into a superconducting device. We believe that hBN will be compatible with the device because of its low dielectric loss tangent. The device, a coplanar waveguide resonator, was designed for high sensitivity to loss at the metal-substrate interface, allowing us to compare loss between a device with hBN and without. We fabricate a Nb on hBN on sapphire resonator and compare it to a standard Nb on sapphire resonator. The fabrication process was performed at the Cornell Nanoscale Facility at Cornell University, using the AJA sputter deposition tool, ABM Contact Mask Aligner, and Plasmatherm 770 Etcher. In this work, we explore the various adjustments made in order to accommodate and prevent damage to the hBN substrate. Additionally, certain adjustments to the device design were made in order to accommodate the testing platform at Fermilab.