Free-standing silicon shadow masks for transmon qubit fabrication

Understand

Nanofabrication techniques for superconducting qubits rely on resist-based masks patterned by electron-beam or optical lithography.

• We have developed an alternative nanofabrication technique based on free-standing silicon shadow masks fabricated from silicon-on-insulator wafers.
• These silicon shadow masks not only eliminate organic residues associated with resist-based lithography, but also provide a pathway to better understand and control surface-dielectric losses in superconducting qubits by decoupling mask fabrication from substrate preparation.
• We have successfully fabricated aluminum 3D transmon superconducting qubits with these shadow masks and found coherence quality factors comparable to those fabricated with standard techniques.