Resonator Cavities Compatible with Epitaxial InAs-Al Heterostructures*

Epitaxial Al-InAs structures are prime candidates for tunable superconducting qubits, the so-called
“gatemon” where the Josephson energy can be tuned in-situ with an applied electric field to an InAs Josephson junction, eliminating the need for flux tuning in superconducting qubits [1]. Here we have characterized microwave cavities needed for coupling to superconducting gatemon qubits. We present resonator quality factors for a fixed design on various levels of the buffer layers used as substrates. We make a comparison to bare InP and Si to establish a comparative baseline.
[1] Larsen et al., Phys. Rev. Lett. 115, 127001 (2015).