Analyzing TLS across Josephson Junction process parameters

Two-level systems (TLS) losses are understood to be a product of energetic states in amorphous materials in and around qubits. The impact of TLSs within the Josephson Junction is related to the amount of barrier oxide and the oxidation parameter used to create the barrier. Since TLS within the barrier are likely to be more strongly coupled to the qubit than those on other interfaces and surfaces, optimizing the junction barrier for TLS, and not just for frequency targeting, is an important consideration for qubit performance. We will show how changes in Josephson Junction oxidation exposure parameter and junction oxide volume affect the landscape and coupling strengths of coherent and incoherent TLS across a significant number of flux-tunable qubits, and attempt to disentangle the volume contribution from oxidation exposure parameter.