Al transmon qubits on silicon-on-insulator for quantum device integration

Andrew J. Keller, Paul B. Dieterle, Michael Fang, Brett Berger, Johannes M. Fink, Oskar Painter
2017 Applied Physics Letters  
We present the fabrication and characterization of transmon qubits formed from aluminum Josephson junctions on two different silicon-based substrates: (i) high-resistivity silicon (Si) and (ii) silicon-on-insulator (SOI). Key to the qubit fabrication process is the use of an anhydrous hydrofluoric vapor process which removes silicon surface oxides without attacking aluminum, and in the case of SOI substrates, selectively removes the lossy buried oxide underneath the qubit region. For qubits
more » ... a transition frequency of approximately 5GHz we find qubit lifetimes and coherence times comparable to those attainable on sapphire substrates (T_1,Si = 27μs, T_2,Si = 6.6μs; T_1,SOI = 3.5μs, T_2,SOI = 2.2μs). This qubit fabrication process in principle permits co-fabrication of silicon photonic and mechanical elements, providing a route towards chip-scale integration of electro-opto-mechanical transducers for quantum networking of superconducting microwave quantum circuits.
doi:10.1063/1.4994661 fatcat:cbdbnxgwf5ezjp6vmdzjqd53pu