Si/SiGe quantum dot with superconducting single-electron transistor charge sensor

摘要

We report a robust process for fabrication of surface-gated Si/SiGe quantumdots (QDs) with an integrated superconducting single-electron transistor(S-SET) charge sensor. A combination of a deep mesa etch and AlOx backfill isused to reduce gate leakage. After the leakage current is suppressed, Coulomboscillations of the QD and the current-voltage characteristics of the S-SET areobserved at a temperature of 0.3 K. Coupling of the S-SET to the QD isconfirmed by using the S-SET to perform sensing of the QD charge state.