Si/SiGe quantum dot with superconducting single-electron transistor   charge sensor
  We report a robust process for fabrication of surface-gated Si/SiGe quantum dots (QDs) with an integrated superconducting single-electron transistor (S-SET) charge sensor. A combination of a deep mesa etch and AlOx backfill is used to reduce gate leakage. After the leakage current is suppressed, Coulomb oscillations of the QD and the current-voltage characteristics of the S-SET are observed at a temperature of 0.3 K. Coupling of the S-SET to the QD is confirmed by using the S-SET to perform sensing of the QD charge state. 
Mingyun Yuan, Feng Pan, Zhen Yang, T. J. Gilheart, Fei Chen, D. E.   Savage, M. G. Lagally, M. A. Eriksson, and A. J. Rimberg
cond-mat.mes-hall