Thermal oxidation of Si/SiGe heterostructures for use in quantum dot qubits

ORAL

Abstract

Here we demonstrate dry thermal oxidation of a Si/SiGe heterostructure at 700$^{\circ}$C and use a Hall bar device to measure the mobility after oxidation to be 43,000 cm$^{2}$V$^{-1}$s$^{-1}$ at a carrier density of 4.1$\times$10$^{11}$ cm$^{-2}$. Surprisingly, we find no significant reduction in mobility compared with an Al$_{2}$O$_{3}$ device made with atomic layer deposition on the same heterostructure, indicating thermal oxidation can be used to process Si/SiGe quantum dot devices. This result provides a path for investigating improvements to the gate oxide in Si/SiGe qubit devices, whose performance is believed to be limited by charge noise in the oxide layer. This work was supported in part by ARO (W911NF-12-0607) and NSF (DMR-1206915 and PHY-1104660). Development and maintenance of the growth facilities used for fabricating samples is supported by DOE (DE-FG02-03ER46028). This research utilized NSF-supported shared facilities at the University of Wisconsin-Madison.

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Authors

  • Samuel F. Neyens

    Wisconsin Institute for Quantum Information, University of Wisconsin-Madison

  • Ryan H. Foote

    University of Wisconsin-Madison, Wisconsin Institute for Quantum Information, University of Wisconsin-Madison

  • T. J. Knapp

    Wisconsin Institute for Quantum Information, University of Wisconsin-Madison, University of Wisconsin: Madison

  • Thomas McJunkin

    Wisconsin Institute for Quantum Information, University of Wisconsin-Madison

  • D. E. Savage

    University of Wisconsin-Madison, University of Wisconsin Madison, Wisconsin Institute for Quantum Information, University of Wisconsin-Madison

  • M. G. Lagally

    University of Wisconsin-Madison, University of Wisconsin Madison, Wisconsin Institute for Quantum Information, University of Wisconsin-Madison

  • S. N. Coppersmith

    University of Wisconsin, Madison, University of Wisconsin-Madison, University of Wisconsin-Madison, Madison, WI 53706, USA, Univ of Wisconsin, Madison, University of Wisconsin Madison, Wisconsin Institute for Quantum Information, University of Wisconsin-Madison

  • M. A. Eriksson

    University of Wisconsin-Madison, University of Wisconsin Madison, Wisconsin Institute for Quantum Information, University of Wisconsin-Madison