Fabrication process and failure analysis for robust quantum dots in silicon

ORAL

Abstract

We investigate several yield limiting steps in the fabrication of overlapping aluminum gate quantum dot devices in Si/SiGe. The thin, ~2 nm oxide that grows natively on aluminum and low thermal budget of aluminum devices presents a challenge for fabrication of quantum dot arrays with high yield. Gate-to-gate leakage from pinholing of the aluminum oxide, damage from electrostatic discharge (ESD), low breakdown voltages and gate geometry/morphology all present a significant risk of device failure in the active region. Additionally, dewetting of aluminum and formation of alloys during fabrication of interconnects from the active region of the device to the bond pads can result in failure of electrical signal transmission. We present low-temperature oxidation techniques for a thicker aluminum oxide with breakdown voltages of over 4 volts, reducing the risk of damage due to ESD and gate-to-gate leakage. TEM images of overlapping gate structures identify failure modes stemming from gate geometry/morphology. Finally, we investigate the fabrication of interconnects between the active region and device bond pads to introduce thermal anneals into the fabrication process, prevent damage due to ESD, and to identify the maximum processing temperature at different stages of device fabrication.

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Presenters

  • John Dodson

    • University of Wisconsin - Madison

Authors

  • John Dodson

    • University of Wisconsin - Madison

  • Nathan Holman

    • University of Wisconsin - Madison
    • Department of Physics, University of Wisconsin-Madison, Madison WI, USA

  • Brandur Thorgrimsson

    • University of Wisconsin - Madison

  • Samuel Neyens

    • Department of Physics, University of Wisconsin-Madison, Madison WI, USA
    • University of Wisconsin - Madison
    • Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA

  • Evan R MacQuarrie

    • University of Wisconsin - Madison
    • Department of Physics, University of Wisconsin-Madison, Madison WI, USA
    • Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA

  • Ryan H Foote

    • University of Wisconsin - Madison

  • Thomas McJunkin

    • University of Wisconsin - Madison
    • Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA

  • Lisa F Edge

    • HRL
    • HRL laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA
    • HRL Laboratories
    • HRL Laboratories LLC, 3011 Malibu Canyon Road, Malibu, California 90265, USA
    • HRL Laboratories, LLC

  • Susan Nan Coppersmith

    • University of Wisconsin - Madison
    • University of New South Wales, Sydney, Australia
    • Department of Physics, University of Wisconsin-Madison
    • University of Wisconsin-Madison
    • University of New South Wales
    • University of Wisconsin-Madison, The University of New South Wales

  • Mark Alan Eriksson

    • University of Wisconsin - Madison
    • Physics, University of Wisconsin - Madison, Madison, WI USA
    • Department of Physics, University of Wisconsin-Madison, Madison WI, USA
    • Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA
    • University of Wisconsin-Madison