Improving stability in two-dimensional transistors with amorphous gate oxides by Fermi-level tuning

Nature Electronics, vol. 5, pp. 356–366

Abstract

Electronic devices based on two-dimensional semiconductors suffer from limited electrical stability because charge carriers originating from the semiconductors interact with defects in the surrounding insulators. In field-effect transistors, the resulting trapped charges can lead to large hysteresis and device drifts, particularly when common amorphous gate oxides (such as silicon or hafnium dioxide) are used, hindering stable circuit operation. Here, we show that device stability in graphene-based field-effect transistors with amorphous gate oxides can be improved by Fermi-level tuning. We deliberately tune the Fermi level of the channel to maximize the energy distance between the charge carriers in the channel and the defect bands in the amorphous aluminium gate oxide. Charge trapping is highly sensitive to the energetic alignment of the Fermi level of the channel with the defect band in the insulator, and thus, our approach minimizes the amount of electrically active border traps without the need to reduce the total number of traps in the insulator.

Authors 10

1. Theresia Knobloch

   TU Wien

   Affiliation as printed

   Institute for Microelectronics, TU Wien, Vienna, Austria

2. Burkay Uzlu Aachen AMO GmbH Chair of Electronic Devices

   AMO (Germany) · RWTH Aachen University

   Affiliation as printed

   AMO GmbH, Aachen, Germany

   Chair of Electronic Devices, RWTH Aachen University, Aachen, Germany

3. Yu. Yu. Illarionov corresponding

   TU Wien · Ioffe Institute

   Affiliation as printed

   Institute for Microelectronics, TU Wien, Vienna, Austria

   Ioffe Institute, Saint Petersburg, Russia

4. Zhenxing Wang Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH, Aachen, Germany

5. Martin Otto Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH, Aachen, Germany

6. Lado Filipovic

   TU Wien

   Affiliation as printed

   Institute for Microelectronics, TU Wien, Vienna, Austria

7. Michael Waltl

   TU Wien

   Affiliation as printed

   Christian Doppler Laboratory for Single-Defect Spectroscopy in Semiconductor Devices at the Institute for Microelectronics, TU Wien, Vienna, Austria

8. Daniel Neumaier Aachen AMO GmbH

   University of Wuppertal · AMO (Germany)

   Affiliation as printed

   AMO GmbH, Aachen, Germany

   Chair of Smart Sensor Systems, University of Wuppertal, Wuppertal, Germany

9. Max C. Lemme Aachen AMO GmbH Chair of Electronic Devices

   AMO (Germany) · RWTH Aachen University

   Affiliation as printed

   AMO GmbH, Aachen, Germany

   Chair of Electronic Devices, RWTH Aachen University, Aachen, Germany

10. Tibor Grasser corresponding

    TU Wien

    Affiliation as printed

    Institute for Microelectronics, TU Wien, Vienna, Austria