Digging deeper: Buried layers and interfaces studied by modified total electron yield and soft x-ray absorption spectroscopy

Applied Physics Letters, vol. 120

Abstract

We report on the soft x-ray absorption spectroscopy investigation of thin film capacitors using a modified total electron yield detection mode. This mode utilizes two ammeters instead of one as commonly employed in the classical total electron yield scheme to measure photocurrents of devices under soft x-ray irradiation. The advantage of this configuration over the surface sensitive classical total electron yield mode is that it can provide information from buried layers and interfaces up to a thickness equal to the penetration depth of soft x-rays. The method can be easily adapted to existing synchrotron end stations. We investigate dielectric capacitors with dissimilar electrodes to assess the feasibility of the modified total electron yield method. Furthermore, in operando soft x-ray absorption spectroscopy measurements are performed on ferroelectric capacitors under bias and using two ammeters. The experimental results are discussed in terms of the external and internal photoemission processes and their distribution in thin film capacitors under an external bias condition. The proposed detection method opens the way to perform electronic and chemical state analyses of the buried interfaces and layers in various devices like multiferroic tunnel junctions, memristive devices, etc., during operation under an applied bias.

Authors 15

1. E. Kröger

   Christian-Albrechts-Universität zu Kiel

   Affiliation as printed

   Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel 1 , 24098 Kiel, Germany

2. A. Petraru

   Christian-Albrechts-Universität zu Kiel

   Affiliation as printed

   Nanoelektronik, Technische Fakultät Kiel, Christian-Albrechts-Universität zu Kiel 2 , 24143 Kiel, Germany

3. A. Hanff

   Christian-Albrechts-Universität zu Kiel

   Affiliation as printed

   Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel 1 , 24098 Kiel, Germany

4. Rohit Soni

   Indian Institute of Science Education and Research Berhampur

   Affiliation as printed

   Department of Physical Sciences, Indian Institute of Science Education and Research Berhampur 3 , Berhampur 760010, India

5. M. Kalläne

   Christian-Albrechts-Universität zu Kiel

   Affiliation as printed

   Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel 1 , 24098 Kiel, Germany

   Ruprecht-Haensel-Labor, Christian-Albrechts-Universität zu Kiel 4 , 24098 Kiel, Germany

6. Jonathan D. Denlinger

   Lawrence Berkeley National Laboratory · Advanced Light Source

   Affiliation as printed

   Advanced Light Source, Lawrence Berkeley National Laboratory 5 , Berkeley, California 94720, USA

7. Timothy Learmonth

   Boston University

   Affiliation as printed

   Department of Physics, Boston University 6 , Boston, Massachusetts 02215, USA

8. Jinghua Guo

   Lawrence Berkeley National Laboratory · Advanced Light Source

   Affiliation as printed

   Advanced Light Source, Lawrence Berkeley National Laboratory 5 , Berkeley, California 94720, USA

9. Kevin E. Smith

   Boston University

   Affiliation as printed

   Department of Physics, Boston University 6 , Boston, Massachusetts 02215, USA

10. Theodor Schneller Aachen Institute for Materials in Electrical Engineering (IWE2)

    Jülich Aachen Research Alliance · RWTH Aachen University

    Affiliation as printed

    Institute for Materials in Electrical Engineering (IWE2), and Jülich Aachen Research Alliance for Future Information Technology (JARA-FIT), RWTH Aachen University 7 , 52074 Aachen, Germany

11. Byron Freelon

    University of Houston

    Affiliation as printed

    Department of Physics and Texas Center for Superconductivity, University of Houston 8 , Houston, Texas 77004, USA

12. Lutz Kipp

    Deutsches Elektronen-Synchrotron DESY · Christian-Albrechts-Universität zu Kiel

    Affiliation as printed

    Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel 1 , 24098 Kiel, Germany

    Ruprecht-Haensel-Labor, Christian-Albrechts-Universität zu Kiel 4 , 24098 Kiel, Germany

    Ruprecht-Haensel-Labor, Deutsches Elektronen-Synchrotron DESY 9 , 22607 Hamburg, Germany

13. H. Kohlstedt corresponding

    Christian-Albrechts-Universität zu Kiel

    Affiliation as printed

    Nanoelektronik, Technische Fakultät Kiel, Christian-Albrechts-Universität zu Kiel 2 , 24143 Kiel, Germany

14. Kai Roßnagel

    Deutsches Elektronen-Synchrotron DESY · Christian-Albrechts-Universität zu Kiel

    Affiliation as printed

    Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel 1 , 24098 Kiel, Germany

    Ruprecht-Haensel-Labor, Christian-Albrechts-Universität zu Kiel 4 , 24098 Kiel, Germany

    Ruprecht-Haensel-Labor, Deutsches Elektronen-Synchrotron DESY 9 , 22607 Hamburg, Germany

15. Gitanjali Kolhatkar

    Christian-Albrechts-Universität zu Kiel

    Affiliation as printed

    Nanoelektronik, Technische Fakultät Kiel, Christian-Albrechts-Universität zu Kiel 2 , 24143 Kiel, Germany