Interface Structures and Electrical Properties of Micro-Fabricated Epitaxial Hf-Digermanide/n-Ge(001) Contacts

We investigated the interface crystalline structures and electrical conduction properties of epitaxial Hf-digermanide(HfGe 2 )/ {n} -Ge(001) contacts with different electrode sizes of 20, 45, and 90~{\mu }\text{m} prepared via microfabrication. It was found that the microfabrication process improv...

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Bibliographic Details
Published in:IEEE journal of the Electron Devices Society 2022-01, Vol.10, p.744-750
Main Authors: Kasahara, Kentaro, Senga, Kazuki, Sakashita, Mitsuo, Shibayama, Shigehisa, Nakatsuka, Osamu
Format: Article
Language:English
Subjects:
Capacitance-voltage characteristics
Diffraction
Dipoles
Electric contacts
Electrical conduction
Electrical properties
Electrodes
Epitaxial growth
epitaxy
Field emission
Germanium
Handheld computers
metal/semiconductor contact
Microfabrication
Schottky barrier height
Strain relaxation
Substrates
Temperature dependence
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Summary:We investigated the interface crystalline structures and electrical conduction properties of epitaxial Hf-digermanide(HfGe 2 )/ {n} -Ge(001) contacts with different electrode sizes of 20, 45, and 90~{\mu }\text{m} prepared via microfabrication. It was found that the microfabrication process improved the interface uniformity of the HfGe 2 / {n} -Ge(001) contacts. Detailed transmission electron microscopy analysis confirmed the growth of epitaxial HfGe 2 on Ge(001) and implied that microfabrication suppressed the strain relaxation of HfGe 2 . These results imply that the applied strain of the epitaxial HfGe 2 , which was controlled via microfabrication in this study, is a possible parameter that may be used to improve the interface uniformity HfGe 2 / {n} -Ge(001) contacts. The Schottky barrier heights (SBHs) of the HfGe 2 / {n} -Ge(001) contacts estimated from the capacitance-voltage characteristics were small and in the range of 0.4 to 0.5 eV independent of the electrode size. Furthermore, considering the temperature dependence of the current density-voltage characteristics, we found that both the thermionic field emission current and the tunneling current through the interface dipole layer were possibly flowed in series and that the SBH for the 20~{\mu }\text{m} sample was 0.24 eV, whereas those for both the 45 and 90~{\mu }\text{m} samples were 0.31 eV.
ISSN:2168-6734
2168-6734
DOI:10.1109/JEDS.2021.3139728