Electrical and structural properties of group-4 transition-metal nitride (TiN, ZrN, and HfN) contacts on Ge

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Abstract

Electrical and structural properties were investigated for group-4 transition-metal nitride contacts on Ge (TiN/Ge, ZrN/Ge, and HfN/Ge), which were prepared by direct sputter depositions using nitride targets. These contacts could alleviate the intrinsic Fermi-level pinning (FLP) position toward the conduction band edge. It was revealed that this phenomenon is induced by an amorphous interlayer (a-IL) containing nitrogen atoms at the nitride/Ge interfaces. The strength of FLP alleviation positively depended on the thickness of a-IL. TiN/Ge and ZrN/Ge contacts with ∼2 nm-thick a-ILs showed strong FLP alleviations with hole barrier heights (ΦBP) in the range of 0.52-56 eV, and a HfN/Ge contact with an ∼1 nm-thick a-IL showed a weaker one with a ΦBP of 0.39 eV. However, TaN/Ge contact without a-IL did not show such FLP alleviation. Based on the results of depth distributions for respective elements, we discussed the formation kinetics of a-ILs at TiN/Ge and ZrN/Ge interfaces. Finally, we proposed an interfacial dipole model to explain the FLP alleviation.

Original languageEnglish
Article number115701
JournalJournal of Applied Physics
Volume118
Issue number11
DOIs
Publication statusPublished - Jan 1 2015

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metal nitrides
transition metals
electrical properties
interlayers
nitrides
nitrogen atoms
conduction bands
dipoles
kinetics

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

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title = "Electrical and structural properties of group-4 transition-metal nitride (TiN, ZrN, and HfN) contacts on Ge",
abstract = "Electrical and structural properties were investigated for group-4 transition-metal nitride contacts on Ge (TiN/Ge, ZrN/Ge, and HfN/Ge), which were prepared by direct sputter depositions using nitride targets. These contacts could alleviate the intrinsic Fermi-level pinning (FLP) position toward the conduction band edge. It was revealed that this phenomenon is induced by an amorphous interlayer (a-IL) containing nitrogen atoms at the nitride/Ge interfaces. The strength of FLP alleviation positively depended on the thickness of a-IL. TiN/Ge and ZrN/Ge contacts with ∼2 nm-thick a-ILs showed strong FLP alleviations with hole barrier heights (ΦBP) in the range of 0.52-56 eV, and a HfN/Ge contact with an ∼1 nm-thick a-IL showed a weaker one with a ΦBP of 0.39 eV. However, TaN/Ge contact without a-IL did not show such FLP alleviation. Based on the results of depth distributions for respective elements, we discussed the formation kinetics of a-ILs at TiN/Ge and ZrN/Ge interfaces. Finally, we proposed an interfacial dipole model to explain the FLP alleviation.",
author = "Keisuke Yamamoto and Ryutaro Noguchi and Masatoshi Mitsuhara and Minoru Nishida and Toru Hara and Dong Wang and Hiroshi Nakashima",
year = "2015",
month = "1",
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doi = "10.1063/1.4930573",
language = "English",
volume = "118",
journal = "Journal of Applied Physics",
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T1 - Electrical and structural properties of group-4 transition-metal nitride (TiN, ZrN, and HfN) contacts on Ge

AU - Yamamoto, Keisuke

AU - Noguchi, Ryutaro

AU - Mitsuhara, Masatoshi

AU - Nishida, Minoru

AU - Hara, Toru

AU - Wang, Dong

AU - Nakashima, Hiroshi

PY - 2015/1/1

Y1 - 2015/1/1

N2 - Electrical and structural properties were investigated for group-4 transition-metal nitride contacts on Ge (TiN/Ge, ZrN/Ge, and HfN/Ge), which were prepared by direct sputter depositions using nitride targets. These contacts could alleviate the intrinsic Fermi-level pinning (FLP) position toward the conduction band edge. It was revealed that this phenomenon is induced by an amorphous interlayer (a-IL) containing nitrogen atoms at the nitride/Ge interfaces. The strength of FLP alleviation positively depended on the thickness of a-IL. TiN/Ge and ZrN/Ge contacts with ∼2 nm-thick a-ILs showed strong FLP alleviations with hole barrier heights (ΦBP) in the range of 0.52-56 eV, and a HfN/Ge contact with an ∼1 nm-thick a-IL showed a weaker one with a ΦBP of 0.39 eV. However, TaN/Ge contact without a-IL did not show such FLP alleviation. Based on the results of depth distributions for respective elements, we discussed the formation kinetics of a-ILs at TiN/Ge and ZrN/Ge interfaces. Finally, we proposed an interfacial dipole model to explain the FLP alleviation.

AB - Electrical and structural properties were investigated for group-4 transition-metal nitride contacts on Ge (TiN/Ge, ZrN/Ge, and HfN/Ge), which were prepared by direct sputter depositions using nitride targets. These contacts could alleviate the intrinsic Fermi-level pinning (FLP) position toward the conduction band edge. It was revealed that this phenomenon is induced by an amorphous interlayer (a-IL) containing nitrogen atoms at the nitride/Ge interfaces. The strength of FLP alleviation positively depended on the thickness of a-IL. TiN/Ge and ZrN/Ge contacts with ∼2 nm-thick a-ILs showed strong FLP alleviations with hole barrier heights (ΦBP) in the range of 0.52-56 eV, and a HfN/Ge contact with an ∼1 nm-thick a-IL showed a weaker one with a ΦBP of 0.39 eV. However, TaN/Ge contact without a-IL did not show such FLP alleviation. Based on the results of depth distributions for respective elements, we discussed the formation kinetics of a-ILs at TiN/Ge and ZrN/Ge interfaces. Finally, we proposed an interfacial dipole model to explain the FLP alleviation.

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