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

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 (Φ{sub BP}) 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 Φ{sub BP} 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.
Authors:
;  [1] ; ;  [2] ; ;  [3] ;  [4]
  1. Art, Science and Technology Center for Cooperative Research, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)
  2. Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)
  3. Department of Engineering Sciences for Electronics and Materials, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)
  4. National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
Publication Date:
OSTI Identifier:
22489513
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DEPTH; DIPOLES; FERMI LEVEL; HAFNIUM NITRIDES; INTERFACES; SPATIAL DISTRIBUTION; SPUTTERING; TANTALUM NITRIDES; THICKNESS; TITANIUM NITRIDES; TRANSITION ELEMENTS; ZIRCONIUM NITRIDES