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In‐Situ Observation of the Formation of NiSi/Ni 2 Si Heterojunction in SiGe Nanowire with Al 2 O 3 Diffusion Barrier Layer
Author(s) -
Lee YuChuan,
Lyu LianMing,
Lu MingYen
Publication year - 2021
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202100422
Subject(s) - materials science , heterojunction , nanowire , diffusion barrier , activation energy , diffusion , transmission electron microscopy , layer (electronics) , fabrication , semiconductor , electrical resistivity and conductivity , nanotechnology , analytical chemistry (journal) , optoelectronics , chemistry , medicine , physics , alternative medicine , pathology , chromatography , thermodynamics , engineering , electrical engineering
In complementary metal‐oxide‐semiconductor technology, the metal silicides/germanides have prominent advantages such as low resistivity, high thermal and chemical stability. Here, a study to probe the phase transformations and the diffusion behaviors of Ni in Si 1‐ x Ge x nanowire (NW) by in situ transmission electron microscopy is conducted. The Si 1‐ x Ge x NWs are dispersed on Si 3 N 4 membrane and contacted with Ni by E‐beam lithography process for in situ study. The sample is heated to 723 K, Ni is diffused into Si 1‐ x Ge x NW and Ni 2 Si is formed accordingly. The diffusion mechanism is confirmed to be reaction‐controlled and the activation energy can be extracted to be 0.708 eV. On the other hand, in this study Al 2 O 3 layer‐coated Si 1‐ x Ge x NW is probed for comparison, while the Al 2 O 3 layer serves as the diffusion barrier to modulate the diffusion rate of Ni. This increases the activation energy to 1.38 eV. Importantly, it is found that the NiSi/Ni 2 Si heterojunction is formed at the diffusion front. The results provide the insights for fabrication of semiconducting devices.