In‐Situ Observation of the Formation of NiSi/Ni2Si Heterojunction in SiGe Nanowire with Al2O3 Diffusion Barrier Layer

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 Si1‐xGex nanowire (NW) by in situ transm...

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Bibliographic Details
Published inAdvanced materials interfaces Vol. 8; no. 14
Main Authors Lee, Yu‐Chuan, Lyu, Lian‐Ming, Lu, Ming‐Yen
Format Journal Article
LanguageEnglish
Published Weinheim John Wiley & Sons, Inc 01.07.2021
Subjects
Activation energy
Aluminum oxide
Barrier layers
diffusion barrier
Diffusion barriers
Diffusion layers
diffusion mechanism
Diffusion rate
Germanides
Heterojunctions
in situ transmission electron microscopy
Metal silicides
Nanowires
Nickel silicide
Phase transitions
Si 1‐ xGe x nanowires
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Summary: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 Si1‐xGex nanowire (NW) by in situ transmission electron microscopy is conducted. The Si1‐xGex NWs are dispersed on Si3N4 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 Si1‐xGex NW and Ni2Si 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 Al2O3 layer‐coated Si1‐xGex NW is probed for comparison, while the Al2O3 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/Ni2Si heterojunction is formed at the diffusion front. The results provide the insights for fabrication of semiconducting devices. The observation of interface reaction materials is a big issue for suitable design in integrated circuits. In nanoscale, in situ transmission electron microscopy is powerful for quantitatively analyzing the diffusion mechanism in SiGe nanowire, potential material of metal‐oxide‐semiconductor, with Al2O3 diffusion barrier layer. The diffusion, activation energies, and composition properties are well studied.
ISSN:2196-7350
2196-7350
DOI:10.1002/admi.202100422