摘要
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.