Low‐Temperature Formation of NiSi₂ Phase in Ni/Si System

Abstract

The silicide phase formation is examined in the Ni/Si system. The multiphase of NiSi and NiSi 2 is confirmed in a specimen, in which a 30-mm-thick Ni film is sputterdeposited on Si(100) at 350°C and subsequently annealed at 400°C for 1 h. This is interpreted that the NiSi and NiSi 2 phases nucleate from the amorphous alloys, as a supercooled melt, at a composition corresponding to those of eutectic points in different composition, which appear in the intermixed Ni-Si alloy layer with a Ni concentration gradient owing to intermixing between Ni and Si at the interface. To confirm this idea, we performed Ni deposition on a 350°C -heated Si substrate with a thin SiO 2 layer. The results show the direct formation of NiSi 2 in a nonuniform fashion. This is because the thin SiO 2 layer suppresses Ni diffusion into Si, resulting in the formation of a Ni-Si alloy with a Si-rich composition, from which NiSi 2 nucleates at a low temperature. We can demonstrate that the high-temperature phase of NiSi 2 nucleates under kinetic constraints from an amorphous alloy with a suitable composition. C⃝ 2016 Wiley Periodicals, Inc. Electron Comm Jpn, 99(9): 85-91, 2016; Published online in Wiley Online Library (wileyonlinelibrary.com).

Role of polarity in SiN on Al/GaN and the pathway to stable contacts

“…The low thermal chemical stability in this case may point towards an interaction between the Ni and Si-clusters in the Si-rich SiN materials matrix. Ni-silicides could indeed form at around 400 °C [72]. In case of the oxygen terminated surface, the extracted barrier is at a higher 1.07 eV.…”