Nickel monosilicide

Nickel monosilicide is an intermetallic compound formed out of nickel and silicon. Like other nickel silicides, NiSi is of importance in the area of microelectronics.

NiSi

Identifiers
CAS Number	12035-57-3 Y
3D model (JSmol)	Interactive image
ChemSpider	8351596
PubChem CID	10176091
CompTox Dashboard (EPA)	DTXSID80923344
InChI InChI=1S/Ni.Si Key: PEUPIGGLJVUNEU-UHFFFAOYSA-N
SMILES [Si].[Ni]
Properties
Chemical formula	NiSi
Molar mass	86.778 g/mol
Melting point	1,000 °C; 1,832 °F; 1,273 K[1]
Magnetic susceptibility (χ)	−0.3×10−6 emu/g[2]
Structure[3]
Crystal structure	Orthorhombic, oP8
Space group	Pnma, No. 62
Lattice constant	a = 0.519 nm, b = 0.333 nm, c = 0.5628 nm
Formula units (Z)	4
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Nickel monosilicide can be prepared by depositing a nickel layer on silicon and subsequent annealing. In the case of Ni films with thicknesses above 4 nm, the normal phase transition is given by Ni₂Si at 250 °C followed by NiSi at 350 °C and NiSi₂ at approximately 800 °C.^[4] For films with an initial Ni thickness below 4 nm a direct transition from orthorhombic Ni₂Si to epitaxial NiSi_2−x, skipping the nickel monosilicide phase, is observed.^[5]

Uses

Several properties make NiSi an important local contact material in the area of microelectronics, among them a reduced thermal budget, low resistivity of 13–14 μΩ·cm and a reduced Si consumption when compared to alternative compounds.^[6]