SmSi 2 Sm 5Si 4, Sm 5Si 3, SmSi, Sm 3Si 5 NdSi Nd 5Si 3, Nd 5Si 4, Nd 5Si 3, Nd 3Si 4, Nd 2Si 3, NdSi x PrSi 2 Pr 5Si 3, Pr 3Si 2, Pr 5Si 4, PrSi LaSi 2 La 5Si 3, La 3Si 2, La 5 Si 4, LaSiĬeSi 2 Ce 5Si 3, Ce 3Si 2, Ce 5Si 4, CeSi, Ce 3Si 5 RhSi Rh 2Si, Rh 5Si 3, Rh 3Si 2, Rh 20Si 13 ZrSi Zr 5Si 3, Zr 5Si 4, ZrSi 2, Zr 3Si 2, Zr 2Si, Zr 3Si Many silicides may be obtained by heating elemental silicon with elemental metals at about 600–700 ☌ (1,112–1,292 ☏). Mercury, thallium, bismuth, and lead are immiscible with liquid silicon. melted potassium hydroxide, or fluorine and chlorine when red-hot. The transition metal silicides are, in contrast, usually inert to aqueous solutions of everything with exception of hydrofluoric acid however, they react with more aggressive agents, e.g. Rubidium silicide is pyrophoric, igniting in contact with air. For example, sodium silicide, Na 2Si, reacts rapidly with water to yield sodium silicate, Na 2SiO 3, and hydrogen gas. Group 1 silicides are even more reactive. Mg 2Si reacts similarly with sulfuric acid. These reactions are typical of a Group 2 silicide. Silane is pyrophoric, that is, due to the presence of oxygen, it spontaneously combusts in air: This gas is the silicon analogue of methane, CH 4, but is more reactive. When magnesium silicide is placed into hydrochloric acid, HCl(aq), the gas silane, SiH 4, is produced. Na 2Si and Ca 2Si react with water, yielding hydrogen and/or silanes. It is commonly implemented in MOS/ CMOS processes for ohmic contacts of the source, drain, and poly-Si gate.Īlkali and alkaline earth metals This is a process in which silicide contacts are formed only in those areas in which deposited metal (which after annealing becomes a metal component of the silicide) is in direct contact with silicon, hence, the process is self-aligned. Open three-dimensional Si skeletons: SrSi 2, ThSi 2, α-USi 2Ī silicide prepared by a self-aligned process is called a salicide.Planar hexagonal graphite-like Si layers: β-USi 2, silicides of other lanthanoids and actinoids.Si n chains: USi, (Ti, Zr, Hf, Th, Ce, Pu)Si, CaSi, SrSi, YSi.Si 2 pairs: U 3Si 2, hafnium and thorium silicides.Isolated silicon atoms: electrically conductive (or semiconductive) CrSi, MnSi, FeSi, CoSi, Cu 5Si, (V,Cr,Mn) 3Si, Fe 3Si, Mn 3Si, and nonconductive (Mg,Ge,Sn,Pb) 2Si, (Ca,Ru,Ce,Rh,Ir,Ni) 2Si.Silicon atoms in silicides can have many possible organizations: JSTOR ( August 2021) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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