Silicon Compounds, Silicon Halides

Abstract

All of the halogens form single and mixed silicon halides. Monomeric silicon halides and halohydrides are generally tetrahedral compounds. A large number of halogenated polysilanes are also known. The only compounds of industrial importance are tetrachlorosilane and trichlorosilane. Both are used as precursors: the former primarily for high purity fumed silica; the latter for organosilanes and semiconductor‐grade silicon metal. Dichlorosilane, a by‐product of the other chlorosilanes, also finds use in the semiconductor industry.

Elimination of silicon gas phase nucleation using tetrafluorosilane (SiF4) precursor for high quality thick silicon carbide (SiC) homoepitaxy

“…In the case of chlorinated silanes with a weak SiCl bond, hydrogen reacts and reduces chlorosilanes starting at 1000 °C for tetrachlorosilane (SiCl 4 ) or even at lower temperatures for silicon chlorohydrides (SiHCl 3 , SiH 2 Cl 2 ). On the other hand, SiF 4 , with the strongest SiF bond is reduced by hydrogen at much higher temperatures starting only above 2000 °C 29. This ability of SiF 4 among all Si precursors to remain inert in hydrogen environment even until 2000 °C is the reason for the effective elimination of liquid Si droplet formation and Si parasitic deposition observed at SiC growth temperatures.…”

Study of SiC Epitaxial Growth Using Tetrafluorosilane and Dichlorosilane in Vertical Hotwall CVD Furnace

“…Recently, tetrafluorosilane (TFS, SiF 4 ), a fluorine based gas having the strongest Si-halogen bond (Si-F bond energy 565kJ/mol vs. Si-Cl bonding energy 381kJ/mol) [3], has been introduced as a novel Si-precursor in SiC epitaxial growth [4]. As a thermodynamically stable compound, TFS breaks to elemental compounds only at a very high temperature above 2000˚C [5]. Interestingly, it reacts with C-containing species at a temperature less than 2000˚C to facilitate the epi-growth of SiC.…”