Dichlorosilane

Dichlorosilane, or DCS as it is commonly known, is a chemical compound with the formula H2SiCl2. In its major use, it is mixed with ammonia (NH3) in LPCVD chambers to grow silicon nitride in semiconductor processing. A higher concentration of DCS·NH3 (i.e. 16:1), usually results in lower stress nitride films. Dichlorosilane was originally prepared by Stock and Somieski by the reaction of SiH4 with hydrogen chloride. Dichlorosilane reacts with water vapor to initially give monomeric prosiloxane: SiH2Cl2 + H2O → SiH2O + 2 HCl Monomeric polymerizes rapidly upon condensation or in solution. Most dichlorosilane results as a byproduct of the reaction of HCl with silicon, a reaction intended to give trichlorosilane. Disproportionation of trichlorosilane is the preferred route. Stock and Somieski completed the hydrolysis of dichlorosilane by putting the solution of H2SiCl2 in benzene in brief contact with a large excess of water. A large-scale hydrolysis was done in a mixed ether/alkane solvent system at 0 °C, which gave a mixture of volatile and nonvolatile [H2SiO]n. Fischer and Kiegsmann attempted the hydrolysis of dichlorosilane in hexane, using NiCl2⋅6H2O as the water source, but the system failed.