How are silanes manufactured?
(1) Magnesium silicide method: react the mixed powder of silicon and magnesium in hydrogen at about 500°C, and react the generated magnesium silicide with ammonium chloride in low-temperature liquid ammonia to obtain silane. Purification of it in a distillation apparatus cooled with liquid nitrogen yields pure silane.
(2) Heterogeneous reaction method: react silicon powder, silicon tetrachloride and hydrogen in a fluidized bed furnace heated above 500°C to obtain trichlorosilane. Trichlorosilane is separated by distillation. Dichlorosilane is obtained by heterogeneous reaction in the presence of a catalyst. The obtained dichlorosilane is a mixture with silicon tetrachloride and trichlorosilane, so pure dichlorosilane can be obtained after distillation. Trichlorosilane and monosilane are obtained from dichlorosilane using a heterogeneous reaction catalyst. The obtained monosilane is purified by a low-temperature high-pressure distillation device.
(3) Treat the silicon-magnesium alloy with hydrochloric acid.
Mg2Si+4HCl—→2MgCl2+SiH4
(4) Silicon-magnesium alloy reacts with ammonium bromide in liquid ammonia.
(5) Using lithium aluminum hydride, lithium borohydride, etc. as reducing agents, reduce tetrachlorosilane or trichlorosilane in ether.
2. What is the starting material for silane?
The raw materials for the preparation of silane are mainly silicon powder and hydrogen. The purity requirements of silicon powder are relatively high, generally reaching more than 99.999%. Hydrogen is also refined to ensure the high purity of the prepared silane。
3. What is the function of silane?
As a gas source that provides silicon components, silane can be used to manufacture high-purity polycrystalline silicon, single crystal silicon, microcrystalline silicon, amorphous silicon, silicon nitride, silicon oxide, heterogeneous silicon, and various metal silicides. Because of its high purity and fine control, it has become an important specialty gas that cannot be replaced by many other silicon sources. Silane is widely used in microelectronics and optoelectronics industries, and is used in the manufacture of solar cells, flat panel displays, glass and steel coatings, and is the only intermediate product in the world for large-scale production of granular high-purity silicon. The high-tech applications of silane are still emerging, including the use in the manufacture of advanced ceramics, composite materials, functional materials, biomaterials, high-energy materials, etc., and become the basis of many new technologies, new materials, and new devices.
4. Are silanes environmentally friendly?
Yes, the silane treatment agent does not contain heavy metal ions and other pollutants, and it complies with ROHS and SGS environmental protection standards.
5. Application of silane
Skeleton structure of chlorosilanes and alkyl chlorosilanes, epitaxial growth of silicon, raw materials of polysilicon, silicon oxide, silicon nitride, etc., solar cells, optical fibers, colored glass manufacturing, chemical vapor deposition.
