A typical representative of the metal hydride process is MEMC Corporation of the United States. The silane gas is synthesized by reacting sodium aluminum hydride with silicon tetrafluoride gas. The main reaction is:

The crude silane gas produced by the reaction is purified and purified by an adsorption tower, a de-weighting tower and a de-lighting tower, and the purity of the crude silane gas is increased to a high-purity electronic grade silane gas of 6 N or more, and the liquid silane obtained by the low-temperature liquefaction treatment is stored in the product. In the silane storage tank, the liquid silane gas is evaporated to a normal temperature silane gas for use in the silane reduction polysilicon section.

Features:
Manufacture of silicon tetrafluoride, which can be used as a raw material of sodium fluorosilicate, a by-product of fertilizer enterprises, even if it is easy to use raw materials of fluorite sulfuric acid;

The by-product sodium aluminum fluoride can be used as an electrolytic aluminum raw material (instead of cryolite), which can be sold in the sulfate industry;

In the liquid phase reaction, the fluorosilicic acid pyrolysis product HF is not discharged into the system, but is returned to the first reactor as a fluorine source;

The US MEMC company has been used for more than 1,000 tons in 20 years, and its technology is mature.

problem:
Consuming a large amount of high-priced raw materials sodium metal and aluminum powder, the cost is relatively high;

It is difficult to achieve ultra-high purity semiconductor use.