Polycrystalline silicon reduction system and feeding mode of reducing gas raw materials thereof

Abstract

Provided are a polycrystalline silicon reduction system and a feeding mode of reducing gas raw materials thereof. The polycrystalline silicon reduction system comprises a bubbling vaporizer, a hydrogen heater, a plurality of static mixers connected with the bubbling vaporizer and the hydrogen heater and a plurality of polycrystalline silicon reduction furnaces respectively connected with corresponding static mixers. The polycrystalline silicon reduction system uses hydrogen to bubble in trichlorosilane liquid, simultaneously the trichlorosilane liquid is heated by an external heat source to enable trichlorosilane to be vaporized, and the mixed gas of trichlorosilane and hydrogen is finally obtained through hydrogen bubbling so that evaporation of trichlorosilane is speeded up. By controlling pressure and temperature of the bubbling vaporizer, the vented gas of the mixed gas of the bubbling vaporizer is controlled to be in a low proportion, after being heated through the hydrogen heater, bypass hydrogen is fully mixed with the vented gas of the mixed gas of the bubbling vaporizer in the static mixers to a high preset proportion, and then the mixture directly enters the corresponding reduction furnaces.

Description

technical field [0001] The present invention generally relates to polysilicon reduction systems. Specifically, it relates to the feeding method or supply method of the reducing gas raw material in the polysilicon reduction system. Background technique [0002] Polysilicon is an important semiconductor raw material, and the mainstream process for its production is the improved Siemens method. Polysilicon reduction is an important production link of the improved Siemens method, and its raw materials are trichlorosilane and hydrogen. The production method of polycrystalline silicon is to deposit on the surface of the original silicon rod. As the reaction progresses, the more deposited on the surface of the silicon rod, the larger the diameter of the silicon rod, and the consumption of trichlorosilane and hydrogen also increases with the diameter. And increase. Therefore, during the entire polysilicon deposition process, the amount of trichlorosilane gas and hydrogen gas inta...

AI Technical Summary

Problems solved by technology

Disadvantages: There are two kinds of material components in the bubble vaporizer. In order to determine their ratio, two parameters of temperature and pressure need to be controlled separately.

Disadvantages: It needs a lot of heat to turn liquid trichlorosilane into a gaseous state. If it is heated by steam, the pressure quality of the steam is required to be high, generally 0.6Mpa is required; and it is easy to liquefy during retransportation

But there is no guarantee that the liquid trichlorosilane will be completely vaporized

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