Method and device for producing polysilicon by using plasma assisting fluidized bed process

Abstract

The invention discloses a method and a device for producing polysilicon by using a plasma assisting fluidized bed process. One or more of silane or halogenated silanes are adopted as raw gases, nitrogen is adopted as a reducing gas, all or partial raw gases are converted into plasma through a plasma generation device after mixed with the nitrogen, mixed gases after being carried out plasma react to be deposited for manufacturing the granular polysilicon; or the raw gases directly enter into a fluidized bed reactor and are mixed with the converted nitrogen subjected to plasma in the fluidized bed reactor, and the mixed gases subjected to plasma react to be deposited for manufacturing the granular polysilicon. The invention realizes normal pressure continuous operation, lower reaction temperature, high deposition rate and high once through yield of the polysilicon, can directly utilize side products in the traditional polysilicon production process by lower unit electricity consumption and operation cost and produce the granular polysilicon with high purity.

Description

technical field [0001] The present invention relates to a method and device for producing polysilicon, more specifically to a method and device for producing polysilicon by using plasma assistance combined with a fluidized bed process. technical background [0002] At present, the vast majority of polysilicon production methods are the improved Siemens process, which mainly uses a bell-type reactor and a silicon core of about 8mm connected to the electrode as the deposition substrate, adopts a high-temperature reduction process, and uses high-purity SiHCl 3 in H 2 Reductive deposition in the atmosphere to generate polysilicon. [0003] The above-mentioned chemical vapor deposition process is carried out in a bell-type reduction furnace. The reaction vessel is sealed. The chassis is equipped with a discharge port, a feed port and a number of counter electrodes. 1500-3000mm silicon core, the two silicon rods on each pair of electrodes are connected to each other through a sh...

AI Technical Summary

Problems solved by technology

[0004] However, this improved Siemens production process has the following disadvantages: 1) Due to the small specific surface area of ​​silicon rod deposition, the space utilization rate in the reactor is low, the primary conversion rate of raw materials is low, and the output is limited

Calculated with an actual yield of 8%, only 16.5 grams of elemental silicon can be obtained per kilogram of trichlorosilane, and most of the trichlorosilane is converted into silicon tetrachloride during the deposition process. After the by-product silicon tetrachloride is separated, Trichlorosilane is re-synthesized as a raw material. This cycle consumes energy and electricity and is inefficient.

2) The composition of tail gas produced by chlorosilane cracking process is complex, and the separation cost is high

Therefore, it can only be produced intermittently, with large heat loss and high energy consumption.

4) Since the product is rod-shaped polysilicon, the process and cost of crushing and packaging are increased, and new impurities may also be introduced

However, with this method, since there is no crystal nucleus in the system, the generation of polysilicon requires high energy

Images