Method and system for producing polysilicon

Abstract

The invention provides a method for producing polysilicon, which comprises the following steps: before the reaction starts, first use microwaves to heat the silicon core in the reduction furnace to the first set temperature, and then apply current after the silicon core is broken down, so as to Chemically deposit polysilicon on the surface of the core to obtain silicon rods; during the reaction process, if the power is cut off on the silicon rods, the silicon rods are heated to the second set temperature by using microwaves before restarting after the power failure, and then the silicon rods are struck. After piercing, current is applied to continue to chemically deposit polysilicon on the surface of the silicon rod. The present invention also provides a polysilicon production system, which includes an energy feeding unit and a protection unit. The energy feeding unit includes an energy feeding antenna, and the energy feeding antenna is arranged at an opening on the reduction furnace that can communicate with the interior of the reduction furnace for generating and emitting Microwave; the protection unit is used to separate the energy feeding antenna from the atmosphere in the reduction furnace to protect the energy feeding antenna. The invention can realize stable growth of polysilicon, obtain polysilicon products with good performance, and improve product quality.

Description

technical field [0001] The invention belongs to the technical field of polysilicon, and in particular relates to a method and system for producing polysilicon. Background technique [0002] In the existing polysilicon production process, the Siemens method is mostly used to produce polysilicon, which is to obtain the temperature required for the vapor chemical deposition reaction by heating the silicon core or the silicon rod itself with an electric current. Comparison of heating methods single. And in the actual operation process, since the silicon core and the silicon rod are both semiconductor materials, they are almost non-conductive at room temperature, and it is difficult to pass the current, and the silicon core or the silicon rod needs to be broken down first. [0003] At present, before the silicon core or silicon rod is heated up (that is, when the temperature is low), the current is passed through by first breaking down the silicon core or silicon rod and then pa...

AI Technical Summary

Problems solved by technology

[0004] (1) High-voltage breakdown will affect the insulation performance of insulating components, causing abnormal conditions such as grounding and arcing in the late stage of polysilicon growth;

[0005] (2) Halogen lamp heating will destroy the sealing of the reduction furnace, which may bring safety risks such as flash explosion, and may also introduce oxidation and impurities, which will affect the quality of polysilicon products;

When the polysilicon growth process is powered off and then restarted, the silicon rod needs to be broken down again. At this time, as the diameter of the silicon rod increases and the temperature decreases, the resistance of the silicon rod increases, and the difficulty of using high voltage breakdown increases;

[0007] (4) At the end of the reaction or in case of rod down, leakage or other emergencies, when it is necessary to cut off the power supply and stop the power supply, after the residual chlorosilane and other materials in the reduction furnace lack heat sources, only conventional gas replacement and purging methods are used. , it is difficult to completely volatilize and remove, which not only affects the product quality, but also may bring safety risks, and the thermal stress generated by continuing to energize and heat can easily lead to cracking or falling of the polysilicon rod

In order to solve the residual problem of residual chlorosilane and other materials on the surface of the silicon core and in the reduction furnace after the reaction, and prevent the residual chlorosilane and other materials from affecting the quality of polysilicon and causing safety hazards in contact with air during furnace dismantling

The traditional method is to simply rely on gas replacement and purging to volatilize the material away; there are also methods such as electric heating and electromagnetic induction heating. These methods all have problems such as long time, low efficiency, and high energy consumption.

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