Fluidized bed reactor and method for preparing granular polysilicon and trichlorosilane by employing same

Abstract

The invention discloses a fluidized bed reactor and a method for preparing granular polysilicon and trichlorosilane by employing the same. By utilizing a positive electrode and a negative electrode in the fluidized bed reactor and enabling the current to flow through silicon particles, heat is supplied for the silicon particles in the reactor in a resistance heating manner. By employing the fluidized bed reactor, the purity of the products can be improved, the cost is reduced, industrialized application of large-diameter reactors is allowed, the output is improved, also the inner wall temperature of the reactor is reduced and further silicon deposition is reduced.

Description

technical field [0001] The invention relates to the technical field of polysilicon preparation, in particular to a fluidized bed reactor using resistance heating and a method for preparing high-purity granular polysilicon and trichlorosilane. Background technique [0002] Polysilicon materials have always been the basic raw materials for the semiconductor and photovoltaic industries. In recent years, the rapid growth of the photovoltaic industry has promoted the rapid development of the polysilicon industry. The methods for preparing polysilicon include improved Siemens method, metallurgical method, fluidized bed method, etc. Among them, the polysilicon produced by the improved Siemens method accounts for more than 80% of the world's total output. The core process is that trichlorosilane is purified by rectification and sent to the reactor together with high-purity hydrogen. The surface of the silicon core in the reactor (the silicon core is heated) to 1000~1150℃) chemical v...

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Problems solved by technology

However, due to the strong back-mixing characteristics of the fluidized bed, part of the silicon-containing gas enters the heating zone. Since the temperature of the heating element is higher than the temperature of the gas phase and the temperature of the solid particles, deposition occurs on the heating element, which will eventually lead to a decrease in heating efficiency, and even face unfavorable conditions. The problem of non-stop maintenance or replacement of heating elements will affect the operating cycle of the reactor and directly affect the production capacity of the reactor

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