Application of silica powder to polycrystalline silicon cast ingot preparation

Abstract

The invention discloses application of silica powder to polycrystalline silicon cast ingot preparation. A preparation method of the polycrystalline silicon cast ingot comprises the following steps: step 1, the silica powder, silicon reuse materials, silica particles, polycrystalline silicon block materials, polycrystalline silicon bar materials, and silicon seed crystal are fed in the quartz crucible of an ingot furnace to serve as silicon materials used for the cast ingot; step 2, the ingot furnace is subjected to vacuum pumping and heating; step 3, the silicon materials used for the cast ingot are melted; step 4, argon is introduced to the ingot furnace, and pressure maintaining and cooling are performed for controlled directional solidification crystal growth; step 5, the argon is continuously introduced to the ingot furnace to perform anneal, and step 6, the argon is continuously introduced to the ingot furnace to cool to obtain the polycrystalline silicon cast ingot. According tothe application of silica powder to polycrystalline silicon cast ingot preparation, the silica powder is taken as one of the preparing silicon materials for the polycrystalline silicon cast ingot, unique charging mode is adopted, the charge batch of the silicon materials and the silica powder is effectively increased, the heat transfer effect among silicon materials is improved, sufficient meltingof the silica powder is guaranteed, rate of finished products of the polycrystalline silicon cast ingot is improved, thereby the minority carrier lifetime of the polycrystalline silicon is improved,and meanwhile, the silica powder need not to be pressed into a powder cake in advance, thereby lowering the preparation cost.

Description

technical field [0001] The invention belongs to the technical field of preparation of polycrystalline silicon ingots, and in particular relates to the application of silicon powder in the preparation of polycrystalline silicon ingots. Background technique [0002] Polysilicon powder is an essential raw material for the photovoltaic ingot casting industry. It has superior furnace loading advantages, which can increase the furnace loading and improve the yield of products. [0003] At present, most of the use of silicon powder in the photovoltaic ingot industry is to fill the gaps of bulk silicon materials and increase the furnace capacity, but this results in insufficient melting of silicon powder, low yield of silicon ingots, and low product life. Low, unable to meet the current market demand. [0004] In order to eliminate this deficiency, the conventional method is nothing more than pressing the silicon powder into a powder cake, purifying the first ingot, removing the he...

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Problems solved by technology

[0003] At present, most of the use of silicon powder in the photovoltaic ingot industry is to fill the gaps of bulk silicon materials and increase the furnace capacity, but this results in insufficient melting of silicon powder, low yield of silicon ingots, and low product life. Too low to meet current market demand

[0004] In order to eliminate this deficiency, the conventional method is nothing more than pressing the silicon powder into a powder cake, purifying the first ingot, removing the head and tail impurities, and then going through the second ingot casting, which greatly increases the input cost and cannot bring higher cost. economic benefits

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