Method for improving poly-crystal quality by using re-melting technology

Abstract

The invention relates to a method for improving poly-crystal quality by using a re-melting technology. The method comprises the steps that: material is loaded; a silicon material is ensured to be completely molten before entering a crystal growth process, a heat exchanger DS-Block central point temperature TC2 is 1400 DEG C (plus or minus 3 DEG C); a first step of crystal growth is carried out, wherein a thermal insulation cage is rapidly lifted to 8-10cm such that a crucible bottom temperature is rapidly reduced; a second step of crystal growth is carried out, wherein the thermal insulation cage is lifted to 10-12cm; a third step of crystal growth is carried out, wherein the thermal insulation cage is rapidly lowered to a zero position; a fourth step of crystal growth is carried out, wherein the thermal insulation cage position in the third step, and an ingot furnace temperature-control point temperature TC1 are maintained, and a crystal growth residual height is ensured at 1.3-1.7cm; a sixth step of crystal growth is carried out, wherein growth is carried out on rest crystal surface after re-melting; after the sixth step, growth is carried out according to normal crystal growth processes; and annealing and cooling are carried out according to normal processes after crystal growth is finished. The method provided by the invention has the advantages of simple operation and low cost. With the invention, crystal growth quality is substantially improved, and polysilicon photoelectric conversion efficiency is improved by 0.1-0.3%.

Description

technical field [0001] The invention relates to a method for improving the quality of polycrystalline crystals by using a remelting process, especially in a polycrystalline silicon chip manufacturing process for solar silicon-based batteries, by adjusting the position of the heat insulation cage in the crystal growth stage, the temperature of the temperature control point of the ingot furnace and the temperature of the ingot furnace. A method for improving the quality of crystal growth in a polycrystalline ingot furnace by controlling the initial growth height of the crystal and the melting height of the crystal during remelting. Background technique [0002] Polycrystalline silicon wafers are commonly used raw materials for the preparation of solar silicon-based cells. The polysilicon raw material is cast into a polysilicon ingot by an ingot casting furnace, and then cut into strips, and then sliced ​​to become a polysilicon wafer. Therefore, the ingot furnace is the basic...

AI Technical Summary

Problems solved by technology

Some of these methods play a certain role in improving the quality of polysilicon wafers and increasing the photoelectric conversion efficiency, but these existing methods have the disadvantages of difficult operation and high cost.