Crucible for casting polysilicon ingot and method for preparing same, polysilicon ingot and method for preparing same

Abstract

The invention provides a crucible for polycrystalline-silicon ingot casting. The crucible comprises a crucible body and a doping layer. The crucible body comprises a base and a side wall extending upwards from the base, the doping layer is attached to the internal surface of the portion, between the portion the first height away from the base and the portion the second height away from the base, of the side wall, the first height is the distance from the fused silicon liquid level formed after a prefilled silicon material in the crucible is fused to the base of the crucible body, and the second height is the distance from the upper surface of a silicon ingot when fused silicon liquid is fully converted into a solid silicon ingot to the base of the crucible body; the material of the doping layer comprises silica wool or carbon fibers and a doped material loaded in silica wool or carbon fibers, the doped material comprises a first doping agent, and the first doping agent comprises P-shaped doping elements and any one of N-shaped doping elements and / or germanium elements; the initial atomic volume concentration of the first doping agent in the prefilled silicon material in the crucible is 1*10<13>-7*10<18> atmos / cm<3>. By means of the crucible, the heat transmission speed of the side wall of the crucible can be effectively decreased, the temperature of the doping layer is reduced, and it is avoided that the first doping agent is fused in advance.

Description

technical field [0001] The invention relates to the technical field of solar cell materials, in particular to a polycrystalline silicon ingot crucible and a preparation method thereof, and a polycrystalline silicon ingot and a preparation method thereof. Background technique [0002] In order to meet the requirements of cell processing, the required electrical properties must be obtained by adjusting the concentration of dopants during the polysilicon growth process. Existing dopants include group III elements boron and gallium (to prepare P-type silicon wafers) and group V element phosphorus (to prepare N-type silicon wafers). Among them, because the segregation coefficient (0.8) of boron in silicon is closer to 1, the resistivity distribution of the obtained boron-doped silicon crystal is relatively uniform. However, the light-induced attenuation phenomenon will occur after the solar cells made of boron-doped silicon wafers are used, which reduces the conversion efficienc...

AI Technical Summary

Problems solved by technology

However, the temperature in the ingot casting furnace is relatively high during the chemical material stage, and this type of coating is in the form of a master alloy of compensating elements and silicon or pure elements, and there is a risk of melting in advance, so that the compensating elements will be melted into the silicon material during the material chemical stage. , affecting the overall resistivity of the ingot. Due to the melting of compensation elements at the tail of the ingot and the area that does not need compensation, the resistivity rises too high, especially at the tail. The resistivity at the tail is poor, while at the head of the ingot due to reduced compensation or even no compensation, the resistivity is lower than the set value of the batching, resulting in low resistivity at the head of the ingot

Therefore, the early melting of compensation elements will affect the overall yield of the ingot, resulting in an increase in the production cost of this type of ingot

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