Pseudo-single crystal silicon ingot casting crucible with aluminum oxide thin film used as barrier layer

Abstract

The invention discloses a pseudo-single crystal silicon ingot casting crucible with an aluminum oxide thin film used as a barrier layer. The pseudo-single crystal silicon ingot casting crucible is characterized in that a silicon nitride coating and the barrier layer are arranged on the inner surface of a base of the pseudo-single crystal silicon ingot casting crucible, the barrier layer is a solargrade single crystal silicon wafer, and the Al2O3 thin film is deposited on the surface of the solar grade single crystal silicon wafer. The pseudo-single crystal silicon ingot casting crucible has the advantages that the widths of red zones at the bottoms of pseudo-single crystal silicon cast ingots cast by the aid of the pseudo-single crystal silicon ingot casting crucible can be constrained toreach approximately 5 mm, the minority carrier lifetime of the cast ingots are longer than 2 micro-seconds, and the utilization rate of pseudo-single crystal silicon ingots can be effectively increased; the pseudo-single crystal silicon ingots can be cut to obtain silicon wafers, impurities in the silicon wafers are low in concentration, the silicon wafers are long in minority carrier lifetime, batteries manufactured from the silicon wafers are high in efficiency, and the average conversion efficiency of the batteries is 18%-18.5%.

Description

technical field [0001] The invention belongs to the field of quasi-single-crystal silicon ingots, and in particular relates to a crucible for quasi-single-crystal silicon ingots using an aluminum oxide film as a barrier layer. Background technique [0002] As a renewable clean energy, solar energy has been widely used in grid-connected power generation, civil Power generation, public facilities and integrated energy-saving buildings. In the field of solar power generation, crystalline silicon photovoltaic power generation systems occupy a major position in the new energy photovoltaic power generation market. The market has increasingly stringent requirements on the quality of mono / polysilicon, the raw material that affects photovoltaic power generation. [0003] In the current quasi-single crystal casting / polycrystalline casting process, impurities in the crucible such as iron, oxygen, carbon, etc. will diffuse into the silicon ingot at high temperature, and metal impuriti...

AI Technical Summary

Problems solved by technology

However, the effect of reducing the width of the red zone at the bottom of the silicon ingot is relatively limited, and the use of high-purity materials increases the cost of ingot casting

[0005] For example, the Chinese patent application with the application number 201610932534.7 discloses a method for preparing a silicon nitride coating with high-efficiency insulation properties, which is applied to the casting of polycrystalline silicon ingots. When the ingot is squared, the minimum width of the red zone at the bottom is 23mm ;Compared to the red zone width of silicon ingots produced by traditional industrial methods, which is 20-28mm, the effect is not ideal. In addition, because of the high purity of the raw materials used, the production cost is high.

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