Quartz crucible and method for casting quasi-single crystal

Abstract

The invention discloses a quartz crucible. The bottom of the quartz crucible is provided with a pit which is spontaneously generated by inducing seed crystal. The invention also discloses a method for casting quasi-single crystal by using the quartz crucible. By using the quartz crucible of the invention, the quality of grown cast crystalline silicon is effectively improved so as to improve the electrical performance of a solar cell. By the method for casting the quasi-single crystal in the invention, the diameter of the obtained crystal grain is about 5 to 10cm, tests show that the dislocation density is about 10<3>cm<-2> which is far less than a number range of 10<4> to 10<5>cm<-2> of silicon crystal obtained by the conventional casting method under the same condition; and accordingly, the minority carrier lifetime value of a silicon slice obtained by the method of the invention is about 18us which is greater than the minority carrier lifetime value of 11us of the silicon slice prepared from the same raw material by the conventional casting method.

Description

technical field [0001] The invention relates to the photovoltaic industry, in particular to a quasi-single crystal casting quartz crucible and a quasi-single crystal casting method thereof. Background technique [0002] Judging from the current photovoltaic market, silicon solar cells occupy most of the market share. According to the different types of materials used, silicon solar cells can be divided into crystalline silicon solar cells and thin film silicon solar cells. Due to expensive equipment, complex process and low conversion efficiency, the market share of thin-film silicon solar cells is far smaller than that of crystalline silicon solar cells. According to market statistics, the share of crystalline silicon solar cells was 85% in 2009. about. In crystalline silicon solar cells, due to the relatively simple manufacturing process and relatively low manufacturing cost of polycrystalline silicon materials, since 2003, the market share of polycrystalline silicon has...

AI Technical Summary

Problems solved by technology

[0007] However, the above casting quasi-single crystal technology has certain disadvantages

For BP Solar's Mono 2 For quasi-single crystal technology, the growth of quasi-single crystal needs the assistance of seed crystal, and the addition of seed crystal directly increases the production cost of the casting method; for dendrite casting quasi-single crystal technology, precise control of the initial stage of silicon crystal crystallization is very important, and a special casting furnace is required In order to control the growth of dendrites well, the previous results were all obtained in the laboratory, and there are still some problems in industrial production.

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