Method for preparing (110) float zone silicon crystal

Abstract

The invention discloses a method for preparing a (110) float zone silicon crystal. The key point of the technical scheme is that: 1, in the seeding technology, by controlling and adjusting the descending speed of a lower shaft and adjusting the power, the seeding neck diameter is controlled in a range from 2 to 6 mm, wherein the seeding neck diameter is more than or equal to 1.5 times the diameter of a single crystal; 2, in the shouldering technology, by controlling and adjusting the descending speed and rotating speed of the lower shaft and the descending speed and rotating speed of an uppershaft and adjusting the power, the shouldering angle is 50+ / -5 degrees; and 3, in the ending technology, the ending length is more than 1.2 times the diameter of the single crystal, and the minimum tail diameter is less than or equal to 5mm. The method overcomes the defects that the (110) silicon single crystal prepared by the conventional direct pulling method has high impurity content and cannot meet the requirement on the silicon single crystal of a high-efficiency solar cell, and successfully prepares a low-impurity content and long-service life (110) dislocation-free float zone silicon crystal by a floating zone method, wherein the (110) float zone silicon crystal has the dislocation density of less than or equal to 500 units / cm<2> and the minority carrier lifetime of more than or equal to 300us, and meets the requirement of a silicon material for preparing the high-efficiency solar cell.

Description

technical field [0001] The invention relates to a method for producing silicon single crystal, in particular to a method for preparing <110> zone melting silicon single crystal. Background technique [0002] The Chinese patent with the authorized notification number CN 100585031C discloses a method for manufacturing a <110> dislocation-free silicon single crystal and an improvement to the graphite thermal system used in the manufacturing method. This method uses the Czochralski method to grow silicon single crystals, and this method will inevitably introduce a large amount of impurity elements during the single crystal preparation process, resulting in a low minority carrier lifetime of the single crystal, which leads to the use of this type of silicon single crystal preparation The photoelectric conversion efficiency of solar cells is low, which cannot meet the requirements for preparing high-efficiency silicon solar cells. [0003] Suspension zone melting meth...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the defect of high impurity content of silicon single crystal prepared by the existing Czochralski method, and to solve the problem that the existing silicon single crystal cannot meet the technical requirements of high-efficiency solar cells. Method for preparing zone-melted silicon single crystal with low impurity content and long life by zone melting method