Patent ID: 11901475
Assignee: SHIN-ETSU CHEMICAL CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  C  Y | IPC C  H

Claim 6:
7. A method for manufacturing a solar cell, comprising:
preparing a Czochralski silicon single crystal ingot doped with a p-type dopant or an n-type dopant and containing oxygen atoms of at least 12 ppm;
preparing a silicon substrate from the Czochralski silicon single crystal ingot;
subjecting the silicon substrate to texture etching; and
subjecting the silicon substrate to low temperature thermal treatment at a temperature of 800° C. or more and less than 1200° C. so as to fabricate a solar cell,
wherein either the Czochralski silicon single crystal ingot or the silicon substrate is subjected to, before the low temperature thermal treatment, high temperature thermal treatment at a temperature of more than 1200° C. for 5 minutes or more and 30 minutes or less in an atmosphere consisting of either phosphoryl chloride or nitrogen so that oxygen precipitate nuclei are dissolved and a homogeneous solid solution of oxygen precipitate nuclei is formed;
subjecting the fabricated solar cell to an electroluminescence image test to check that spiral oxygen-induced defect patterns are not observed;
wherein the conversion efficiency of the solar cell in which the spiral oxygen-induced defect patterns are not observed in the electroluminescence image test is about 20% and the variation thereof is about 0.1%.