Method for manufacturing substrate for solar cell and substrate for solar cell

A method for manufacturing a solar cell, comprising:

• producing 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;
• subjecting the Czochralski silicon single crystal ingot to 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 oxide precipitate nuclei are dissolved and a homogeneous solid solution of oxygen precipitate nuclei is formed throughout the ingot;
• slicing a silicon substrate from the Czochralski silicon single crystal ingot subjected to the high temperature thermal treatment;
• subjecting the silicon substrate to texture etching;
• 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;
• and
• subjecting the fabricated solar cell to an electroluminescence image test to check that spiral oxygen-induced defect patterns are not observed.

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%.

A method for manufacturing a solar cell, comprising:

• producing a Czochralski silicon single crystal ingot doped with a p-type dopant or an n-type dopant and containing at least 12 ppm of oxygen atoms;
• slicing a silicon substrate from the Czochralski silicon single crystal ingot;
• subjecting the silicon substrate to 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 oxide precipitate nuclei are dissolved and a homogenous solid solution of oxide precipitate nuclei is formed throughout the silicon substrate;
• subjecting the silicon substrate to texture etching either before or after the high temperature thermal treatment;
• 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;
• and
• subjecting the fabricated solar cell to an electroluminescence image test that can observe spiral oxygen-induced defect patterns.

A method for manufacturing a solar cell, comprising:

• producing a Czochralski silicon single crystal ingot doped with a p-type dopant or an n-type dopant and containing at least 12 ppm of oxygen atoms;
• slicing a silicon substrate from the Czochralski silicon single crystal ingot;
• subjecting the silicon substrate to 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 oxide precipitate nuclei are dissolved and a homogenous solid solution of oxide precipitate nuclei is formed throughout the silicon substrate wherein the silicon substrate is free from a spiral defect pattern of oxide precipitate nuclei;
• subjecting the silicon substrate to texture etching either before or after the high temperature thermal treatment;
• and
• subjecting the silicon substrate to low temperature thermal treatment at a temperature of 1200° C. or less.

A method for manufacturing a solar cell, comprising:

• producing 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;
• subjecting the Czochralski silicon single crystal ingot to 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 oxide precipitate nuclei are dissolved and a homogenous solid solution of oxide precipitate nuclei is formed throughout the Czochralski silicon single crystal ingot such that the Czochralski silicon single crystal ingot is free from a spiral defect pattern of oxide precipitate nuclei;
• slicing a silicon substrate from the Czochralski silicon single crystal ingot subjected to the high temperature thermal treatment;
• subjecting the silicon substrate to texture etching;
• 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;
• and
• subjecting the fabricated solar cell to an electroluminescence image test that can observe spiral oxygen-induced defect patterns.

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;
• 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 oxide precipitate nuclei may be dissolved and a homogenous solid solution of oxide precipitate nuclei may be formed throughout the silicon substrate;
• subjecting the silicon substrate to texture etching either before or after the high temperature thermal treatment;
• 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%.