Method of manufacturing solar cell

1. A method of manufacturing a solar cell, the method comprising:

forming a silicon oxide film on a semiconductor substrate; and

successively exposing the silicon oxide film to a temperature in a range of 570° C. to 700° C. to anneal the silicon oxide film,

wherein the silicon oxide film is slowly heated from a temperature lower than 700° C. to about 700° C. for a first time period, maintained at the temperature of about 700° C. for a second time period, and then slowly cooled to the lower temperature for a third time period during annealing, and

wherein a temperature increase per minute for the first time period is about a 10° C. increase per minute.

2. The method according to claim 1 , wherein the first time period is 8 to 12 minutes.

3. The method according to claim 1 , wherein the lower temperature is equal to or higher than 600° C.

4. The method according to claim 1 , wherein the second time period is 12 to 18 minutes.

5. The method according to claim 1 , wherein a temperature decrease per minute for the third time period is smaller than a temperature increase per minute for the first time period.

6. The method according to claim 5 , wherein the temperature decrease per minute for the third time period is about a 10° C. decrease per minute.

7. The method according to claim 1 , wherein the first time period is shorter than the second time period or the third time period.

8. The method according to claim 1 , wherein a sum of the first time period, the second time period and the third time period is less than or equal to than 1 hour.

9. The method according to claim 1 , wherein the forming of the silicon oxide film and the exposing the silicon oxide film to the temperature in the range of 570° C. to 700° C. are performed through an in-situ process.

10. The method according to claim 1 , wherein the silicon oxide film is formed by wet-etching a surface of the semiconductor substrate, exposing the surface of the semiconductor substrate, or using thermal oxidation.

11. The method according to claim 10 , wherein the silicon oxide film is SiO 2 .

12. The method according to claim 11 , wherein the silicon oxide is converted into a tunneling layer, and a thickness of the tunneling layer is in a range of 1 to 1.5 nm.

13. A method of manufacturing a solar cell, the method comprising:

forming a silicon oxide film on a semiconductor substrate at a first temperature;

annealing the silicon oxide film at a second temperature to form a tunneling layer; and

forming a polysilicon film on the tunneling layer,

wherein the silicon oxide film is slowly heated from a temperature lower than 700° C. to about 700° C. for a first time period, maintained at the temperature of about 700° C. for a second time period, and then slowly cooled to the lower temperature for a third time period during annealing, and

wherein a temperature increase per minute for the first time period is about a 10° C. increase per minute.

14. The method according to claim 13 , wherein the silicon oxide film is formed through chemical oxidation in the forming of the silicon oxide film, and

wherein annealing is performed in a chamber at the second temperature in the forming of the tunneling layer.

15. The method according to claim 13 , wherein the silicon oxide film is formed through thermal oxidation in a chamber in the forming of the silicon oxide film, and

wherein the forming of the tunneling layer is successively performed in the chamber through an in-situ process.

16. The method according to claim 15 , wherein the first temperature is the same as the second temperature.

17. The method according to claim 16 , wherein the second temperature is in a range of 570° C. to 700° C.

18. The method according to claim 13 , wherein the polysilicon film is formed by directly depositing polysilicon on the tunneling layer.