SOLAR CELL AND METHOD FOR MANUFACTURING THE SAME

• US 20100206369A1
• Filed: 02/12/2010
• Published: 08/19/2010
• Est. Priority Date: 02/13/2009
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Choul, Choe, Youngho, Lee, Sungeun, KIM, Sunyoung
• Granted Patent: US 9,054,240 B2
• Time in Patent Office: Days
• US Class Current: 136/255
• CPC Class Codes: H01L 31/02167 for solar cells
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: H01L 31/022441 Electrode arrangements specially adapted for back-contact solar cells
• CPC Class Codes: H01L 31/035281 Shape of the body
• CPC Class Codes: H01L 31/03529 Shape of the potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/0682 back-junction, i.e. rearside emitter, solar cells, e.g. interdigitated base-emitter regions back-junction cells
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A solar cell and a method for manufacturing the same are disclosed. The solar cell includes a semiconductor layer containing first impurities, a first portion positioned on a first part of one surface of the semiconductor layer, the first portion being more heavily doped with second impurities different from the first impurities than the semiconductor layer, a second portion positioned on a second part of the one surface of the semiconductor layer, the second portion being more heavily doped with the first impurities than the semiconductor layer, and a third portion positioned between the first portion and the second portion, the third portion having an impurity concentration lower than an impurity concentration of the first portion and an impurity concentration of the second portion.

Claims

1. A solar cell, comprising:

a semiconductor layer containing first impurities;

a first portion positioned on a first part of one surface of the semiconductor layer, the first portion being more heavily doped with second impurities different from the first impurities than the semiconductor layer;

a second portion positioned on a second part of the one surface of the semiconductor layer, the second portion being more heavily doped with the first impurities than the semiconductor layer; and

a third portion positioned between the first portion and the second portion, the third portion having an impurity concentration lower than an impurity concentration of the first portion and an impurity concentration of the second portion.

2. The solar cell of claim 1, wherein the impurity concentration of the third portion is substantially equal to or higher than an impurity concentration of the semiconductor layer.

3. The solar cell of claim 1, wherein the first portion and the second portion are spaced apart from each other by the third portion in vertical and horizontal directions.

4. The solar cell of claim 1, wherein the first impurities are n-type impurities, and the second impurities are p-type impurities.

5. The solar cell of claim 1, wherein the first portion protrudes further than the second portion.

6. The solar cell of claim 5, wherein the third portion includes a depression based on an imaginary inclined surface between the first portion and the second portion.

7. The solar cell of claim 5, wherein the third portion includes a protrusion based on an imaginary inclined surface between the first portion and the second portion.

8. The solar cell of claim 5, wherein the third portion includes a fourth portion having a first inclination and a fifth portion having a second inclination between the first portion and the second portion, the second inclination being greater than the first inclination.

9. The solar cell of claim 8, wherein the fourth portion and the fifth portion are protrusions based on an imaginary inclined surface between the first portion and the second portion.

10. The solar cell of claim 8, wherein the first portion is positioned closer to the fourth portion than the fifth portion.

11. The solar cell of claim 5, wherein a base surface of the first portion is positioned at a higher level than an upper surface of the second portion.

12. The solar cell of claim 5, wherein a distance between the first portion and the second portion in a vertical direction is greater than a distance between the first portion and the second portion in a horizontal direction.

13. The solar cell of claim 1, further comprising an anti-reflection layer on a surface opposite the one surface of the semiconductor layer.

14. The solar cell of claim 13, wherein the one surface of the semiconductor layer is an incident surface on which light is incident.

15. A solar cell, comprising:

a semiconductor layer;

a first impurity region positioned on a first part of one surface of the semiconductor layer, the first part having a first height;

a second impurity region positioned on a second part of the one surface of the semiconductor layer, the second part having a second height different from the first height; and

a third portion positioned between the first impurity region and the second impurity region, the third portion having an inclined portion.

16. The solar cell of claim 15, wherein the inclined portion includes a depression.

17. The solar cell of claim 15, wherein the inclined portion includes a protrusion.

18. The solar cell of claim 15, wherein the inclined portion includes a fourth portion having a first inclination and a fifth portion having a second inclination between the first portion and the second portion, the second inclination being greater than the first inclination.

19. The solar cell of claim 18, wherein the fourth portion and the fifth portion are protrusions.

20. The solar cell of claim 18, wherein the first portion is positioned closer to the fourth portion than the fifth portion.

21. The solar cell of claim 15, wherein the first height is greater than the second height.

22. A method for manufacturing a solar cell, the method comprising:

doping a semiconductor substrate with first impurities to form a first impurity layer;

forming a masking layer on the first impurity layer;

forming a resist layer on the masking layer;

curing a portion of the resist layer to form a resist pattern having a first portion and a second portion;

removing the second portion of the resist layer, a portion of the masking layer underlying the second portion, and a portion of the first impurity layer underlying the second portion to expose a portion of the semiconductor substrate;

removing the first portion of the resist layer and the exposed portion of the semiconductor substrate;

forming a second impurity layer on the exposed portion of the semiconductor substrate;

removing a remaining portion of the masking layer;

forming a passivation layer on the second impurity layer and a remaining portion of the first impurity layer;

removing a portion of the passivation layer to expose a portion of the remaining portion of the first impurity layer and a portion of the second impurity layer; and

forming a first electrode connected to the exposed portion of the first impurity layer and forming a second electrode connected to the exposed portion of the second impurity layer.

23. The method of claim 22, wherein the forming of the resist pattern comprises:

forming a portion, to which light or heat is applied, as the first portion of the resist layer and forming a portion, to which the light or the heat is not applied, as the second portion of the resist layer; and

crosslinking a resist of the first portion of the resist layer.

24. The method of claim 22, wherein the removing of the portions of the masking layer and the first impurity layer underlying the second portion of the masking layer comprises removing the portions of the masking layer and the first impurity layer underlying the second portion of the masking layer using an etchant based on inorganic acid containing at least one of hydrofluoric acid, nitric acid, acetic acid, sulfuric acid, and hydrochloric acid.

25. A method for manufacturing a solar cell, the method comprising:

doping a semiconductor substrate with first impurities to form a first impurity layer;

forming a masking layer on the first impurity layer;

forming a resist layer on the masking layer;

curing a portion of the resist layer to form a resist pattern having a first portion and a second portion;

removing the second portion of the resist layer and the masking layer underlying the second portion to expose a portion of the first impurity layer;

removing the first portion of the resist layer, the exposed portion of the first impurity layer, and a portion of the semiconductor substrate underlying the exposed portion of the first impurity layer;

forming a second impurity layer on the exposed portion of the semiconductor substrate;

removing a remaining portion of the masking layer;

forming a passivation layer on the second impurity layer and a remaining portion of the first impurity layer;

removing a portion of the passivation layer to expose a portion of the remaining portion of the first impurity layer and a portion of the second impurity layer; and

forming a first electrode connected to the exposed portion of the first impurity layer and forming a second electrode connected to the exposed portion of the second impurity layer.

26. The method of claim 25, wherein the removing of the first part of the resist layer, the exposed portion of the first impurity layer, and the portion of the semiconductor substrate under the exposed portion of the first impurity layer comprises removing the first part of the resist layer, the exposed portion of the first impurity layer, and the portion of the semiconductor substrate underlying the exposed portion of the first impurity layer using a strong alkali etchant.

27. A method for manufacturing a solar cell comprising:

doping a semiconductor substrate with first impurities to form a first impurity layer;

forming a masking layer on the first impurity layer;

forming a resist layer on the masking layer;

curing a portion of the resist layer to form a resist pattern having a first portion and a second portion;

removing the second portion of the resist layer and a portion of the masking layer underlying the second portion to expose a portion of the first impurity layer;

removing the exposed portion of the first impurity layer to expose a portion of the semiconductor substrate;

doping the exposed portion of the semiconductor substrate with second impurities to form a second impurity layer;

lifting off a remaining portion of the masking layer and the first portion of the resist layer;

forming a passivation layer on the second impurity layer and a remaining portion of the first impurity layer;

removing a portion of the passivation layer to expose a portion of the remaining portion of the first impurity layer and a portion of the second impurity layer; and

forming a first electrode connected to the exposed portion of the first impurity layer and forming a second electrode connected to the exposed portion of the second impurity layer.