Solar cell having an emitter region with wide bandgap semiconductor material

• US 10,490,685 B2
• Filed: 12/21/2018
• Issued: 11/26/2019
• Est. Priority Date: 03/23/2012
• Status: Active Grant

• Current Assignee: Maxeon Solar Pte Limited
• Original Assignee: Sunpower Corporation (Totalenergies Se)
• Inventors: Swanson, Richard M., Bunea, Marius M., Johnson, Michael C., Smith, David D., Shen, Yu-Chen, Cousins, Peter J., Dennis, Tim
• Primary Examiner(s): Booth, Richard A
• Application Number:
  US16/230,968
• Publication Number:
  US 20190131477A1
• Time in Patent Office: 340 Days
• CPC Class Codes: H01L 31/02167 for solar cells
• CPC Class Codes: H01L 31/022441 Electrode arrangements specially adapted for back-contact solar cells
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/068 the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
• 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 31/072 the potential barriers being only of the PN heterojunction type
• CPC Class Codes: H01L 31/0745 comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells
• CPC Class Codes: H01L 31/0747 comprising a heterojunction of crystalline and amorphous materials, e.g. heterojunction with intrinsic thin layer
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/546 Polycrystalline silicon PV cells
• 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

Solar cells having emitter regions composed of wide bandgap semiconductor material are described. In an example, a method includes forming, in a process tool having a controlled atmosphere, a thin dielectric layer on a surface of a semiconductor substrate of the solar cell. The semiconductor substrate has a bandgap. Without removing the semiconductor substrate from the controlled atmosphere of the process tool, a semiconductor layer is formed on the thin dielectric layer. The semiconductor layer has a bandgap at least approximately 0.2 electron Volts (eV) above the bandgap of the semiconductor substrate.

Claims

1. A solar cell, comprising:

a semiconductor substrate;

a first oxide layer disposed on a first region of the semiconductor substrate;

a first emitter region of a first conductivity type above the first region of the semiconductor substrate and on the first oxide layer, wherein the first emitter region comprises a polycrystalline semiconductor material;

a second oxide layer disposed on a second region of the semiconductor substrate; and

a second emitter region of a second conductivity type above the second region of the semiconductor substrate and on second oxide layer, the second conductivity type opposite the first conductivity type, wherein the second emitter region comprises an amorphous silicon.

2. The solar cell of claim 1, wherein the semiconductor substrate is an N-type doped single crystalline silicon substrate.

3. The solar cell of claim 1, wherein the polycrystalline semiconductor material comprises silicon.

4. The solar cell of claim 1, wherein the first conductivity type is N-type, and the second conductivity type is P-type.

5. The solar cell of claim 1, wherein the first conductivity type is P-type, and the second conductivity type is N-type.

6. The solar cell of claim 1, wherein the amorphous silicon has a dopant concentration approximately in the range of 1×

10¹⁷-1×

10²¹ atoms/cm³.

7. The solar cell of claim 1, wherein the first oxide layer comprises silicon.

8. The solar cell of claim 1, wherein the second oxide layer comprises silicon.

9. A solar cell, comprising:

a semiconductor substrate;

a first oxide layer disposed on a first region of the semiconductor substrate;

a first emitter region of a first conductivity type above the first region of the semiconductor substrate and on the first oxide layer, wherein the first emitter region comprises a polycrystalline semiconductor material;

a second oxide layer disposed on a second region of the semiconductor substrate;

a second emitter region of a second conductivity type above the second region of the semiconductor substrate and on second oxide layer, the second conductivity type opposite the first conductivity type, wherein the second emitter region comprises an amorphous silicon; and

a doping material on the second emitter region.

10. The solar cell of claim 9, wherein the semiconductor substrate is an N-type doped single crystalline silicon substrate.

11. The solar cell of claim 9, wherein the polycrystalline semiconductor material comprises silicon.

12. The solar cell of claim 9, wherein the first conductivity type is N-type, and the second conductivity type is P-type.

13. The solar cell of claim 9, wherein the first conductivity type is P-type, and the second conductivity type is N-type.

14. The solar cell of claim 9, wherein the amorphous silicon has a dopant concentration approximately in the range of 1×

10¹⁷-1×

10²¹ atoms/cm³.

15. The solar cell of claim 9, wherein the first oxide layer comprises silicon.

16. The solar cell of claim 9, wherein the second oxide layer comprises silicon.