UV-curing of light-receiving surfaces of solar cells

Patent metadata

Field	Value
Publication number	US-11374145-B2
Application number	US-201916704983-A
Country	US
Kind code	B2
Filing date	Dec 5, 2019
Priority date	Nov 11, 2016
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

Methods of fabricating solar cells using UV-curing of light-receiving surfaces of the solar cells, and the resulting solar cells, are described herein. In an example, a method of fabricating a solar cell includes forming a passivating dielectric layer on a light-receiving surface of a silicon substrate. The method also includes forming an anti-reflective coating (ARC) layer below the passivating dielectric layer. The method also includes exposing the ARC layer to ultra-violet (UV) radiation. The method also includes, subsequent to exposing the ARC layer to ultra-violet (UV) radiation, thermally annealing the ARC layer.

First claim

What is claimed is:

1. A method of fabricating a solar cell, the method comprising:
forming a passivating dielectric layer on a light-receiving surface of a silicon substrate;
forming an anti-reflective coating (ARC) layer below the passivating dielectric layer;
exposing the ARC layer to ultra-violet (UV) radiation;
subsequent to forming the ARC layer and prior to exposing the ARC layer to UV radiation, heating at a temperature approximately in the range of 200-500 degrees Celsius; and
subsequent to exposing the ARC layer to ultra-violet (UV) radiation, thermally annealing the ARC layer.

2. The method of claim 1 , wherein exposing the ARC layer to UV radiation comprises exposing the ARC layer to light having a wavelength approximately in the range of 250-450 nanometers.

3. The method of claim 1 , wherein exposing the ARC layer to UV radiation comprises exposing for a duration approximately in the range of 1 second 1 day.

4. The method of claim 1 , wherein thermally annealing the ARC layer comprises heating at a temperature approximately in the range of 200-500 degrees Celsius.

5. The method of claim 4 , wherein the heating comprises using a process selected from the group consisting of a forming gas anneal (FGA) process, a rapid thermal anneal (RTA) process, an intra-red (IR) heating process, a furnace heating process, and a laser annealing process.

6. The method of claim 1 , wherein forming the passivating dielectric layer comprises forming a thermal silicon oxide layer on a light-receiving surface of the silicon substrate, and wherein the silicon substrate is an N-type monocrystalline silicon substrate.

7. The method of claim 1 , wherein forming the passivating dielectric layer comprises forming the passivating dielectric layer by atomic layer deposition (ALD), the passivating dielectric layer selected from the group consisting of silicon oxide.

8. The method of claim 1 , wherein forming the ARC layer comprises forming a silicon nitride layer.

9. The method of claim 1 , further comprising:
subsequent to forming the passivating dielectric layer, forming an N-type micro- or poly-crystalline silicon layer on the passivating dielectric layer, wherein the ARC layer is formed on the N-type micro- or poly-crystalline silicon layer.

10. The method of claim 1 , further comprising:
subsequent to forming the passivating dielectric layer, forming an intermediate material layer on the passivating dielectric layer, the intermediate material layer selected from the group consisting of an amorphous silicon (a-Si) layer, a silicon-rich silicon nitride layer, and a Group III-V material layer, wherein the ARC layer is formed on the intermediate material layer.

11. The method of claim 1 , wherein forming the ARC layer comprises forming the ARC layer having an amount of hydrogen therein, the method further comprising:
removing at least a portion of the amount of hydrogen from the ARC layer.

12. The method of claim 11 , wherein removing the portion of the amount of hydrogen from the ARC layer is performed during the thermal annealing of the ARC layer.

13. A method of fabricating a solar cell, the method comprising:
forming a passivating dielectric layer on a light-receiving surface of a silicon substrate;
forming an anti-reflective coating (ARC) layer below the passivating dielectric layer;
increasing the saturation current density (J 0 ) at an interface at the light-receiving surface of the silicon substrate, wherein increasing the saturation current density at the interface comprises exposing the ARC layer to UV radiation having a wavelength approximately in the range of 250-450 nanometers for a duration approximately in the range of 1 second 1 day;
subsequent to forming the ARC layer and prior to exposing the ARC layer to UV radiation, heating at a temperature approximately in the range of 200-500 degrees Celsius; and
subsequent to increasing the saturation current density, thermally annealing the ARC layer.

14. The method of claim 13 , wherein thermally annealing the ARC layer comprises heating at a temperature approximately in the range of 200-500 degrees Celsius using a process selected from the group consisting of a forming gas anneal (FGA) process, a rapid thermal anneal (RTA) process, an intra-red (IR) heating process, a furnace heating process, and a laser annealing process.

15. A method of fabricating a solar cell, the method comprising:
forming a thermal silicon oxide layer on a light-receiving surface of an N-type monocrystalline silicon substrate;
forming an anti-reflective coating (ARC) layer below the thermal silicon oxide layer;
increasing the saturation current density (J 0 ) at an interface at the light-receiving surface of the silicon substrate, wherein increasing the saturation current density at the interface comprises exposing the ARC layer to UV radiation having a wavelength approximately in the range of 250-450 nanometers for a duration approximately in the range of 1 second-1 day;
subsequent to forming the ARC layer and prior to exposing the ARC layer to UV radiation, heating at a temperature approximately in the range of 200-500 degrees Celsius; and
subsequent to increasing the saturation current density, thermally annealing the ARC layer.

16. The method of claim 1 , wherein the ARC layer includes hydrogen.

17. The method of claim 1 , wherein the exposing the ARC layer to UV radiation and the thermally annealing the ARC layer reduce hydrogen bonds at the interface between the ARC layer and the passivating dielectric layer.

18. The method of claim 1 , wherein the ARC layer that is exposed to UV radiation includes silicon nitride, aluminum oxide or indium tin oxide.

19. The method of claim 1 , wherein the passivating dielectric layer includes an oxide.

Assignees

• Sunpower Corp
• Total Marketing Services

Inventors

• Shen Yu-Chen
• Jaffrennou Périne
• Poulain Gilles Olav Tanguy Sylvain
• Johnson Michael C
• Rim Seung Bum

Classifications

• H10F77/703

  of the semiconductor bodies, e.g. textured active layers · CPC title

• H10F77/311

  for photovoltaic cells · CPC title

• H10F71/128

  Annealing · CPC title

• H10F71/00 Primary

  Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00) · CPC title

• H10F10/166

  the Group IV-IV heterojunctions being heterojunctions of crystalline and amorphous materials, e.g. silicon heterojunction [SHJ] photovoltaic cells · CPC title