PHOTOVOLTAIC DEVICE AND METHOD OF MANUFACTURING PHOTOVOLTAIC DEVICES

• US 20110189811A1
• Filed: 04/08/2011
• Published: 08/04/2011
• Est. Priority Date: 05/31/2007
• Status: Abandoned Application

• Current Assignee: Thinsilicon Corporation
• Original Assignee: Thinsilicon Corporation
• Inventors: Stephens, Jason M., Coakley, Kevin Michael, Hussen, Guleid
• Application Number:
  US13/083,084
• Publication Number:
  US 20110189811A1
• Time in Patent Office: Days
• US Class Current: 438/72
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/046 PV modules composed of a plurality of thin film solar cells deposited on the same substrate
• CPC Class Codes: H01L 31/1872 Recrystallisation
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A photovoltaic device includes a supporting layer, a semiconductor layer stack, and a conductive and light transmissive layer. The supporting layer is proximate to a bottom surface of the device. The semiconductor layer stack includes first and second semiconductor sub-layers, with the second sub-layer having a crystalline fraction of at least approximately 85%. A conductive and light transmissive layer between the supporting layer and the semiconductor layer stack, where an Ohmic contact exists between the first semiconductor sub-layer and the conductive and light transmissive layer.

Claims

1. A method for manufacturing a photovoltaic device, the method comprising:

providing a supporting layer proximate to a bottom surface of the device;

depositing a conductive and light transmissive layer above the supporting layer;

depositing a semiconductor layer stack in an amorphous state above the conductive and light transmissive layer, the semiconductor layer stack comprising first and second sub-layers; and

increasing a level of crystallinity in the second sub-layer, the second sub-layer having a crystalline fraction of at least approximately 85% after increasing the level of crystallinity.

2. The method of claim 1, wherein the semiconductor layer stack comprises a third sub-layer, the second sub-layer disposed between the first and third sub-layers, the first and third sub-layers each doped with different types of dopants.

3. The method of claim 2, wherein a first dopant junction exists between the first and second sub-layers and a second dopant junction exists between the second and third sub-layers, and a junction diffusion width of each of the first and second dopant junctions is 100 nanometers or less after increasing the level of crystallinity in the second sub-layer.

4. The method of claim 2, wherein a dopant junction exists between the first and second sub-layers, the dopant junction having a junction diffusion width that does not increase by more than approximately 50 nanometers during increasing the crystallinity of the second sub-layer.

5. The method of claim 1, wherein increasing the level of crystallinity occurs after depositing the conductive and light transmissive layer.

6. The method of claim 1, wherein the supporting layer has a softening point below 750 degrees Celsius.

7. The method of claim 1, wherein the semiconductor layer stack remains in a solid state during increasing the level of crystallinity in the second sub-layer.

8. The method of claim 1, wherein increasing the level of crystallinity comprises exposing the second sub-layer to one or more electron beams or one or more continuous-wave laser beams.

9. A method for manufacturing a photovoltaic device, the method comprising:

providing a substrate;

depositing a reflective electrode above the substrate;

depositing an optical spacer layer above the reflective electrode, the optical spacer layer comprising a conductive and light transmissive material;

depositing a semiconductor layer stack above the optical spacer layer, the semiconductor layer stack deposited in an amorphous state, the semiconductor layer stack comprising first and second sub-layers;

increasing a level of crystallinity in the second sub-layer, the second sub-layer having a crystalline fraction of at least 85% after increasing the level of crystallinity; and

depositing a light transmissive electrode above the semiconductor layer stack.

10. The method of claim 9, wherein the semiconductor layer stack remains in a solid state during increasing the level of crystallinity in the second sub-layer.

11. The method of claim 9, wherein increasing the level of crystallinity comprises exposing the second sub-layer to one or more electron beams.

12. The method of claim 9, wherein increasing the level of crystallinity comprises heating the second sub-layer at a rate of at least approximately 400 degrees Celsius per second.

13. The method of claim 9, wherein increasing the level of crystallinity comprises exposing the second sub-layer to one or more continuous-wave laser beams.

14. A method for manufacturing a photovoltaic device, the method comprising:

providing a light transmissive superstrate;

depositing a light transmissive electrode above the superstrate;

depositing a semiconductor layer stack above the light transmissive electrode, the semiconductor layer stack deposited in an amorphous state, the semiconductor layer stack comprising first and second sub-layers;

increasing a level of crystallinity in the second sub-layer, the second sub-layer having a crystalline fraction of at least 85% after increasing the level of crystallinity;

depositing an optical spacer layer above the semiconductor layer stack, the optical spacer layer comprising a conductive and light transmissive material; and

depositing a reflective electrode above the optical spacer layer.

15. The method of claim 14, wherein an Ohmic contact exists between the semiconductor layer stack and the optical spacer layer.

16. The method of claim 14, wherein increasing the level of crystallinity occurs after depositing the light transmissive electrode.

17. The method of claim 14, wherein the superstrate has a softening point below 750 degrees Celsius.

18. The method of claim 14, wherein increasing the level of crystallinity comprises exposing the second sub-layer to one or more electron beams.

19. The method of claim 14, wherein increasing the level of crystallinity comprises heating the second sub-layer at a rate of at least approximately 400 degrees Celsius per second.

20. The method of claim 14, wherein increasing the level of crystallinity comprises exposing the second sub-layer to one or more continuous-wave laser beams.