Process for producing photovoltaic devices

• US 20030044539A1
• Filed: 08/07/2002
• Published: 03/06/2003
• Est. Priority Date: 02/06/2001
• Status: Abandoned Application

• Current Assignee: BP Corporation North America Incorporated (BP PLC)
• Original Assignee: BP Corporation North America Incorporated (BP PLC)
• Inventors: Oswald, Robert S.
• Application Number:
  US10/214,227
• Publication Number:
  US 20030044539A1
• Time in Patent Office: Days
• US Class Current: 427/404
• CPC Class Codes: H01L 31/03921 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/075 the potential barriers being only of the PIN type, e.g. amorphous silicon PIN solar cells
• CPC Class Codes: H01L 31/202 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/206 Particular processes or apparatus for continuous treatment of the devices, e.g. roll-to roll processes, multi-chamber deposition
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A continuous process for depositing a thin film layer or layers on a substrate during the production of thin film photovoltaic devices comprising moving the substrate at an elevated temperature in a reduced pressure environment past one or more sources of material to be deposited thereby forming on the substrate at least one thin film of the material from the source.

Claims

1. A process for making a photovoltaic device comprising depositing at least one thin film layer on a substrate using one or more sources of material to be deposited, whereby the substrate and a means for depositing the material move in opposite relation to each other thereby forming on the substrate at least one thin film of the material.

2. The process of claim 1 wherein the material deposited comprises one or more of a transparent conductive oxide, amorphous silicon or a metal.

3. The process of claim 1 wherein the process is a continuous process.

4. The process of claim 1 wherein the process is a semi-continuous process.

5. The process of claim 1 comprising the steps of depositing a layer comprising a transparent conductive oxide layer, depositing at least one layer comprising amorphous silicon and depositing at least one layer comprising a metal, and wherein all the layers are deposited at a relatively similar elevated temperature and a relatively similar reduced pressure.

6. The process of claim 5 wherein the depositing steps are accomplished wherein there is no more than about a 20°

C. difference in temperature between each step.

7. The process of claim 6 wherein as between two sequential deposition steps the pressure surrounding the substrate does not vary by more than about 10 Torr between each step.

8. The process of claim 1 further comprising laser scribing at least one layer.

9. The process of claim 5 further comprising laser scribing at least one layer.

10. The process of claim 9 wherein the laser scribing is conducted at about the same pressure and at about the same temperature used to deposit the layer scribed.

11. A process for making a photovoltaic device comprising (a) depositing a CTO layer on a substrate by moving the substrate past one or more sources of the CTO layer, (b) scribing the CTO layer, (c) depositing an amorphous silicon layer on the substrate by moving the substrate past one or more sources of the amorphous silicon;

(d) scribing the amorphous silicon layer; and

(e) depositing a metal layer on the substrate by moving the substrate past one or more sources of the metal layer and (f) laser scribing the metal layer, where each of the steps (a) through (e) are conducted at or about the same pressure.

12. The process of claim 11 wherein each of steps (a) through (e) are conducted at or about the same temperature.

13. An apparatus suitable for manufacturing a semiconductor layer comprising a means for transporting a substrate;

at least one deposition chamber for maintaining a pressure below atmospheric pressure;

a means for continuously depositing a semiconductor layer on a substrate as a substrate and the means for depositing the semiconductor layer move in opposite relation to each other.

14. The apparatus of claim 13 further comprising a means for depositing a metal layer on a substrate as a substrate and the means for depositing the metal layer move in opposite relation to each other.

15. An apparatus for depositing at least one layer on a substrate to form a photovoltaic device comprising:

a means for transporting the substrate, at least one deposition chamber, a means for depositing photovoltaically active layers on the substrate, means for depositing a front contact layer on the substrate, means for depositing a back contact layer on the substrate, wherein at least one of the depositing means can accomplish the deposition in a continuous manner as the substrate passes the depositing means.

16. The apparatus of claim 15 further comprising at least one laser for scribing at least one layer.

17. The apparatus of claim 16 further comprising a laser scribing chamber and wherein at least one laser is positioned outside the chamber and the chamber having a window to permit the passage of laser light beams into the chamber.

18. The apparatus of claim 15 wherein at least one of the depositing means is stationary.

19. The apparatus of claim 16 further comprising at least one laser scanner.

20. The apparatus of claim 15 wherein the deposition chamber is a low-pressure deposition chamber.

21. A photovoltaic device formed by depositing one or more layers on a substrate wherein at least one of the layers is deposited in a continuous manner as the substrate and means for depositing the layer move in opposite relation to each other.

22. The photovoltaic device of claim 21 comprising at least one amorphous silicon layer.

23. The photovoltaic device of claim 22 comprising at least one p-i-n junction.

27. A building facade comprising the photovoltaic devices of claim 21.

24. A semiconductor layer having an oscillating level of impurities through at least a portion of the depth of the layer.

25. The semiconductor layer of claim 24 that is photovoltaically active.

26. A photovoltaic device comprising a semiconductor layer of claim 24.