BACK CONTACT SOLAR CELLS USING PRINTED DIELECTRIC BARRIER

• US 20100055822A1
• Filed: 08/27/2009
• Published: 03/04/2010
• Est. Priority Date: 08/27/2008
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Mishra, Rohit, Weidman, Timothy W., Holtam, Tristan, Stewart, Michael P., Cha, Yonghwa Chris, Wijekoon, Kapila P., Shah, Vinay
• Granted Patent: US 7,951,637 B2
• Time in Patent Office: Days
• US Class Current: 438/57
• CPC Class Codes: H01L 21/225 using diffusion into or out of a solid from or into a solid phase, e.g. a doped oxide layer H01L21/221 - H01L21/222 take precedence
• CPC Class Codes: H01L 21/306 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/31
• CPC Class Codes: H01L 21/308 using masks H01L21/3063, H01L21/3065 take precedence
• CPC Class Codes: H01L 21/67034 for drying
• CPC Class Codes: H01L 21/67727 using a general scheme of a conveying path within a factory
• CPC Class Codes: H01L 21/67736 Loading to or unloading from a conveyor
• CPC Class Codes: H01L 21/67745 characterized by movements or sequence of movements of transfer devices
• CPC Class Codes: H01L 21/6776 Continuous loading and unloading into and out of a processing chamber, e.g. transporting belts within processing chambers
• CPC Class Codes: H01L 31/022441 Electrode arrangements specially adapted for back-contact solar cells
• CPC Class Codes: H01L 31/0516 specially adapted for interconnection of back-contact 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 31/1804 comprising only elements of Group IV of the Periodic Table
• 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

Embodiments of the invention contemplate the formation of a high efficiency solar cell using novel methods to form the active doped region(s) and the metal contact structure of the solar cell device. In one embodiment, the methods include the steps of depositing a dielectric material that is used to define the boundaries of the active regions and/or contact structure of a solar cell device. Various techniques may be used to form the active regions of the solar cell and the metal contact structure.

Claims

1. An apparatus for forming solar cell device, comprising:

an automation assembly configured to receive a substrate for processing;

a plurality of transport elements that each have a substrate supporting surface coupled to the automation assembly;

a first deposition station having a screen printing mask adapted to form a dopant material comprising a first dopant material on a plurality of regions on a first surface of the substrate disposed on the substrate support surface of the transport element in the automation assembly;

at least one drying chamber adapted to dry the first dopant material formed on the substrate disposed on the substrate supporting surface of the transport element in the automation assembly; and

a second deposition station adapted to form a dielectric layer over the first dopant material and a portion of the first surface of the substrate, wherein the dielectric layer comprises a second dopant material that is an opposite doping type of the first dopant material.

2. The apparatus of claim 1, further comprising:

an electromagnetic radiation source positioned in the automation assembly adapted to emit electromagnetic radiation towards the substrate surface disposed on the substrate support surface of the transport element in the automation assembly.

3. The apparatus of claim 1, further comprising:

a heating chamber adapted to heat the substrate to a desired temperature to cause the first and the second dopant materials to diffuse into the substrate.

4. The apparatus of claim 1, further comprising:

a third deposition station adapted to form a conductive material over the first surface of the substrate disposed on the substrate support surface of the transport element in the automation assembly.

5. The apparatus of claim 1, further comprising:

a first wet processing chamber configured to texture the first surface or a second surface of the substrate disposed on the substrate support surface of the transport element in the automation assembly.

6. The apparatus of claim 1, further comprising:

a second wet processing chamber configured to clean the first surface of the substrate disposed on the substrate support surface of the transport element in the automation assembly.

7. The apparatus of claim 1, further comprising:

a third deposition station having a screen printing mask adapted to provide etching material to etch one or more regions of the dielectric layer, wherein the etching material includes a doping element, wherein residual of the doping element from the etching material is left at the exposed surface of the substrate after etching.

8. A method of forming a solar cell device, comprising:

disposing a dopant material comprising a first dopant on a plurality of regions of a first surface of a substrate in a first deposition station disposed in an automation assembly, wherein the first deposition station comprises a screen printing mask and at least one actuator configured to position the screen printing mask;

forming a dielectric layer over the dopant material and a portion of the surface of the substrate in a second deposition station disposed in the automation assembly, wherein the dielectric layer comprises a second dopant that is an opposite doping type of the first dopant;

heating the substrate to a desired temperature in a heating chamber disposed in the automation assembly to cause the first and the second dopants to diffuse into the first surface of the substrate; and

depositing a conducting layer over the first surface of the substrate in a third deposition station disposed in the automation assembly.

9. The method of claim 8, further comprising:

cleaning the first surface of the substrate in a first wet processing chamber disposed in the automation assembly prior to or after heating the substrate.

10. The method of claim 8, further comprising:

texturing the first surface or a second surface of the substrate in a second wet processing chamber disposed in the automation assembly.

11. The method of claim 10, further comprising:

forming a second dielectric layer over the first surface of the substrate after texturing the first surface of the substrate; and

patterning the second dielectric layer to form a plurality of regions, wherein the plurality of regions are adapted to expose portion of the first and the second dopants diffused into the substrate.

12. The method of claim 8, further comprising:

forming a capping layer over the dielectric layer in the second deposition station disposed in the automation assembly before heating the substrate.

13. The method of claim 12, further comprising:

etching one or more regions of the dielectric layer or capping layer in a fourth deposition chamber comprising a screen printing mask by using an etching material that containing a doping element, wherein residual of the doping element from the etching material is left at the exposed surface of the substrate after etching; and

heating the substrate and the doping element residual to a desired temperature to cause doping elements to diffuse into the substrate.

14. The method of claim 13, further comprising:

forming a plurality of spacer materials between regions having the first and the second dopants.

15. A method of forming a solar cell device, comprising:

disposing a dielectric material on a plurality of regions on a first surface of a substrate;

disposing a first dopant material on the surface of the substrate; and

disposing a second dopant material on the surface of the substrate, wherein at least a portion of the first and second dopant materials are separated from each other by the dielectric material.

16. The method of claim 15, further comprising:

heating the substrate to a desired temperature to cause the first and the second dopant materials to diffuse into the first surface of the substrate.

17. The method of claim 16, further comprising:

removing the dielectric material disposed on the first surface of the substrate while texturing a second surface of the substrate.

18. The method of claim 17, further comprising:

forming a dielectric layer over the first surface of the substrate;

etching the dielectric layer to form a plurality of regions to expose portion of the first surface of the substrate; and

forming a conductive layer on the dielectric layer and the exposed portion of the substrate.

19. The method of claim 16, further comprising:

depositing a conducting layer over the first surface of the substrate.

20. The method of claim 19, further comprising:

removing a portion of the conducting layer to electrically isolate at least one region of the conducting layer in contact with a region of the first substrate surface on which a first dopant material was disposed and at least one region of the conducting layer in contact with a region of the first substrate surface on which a second dopant material was disposed.

21. The method of claim 19, further comprising:

removing dielectric material disposed on the first surface of the substrate before depositing the conducting layer.

22. The method of claim 15, further comprising:

disposing a spacer material on a plurality of regions of the first surface of the substrate.

23. The method of claim 15, further comprising:

removing material from a second surface of the substrate to form a desirable roughness on the second surface.

24. The method of claim 15, further comprising:

etching one or more regions of the first dopant material to expose a portion of the first surface of the substrate, wherein a dopant containing residue is left at the exposed surface of the substrate; and

heating the substrate, the first dopant material and dopant containing residue to a desired temperature to cause the doping atoms in the first dopant material and the dopant containing residue to diffuse into the substrate.

25. The method of claim 24, wherein etching one or more regions of the doped dielectric layer further comprises:

using an etching material that contains a third doping material, wherein the third doping material contains a doping atom that is different than the first doped material.