PASSIVATED CONTACT FORMATION USING ION IMPLANTATION

• US 20170141254A1
• Filed: 11/11/2016
• Published: 05/18/2017
• Est. Priority Date: 11/13/2015
• Status: Active Grant

• Current Assignee: Alliance For Sustainable Energy LLC
• Original Assignee: Alliance For Sustainable Energy LLC
• Inventors: STRADINS, Pauls, YOUNG, David L., NEMETH, William
• Granted Patent: US 9,985,159 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 31/02167 for solar cells
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/028 including, apart from doping material or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/0288 characterised by the doping material
• CPC Class Codes: H01L 31/061 the potential barriers being of the point-contact type H01L31/07 takes precedence
• 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 31/0687 Multiple junction or tandem solar cells
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/1864 Annealing
• CPC Class Codes: H01L 31/1872 Recrystallisation
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials
• 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

Methods for forming passivated contacts include implanting compound-forming ions into a substrate to about a first depth below a surface of the substrate, and implanting dopant ions into the substrate to about a second depth below the surface. The second depth may be shallower than the first depth. The methods also include annealing the substrate.

Claims

1. A method comprising:

implanting compound-forming ions into a substrate to about a first depth below a surface of the substrate;

implanting dopant ions into the substrate to about a second depth below the surface, the second depth being shallower than the first depth; and

annealing the substrate.

2. The method of claim 1, wherein the annealing of the substrate forms a compound layer at about the first depth and a doped layer at least between about the second depth and the surface of the substrate.

3. The method of claim 2, wherein the compound layer is configured to provide carrier transport.

4. The method of claim 2, wherein the compound layer has a thickness of about 10 nanometers or less.

5. The method of claim 2, wherein the compound layer comprises a layer having one or more areas substantially free of compound-forming atoms, the one or more areas being permeable by dopants.

6. The method of claim 2, wherein the doped layer has a monocrystalline structure.

7. The method of claim 6, further comprising depositing at least one additional layer on the surface of the substrate via epitaxial growth.

8. The method of claim 1, further comprising depositing metal on the surface of the substrate to form at least one low resistance contact.

9. The method of claim 1, further comprising depositing one or more additional layers on the surface of the substrate.

10. The method of claim 9, wherein the one or more additional layers form a portion of a multi junction solar cell.

11. The method of claim 1, wherein the compound-forming ions and the dopant ions are implanted into a functional region of the substrate.

12. The method of claim 1, wherein the annealing of the substrate comprises:

performing a first anneal of the substrate prior to implanting the dopant ions; and

performing a second anneal of the substrate subsequent to implanting the dopant ions.

13. The method of claim 1, wherein:

the first depth is between about 20 nanometers below the surface of the substrate and about 300 nanometers below the surface of the substrate, and

the second depth is between about 10 nanometers below the surface of the substrate and about 300 nanometers below the surface of the substrate.

14. The method of claim 1, wherein the compound-forming ions comprise at least one of oxygen ions, nitrogen ions, or hafnium ions.

15. The method of claim 1, wherein the dopant ions comprise at least one of phosphorus ions, arsenic ions, antimony ions, boron ions, aluminum ions, indium ions, or gallium ions.

16. The method of claim 1, wherein the substrate comprises monocrystalline silicon.

17. A method comprising:

creating a first region within a substrate by using an ion implantation device, wherein;

the first region includes compound-forming ions,

the first region extends from about a first depth below a surface of the substrate to about a second depth below the surface of the substrate, and

the second depth is shallower than the first depth;

creating a second region within the substrate by using the ion implantation device, wherein;

the second region includes dopant ions,

the second region extends from about a third depth below the surface of the substrate to about a fourth depth below the surface of the substrate,

the fourth depth is shallower than the third depth; and

annealing the substrate, thereby transforming the first region into a compound layer and transforming the second region into a doped layer.

18. The method of claim 17, wherein the third depth is shallower than the second depth.

19. The method of claim 17, wherein:

the creating of the second region comprises leaving a gap region between the third depth and the second depth,

the gap region has a monocrystalline structure, and

the annealing of the substrate transforms the gap region into a portion of the doped layer.

20. The method of claim 17, wherein:

the creating of the second region comprises leaving a gap region between the fourth depth and the surface of the substrate,

the gap region has a monocrystalline structure, and

the annealing of the substrate transforms the gap region into a portion of the doped layer.