Multi-wafer based light absorption apparatus and applications thereof

• US 9,991,411 B2
• Filed: 06/19/2017
• Issued: 06/05/2018
• Est. Priority Date: 07/24/2015
• Status: Active Grant

• Current Assignee: Artilux, Inc.
• Original Assignee: Artilux Corporation
• Inventors: Cheng, Szu-Lin, Liu, Han-Din, Chen, Shu-Lu, Na, Yun-Chung, Chen, Hui-Wen
• Primary Examiner(s): Gerbreyesus, Yosef
• Application Number:
  US15/626,969
• Publication Number:
  US 20170294550A1
• Time in Patent Office: 351 Days
• CPC Class Codes: H01L 27/14629 Reflectors
• CPC Class Codes: H01L 27/14634 Assemblies, i.e. Hybrid structures
• CPC Class Codes: H01L 27/1469 Assemblies, i.e. hybrid integration
• CPC Class Codes: H01L 31/02005 for device characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/02161 for devices characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• 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 31/0549 comprising spectrum splitting means, e.g. dichroic mirrors
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 31/107 the potential barrier working in avalanche mode, e.g. avalanche photodiodes
• CPC Class Codes: H01L 31/1812 including only AIVBIV alloys, e.g. SiGe
• CPC Class Codes: H01L 31/1892 methods involving the use of temporary, removable substrates
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells

Abstract

Structures and techniques introduced here enable the design and fabrication of photodetectors (PDs) and/or other electronic circuits using typical semiconductor device manufacturing technologies meanwhile reducing the adverse impacts on PDs'"'"' performance. Examples of the various structures and techniques introduced here include, but not limited to, a pre-PD homogeneous wafer bonding technique, a pre-PD heterogeneous wafer bonding technique, a post-PD wafer bonding technique, their combinations, and a number of mirror equipped PD structures. With the introduced structures and techniques, it is possible to implement PDs using typical direct growth material epitaxy technology while reducing the adverse impact of the defect layer at the material interface caused by lattice mismatch.

Claims

1. A method for fabricating a photodetector using a donor wafer and a carrier wafer, the method comprising:

forming a photosensitive material layer on a front side of the donor wafer;

forming a passivation layer on top of the photosensitive material layer;

performing a wafer bonding process to bond together the donor wafer and the carrier wafer, the passivation layer facing a front side of the carrier wafer; and

removing at least a part of threading dislocation density (TDD) defects near an interface between the photosensitive material layer and a substrate of the donor wafer by removing at least a portion of a back side of the donor wafer.

2. The method of claim 1, wherein the photosensitive material layer comprises a number of Si_xGe_(1-x) layers, wherein 0≤

x<

1.

3. The method of claim 2, wherein, in the number of Si_xGe_(1-x) layers, an x value of one Si_xGe_(1-x) layer is different than another Si_xGe_(1-x) layer.

4. The method of claim 1, wherein the passivation layer comprises a material also contained on top of the carrier wafer.

5. The method of claim 4, wherein the material also contained on top of the carrier wafer comprises silicon.

6. The method of claim 1, wherein the passivation layer comprises a semiconductor material that is not silicon-germanium based but exhibits a passivation effect to the photosensitive material layer.

7. The method of claim 1, wherein the passivation layer comprises a semiconductor material that is lattice-matched to germanium.

8. The method of claim 7, where the semiconductor material is gallium arsenide.

9. The method of claim 1, wherein forming the photosensitive material layer comprises:

doping the photosensitive material layer according to a predetermined doping profile suitable for the photodetector.

10. The method of claim 1, further comprising:

doping the passivation layer by impurities.

11. The method of claim 1, further comprising:

doping the passivation layer and the carrier wafer by a same kind of dopant.

12. The method of claim 11, wherein the dopant is N-type.

13. The method of claim 1, further comprising:

polishing the front side of the donor wafer after forming the passivation layer and prior to performing the wafer bonding process.

14. The method of claim 1, further comprising:

annealing the donor wafer after forming the passivation layer and prior to performing the wafer bonding process.

15. The method of claim 1, further comprising:

patterning the carrier wafer prior to the wafer bonding process.

16. The method of claim 1, further comprising:

forming another passivation layer on the front side of the carrier wafer prior to the wafer bonding process.

17. The method of claim 1, wherein the wafer bonding process includes one or more of:

a dry wafer bonding, a wet wafer bonding, a chemical wafer bonding, or a plasma assisted wafer bonding.

18. The method of claim 1, further comprising:

fabricating other portions of the photodetector on the carrier wafer.

19. The method of claim 1, further comprising:

prior to forming the photosensitive material layer, forming a separation layer on the donor wafer.

20. The method of claim 1, wherein the method is performed prior to a completion of active components of the photodetector.

21. A semiconductor fabrication system including one or more machines for fabricating a photodetector using a donor wafer and a carrier wafer, the one or more machines configured to perform operations comprising:

forming a photosensitive material layer on a front side of the donor wafer;

forming a passivation layer on top of the photosensitive material layer;

performing a wafer bonding process to bond together the donor wafer and the carrier wafer, the passivation layer facing a front side of the carrier wafer; and

removing at least a part of threading dislocation density (TDD) defects near an interface between the photosensitive material layer and a substrate of the donor wafer by removing at least a portion of a back side of the donor wafer.