Ge photodetectors

• US 20030235931A1
• Filed: 12/02/2002
• Published: 12/25/2003
• Est. Priority Date: 06/19/2002
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Kimerling, Lionel C., Liu, Jifeng, Wada, Kazumi, Cannon, Douglas D., Ishikawa, Yasuhiko
• Granted Patent: US 6,812,495 B2
• Time in Patent Office: Days
• US Class Current: 438/22
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 27/146 Imager structures
• CPC Class Codes: H01L 31/103 the potential barrier being of the PN homojunction type
• CPC Class Codes: H01L 31/1808 including only Ge
• CPC Class Codes: H01L 31/1864 Annealing
• 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
• CPC Class Codes: Y10S 438/933 Germanium or silicon or Ge-Si on III-V

Abstract

A photodetector device includes a plurality of Ge epilayers that are grown on a substrate and annealed in a defined temperature range. The Ge epilayers form a tensile strained Ge layer that allows the photodetector device to operate efficiently in the C-band and L-band.

Claims

1. A photodetector device comprising:

a substrate; and

a plurality of Ge epilayers that are grown on said substrate and annealed in a defined temperature range, said Ge epilayers forming a tensile strained Ge layer that allows said photodetector device to operate efficiently in the C-band and L-band.

2. The photodetector device of claim 1, wherein said Ge epilayers are 1-micron thick.

3. The photodetector device of claim 1, wherein said Ge epilayers are approximately 0.5-micron thick.

4. The photodetector device of claim 1, wherein said tensile strained Ge layer shows bandgap shrinkage under tensile strain approximately 0.2%.

5. The photodetector device of claim 1, wherein said tensile strained Ge layer shows bandgap shrinkage under tensile strain between approximately 0.2% and 0.32%.

6. The photodetector device of claim 1, wherein said substrate is a silicon substrate.

7. The photodetector device of claim 6, wherein said epilayers are grown on said silicon substrate at 700°

C.

8. The photodetector device of claim 1, wherein said epilayers are grown on said substrate at a temperature of approximately over 600°

C.

9. The photodetector device of claim 7, wherein said epilayers are annealed at said defined temperature between 700°

C. and 900°

C.

10. The photodetector device of claim 8, wherein said epilayers are annealed using isothermal annealing at said defined temperature of 900°

C.

11. A method of forming a photodetector device, said method comprising:

forming a plurality of Ge epilayers on a substrate;

annealing said Ge epilayers in a defined temperature range; and

developing a tensile strained Ge layer using said annealed Ge epilayers, said tensile strained Ge layer allowing said photodetector device to operate efficiently in the C-band and L-band.

12. The method of claim 11, wherein said Ge epilayers are 1-micron thick.

13. The method of claim 11, wherein said Ge epilayers are approximately 0.5-micron thick.

14. The method of claim 11, wherein said tensile strained Ge layer shows bandgap shrinkage under tensile strain approximately 0.2%.

15. The method of claim 11, wherein said tensile strained Ge layer shows bandgap shrinkage under tensile strain between approximately 0.2% and 0.32%.

16. The method of claim 11, wherein said substrate is a silicon substrate.

17. The method of claim 16, wherein said epilayers are grown on said silicon substrate at 700°

C.

18. The method of claim 11, wherein said epilayers are grown on said substrate at a temperature of approximately over 600°

C.

19. The method of claim 17, wherein said epilayers are annealed at said defined temperature between 700°

C. and 900°

C.

20. The method of claim 18, wherein said epilayers are annealed using isothermal annealing at said defined temperature of 900°

C.

21. A photodetector device comprising:

a substrate; and

a plurality of SiGe epilayers that are grown on said substrate at a high temperature so as to form a SiGe structure, said SiGe epilayers forming a tensile strained SiGe layer by cooling to room temperature the SiGe structure using bi-metal effect, said tensile strained SiGe layer allowing said photodetector device to operate efficiently in the C-band and L-band.

22. The photodetector device of claim 21, wherein said SiGe epilayers are 1-micron thick.

23. The photodetector device of claim 21, wherein said SiGe epilayers are approximately 0.5-micron thick.

24. The photodetector device of claim 21, wherein said tensile strained SiGe layer shows bandgap shrinkage under tensile strain between approximately 0.2% and 0.32%.

25. The photodetector device of claim 21, wherein said substrate is a silicon substrate.

26. The photodetector device of claim 25, wherein said epilayers are grown on said silicon substrate at 700°

C.

27. The photodetector device of claim 26, wherein said epilayers are annealed using isothermal annealing at said defined temperature of 1330°

C.

28. A method of forming a photodetector device, said method comprising:

growing a plurality of SiGe epilayers on a silicon substrate at a high temperature so as to form a SiGe structure; and

forming a tensile strained SiGe layer by cooling to room temperature the SiGe structure using bi-metal effect, said tensile strained SiGe layer allowing said photodetector device to operate efficiently in the C-band and L-band.

29. The method of claim 28, wherein said Ge epilayers are 1-micron thick.

30. The method of claim 28, wherein said Ge epilayers are approximately 0.5-micron thick.

31. The method of claim 28, wherein said tensile strained Ge layer shows bandgap shrinkage under tensile strain approximately 0.2%.

32. The method of claim 28 wherein said tensile strained Ge layer shows bandgap shrinkage under tensile strain between approximately 0.2% and 0.32%.

33. The method of claim 28, wherein said substrate is a silicon substrate.

34. The method of claim 33, wherein said epilayers are grown on said silicon substrate at 700°

C.

35. The method of claim 34, wherein said epilayers are annealed using isothermal annealing at said defined temperature of 1330°

C.