Optoelectronic device

• US 10,185,203 B1
• Filed: 09/08/2017
• Issued: 01/22/2019
• Est. Priority Date: 07/05/2017
• Status: Active Grant

• Current Assignee: Rockley Photonics Limited
• Original Assignee: Rockley Photonics Limited
• Inventors: Yu, Guomin, Abediasl, Hooman, Lerose, Damiana, Nagra, Amit Singh, Srinivasan, Pradeep, Jones, Haydn Frederick
• Primary Examiner(s): Dinh, Jack
• Application Number:
  US15/700,055
• Publication Number:
  US 20190011799A1
• Time in Patent Office: 501 Days
• CPC Class Codes: G01J 1/0425 using optical fibers
• CPC Class Codes: G01J 5/024 Special manufacturing steps or sacrificial layers or layer structures
• CPC Class Codes: G01J 5/0818 Waveguides
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G02B 6/131 by using epitaxial growth epitaxial growth for semiconductors H01L21/02365
• CPC Class Codes: G02B 6/136 by etching
• CPC Class Codes: G02F 1/0102 Constructional details, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/025 in an optical waveguide structure G02F1/017, G02F1/2257 take precedence
• CPC Class Codes: G02F 1/225 in an optical waveguide structure
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H10K 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one organic radiation-sensitive element covered by group H10K30/00
• CPC Class Codes: Y02P 80/30 Reducing waste in manufacturing processes; Calculations of released waste quantities

Abstract

An optoelectronic device and method of making the same. The device comprising: a substrate; a regrown cladding layer, on top of the substrate; and an optically active region, above the regrown cladding layer; wherein the regrown cladding layer has a refractive index which is less than a refractive index of the optically active region, such that an optical mode of the optoelectronic device is confined to the optically active region, and wherein the optically active region is formed of: SiGeSn, GeSn, InGaNAs, or InGaNAsSb.

Claims

1. An optoelectronic device, comprising:

a substrate;

a regrown cladding layer, on the substrate;

an insulating layer;

an optically active region, above the regrown cladding layer;

a first waveguide; and

a second waveguide,

wherein;

the regrown cladding layer has a refractive index which is less than a refractive index of the optically active region, such that an optical mode of the optoelectronic device is confined to the optically active region,

the optically active region is formed of;

SiGeSn, GeSn, InGaNAs, or InGaNAsSb,

the insulating layer is directly on the substrate, over a first region of the substrate,

the regrown cladding layer is on the substrate, over a second region of the substrate, different from the first region of the substrate,

the first waveguide is on the insulating layer,

the second waveguide is in the optically active region,

the substrate is a silicon substrate,

the insulating layer is an oxide layer,

the first waveguide is over the first region of the substrate and extends to a boundary between the first region of the substrate and the second region of the substrate,

the second waveguide is over the second region of the substrate and extends to the boundary between the first region of the substrate and the second region of the substrate,

the first waveguide is configured to support a first optical mode, and

the second waveguide is configured to support a second optical mode, coupled to the first optical mode.

2. The optoelectronic device of claim 1, wherein the optically active region is an electro-absorption modulator or a photodiode.

3. The optoelectronic device of either claim 1, wherein the optically active region is formed of Si_xGe_1-x-ySn_y where 5%≤

x≤

20%, 1%≤

y≤

10%.

4. The optoelectronic device of claim 1, wherein the cladding layer is formed of silicon or SiGe and is epitaxially grown silicon or SiGe.

5. The optoelectronic device of claim 1, further comprising a silicon seed layer between the cladding layer and the optically active region.

6. The optoelectronic device of claim 1, wherein the optically active region comprises a silicon-germanium region.

7. The optoelectronic device of claim 1, wherein a length of the optically active region is between 30 μ

m and 60 μ

m.

8. The optoelectronic device of claim 1, further comprising:

an insulating layer, disposed on a first and/or second horizontal side of the cladding layer, wherein the cladding layer has a height from the substrate substantially equal to or greater than that of the insulating layer.

9. The optoelectronic device of claim 1, wherein the optically active region is disposed within a cavity of a silicon-on-insulator layer which is disposed above the substrate.

10. The optoelectronic device of claim 1, further comprising:

an input waveguide, coupled to a first side of the optically active region; and

an output waveguide, coupled to a second side of the optically active region;

wherein the interface between the input waveguide and the optically active region and the interface between the output waveguide and the optically active region are at an angle greater than 0°

relative to a guiding direction of the input waveguide and/or output waveguide.

11. The optoelectronic device of claim 1, wherein the optically active region includes a waveguide ridge, and has:

an upper surface and a lower surface;

a lower doped region, located at and/or adjacent to at least a portion of the lower surface of the optically active region, and extends laterally outwards from the waveguide ridge in a first direction;

an upper doped region, located at and/or adjacent to at least a portion of the upper surface of the waveguide ridge of the optically active region, and extends laterally outwards from the waveguide ridge in a second direction; and

an intrinsic region located between the lower doped region and the upper doped region.

12. The optoelectronic device of claim 1, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a ridge extending from the cladding layer;

a first slab region at a first side of the ridge and a second slab region at a second side of the ridge; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

13. The optoelectronic device of claim 1, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a ridge extending from the cladding layer, at least a portion of the ridge being formed from a chosen semiconductor material which is different from the material of the cladding layer;

wherein the cladding layer includes a first slab region at a first side of the ridge and a second slab region at a second side of the ridge; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

14. The optoelectronic device of claim 1, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a ridge extending from the cladding layer, at least a portion of the ridge being formed from a chosen semiconductor material which is different from the material of the cladding layer;

a first slab region at a first side of the ridge and a second slab region at a second side of the ridge; and

either the first slab region or the second slab region is the material of the cladding layer; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

15. The optoelectronic device of claim 1, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a silicon base, disposed on top of the cladding layer;

a ridge extending from the silicon base, at least a portion of the ridge being formed from a chosen semiconductor material which is different from the material of the silicon base;

wherein the silicon base includes a first slab region at a first side of the ridge, and a second slab region at a second side of the ridge; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

16. The optoelectronic device of claim 1, wherein the optically active region includes:

a waveguide ridge; and

a waveguide slab;

wherein at least one of;

a sidewall of the ridge;

a portion of the slab;

the entirety of the slab;

a portion of the ridge adjacent to the slab; and

both sidewalls of the ridge;

are formed of crystalline or amorphous silicon and contain dopants.

17. The optoelectronic device of claim 16, wherein the remainder of the waveguide ridge and waveguide slab is formed of SiGeSn, GeSn, InGaNAs or InGaNAsSb.

18. The optoelectronic device of claim 1, wherein

the optically active region is formed of SiGeSn, GeSn, InGaNAs, or InGaNAsSb having a first composition and the cladding layer is formed of the same material having a second composition different from the first composition.

19. The optoelectronic device of claim 1, wherein the device is driveable at a voltage of between 1.8 V and 2 V.

20. An optoelectronic device, formed on a silicon-on-insulator wafer comprising a substrate, an insulating layer, and a silicon-on-insulator layer, comprising:

a cladding layer, formed of a different material from the material of the insulating layer, on the substrate;

an optically active region, above the cladding layer and formed of SiGeSn, GeSn, InGaNAs, or InGaNAsSb;

a first waveguide; and

a second waveguide,

wherein;

the cladding layer has a refractive index which is less than a refractive index of the optically active region such that an optical mode of the optoelectronic device is highly confined inside the optically active region,

the insulating layer does not extend below the optically active region,

the insulating layer is directly on the substrate, over a first region of the substrate,

the cladding layer is on the substrate, over a second region of the substrate, different from the first region of the substrate,

the first waveguide is on the insulating layer,

the second waveguide is in the optically active region,

the substrate is a silicon substrate,

the insulating layer is an oxide layer,

the first waveguide is over the first region of the substrate and extends to a boundary between the first region of the substrate and the second region of the substrate,

the second waveguide is over the second region of the substrate and extends to the boundary between the first region of the substrate and the second region of the substrate,

the first waveguide is configured to support a first optical mode, and

the second waveguide is configured to support a second optical mode, coupled to the first optical mode.

21. The optoelectronic device of claim 20, wherein the optically active region is an electro-absorption modulator or a photodiode.

22. The optoelectronic device of either claim 20, wherein the cladding layer is formed of silicon or SiGe.

23. The optoelectronic device of claim 21, wherein the optically active region is formed of Si_xGe_1-x-ySn_y where 5%≤

x≤

20% and 1%≤

y≤

10%.

24. The optoelectronic device of claim 20, wherein the cladding layer is formed of silicon or SiGe and is epitaxially grown silicon.

25. The optoelectronic device of claim 20, further comprising a germanium seed layer or SiGe layer, functional as a seed layer, between the cladding layer and the optically active region.

26. The optoelectronic device of claim 20, wherein the optically active region comprises a silicon-germanium region.

27. The optoelectronic device of claim 20, wherein a length of the optically active region is between 30 μ

m and 60 μ

m.

28. The optoelectronic device of claim 20, further comprising:

an insulating layer, disposed on a first and/or second horizontal side of the cladding layer, wherein the cladding layer has a height from the substrate substantially equal to or greater than that of the insulating layer.

29. The optoelectronic device of claim 20, wherein the optically active region is disposed within a cavity of a silicon-on-insulator layer.

30. The optoelectronic device of claim 20, further comprising:

an input waveguide, coupled to a first side of the optically active region; and

an output waveguide, coupled to a second side of the optically active region;

wherein the interface between the input waveguide and the optically active region and the interface between the output waveguide and the optically active region are at an angle greater than 0°

relative to a guiding direction of the input waveguide or output waveguide.

31. The optoelectronic device of claim 20, wherein the optically active region includes a waveguide ridge, and has:

an upper surface and a lower surface;

a lower doped region, located at and/or adjacent to at least a portion of the lower surface of the optically active region, and extends laterally outwards from the waveguide ridge in a first direction;

an upper doped region, located at and/or adjacent to at least a portion of the upper surface of the waveguide ridge of the optically active region, and extends laterally outwards from the waveguide ridge in a second direction; and

an intrinsic region located between the lower doped region and the upper doped region.

32. The optoelectronic device of claim 20, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a ridge extending from the cladding layer;

a first slab region at a first side of the ridge and a second slab region at a second side of the ridge; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

33. The optoelectronic device of claim 20, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a ridge extending from the cladding layer, at least a portion of the ridge being formed from a material which is different from the material of the cladding layer;

wherein the cladding layer includes a first slab region at a first side of the ridge and a second slab region at a second side of the ridge; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

34. The optoelectronic device of claim 20, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a ridge extending from the cladding layer, at least a portion of the ridge being formed from a chosen semiconductor material which is different from the material of the cladding layer;

a first slab region at a first side of the ridge and a second slab region at a second side of the ridge; and

either the first slab region or the second slab region is the material of the cladding layer; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

35. The optoelectronic device of claim 20, wherein the optically active region includes a rib waveguide modulation region, the rib waveguide modulation region having:

a silicon base, disposed on top of the cladding layer;

a ridge extending from the silicon base, at least a portion of the ridge being formed from a material which is different from the material of the cladding layer;

wherein the silicon base includes a first slab region at a first side of the ridge, and a second slab region at a second side of the ridge; and

wherein;

a first doped region extends along;

the first slab region and along a first sidewall of the ridge, the first sidewall contacting the first slab region; and

a second doped region extends along;

the second slab region and along a second sidewall of the ridge, the second sidewall contacting the second slab region.

36. The optoelectronic device of claim 20, wherein the optically active region includes:

a waveguide ridge; and

a waveguide slab;

wherein at least one of;

a sidewall of the ridge;

a portion of the slab;

the entirety of the slab;

a portion of the ridge adjacent to the slab; and

both sidewalls of the ridge;

are formed of crystalline or amorphous silicon and contain dopants.

37. The optoelectronic device of claim 36, wherein the remainder of the waveguide ridge and waveguide slab is formed of SiGeSn, GeSn, InGaNAs, or InGaNAsSb.

38. The optoelectronic device of claim 20, wherein

the optically active region is formed of SiGeSn, GeSn, InGaNAs, or InGaNAsSb having a first composition and the cladding layer is formed of the same material having a second composition different from the first composition.

39. The optoelectronic device of claim 20, wherein the device is driveable at a voltage of between 1.8 V and 2 V.