Emitter oxidation uniformity within a wafer

Patent metadata

Field	Value
Publication number	US-11239638-B2
Application number	US-201916244842-A
Country	US
Kind code	B2
Filing date	Jan 10, 2019
Priority date	Sep 4, 2018
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

A wafer may comprise a substrate layer and a plurality of vertical cavity surface emitting lasers (VCSELs) formed on or within the substrate layer. A respective trench-to-trench distance associated with the plurality of VCSELs may vary across the wafer based on a predicted variation of an oxidation rate of an oxidation layer across the wafer.

First claim

What is claimed is:

1. A wafer, comprising:
a substrate layer,
a plurality of vertical cavity surface emitting lasers (VCSELs) formed on or within the substrate layer,
wherein the plurality of VCSELs includes a first VCSEL and second VCSEL,
wherein a first trench-to-trench distance, across the first VCSEL and between a first set of trenches of the first VCSEL, varies from a second trench-to-trench distance, across the second VCSEL and between a second set of trenches of the second VCSEL, proportional to a predicted rate of change of an oxidation rate of an oxidation layer across the wafer from a center of the wafer to an edge of the wafer, and
wherein the predicted rate of change of the oxidation rate is based on one or more historical measurements associated with at least one of a furnace associated with the wafer or a wafer type of the wafer.

2. The wafer of claim 1 , wherein the wafer includes regions associated with different oxidation rates.

3. The wafer of claim 1 , wherein oxide apertures associated with the plurality of VCSELs have a diameter within approximately 0.5 microns of each other.

4. The wafer of claim 1 , wherein the first trench-to-trench distance is defined by a respective mesa diameter of the plurality of VCSELs.

5. The wafer of claim 1 , wherein the wafer further comprises:
an epitaxial layer, and
wherein the first set of trenches and the second set of trenches are defined by the epitaxial layer.

6. The wafer of claim 1 , wherein the first set of trenches and the second set of trenches expose the oxidation layer.

7. The wafer of claim 1 , wherein the first set of trenches includes three or more trenches.

8. The wafer of claim 1 , wherein the first trench-to-trench distance corresponds to a variation of a diameter of a respective implant protection layer of the plurality of VCSELs.

9. The wafer of claim 1 , wherein the second trench-to-trench distance is greater than the first trench-to-trench distance; and
the first VCSEL is closer to the center of the wafer than the second VCSEL.

10. A wafer, comprising:
a substrate layer,
a plurality of vertical cavity surface emitting lasers (VCSELs) formed on or within the substrate layer,
wherein a respective trench-to-trench distance, between a respective plurality of trenches for respective VCSELs of the plurality of VCSELs, varies across the wafer proportional to a predicted rate of change of an oxidation rate of an oxidation layer across the wafer from a center of the wafer to an edge of the wafer, and
wherein the predicted rate of change of the oxidation rate is based on one or more historical measurements associated with at least one of a furnace associated with the wafer or a wafer type of the wafer.

11. The wafer of claim 10 , wherein the respective trench-to-trench distance corresponds to a variation of a diameter of a respective implant protection layer of the plurality of VCSELs.

12. The wafer of claim 10 , wherein the wafer includes regions associated with different oxidation rates.

13. The wafer of claim 10 , wherein oxide apertures associated with the plurality of VCSELs have a diameter within approximately 0.5 microns of each other.

14. The wafer of claim 10 , wherein the wafer further comprises:
an epitaxial layer, and
wherein the respective plurality of trenches are defined by the epitaxial layer.

15. The wafer of claim 10 , wherein the respective plurality of trenches expose the oxidation layer.

16. The wafer of claim 10 , wherein the respective plurality of trenches includes, for each of the respective VCSELs, three or more trenches.

17. The wafer of claim 10 , wherein a first trench-to-trench distance of a first VCSEL, of the plurality of VCSELs, is less than a second trench-to-trench distance of a second VCSEL, of the plurality of VCSELs; and
the first VCSEL is closer to the center of the wafer than the second VCSEL.

18. A wafer, comprising:
a substrate layer,
a plurality of emitters formed on or within the substrate layer,
wherein the plurality of emitters includes a first emitter and second emitter, and
wherein a first trench-to-trench distance, across the first emitter and between a first set of trenches of the first emitter, varies from a second trench-to-trench distance, across the second emitter and between a second set of trenches of the second emitter, proportional to a predicted rate of change of an oxidation rate of an oxidation layer across the wafer from a center of the wafer to an edge of the wafer, and
wherein the predicted rate of change of the oxidation rate is based on one or more historical measurements associated with at least one of a furnace associated with the wafer or a wafer type of the wafer.

19. The wafer of claim 18 , wherein the wafer includes regions associated with different oxidation rates.

20. The wafer of claim 18 , wherein oxide apertures associated with the plurality of emitters have a diameter within approximately 0.5 microns of each other.

21. The wafer of claim 18 , wherein the wafer further comprises:
an epitaxial layer, and
wherein the first set of trenches and the second set of trenches are defined by the epitaxial layer.

22. The wafer of claim 18 , wherein the first set of trenches and the second set of trenches expose the oxidation layer.

23. The wafer of claim 18 , wherein the first set of trenches includes three or more trenches.

24. The wafer of claim 18 , wherein the first trench-to-trench distance corresponds to a variation of a diameter of a respective implant protection layer of the plurality of emitters.

25. The wafer of claim 18 , wherein the emitters comprise vertical external cavity surface emitting lasers (VECSELs).

26. The wafer of claim 18 , wherein the second trench-to-trench distance is greater than the first trench-to-trench distance; and
the first emitter is closer to the center of the wafer than the second emitter.

Assignees

• Lumentum Operations Llc

Inventors

• Kesler Benjamin
• Barve Ajit Vijay
• Zhao Guowei

Classifications

• G03F1/00

  Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof · CPC title

• G03F1/50 Primary

  Mask blanks not covered by G03F1/20 - G03F1/34; Preparation thereof · CPC title

• H01S5/0042

  On wafer testing, e.g. lasers are tested before separating wafer into chips · CPC title

• H01S5/18361

  Structure of the reflectors, e.g. hybrid mirrors · CPC title

• H01S5/183

  having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] · CPC title