Waveguide with attenuator

Patent metadata

Field	Value
Publication number	US-11422303-B2
Application number	US-202017108732-A
Country	US
Kind code	B2
Filing date	Dec 1, 2020
Priority date	Dec 1, 2020
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

The present disclosure relates to semiconductor structures and, more particularly, to a waveguide structure with attenuator and methods of manufacture. The structure includes: a waveguide structure including semiconductor material; an attenuator underneath the waveguide structure; an airgap structure vertically aligned with and underneath the waveguide structure and the attenuator; and shallow trench isolation structures on sides of the waveguide structure and merging with the airgap structure.

First claim

What is claimed is:

1. A structure comprising:
a waveguide structure comprising semiconductor material;
an attenuator underneath the waveguide structure;
an airgap structure vertically aligned with and underneath the waveguide structure and the attenuator; and
shallow trench isolation structures on sides of the waveguide structure and merging with the airgap structure,
wherein the attenuator comprises Ge material, the semiconductor material comprises Si material and the Ge material seals the airgap structure.

2. The structure of claim 1 , wherein the Ge material is within a trench above the airgap structure.

3. The structure of claim 1 , wherein the shallow trench isolation structures comprise dielectric material which also lines the airgap structure.

4. The structure of claim 1 , wherein the airgap structure comprises an aspect ratio of greater than 1:1.

5. The structure of claim 1 , wherein the attenuator comprises an aspect ratio of greater than 1:1.

6. The structure of claim 1 , wherein the airgap structure is sealed with Si and SiGe material.

7. The structure of claim 1 , further comprising a marker layer comprising a same material as the attenuator, the marker layer being formed on bulk substrate.

8. The structure of claim 1 , wherein the attenuator and the waveguide structure are on bulk substrate.

9. A structure comprising:
a waveguide structure on bulk substrate and comprising a first semiconductor material;
an attenuator vertically aligned with and underneath the waveguide structure, the attenuator comprising a second semiconductor material different than the first semiconductor material;
an airgap vertically aligned with the waveguide structure and the attenuator, the airgap being sealed with the second semiconductor material and lined with dielectric material underneath the waveguide structure; and
shallow trench isolation structures comprising dielectric material on sides of the waveguide structure.

10. The structure of claim 9 , wherein the shallow trench isolation structures merge with the airgap.

11. The structure of claim 9 , further comprising dielectric material on a top surface of the waveguide structure.

12. The structure of claim 9 , wherein the waveguide structure is clad on all sides with dielectric material.

13. The structure of claim 9 , wherein the first semiconductor material comprises Si and the second semiconductor material comprises one of Ge and SiGe.

14. The structure of claim 9 , wherein the attenuator comprises an aspect ratio of greater than 1:1.

15. The structure of claim 14 , wherein the attenuator is formed in a trench communicating with the airgap.

16. The structure of claim 9 , wherein the attenuator plugs a trench leading to the airgap.

17. The structure of claim 9 , further comprising a marker layer over the bulk substrate and of a same material as the attenuator.

18. A method comprising:
forming a waveguide structure comprising semiconductor material;
forming an attenuator underneath the waveguide structure;
forming an airgap structure vertically aligned with and underneath the waveguide structure and the attenuator;
forming shallow trench isolation structures on sides of the waveguide structure and merging with the airgap structure; and
forming a marker layer comprising a same material as the attenuator, the marker layer being formed on bulk substrate.

Assignees

• Globalfoundries Us Inc

Inventors

• Levy Mark D
• Adusumilli Siva P
• Bian Yusheng

Classifications

• H01S5/10

  Construction or shape of the optical resonator {, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region (H01S5/20 takes precedence)} · CPC title

• G02B2006/12133

  Functions · CPC title

• G02B2006/12061

  Silicon · CPC title

• G02B6/12004 Primary

  Combinations of two or more optical elements · CPC title

• G02B2006/12035

  Materials · CPC title