Method for fabricating a device for propagating light

• US 9,658,400 B2
• Filed: 08/20/2015
• Issued: 05/23/2017
• Est. Priority Date: 06/01/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kiewra, Edward W., Hofrichter, Jens, La Porta, Antonio, Jubin, Daniel S.
• Primary Examiner(s): HENRY, CALEB E
• Application Number:
  US14/831,383
• Publication Number:
  US 20170052318A1
• Time in Patent Office: 642 Days
• Field of Search: 385 14, 438 27
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/132 by deposition of thin films
• CPC Class Codes: G02B 6/136 by etching

Abstract

A method of forming a device for propagating light includes providing a substrate having a semiconductor material; placing an insulating layer on the substrate; providing a recess reaching through the insulating layer and into the substrate; filling the recess at least partially with a filler material; and arranging a waveguide in or on the filler material.

Claims

1. A method for fabricating a device for propagating light, comprising:

providing a substrate having a semiconductor material;

placing an insulating layer on a surface of the substrate;

forming a recess to penetrate both of a portion of the insulating layer and a portion of the substrate;

filling the recess at least partially with a filler material; and

arranging a waveguide on the filler material,

wherein a bottom surface of the waveguide is coplanar with a top surface of the insulating layer, and

wherein the recess has a recess bottom, and a distance between the waveguide and the recess bottom is larger than a thickness of the insulating layer.

2. The method of claim 1, wherein providing a recess comprises:

etching the insulating layer to access the substrate; and

removing or transforming a part of the semiconductor material of the substrate.

3. The method of claim 2, wherein filling the recess comprises:

filling the recess at least partly with the filler material which has a lower index of refraction than the substrate; and

filling the etched insulating layer to form a planar surface of the insulating layer.

4. The method of claim 1, wherein the filler material has a lower index of refraction than a material of the waveguide.

5. The method of claim 1, wherein the recess is formed such that a distance between the waveguide and an interface between the semiconductor material and the filler material is larger than a predetermined distance.

6. The method of claim 5, wherein the predetermined distance is larger than a radius of a light mode of the waveguide.

7. The method of claim 1, wherein the filler material has a lower index of refraction than the substrate.

8. The method of claim 1, further comprising:

tapering the formed recess such that the recess has a tapered form in the substrate in a direction from the waveguide towards the substrate.

9. The method of claim 1, arranging a further waveguide below or above the waveguide for an adiabatic coupling of light between the two waveguides.

10. The method of claim 9, further comprising:

extending the waveguide in a longitudinal direction and tapering the waveguide or tapering the further waveguide in the longitudinal direction.

11. The method of claim 1, further comprising:

forming front-end electronic components at the insulating layer.

12. The method of claim 1, further comprising:

forming a passivation layer on top of the insulating layer.

13. The method of claim 12, further comprising:

forming back-end electronic components above the passivation layer.