Method of forming optical waveguides in a semiconductor substrate

• US 20030052082A1
• Filed: 09/19/2001
• Published: 03/20/2003
• Est. Priority Date: 09/19/2001
• Status: Abandoned Application

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Kumar, Ajay, Khan, Anisul, Thekdi, Sanjay
• Application Number:
  US09/957,395
• Publication Number:
  US 20030052082A1
• Time in Patent Office: Days
• US Class Current: 216/24
• CPC Class Codes: G02B 2006/12061 Silicon
• CPC Class Codes: G02B 2006/12078 Gallium arsenide or alloys (GaAs, GaAlAs, GaAsP, GaInAs)
• CPC Class Codes: G02B 2006/12176 Etching
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device

Abstract

Optical waveguides can be made accurately using conventional semiconductor processing and equipment by forming an opening in a suitable substrate, conformally depositing a first cladding layer in the opening, filling the opening with a core material, removing excess core material, as by chemical mechanical polishing, and depositing a second cladding layer thereover, said first and second cladding layers and said core material each having a different index of refraction. Such optical waveguides can be connected, horizontally and/or vertically, to other devices formed in or on the substrate.

Claims

1. A method of making an optical waveguide in a substrate material comprising

a) forming an opening in said substrate,

b) depositing a first cladding layer conformally in said opening,

c) filling said opening with a core material;

d) removing excess core material, and

e) depositing a second cladding layer over the substrate.

2. A method according to claim 1 wherein said substrate is selected from the group consisting of silicon, silicon-germanium, gallium arsenide, indium gallium arsenide and indium phosphide.

3. A method according to claim 2 wherein said substrate is silicon.

4. A method according to claim 3 wherein said first and second cladding layers are of silicon oxide each having a different refractive index.

5. A method according to claim 1 wherein excess core material is removed by chemical mechanical polishing.

6. A method of making an optical waveguide in a silicon-containing substrate having a layer of silicon nitride and a layer of silicon oxide thereon comprising

a) masking and patterning an opening in said mask,

b) etching through the silicon oxide and silicon nitride layers to form a hard mask,

c) etching an opening in said substrate,

d) conformally depositing a first cladding layer of silicon oxide in said opening,

e) filling said opening with a core material having a different refractive index than said first cladding layer;

f) planarizing the core and first cladding layer to remove said silicon oxide layer,

g) etching said silicon nitride layer, and

h) depositing a second cladding layer having a different refractive index than the core material and the first cladding layer.

7. A method according to claim 6 wherein said substrate is silicon.

8. A method according to claim 6 wherein said substrate is silicon on insulator.