US4789642A
Expired / Lapsed
US
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Method for fabricating low loss crystalline silicon waveguides by dielectric implantation
Assignee: United States Department of the Air Force
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Filing: 1987-03-26
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Granted: 1988-12-06
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Expires: 2007-03-26
Abstract
Abstract A method of fabricating low loss silicon optical waveguides by high energy ion implantation which converts a buried region into dielectric material. The top silicon surface can them be etched or formed into waveguides that are isolated by the buried dielectric. Annealing of the top silicon layer can be used to improve optical quality and additional silicon can be added to the top surface waveguides by epitaxial growth.
Inventors
- 👤 Joseph P. Lorenzo
- 👤 Richard A. Soref
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:39
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/13; G02B6/134; G02B6/1347
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
76 words
A method of fabricating a silicon optical waveguide comprising the steps of: (a) preparing a crystalline silicon substrate with suitable doping for optical propagation; (b) subjecting a surface of said silicon substrate to ion implantation to form a dielectric layer below the silicon substrate surface; (c) etching said silicon substrate at a surface to provide an exposed waveguide rib bounded by said dielectric layer; and (d) forming a passivating layer on top of said waveguide rib.
Claim 2
Independent Claim
76 words
A method of fabricating a silicon optical waveguide comprising the steps of: (a) preparing a crystalline silicon substrate with suitable doping for optical propagation; (b) subjecting a surface of said silicon substrate to ion implantation to form a dielectric layer below the silicon substrate surface; (c) etching said silicon substrate at a surface to provide an exposed waveguide rib bounded by said dielectric layer; and (d) forming a passivating layer on top of said waveguide rib.
Claim 3
Dependent Claim
34 words
The method of fabricating a silicon optical waveguide of claim 1 further comprising the step of: annealing said substrate at high temperature after said ion implantation to improve optical properties of said silicon substrate.
Claim 4
Dependent Claim
34 words
The method of fabricating a silicon optical waveguide of claim 1 further comprising the step of adjusting the thickness of an optical propagating layer above said dielectric layer by epitaxial growth of additional silicon.
Claim 5
Dependent Claim
29 words
The method of claim 1 wherein the exposed waveguide rib is covered with a passivating layer by conversion of an ion implant at an exposed surface to a dielectric.
Claim 6
Independent Claim
73 words
A method of fabricating a silicon optical waveguide comprising the steps of: (a) preparing a crystalline silicon substrate with suitable doping for optical propagation; (b) etching said silicon substrate at a surface to provide an optical waveguide pattern; (c) defining an optical waveguide from said optical waveguide pattern by ion implantation which provides a bounding dielectric layer beneath said optical waveguide; and (d) forming a protective passivating layer on top of said waveguide.
Claim 7
Independent Claim
73 words
A method of fabricating a silicon optical waveguide comprising the steps of: (a) preparing a crystalline silicon substrate with suitable doping for optical propagation; (b) etching said silicon substrate at a surface to provide an optical waveguide pattern; (c) defining an optical waveguide from said optical waveguide pattern by ion implantation which provides a bounding dielectric layer beneath said optical waveguide; and (d) forming a protective passivating layer on top of said waveguide.
Claim 8
Dependent Claim
33 words
The method of fabricating a silicon optical waveguide of claim 5 further comprising the step of: annealing said substrate at high temperature after ion implantation to improve optical properties of said silicon substrate.
Claim 9
Dependent Claim
22 words
The method of fabricating a silicon optical waveguide of claim 5 wherein ion implantation is used to form a top passivating layer.
Claim 10
Dependent Claim
34 words
The method of fabricating a silicon optical waveguide of claim 5 further comprising the step of: adjusting the thickness of an optical propagating layer above said dielectric layer by epitaxial growth of additional silicon.
Claim 11
Dependent Claim
21 words
The method of fabricating a silicon optical waveguide of claim 5 wherein oxygen ions are implanted to provide said dielectric layer.
Claim 12
Dependent Claim
21 words
The method of fabricating a silicon optical waveguide of claim 5 wherein nitrogen ions are implanted to provide said dielectric layer.
Claim 13
Independent Claim
84 words
A method of fabricating a silicon optical waveguide comprising the steps of: (a) preparing a crystalline silicon substrate with suitable doping for optical propagation; (b) forming an insulating layer on top of said crystalline silicon substrate; (c) patterning said insulating layer for use as an implant mask on said substrate; (d) subjecting said silicon substrate to ion implantation to form a dielectric layer within said substrate, said dielectric layer conforming to the topographical pattern of said insulating layer in order to form optical waveguides.
Claim 14
Independent Claim
84 words
A method of fabricating a silicon optical waveguide comprising the steps of: (a) preparing a crystalline silicon substrate with suitable doping for optical propagation; (b) forming an insulating layer on top of said crystalline silicon substrate; (c) patterning said insulating layer for use as an implant mask on said substrate; (d) subjecting said silicon substrate to ion implantation to form a dielectric layer within said substrate, said dielectric layer conforming to the topographical pattern of said insulating layer in order to form optical waveguides.
Claim 15
Dependent Claim
20 words
The method of fabricating a silicon optical waveguide of claim 9 further comprising the step of removing said insulating layer.
Claim 16
Dependent Claim
33 words
The method of fabricating a silicon optical waveguide of claim 11 further comprising the step of: annealing said substrate at high temperature after ion implantation to improve optical properties of said silicon substrate.
Claim 17
Dependent Claim
34 words
The method of fabricating a silicon optical waveguide of claim 12 further comprising the step of: adjusting the thickness of an optical propagating layer above said dielectric layer by epitaxial growth of additional silicon.
Claim 18
Dependent Claim
25 words
The method of fabricating a silicon optical waveguide of claim 11 further comprising the step of forming a shallow dielectric layer to isolate said waveguides.
Claim 19
Dependent Claim
33 words
The method of fabricating a silicon optical waveguide of claim 11 further comprising the step of forming a second dielectric layer by ion implantation in order to form an additional layer of waveguides.
Claim 20
Dependent Claim
20 words
The method of fabricating a silicon optical waveguide of claim 16 further comprising the step of removing said insulating layer.
Claim 21
Dependent Claim
17 words
The method of fabricating a silicon optical waveguide of claim 11 wherein said insulating layer comprises photoresist.
Claim 22
Dependent Claim
21 words
The method of fabricating a silicon optical waveguide of claim 15 wherein said shallow dielectric layer is formed by ion implantation.
Claim 23
Dependent Claim
19 words
The method of fabricating a silicon optical waveguide of claim 11 wherein said insulating layer is patterned by etching.
Claim 24
Dependent Claim
19 words
The method of fabricating a silicon optical waveguide of claim 11 wherein the ion implantation comprises oxygen ion implantation.
Claim 25
Dependent Claim
19 words
The method of fabricating a silicon optical waveguide of claim 11 wherein the ion implantation is nitrogen ion implantation.
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