CN110908037B - Optical waveguide and method for manufacturing the same - Google Patents
Optical waveguide and method for manufacturing the same Download PDFInfo
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- CN110908037B CN110908037B CN201911204311.9A CN201911204311A CN110908037B CN 110908037 B CN110908037 B CN 110908037B CN 201911204311 A CN201911204311 A CN 201911204311A CN 110908037 B CN110908037 B CN 110908037B
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- cladding layer
- lower cladding
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/13—Integrated optical circuits characterised by the manufacturing method
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12083—Constructional arrangements
- G02B2006/12085—Integrated
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12166—Manufacturing methods
Abstract
The invention discloses an optical waveguide and a manufacturing method thereof. The optical waveguide includes: a semiconductor substrate; a lower cladding layer on an upper surface of the semiconductor substrate; a waveguide structure located in a first region of an upper surface of the lower cladding layer; the first upper cladding obtained by adopting a high-temperature oxidation vapor deposition process is positioned on the second region of the upper surface of the lower cladding and the upper surface of the waveguide structure; and the second upper cladding layer is positioned on the upper surface of the first upper cladding layer. The manufacturing method comprises the following steps: providing a semiconductor substrate; forming a lower cladding layer on an upper surface of the semiconductor substrate; forming a waveguide structure in a first region of an upper surface of the lower cladding layer; depositing a first upper cladding layer on the second region of the upper surface of the lower cladding layer and the upper surface of the waveguide structure by adopting a high-temperature oxidation process; and forming a second upper cladding layer on the upper surface of the first upper cladding layer. The optical waveguide and the manufacturing method thereof provided by the invention effectively reduce the transmission loss of the waveguide.
Description
Technical Field
The invention relates to the technical field of integrated circuits, in particular to an optical waveguide and a manufacturing method thereof.
Background
An optical waveguide (optical waveguide) is a dielectric device that guides light waves to propagate therein, and is also called a dielectric optical waveguide. There are two main categories of optical waveguides: one is an integrated optical waveguide, including planar (thin film) dielectric optical waveguides and strip dielectric optical waveguides, which are typically part of an optoelectronic integrated device (or system) and are therefore called integrated optical waveguides; another type is a cylindrical optical waveguide, commonly referred to as an optical fiber.
Fig. 1 is a schematic structural diagram of a conventional integrated optical waveguide, which includes a substrate 11, a lower cladding layer 12, a core layer 13, and an upper cladding layer 14. The lower cladding layer 12 is a silicon dioxide layer formed by a Thermal Oxidation (Thermal Oxidation) process, and the upper cladding layer 14 is a silicon dioxide layer formed by a Plasma Enhanced Chemical Vapor Deposition (PECVD) process. The optical waveguide shown in fig. 1 has a simple structure, but has a large waveguide loss.
Disclosure of Invention
The invention aims to solve the problem of large waveguide loss of the existing optical waveguide.
The invention is realized by the following technical scheme:
a method of manufacturing an optical waveguide, comprising:
providing a semiconductor substrate;
forming a lower cladding layer on an upper surface of the semiconductor substrate;
forming a waveguide structure in a first region of an upper surface of the lower cladding layer;
depositing a first upper cladding layer on a second region of the upper surface of the lower cladding layer and the upper surface of the waveguide structure by adopting a high-temperature oxidation vapor deposition process, wherein the first region and the second region form the upper surface of the lower cladding layer;
and forming a second upper cladding layer on the upper surface of the first upper cladding layer.
Optionally, the forming a lower cladding layer on the upper surface of the semiconductor substrate includes:
and forming the lower cladding layer on the upper surface of the semiconductor substrate by adopting a high-temperature thermal oxidation process.
Optionally, the material of the lower cladding layer is silica, and the thickness of the lower cladding layer is 1 micrometer to 20 micrometers.
Optionally, the forming a waveguide structure in the first region of the upper surface of the lower cladding layer includes:
depositing a core layer on the upper surface of the lower cladding layer by adopting a low-pressure chemical vapor deposition process;
and etching the core layer by adopting a dry etching process to obtain the waveguide structure.
Optionally, the core layer is made of Si3N4And the thickness of the core layer is 100 nanometers to 2 micrometers.
Optionally, the material of the first upper cladding layer is silica, and the thickness of the first upper cladding layer is 400 nm to 4 μm.
Optionally, the forming a second upper cladding layer on the upper surface of the first upper cladding layer includes:
and depositing the second upper cladding layer on the upper surface of the first upper cladding layer by adopting a plasma chemical vapor deposition process.
Optionally, the material of the second upper cladding layer is silica, and the thickness of the second upper cladding layer is 1 micrometer to 20 micrometers.
Based on the same inventive concept, the present invention also provides an optical waveguide, comprising:
a semiconductor substrate;
a lower cladding layer on an upper surface of the semiconductor substrate;
a waveguide structure located in a first region of an upper surface of the lower cladding layer;
the first upper cladding obtained by adopting a high-temperature oxidation vapor deposition process is positioned on a second region of the upper surface of the lower cladding and the upper surface of the waveguide structure, and the first region and the second region form the upper surface of the lower cladding;
and the second upper cladding layer is positioned on the upper surface of the first upper cladding layer.
Optionally, the material of the lower cladding layer is silica, and the thickness of the lower cladding layer is 1 micrometer to 20 micrometers.
Optionally, the material of the waveguide structure is Si3N4The thickness of the waveguide structure is 100 nanometers to 2 micrometers.
Optionally, the material of the first upper cladding layer is silica, and the thickness of the first upper cladding layer is 400 nm to 4 μm.
Optionally, the material of the second upper cladding layer is silica, and the thickness of the second upper cladding layer is 1 micrometer to 20 micrometers.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the optical waveguide and the manufacturing method thereof provided by the invention adopt a high-temperature oxidation vapor deposition process to add an upper cladding layer between the waveguide structure and the original upper cladding layer. The upper cladding layer deposited by adopting the high-temperature oxidation vapor deposition process is more compact and is more beneficial to the transmission of the waveguide, so that the transmission loss of the waveguide is obviously reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic diagram of a conventional integrated optical waveguide structure;
fig. 2 to 7 are schematic structural diagrams of a manufacturing process of an optical waveguide according to an embodiment of the present invention.
Detailed Description
The transmission loss of the waveguide depends on the one hand on the material of the waveguide structure itself and on the other hand on the quality of the upper and lower cladding layers. In the existing optical waveguide forming process, since the lower cladding layer is deposited on the semiconductor substrate, the lower cladding layer can be obtained by using a thermal oxidation process. The lower cladding obtained by the thermal oxidation process is compact and has no defects, and the transmission loss caused to the waveguide is small. The upper cladding layer is not supported by a semiconductor substrate, can not be manufactured by a thermal oxidation process, and is formed by a plasma enhanced chemical vapor deposition process in the prior art. The upper cladding obtained by adopting the plasma enhanced chemical vapor deposition process has large ion damage, is lack of compactness and has large transmission loss on the waveguide. Based on the above, the invention provides an optical waveguide and a manufacturing method thereof, which reduces the transmission loss of the waveguide by adding an upper cladding between a waveguide structure and the original upper cladding by adopting a high-temperature oxidation vapor deposition process.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
The present embodiment provides a method for manufacturing an optical waveguide, including the steps of:
providing a semiconductor substrate;
forming a lower cladding layer on an upper surface of the semiconductor substrate;
forming a waveguide structure in a first region of an upper surface of the lower cladding layer;
depositing a first upper cladding layer on a second region of the upper surface of the lower cladding layer and the upper surface of the waveguide structure by adopting a high-temperature oxidation vapor deposition process, wherein the first region and the second region form the upper surface of the lower cladding layer;
and forming a second upper cladding layer on the upper surface of the first upper cladding layer.
As shown in fig. 2, a semiconductor substrate 21 is provided, which semiconductor substrate 21 may be a silicon-based substrate. The silicon-based substrate may be a bulk silicon substrate, for example, a P-type silicon substrate, or an N-type silicon substrate.
As shown in fig. 3, a lower cladding layer 22 is formed on the upper surface of the semiconductor substrate 21. Further, the lower cladding layer 22 may be formed on the upper surface of the semiconductor substrate 21 by using a high-temperature thermal oxidation process, which may be a dry oxidation process or a wet oxidation process. As a specific example, the material of the lower cladding layer 22 may be silica, and the thickness of the lower cladding layer 22 may be 1 to 20 micrometers.
The waveguide structure is formed on the first region of the upper surface of the lower cladding layer 22, and can be realized by a thin film deposition process and an etching process.
As shown in fig. 4, a low pressure chemical vapor deposition process may be used to deposit a core layer 23 on the upper surface of the lower cladding layer 22, where the core layer 23 is used to form the waveguide structure. As a specific embodiment, the material of the core layer 23 may be Si3N4The thickness of the core layer 23 may be 100 nm to 2 μm.
As shown in fig. 5, the core layer 23 may be etched by a dry etching process to obtain the waveguide structure 24, where the dry etching process may be a reactive ion etching process or a plasma etching process. Specifically, a photoresist layer is formed on the upper surface of the core layer 23 or a mask is used to protect a portion where the waveguide structure 24 needs to be formed, other regions of the core layer 23 that are not protected are etched until the lower cladding layer 22 is exposed, and finally, the photoresist is removed or the mask is removed, so that the waveguide structure 24 is formed.
As shown in fig. 6, a first upper cladding layer 25 is deposited on a second region of the upper surface of the lower cladding layer 22 and the upper surface of the waveguide structure 24 using a high-temperature oxidation (high-temperature oxidation) vapor deposition process, the first region and the second region constituting the upper surface of the lower cladding layer. As a specific example, the temperature of the high temperature oxidation vapor deposition process may be 800 to 1000 degrees, and the reaction formula: SiH2Cl2+2N2O→SiO2+2N2+2 HCl. The material of the first upper cladding layer 25 may be silica, and the thickness of the first upper cladding layer 25 may be 400 nm to 4 μm.
As shown in fig. 7, the second upper cladding layer 26 is deposited on the upper surface of the first upper cladding layer 25 by using a plasma chemical vapor deposition process. As a specific example, the material of the second upper cladding layer 26 may be silica, and the thickness of the second upper cladding layer 26 may be 1 micron to 20 microns.
It should be noted that, in the manufacturing process of the present embodiment, for the manufacturing process of the optical waveguide including the waveguide structure 24, when the optical waveguide is integrated in the optoelectronic integrated chip, the manufacturing process is only a partial manufacturing process of the integrated chip, and the partial manufacturing process does not conflict with the manufacturing process of other devices.
In the manufacturing method of the optical waveguide provided in this embodiment, the first upper cladding layer 25 is disposed between the waveguide structure 24 and the second upper cladding layer 26 by using a high-temperature oxidation process. The upper cladding deposited by adopting the high-temperature oxidation process is more compact and is more beneficial to the transmission of the waveguide, so that the transmission loss of the waveguide is obviously reduced. The waveguide loss of the optical waveguide shown in FIG. 1 was found to be 0.8dB/cm, whereas the waveguide loss of the optical waveguide obtained by the manufacturing method of this example was found to be as low as 0.1 dB/cm.
Example 2
The present embodiment provides an optical waveguide, and fig. 7 is a schematic structural diagram of the optical waveguide, where the optical waveguide includes a semiconductor substrate 21, a lower cladding layer 22, a waveguide structure 24, a first upper cladding layer 25, and a second upper cladding layer 26.
Specifically, the semiconductor substrate 21 may be a silicon-based substrate. The silicon-based substrate may be a bulk silicon substrate, for example, a P-type silicon substrate, or an N-type silicon substrate.
The lower cladding layer 22 is located on the upper surface of the semiconductor substrate 21. As a specific example, the material of the lower cladding layer 22 may be silica, and the thickness of the lower cladding layer 22 may be 1 to 20 micrometers.
The waveguide structure 24 is located in a first region of the upper surface of the lower cladding layer 22. As a specific example, the material of the waveguide structure 24 may be Si3N4The thickness of the waveguide structure 24 may be 100 nanometers to 2 microns.
The first upper cladding layer 25 is obtained by a high temperature oxidation vapor deposition process, and the first upper cladding layer 25 is located on a second region of the upper surface of the lower cladding layer 22 and the upper surface of the waveguide structure 24, and the first region and the second region constitute the upper surface of the lower cladding layer 22. As a specific example, the material of the first upper cladding layer 25 may be silica, and the thickness of the first upper cladding layer 25 may be 400 nm to 4 μm.
The second upper cladding layer 26 is located on the upper surface of the first upper cladding layer 25. As a specific example, the material of the second upper cladding layer 26 may be silica, and the thickness of the second upper cladding layer 26 may be 1 micron to 20 microns.
In the optical waveguide provided in this embodiment, the first upper cladding layer 25 is disposed between the waveguide structure 24 and the second upper cladding layer 26 by using a high-temperature oxidation process. The upper cladding deposited by adopting the high-temperature oxidation process is more compact and is more beneficial to the transmission of the waveguide, so that the transmission loss of the waveguide is obviously reduced.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A method of fabricating an optical waveguide, comprising:
providing a semiconductor substrate;
forming a lower cladding layer on an upper surface of the semiconductor substrate;
forming a waveguide structure in a first region of an upper surface of the lower cladding layer;
depositing a first upper cladding layer on a second region of the upper surface of the lower cladding layer and the upper surface of the waveguide structure by adopting a high-temperature oxidation vapor deposition process, wherein the first region and the second region form the upper surface of the lower cladding layer;
forming a second upper cladding layer on an upper surface of the first upper cladding layer, wherein the second upper cladding layer comprises: depositing the second upper cladding layer on the upper surface of the first upper cladding layer by adopting a plasma chemical vapor deposition process; the thickness of the first upper cladding layer is 400 nanometers to 4 micrometers, the material of the first upper cladding layer is silicon dioxide, the thickness of the second upper cladding layer is 1 micrometer to 20 micrometers, and the material of the second upper cladding layer is silicon dioxide.
2. The method of manufacturing an optical waveguide according to claim 1, wherein the forming of the lower cladding layer on the upper surface of the semiconductor substrate includes:
and forming the lower cladding layer on the upper surface of the semiconductor substrate by adopting a high-temperature thermal oxidation process.
3. The method of manufacturing an optical waveguide according to claim 1, wherein the material of the lower cladding layer is silica, and the thickness of the lower cladding layer is 1 to 20 μm.
4. The method of manufacturing an optical waveguide according to claim 1, wherein the forming a waveguide structure in the first region of the upper surface of the lower cladding layer comprises:
depositing a core layer on the upper surface of the lower cladding layer by adopting a low-pressure chemical vapor deposition process;
and etching the core layer by adopting a dry etching process to obtain the waveguide structure.
5. The method for manufacturing an optical waveguide according to claim 4, wherein the material of the core layer is Si3N4And the thickness of the core layer is 100 nanometers to 2 micrometers.
6. The method of manufacturing an optical waveguide according to claim 1, wherein a material of the first upper cladding layer is silica.
7. The method of manufacturing an optical waveguide according to claim 1, wherein the material of the second upper cladding layer is silica.
8. An optical waveguide, comprising:
a semiconductor substrate;
a lower cladding layer on an upper surface of the semiconductor substrate;
a waveguide structure located in a first region of an upper surface of the lower cladding layer;
a first upper cladding obtained by adopting a high-temperature oxidation vapor deposition process, a second region positioned on the upper surface of the lower cladding and the upper surface of the waveguide structure, wherein the first region and the second region form the upper surface of the lower cladding, the thickness of the first upper cladding is 400 nanometers to 4 micrometers, and the first upper cladding is made of silicon dioxide;
and a second upper cladding layer obtained by depositing on the upper surface of the first upper cladding layer by adopting a plasma chemical vapor deposition process is positioned on the upper surface of the first upper cladding layer, the thickness of the second upper cladding layer is 1-20 micrometers, and the second upper cladding layer is made of silicon dioxide.
9. The optical waveguide of claim 8, wherein the material of the lower cladding layer is silica, and the thickness of the lower cladding layer is 1 to 20 microns.
10. The optical waveguide of claim 8, wherein the material of the waveguide structure is Si3N4The thickness of the waveguide structure is 100 nanometers to 2 micrometers.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005345953A (en) * | 2004-06-07 | 2005-12-15 | Fujikura Ltd | Optical waveguide and manufacturing method thereof |
| CN102540334A (en) * | 2010-12-24 | 2012-07-04 | 苏州东微半导体有限公司 | Manufacturing method for PLC (planar lightwave circuit) optical device |
| CN104635298A (en) * | 2015-02-11 | 2015-05-20 | 深圳太辰光通信股份有限公司 | Planar optical waveguide and manufacturing method thereof |
| CN109143465A (en) * | 2018-09-03 | 2019-01-04 | 中国科学院微电子研究所 | A kind of forming method of optical waveguide device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100679229B1 (en) * | 2004-12-09 | 2007-02-05 | 한국전자통신연구원 | Planar optical waveguide and a method for fabricating the same |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005345953A (en) * | 2004-06-07 | 2005-12-15 | Fujikura Ltd | Optical waveguide and manufacturing method thereof |
| CN102540334A (en) * | 2010-12-24 | 2012-07-04 | 苏州东微半导体有限公司 | Manufacturing method for PLC (planar lightwave circuit) optical device |
| CN104635298A (en) * | 2015-02-11 | 2015-05-20 | 深圳太辰光通信股份有限公司 | Planar optical waveguide and manufacturing method thereof |
| CN109143465A (en) * | 2018-09-03 | 2019-01-04 | 中国科学院微电子研究所 | A kind of forming method of optical waveguide device |
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