CN112925059A - Micro-disk cavity of on-chip integrated waveguide and preparation method thereof - Google Patents
Micro-disk cavity of on-chip integrated waveguide and preparation method thereof Download PDFInfo
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- CN112925059A CN112925059A CN202110357339.7A CN202110357339A CN112925059A CN 112925059 A CN112925059 A CN 112925059A CN 202110357339 A CN202110357339 A CN 202110357339A CN 112925059 A CN112925059 A CN 112925059A
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- 238000002360 preparation method Methods 0.000 title abstract description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 82
- 229910052814 silicon oxide Inorganic materials 0.000 claims abstract description 82
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 70
- 239000004065 semiconductor Substances 0.000 claims abstract description 70
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 70
- 239000010703 silicon Substances 0.000 claims abstract description 70
- 239000000758 substrate Substances 0.000 claims abstract description 68
- 230000001590 oxidative effect Effects 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 40
- 238000005530 etching Methods 0.000 claims description 28
- 238000001312 dry etching Methods 0.000 claims description 14
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 9
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 9
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 6
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims description 6
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 claims description 6
- 238000009616 inductively coupled plasma Methods 0.000 claims description 4
- 238000001020 plasma etching Methods 0.000 claims description 4
- BLIQUJLAJXRXSG-UHFFFAOYSA-N 1-benzyl-3-(trifluoromethyl)pyrrolidin-1-ium-3-carboxylate Chemical compound C1C(C(=O)O)(C(F)(F)F)CCN1CC1=CC=CC=C1 BLIQUJLAJXRXSG-UHFFFAOYSA-N 0.000 claims description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 3
- 229910017604 nitric acid Inorganic materials 0.000 claims description 3
- 239000011259 mixed solution Substances 0.000 claims description 2
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- 230000005540 biological transmission Effects 0.000 abstract description 8
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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
- G02B6/122—Basic optical elements, e.g. light-guiding paths
- G02B6/125—Bends, branchings or intersections
-
- 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
- G02B6/122—Basic optical elements, e.g. light-guiding paths
-
- 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
- G02B6/136—Integrated optical circuits characterised by the manufacturing method by etching
-
- 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
- G02B2006/12035—Materials
- G02B2006/12038—Glass (SiO2 based materials)
-
- 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
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Abstract
The invention discloses a microdisk cavity of an on-chip integrated waveguide and a preparation method thereof. The microdisk cavity includes: oxidizing a silicon wafer; the silicon oxide wafer comprises a silicon-based substrate and a silicon oxide semiconductor layer; the silicon oxide semiconductor layer comprises a functional region and a non-functional region; the functional area comprises a waveguide structure, a micro-disk structure and a first opening positioned in the micro-disk structure; the non-functional region includes a second opening; the micro-disc structure and the first opening form a micro-disc cavity; a first expansion lumen and a second expansion lumen; the first expansion cavity extends into the silicon-based substrate from the first opening along a direction vertical to the plane of the silicon-based substrate; the second expansion cavity extends into the silicon-based substrate from the second opening along the direction vertical to the plane of the silicon-based substrate; the first expansion cavity is communicated with the second expansion cavity; the vertical projection of the waveguide structure and the micro-disk structure on the silicon-based substrate is positioned in a communicating structure formed by the first expansion cavity and the second expansion cavity. The embodiment of the invention reduces the transmission loss of light in the waveguide structure and improves the quality factor of the micro-disk cavity.
Description
Technical Field
The embodiment of the invention relates to an optical technology, in particular to a microdisk cavity of an on-chip integrated waveguide and a preparation method thereof.
Background
An optical microcavity is a tiny device that can confine light in a certain amount of space and time, and because it possesses a high quality factor Q and a small mode volume, the interaction between light and a substance can be greatly enhanced. Therefore, the optical microcavity plays an important role in nonlinear optics, lasers, coherent optical communication, sensing and the like. And the optical waveguide for coupling is integrated on the optical microcavity, so that the development of the field of all-optical integrated photonic devices is effectively promoted.
The microdisk cavity of the on-chip integrated waveguide formed in the prior art has large transmission loss.
Disclosure of Invention
The invention provides a microdisk cavity of an on-chip integrated waveguide and a preparation method thereof, which reduce the transmission loss of light in a waveguide structure and improve the quality factor of the microdisk cavity.
In a first aspect, an embodiment of the present invention provides a microdisk cavity for an on-chip integrated waveguide, where the microdisk cavity includes:
oxidizing a silicon wafer; the silicon oxide wafer comprises a silicon-based substrate and a silicon oxide semiconductor layer;
the silicon oxide semiconductor layer comprises a functional region and a non-functional region; the functional area comprises a waveguide structure, a micro-disk structure and a first opening positioned in the micro-disk structure; the non-functional region includes a second opening; the microdisk structure and the first opening form a microdisk cavity;
a first expansion lumen and a second expansion lumen; the first expansion cavity extends from the first opening into the silicon-based substrate along a direction vertical to the plane of the silicon-based substrate; the second expansion cavity extends from the second opening into the silicon-based substrate along a direction vertical to the plane of the silicon-based substrate; the first expansion cavity is communicated with the second expansion cavity; and the vertical projection of the waveguide structure and the microdisk structure on the silicon-based substrate is positioned in a communicating structure formed by the first expansion cavity and the second expansion cavity.
Optionally, the thickness of the silicon oxide semiconductor layer at the non-opening position of the functional region is greater than the thickness of the silicon oxide semiconductor layer of the non-functional region.
Optionally, the waveguide structure is a linear waveguide structure;
or, the waveguide structure is a bent waveguide structure; the vertical distance from each point on the bent waveguide structure to the microdisk structure is a fixed value.
Optionally, a separation distance L between the waveguide structure and the microdisk structure satisfies: l is more than or equal to 0 mu m and less than or equal to 10 mu m.
Optionally, the first opening is located in a central region of the microdisk structure.
Optionally, the second opening is located on a side of the waveguide structure away from the microdisk structure.
Optionally, the size of the first expansion cavity at the contact surface of the silicon-based substrate and the silicon oxide semiconductor layer is larger than that of the first opening;
the size of the second expansion cavity at the contact surface of the silicon-based substrate and the silicon oxide semiconductor layer is larger than that of the second opening.
In a second aspect, an embodiment of the present invention further provides a method for manufacturing a microdisk cavity for an on-chip integrated waveguide, where the method is used to manufacture the microdisk cavity for an on-chip integrated waveguide according to the first aspect, and the method includes:
providing a silicon monoxide chip; the silicon oxide wafer comprises a silicon-based substrate and a silicon oxide semiconductor layer; the silicon oxide semiconductor layer comprises a functional region and a non-functional region;
etching the non-functional region of the silicon oxide semiconductor layer by adopting a dry etching process so as to enable the functional region of the silicon oxide semiconductor layer to form a waveguide structure and a microdisk structure;
etching the silicon oxide semiconductor layer in the microdisk structure and part of the silicon oxide semiconductor layer in the non-functional area by adopting a dry etching process so as to form a first opening in the microdisk structure and a second opening in the non-functional area; the microdisk structure and the first opening form a microdisk cavity;
respectively etching the silicon-based substrate by taking the first opening structure and the second opening structure as masks to form a first expansion cavity and a second expansion cavity; the first expansion cavity is communicated with the second expansion cavity; and the vertical projection of the waveguide structure and the microdisk structure on the silicon-based substrate is positioned in a communicating structure formed by the first expansion cavity and the second expansion cavity.
Optionally, etching the silicon-based substrate by using the first opening structure and the second opening structure as masks, respectively, to form a first expansion cavity and a second expansion cavity, including:
respectively taking the first opening structure and the second opening structure as masks, and etching the silicon-based substrate by adopting an etching process to form a first expansion cavity and a second expansion cavity; the size of the first expansion cavity at the contact surface of the silicon-based substrate and the silicon oxide semiconductor layer is larger than that of the first opening; the size of the second expansion cavity at the contact surface of the silicon-based substrate and the silicon oxide semiconductor layer is larger than that of the second opening;
the reactant of the etching process comprises at least one of xenon difluoride, potassium hydroxide, tetramethylammonium hydroxide, or a mixed solution of nitric acid, hydrofluoric acid and acetic acid.
Optionally, the dry etching process includes a reactive plasma etching process or an inductively coupled plasma etching process.
According to the technical scheme, the second expansion cavity is arranged, so that the output loss of light in the silicon-based substrate is reduced, and the transmission loss of light in the silicon oxide waveguide structure is reduced; meanwhile, by arranging the first expansion cavity, the output loss of light coupled into the microdisk cavity by the waveguide structure in the silicon-based substrate is reduced, and the quality factor of the microdisk cavity is improved, so that the power of the output light of the microdisk cavity of the integrated waveguide on the whole chip is improved, the problem of large transmission loss of the microdisk cavity of the integrated waveguide on the chip in the prior art is solved, and the application of the microdisk cavity in the aspect of nonlinearity is facilitated.
Drawings
FIG. 1 is a schematic structural diagram of a microdisk cavity for an on-chip integrated waveguide according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a top view of a micro-disk cavity for an on-chip integrated waveguide according to an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional view of a microdisk cavity of the on-chip integrated waveguide taken along section line A 'B' in FIG. 2;
FIG. 4 is a schematic diagram of a top view of another micro-disk cavity for an on-chip integrated waveguide according to an embodiment of the present invention;
FIG. 5 is a schematic flow chart of a method for fabricating a micro-disk cavity for on-chip integrated waveguides according to an embodiment of the present invention;
fig. 6-11 are process diagrams of manufacturing a microdisk cavity for on-chip integrated waveguides according to embodiments of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of a microdisk cavity of an on-chip integrated waveguide provided in an embodiment of the present invention, and fig. 2 is a schematic structural diagram of a microdisk cavity of an on-chip integrated waveguide provided in an embodiment of the present invention in a top view; FIG. 3 is a schematic cross-sectional view of a microdisk cavity of the on-chip integrated waveguide taken along section line A 'B' in FIG. 2; as shown in fig. 1-3, the microdisk chamber includes: oxidizing a silicon wafer 10; the silicon oxide wafer 10 comprises a silicon substrate 11 and a silicon oxide semiconductor layer 12; the silicon oxide semiconductor layer 12 includes a functional region a and a non-functional region B; the functional region a includes a waveguide structure 121, a microdisk structure 122, and a first opening 123 located in the microdisk structure 122; the non-functional region B includes a second opening 124; the microdisk structure 122 and the first opening 123 form a microdisk cavity 125; a first expansion chamber 111 and a second expansion chamber 112; the first expansion cavity 111 extends from the first opening 123 into the silicon-based substrate 11 along a direction perpendicular to the plane of the silicon-based substrate 11; the second expansion cavity 112 extends from the second opening 124 into the silicon-based substrate 11 along a direction perpendicular to the plane of the silicon-based substrate 11; the first expansion chamber 111 communicates with the second expansion chamber 112; the vertical projection of the waveguide structure 121 and the microdisk structure 122 on the si-based substrate 11 is located within the communicating structure formed by the first expansion cavity 111 and the second expansion cavity 112.
The microdisk cavity with the waveguide integrated on the chip is formed by coupling light to the microdisk cavity 125 through the waveguide structure 121, and when the light meets a certain condition, the light coupled into the microdisk cavity 125 generates resonance in the microdisk cavity 125, which plays an important role in nonlinear optics, lasers, coherent light communication, sensing and the like.
Specifically, when light is coupled into the microdisk cavity 125 through the waveguide structure 121, a part of light leaks into the silicon-based substrate 11 due to the low refractive index of the waveguide structure 121 made of silicon oxide semiconductor, and high material absorption loss is generated; in the technical scheme, the second opening 124 is arranged to form the second expansion cavity 112, so that when light is transmitted in the silicon oxide waveguide structure 121, air with a lower refractive index is arranged below the silicon oxide waveguide structure, the light cannot be absorbed by the silicon substrate 11, and the output loss of the light in the waveguide structure 121 is greatly reduced; meanwhile, the first expansion cavity 111 is arranged, so that the output loss of light coupled into the microdisk cavity 125 in the corresponding silicon-based substrate 11 is reduced, the quality factor of the microdisk cavity 125 is improved, the power of light output by the microdisk cavity of the integrated waveguide on the whole chip is improved, and the non-optical characteristic of light output by the microdisk cavity of the integrated waveguide on the chip is improved. Optionally, the second opening 124 is located on a side of the waveguide structure 121 remote from the microdisk structure 123.
Alternatively, referring to fig. 3, the thickness of the silicon oxide semiconductor layer at the non-opening position of the functional region a is greater than the thickness of the silicon oxide semiconductor layer of the non-functional region B.
Wherein the silicon oxide semiconductor layer 12 comprises a silicon oxide semiconductor support layer and a silicon oxide semiconductor functional layer; the silicon oxide semiconductor supporting layer is positioned between the silicon-based substrate and the silicon oxide semiconductor functional layer; the waveguide structure 121 and the microdisk structure 122 of the functional region A are prepared by etching the silicon oxide semiconductor functional layer by the same dry etching process; the second opening 124 of the non-functional area B is made by etching a silicon oxide semiconductor layer support layer, and the first opening 123 of the functional area a is made by etching a silicon oxide semiconductor support layer and a silicon oxide semiconductor functional layer corresponding to the microdisk structure 122; the thickness of the silicon oxide semiconductor layer at the non-opening position of the functional region a is greater than that of the silicon oxide semiconductor layer at the non-functional region B, that is, the waveguide structure 121 and the microdisk structure 122 of the functional region are disposed at one side of the silicon oxide semiconductor support layer, so that the silicon oxide semiconductor support layer can play a role of supporting the waveguide structure 121 and the microdisk cavity 122 after the first expansion cavity 111 and the second expansion cavity 112 are formed.
Alternatively, referring to fig. 1-3, the waveguide structure 121 is a linear waveguide structure; the coupling point of the linear waveguide structure and the microdisk structure 122 is a fixed point, and the coupling mode of the waveguide structure 121 and the microdisk cavity 125 is unique.
Optionally, fig. 4 is a schematic top-view structural diagram of another microdisk cavity for on-chip integrated waveguide according to an embodiment of the present invention; as shown in fig. 4, the waveguide structure 121 is a curved waveguide structure; the vertical distance from each point on the curved waveguide structure 121 to the microdisk structure 122 is a fixed value, and the coupling points of the curved waveguide structure and the microdisk structure 122 are a plurality of vertical distance points, so that the coupling modes of the waveguide structure 121 and the microdisk cavity 125 are various, the coupling efficiency of the waveguide structure 121 and the microdisk cavity 125 is high, more light rays are coupled into the microdisk cavity 125, and the light ray output energy of the microdisk cavity 125 of the on-chip integrated waveguide can be improved. It should be noted that the waveguide structure 121 only needs to realize a coupling function with the microdisk cavity 125, and the specific shape of the waveguide structure 121 is not particularly limited herein.
Alternatively, referring to fig. 2, the waveguide structure 121 and the microdisk structure 122 are spaced apart by a distance L that satisfies: l is more than or equal to 0 mu m and less than or equal to 10 mu m.
When the spacing distance between the waveguide structure 121 and the microdisk structure 122 is large, light output by the waveguide structure 121 is partially lost and cannot be completely transmitted to the microdisk structure 122, so that the light energy output by the microdisk cavity 125 is influenced; if the distance between the waveguide structure 121 and the microdisk structure 122 is small, the difficulty of the fabrication process of the integrated waveguide is increased. Preferably, the separation distance L between the waveguide structure 121 and the microdisk structure 122 satisfies the above range, and the coupling efficiency between the waveguide structure 121 and the microdisk structure 122 can be improved, so that the energy of light output from the microdisk cavity 125 can be improved, and the difficulty of the preparation process of the microdisk cavity integrated with the waveguide on the whole chip can be reduced.
Alternatively, referring to fig. 1-4, the first opening 123 is located in a central region of the microdisk structure 122. The size of the first expansion cavity 111 at the contact surface of the silicon substrate 11 and the silicon oxide semiconductor layer 12 is larger than that of the first opening 123; the size of the second expansion cavity 112 at the interface of the silicon substrate 11 and the silicon oxide semiconductor layer 12 is larger than the size of the second opening 124.
Because the intrinsic loss of the silicon-based substrate 11 is relatively large, the second expansion cavity 112 corresponding to the second opening 124 is etched, and the vertical projection of the waveguide structure 121 on the plane of the silicon-based substrate 11 is located in the second expansion cavity 112, so that the extra loss caused by the silicon-based substrate 11 is reduced, and the transmission loss of light in the waveguide structure 121 is reduced; meanwhile, the silicon substrate 11 corresponding to the first opening 123 is etched to form the first expansion cavity 111, and the vertical projection of the microdisk cavity 125 on the plane of the silicon substrate 11 is located in the first expansion cavity 111, so that the extra loss caused by the silicon substrate 11 is further reduced, the transmission loss of light coupled to the microdisk cavity 125 is reduced, the quality factor of the microdisk cavity 125 is improved, and the power of the output light of the microdisk cavity of the integrated waveguide on the whole chip is improved.
Based on the same inventive concept, the embodiment of the invention also provides a preparation method of the microdisk cavity of the on-chip integrated waveguide, which is used for preparing the microdisk cavity of the on-chip integrated waveguide provided by the embodiment of the invention. Fig. 5 is a schematic flow chart of a method for manufacturing a microdisk cavity for on-chip integrated waveguides according to an embodiment of the present invention. As shown in fig. 5, the preparation method includes:
s110, providing a silicon monoxide chip;
the silicon oxide wafer can be a commercial silicon oxide wafer, and comprises a silicon substrate and a silicon oxide semiconductor layer; the silicon oxide semiconductor layer includes a functional region and a non-functional region.
S120, etching the non-functional area of the silicon oxide semiconductor layer by adopting a dry etching process so as to enable the functional area of the silicon oxide semiconductor layer to form a waveguide structure and a microdisk structure;
fig. 6 to 11 are process diagrams of a process for manufacturing a microdisk cavity for on-chip integrated waveguide according to an embodiment of the present invention, and referring to fig. 6 to 8, a silicon oxide wafer is provided, which includes a silicon substrate 11 and a silicon oxide semiconductor layer 12; coating photoresist on the silicon oxide semiconductor layer 12; photoetching and developing the photoresist by using a mask plate with a preset pattern as a mask to obtain a defined waveguide structure photoresist pattern 31 and a micro-disk structure 122 photoresist pattern 32; then, the waveguide structure photoresist pattern 31 and the microdisk structure photoresist pattern 32 are used as masks, and the waveguide structure 121 and the microdisk structure 122 are formed by etching a part of the silicon oxide semiconductor layer 12 by reactive plasma etching or inductively coupled plasma etching.
It should be noted that, compared to wet etching, since the etching by chemical reaction is isotropic, the size of the actual microdisk structure 122 after reaction is smaller than that of the photoresist pattern 32 of microdisk structure; this may cause problems such as complication of the process for coupling the waveguide structure 121 on the side of the microdisk structure 122. According to the technical scheme, the silicon oxide semiconductor layer 12 is etched through a dry etching process, and compared with a wet etching process, the dry etching process has anisotropy, namely the reaction speed is different in each direction, and the reaction speed can be flexibly controlled, so that the etching precision of the microdisk structure 122 of the integrated waveguide structure 121 is high, and the microdisk structure 122 of the integrated waveguide structure 121 is accurately controlled to be manufactured.
In addition, compared with the prior art, the waveguide structure 121 and the microdisk structure 122 with different material layers are prepared by a wet etching method twice, and the waveguide structure 121 and the microdisk structure 122 are prepared in the same dry etching process, so that the process preparation flow is simplified, and accurate alignment is not needed in the preparation process. In addition, the waveguide structure 121 and the microdisk structure 122 are both made of silicon oxide semiconductor materials, so that phase matching is easier to realize.
S130, etching the silicon oxide semiconductor layer in the microdisk structure and part of the silicon oxide semiconductor layer in the non-functional area by adopting a dry etching process so as to form a first opening in the microdisk structure and a second opening in the non-functional area; the micro-disc structure and the first opening form a micro-disc cavity;
referring to fig. 9-10, a photoresist is coated on the waveguide structure 121 and the microdisk structure 122, then a mask plate with a preset shape is used as a mask, the photoresist is subjected to photolithography and development, the silicon oxide semiconductor layer 12 corresponding to the microdisk structure 122 and the silicon oxide semiconductor layer 12 in the non-functional region are exposed, then the part of the silicon oxide semiconductor layer 12 corresponding to the microdisk structure 122 is etched to form a first opening 123 in the microdisk structure 122, the first opening 123 penetrates through the silicon oxide semiconductor layer 12, and the first opening 123 and the microdisk structure 122 form a microdisk cavity 125, that is, a microdisk cavity with an integrated waveguide on a chip is formed; at the same time, a part of the silicon oxide semiconductor layer 12 of the non-functional region is etched in the same dry etching process to form the second opening 124 in the non-functional region. In this way, the silicon oxide semiconductor layer 12 and a part of the silicon oxide semiconductor layer 12 in the non-functional region corresponding to the microdisk structure 122 are etched by the reactive plasma etching or the inductively coupled plasma etching process, and the etching precision of the microdisk cavity 125 and the second opening 124 of the integrated waveguide structure 121 is increased due to the anisotropy of the dry etching process.
S140, etching the silicon-based substrate by respectively taking the first opening and the second opening as masks to form a first expansion cavity and a second expansion cavity;
specifically, referring to fig. 11, the first opening 123 and the second opening 124 are respectively used as masks, and at least one of xenon difluoride, potassium hydroxide, tetramethylammonium hydroxide, nitric acid, hydrofluoric acid, and acetic acid is used to etch the silicon-based substrate 11 to form the first extension cavity 111 and the second extension cavity 112. Wherein, the size of the first expansion cavity 111 at the contact surface of the silicon substrate 11 and the silicon oxide semiconductor layer 12 is larger than that of the first opening 123; the size of the second expansion cavity 112 at the contact surface of the silicon substrate 11 and the silicon oxide semiconductor layer 12 is larger than that of the second opening 124; the first expansion chamber 111 communicates with the second expansion chamber 112; the vertical projection of the waveguide structure 121 and the microdisk structure 122 on the si-based substrate 11 is located within the communicating structure formed by the first expansion cavity 111 and the second expansion cavity 112. Therefore, because the intrinsic loss of the silicon-based substrate 11 is large, the silicon-based substrate 11 is etched by a wet method to form the first expansion cavity 111, so that the additional loss of input light in the silicon-based substrate 11 is reduced, the transmission loss of the input light in the waveguide structure 121 is reduced, meanwhile, the silicon-based substrate 11 is etched to form the second expansion cavity 112, the additional loss of light coupled to the microdisk cavity 125 in the silicon-based substrate 11 is further reduced, the quality factor of the microdisk cavity 125 is improved, the power of output light of the microdisk cavity of the integrated waveguide on the whole chip is improved, and the application of the microdisk cavity in the aspect of nonlinear optics is facilitated.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A microdisk cavity for on-chip integrated waveguides, comprising:
oxidizing a silicon wafer; the silicon oxide wafer comprises a silicon-based substrate and a silicon oxide semiconductor layer;
the silicon oxide semiconductor layer comprises a functional region and a non-functional region; the functional area comprises a waveguide structure, a micro-disk structure and a first opening positioned in the micro-disk structure; the non-functional region includes a second opening; the microdisk structure and the first opening form a microdisk cavity;
a first expansion lumen and a second expansion lumen; the first expansion cavity extends from the first opening into the silicon-based substrate along a direction vertical to the plane of the silicon-based substrate; the second expansion cavity extends from the second opening into the silicon-based substrate along a direction vertical to the plane of the silicon-based substrate; the first expansion cavity is communicated with the second expansion cavity; and the vertical projection of the waveguide structure and the microdisk structure on the silicon-based substrate is positioned in a communicating structure formed by the first expansion cavity and the second expansion cavity.
2. The microdisk cavity of an on-chip integrated waveguide of claim 1, wherein a thickness of the silicon oxide semiconductor layer at a non-opening position of the functional region is greater than a thickness of the silicon oxide semiconductor layer of the non-functional region.
3. The microdisk cavity for on-chip integrated waveguides of claim 1, wherein the waveguide structure is a linear waveguide structure;
or, the waveguide structure is a bent waveguide structure; the vertical distance from each point on the bent waveguide structure to the microdisk structure is a fixed value.
4. The microdisk cavity of an on-chip integrated waveguide of claim 3, wherein the waveguide structure and the microdisk structure are separated by a distance L that satisfies: l is more than or equal to 0 mu m and less than or equal to 10 mu m.
5. The microdisk cavity of an on-chip integrated waveguide of claim 1, wherein the first opening is located in a central region of the microdisk structure.
6. The microdisk cavity of an on-chip integrated waveguide of claim 1, wherein the second opening is located on a side of the waveguide structure distal from the microdisk structure.
7. The microdisk cavity of an on-chip integrated waveguide according to claim 1, wherein the first expansion cavity has a size at the interface of the silicon-based substrate and the silicon oxide semiconductor layer larger than the size of the first opening;
the size of the second expansion cavity at the contact surface of the silicon-based substrate and the silicon oxide semiconductor layer is larger than that of the second opening.
8. A method for preparing a microdisk cavity for an on-chip integrated waveguide according to any one of claims 1 to 7, comprising:
providing a silicon monoxide chip; the silicon oxide wafer comprises a silicon-based substrate and a silicon oxide semiconductor layer; the silicon oxide semiconductor layer comprises a functional region and a non-functional region;
etching the non-functional region of the silicon oxide semiconductor layer by adopting a dry etching process so as to enable the functional region of the silicon oxide semiconductor layer to form a waveguide structure and a microdisk structure;
etching the silicon oxide semiconductor layer in the microdisk structure and part of the silicon oxide semiconductor layer in the non-functional area by adopting a dry etching process so as to form a first opening in the microdisk structure and a second opening in the non-functional area; the microdisk structure and the first opening form a microdisk cavity;
respectively etching the silicon substrate by taking the first opening and the second opening as masks to form a first expansion cavity and a second expansion cavity; the first expansion cavity is communicated with the second expansion cavity; and the vertical projection of the waveguide structure and the microdisk structure on the silicon-based substrate is positioned in a communicating structure formed by the first expansion cavity and the second expansion cavity.
9. The method according to claim 8, wherein etching the silicon-based substrate with the first opening and the second opening as masks to form a first expansion cavity and a second expansion cavity respectively comprises:
etching the silicon-based substrate by adopting an etching process by taking the first opening and the second opening as masks respectively to form a first expansion cavity and a second expansion cavity; the size of the first expansion cavity at the contact surface of the silicon-based substrate and the silicon oxide semiconductor layer is larger than that of the first opening; the size of the second expansion cavity at the contact surface of the silicon-based substrate and the silicon oxide semiconductor layer is larger than that of the second opening;
the reactant of the etching process comprises at least one of xenon difluoride, potassium hydroxide, tetramethylammonium hydroxide, or a mixed solution of nitric acid, hydrofluoric acid and acetic acid.
10. The method of claim 8, wherein the dry etching process comprises a reactive plasma etching process or an inductively coupled plasma etching process.
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| CN117111209A (en) * | 2023-10-16 | 2023-11-24 | 潍坊先进光电芯片研究院 | Micro-disk and micro-ring coupling composite cavity with PT symmetrical regulation and control |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117111209A (en) * | 2023-10-16 | 2023-11-24 | 潍坊先进光电芯片研究院 | Micro-disk and micro-ring coupling composite cavity with PT symmetrical regulation and control |
| CN117111209B (en) * | 2023-10-16 | 2024-02-13 | 潍坊先进光电芯片研究院 | Micro-disk and micro-ring coupling composite cavity with PT symmetrical regulation and control |
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