CN112331725A - Waveguide type germanium photoelectric detector based on photonic crystal and preparation method - Google Patents
Waveguide type germanium photoelectric detector based on photonic crystal and preparation method Download PDFInfo
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- 229910052732 germanium Inorganic materials 0.000 title claims abstract description 153
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 title claims abstract description 153
- 239000004038 photonic crystal Substances 0.000 title claims abstract description 41
- 238000002360 preparation method Methods 0.000 title abstract description 11
- 238000010521 absorption reaction Methods 0.000 claims abstract description 75
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 53
- 239000010703 silicon Substances 0.000 claims abstract description 53
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 53
- 230000002093 peripheral effect Effects 0.000 claims abstract description 36
- 239000002210 silicon-based material Substances 0.000 claims abstract description 36
- 239000003989 dielectric material Substances 0.000 claims abstract description 26
- 230000001795 light effect Effects 0.000 claims abstract description 9
- 239000000463 material Substances 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 22
- 238000005530 etching Methods 0.000 claims description 14
- 239000000758 substrate Substances 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 230000000737 periodic effect Effects 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 10
- 238000005468 ion implantation Methods 0.000 claims description 7
- 229910000577 Silicon-germanium Inorganic materials 0.000 claims description 6
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 229910005898 GeSn Inorganic materials 0.000 claims description 4
- 238000000137 annealing Methods 0.000 claims description 4
- 238000001259 photo etching Methods 0.000 claims description 4
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims description 4
- 230000031700 light absorption Effects 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 8
- 238000000206 photolithography Methods 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 5
- 238000004891 communication Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000010354 integration Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000001465 metallisation Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000005375 photometry Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000001931 thermography Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
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- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0232—Optical elements or arrangements associated with the device
- H01L31/02327—Optical elements or arrangements associated with the device the optical elements being integrated or being directly associated to the device, e.g. back reflectors
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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
- G02B6/1225—Basic optical elements, e.g. light-guiding paths comprising photonic band-gap structures or photonic lattices
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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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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
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- H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
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Abstract
The invention provides a waveguide type germanium photoelectric detector based on photonic crystals and a preparation method thereof, wherein the germanium photoelectric detector comprises: a silicon waveguide structure; the germanium photoelectric detector is connected with the silicon waveguide structure, and periodically arranged dielectric materials are arranged in a germanium absorption region of the germanium photoelectric detector and a peripheral silicon material region at the periphery of the germanium absorption region to form a photonic crystal structure with a slow light effect. Compared with the traditional waveguide type germanium photoelectric detector, the invention can realize more efficient light absorption efficiency, and realize the preparation of the photoelectric detector with low dark current, low capacitance and high responsivity by reducing the size of the device.
Description
Technical Field
The invention belongs to the field of semiconductor manufacturing and the field of optical communication, and particularly relates to a waveguide type germanium photoelectric detector based on photonic crystals and a preparation method thereof.
Background
The photoelectric detector has wide application in various fields of military and national economy. The optical fiber is mainly used for optical communication, ray measurement and detection, industrial automatic control, photometric measurement and the like in visible light or near infrared wave bands; the infrared band is mainly used for missile guidance, infrared thermal imaging, infrared remote sensing and the like.
Germanium (Ge) photodetectors, because of their ease of integration with silicon (Si), have found wide application in the fields of optical communications, optical interconnects, and optical sensing. However, there is a large lattice mismatch between germanium (Ge) materials and silicon (Si) materials, and epitaxial growth of high quality germanium (Ge) materials is extremely challenging. Recent studies have revealed that when a germanium (Ge) material is epitaxially grown in a narrow channel, linear dislocations are annihilated at the channel sidewalls, thereby ensuring high-quality germanium (Ge) material epitaxial growth. Limited by the relatively low absorption coefficient of germanium (Ge) materials in the C, L communication band, the detector must be long enough to achieve high responsivity, which makes the high speed characteristics and dark current of the detector difficult to further optimize.
Disclosure of Invention
In view of the above disadvantages of the prior art, an object of the present invention is to provide a waveguide type germanium photodetector based on photonic crystal and a method for manufacturing the same, which are used to solve the problem that the capacitance and dark current of the germanium photodetector in the prior art are difficult to be further optimized.
To achieve the above and other related objects, the present invention provides a photonic crystal-based waveguide type germanium photodetector, comprising: a silicon waveguide structure; the germanium photoelectric detector is connected with the silicon waveguide structure, and periodically arranged dielectric materials are arranged in a germanium absorption region of the germanium photoelectric detector and a peripheral silicon material region at the periphery of the germanium absorption region to form a photonic crystal structure with a slow light effect.
Optionally, the silicon waveguide structure is connected with the peripheral silicon material region of the photonic crystal structure, and the germanium absorption region is opposite to the silicon waveguide structure.
Optionally, the light in the peripheral silicon material region enters the germanium absorption region by direct coupling or evanescent coupling.
Optionally, the germanium photodetector comprises: a germanium absorbing region having a peripheral silicon material region at a periphery thereof, the germanium absorbing region having opposite first and second ends and opposite first and second sides, the first end of the germanium absorbing region being disposed opposite to the silicon waveguide structure; a first contact layer and a second contact layer formed in the peripheral silicon material region on the first side and the second side of the germanium absorption region, respectively; and the first electrode and the second electrode are respectively formed on the first contact layer and the second contact layer.
Optionally, the material of the germanium absorption region includes one of SiGe, Ge, GeSn, and GePb.
Optionally, the dielectric material is cylindrical and vertically penetrates through the germanium absorption region and the peripheral silicon material region.
Optionally, the dielectric material, the germanium absorption region and the peripheral silicon material region form a resonant cavity with a periodic structure.
Optionally, the dielectric material comprises silicon dioxide.
The invention also provides a preparation method of the waveguide type germanium photoelectric detector based on the photonic crystal, which comprises the following steps: step 1), providing an SOI substrate, and etching a silicon waveguide structure on a top silicon layer of the SOI substrate; step 2), etching a germanium-based material selective epitaxial region on the top silicon layer of the SOI substrate, wherein a top silicon layer bottom layer with partial thickness is reserved at the bottom of the germanium-based material selective epitaxial region; step 3), selectively epitaxially growing a germanium absorption region in the germanium-based material selective epitaxial region, and forming a first contact layer and a second contact layer in a peripheral silicon material region at the periphery of the germanium absorption region by adopting an ion implantation and annealing method; step 4), forming periodically arranged grooves in the germanium absorption region and the peripheral silicon material region through photoetching and etching processes, and filling dielectric materials in the grooves to form a photonic crystal structure with a slow light effect; and 5) defining a first electrode area and a second electrode area in the first contact layer and the second contact layer by photoetching and etching methods, and forming a first electrode and a second electrode.
Optionally, the height of the germanium absorption region is greater than the depth of the selective epitaxial region of germanium-based material.
As described above, the waveguide type germanium photodetector based on photonic crystal and the manufacturing method thereof of the present invention have the following beneficial effects:
the invention introduces a photonic crystal structure into the waveguide type germanium photoelectric detector, and the resonant cavity formed by the periodic structure has the effect of slow light, so that the absorption efficiency of the detector can be improved, the size of the detector is reduced, and the preparation of the photoelectric detector with low dark current, low capacitance and high responsivity is easier to realize. Meanwhile, the periodic germanium/dielectric layer (such as silicon dioxide) structure can effectively reduce the stress of the germanium material and is beneficial to improving the quality of the germanium material.
Compared with the traditional waveguide type germanium photoelectric detector, the invention can realize more efficient light absorption efficiency, and realize the preparation of the photoelectric detector with low dark current, low capacitance and high responsivity by reducing the size of the device.
Drawings
Fig. 1 to fig. 3 are schematic structural diagrams of a waveguide type photonic crystal-based germanium photodetector according to an embodiment of the present invention, in which fig. 2 is a schematic structural diagram of a cross section at a-a 'of fig. 1, and fig. 3 is a schematic structural diagram of a cross section at B-B' of fig. 1.
Fig. 4 is a schematic structural diagram showing steps of a method for manufacturing a waveguide type germanium photodetector based on a photonic crystal according to an embodiment of the present invention.
Description of the element reference numerals
10 silicon waveguide structure
20 germanium photodetector
201 dielectric material
202 germanium absorption region
203 peripheral silicon material region
204 first contact layer
205 second contact layer
206 first electrode
207 second electrode
210 bottom silicon layer
211 insulating layer
212 top silicon layer
30 reflective structure
S11-S15 steps 1) -5)
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.
For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
In the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.
It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.
As shown in fig. 1 to 3, wherein fig. 2 is a schematic cross-sectional structure at a-a 'of fig. 1, and fig. 3 is a schematic cross-sectional structure at B-B' of fig. 1. The embodiment provides a waveguide type germanium photodetector based on photonic crystal, which comprises a silicon waveguide structure 10 and a germanium photodetector 20.
The silicon waveguide structure 10 and the germanium photodetector 20 are fabricated on the basis of an SOI substrate, in which the top silicon layer 212 is partially removed to form a germanium-based material selective epitaxial region, and a bottom layer of the top silicon layer with a partial thickness is reserved at the bottom of the germanium-based material selective epitaxial region, which is used for the epitaxial fabrication of the germanium absorbing region 202.
The germanium photodetector 20 is connected to the silicon waveguide structure 10, and the germanium absorption region 202 of the germanium photodetector 20 and the peripheral silicon material region 203 at the periphery of the germanium absorption region 202 have periodically arranged dielectric materials 201 therein to form a photonic crystal structure with slow light effect. The germanium photodetector 20 includes: a germanium absorption region 202, first and second contact layers 204, 205, and first and second electrodes 206, 207.
As shown in fig. 2 and 3, the germanium absorption region 202 is formed in the germanium-based material selective epitaxial region, and the germanium absorption region 202 has a peripheral silicon material region 203 at the periphery. The germanium absorption region 202 has a first end and a second end opposite to each other, and a first side and a second side opposite to each other, the first end of the germanium absorption region 202 is disposed opposite to the silicon waveguide structure 10, specifically, as shown in fig. 1, the silicon waveguide structure 10 is connected to the peripheral silicon material region 203 of the photonic crystal structure, and the germanium absorption region 202 faces the silicon waveguide structure 10. The germanium absorption region 202 may be one of SiGe, Ge, GeSn, and GePb. For example, in the present embodiment, the material of the germanium absorption region 202 may be selected to be SiGe, so as to reduce lattice mismatch between the germanium absorption region 202 and the top silicon layer 212, and improve the material quality of the germanium absorption region 202.
The first contact layer 204 and the second contact layer 205 are formed in the peripheral silicon material region 203 on a first side and a second side of the germanium absorption region 202, respectively. Specifically, the first contact layer 204 may be formed by performing P-type ion implantation on the peripheral silicon material region 203 on the first side of the germanium absorption region 202 to form heavily doped P-type silicon as the first contact layer 204; the second contact layer 205 may be formed by N-type ion implantation into the peripheral silicon material region 203 on the second side of the germanium absorption region 202 to form heavily doped N-type silicon as the second contact layer 205, and both the first contact layer 204 and the second contact layer 205 are in direct contact with the germanium absorption region 202.
The first electrode 206 and the second electrode 207 are formed on the first contact layer 204 and the second contact layer 205, respectively. For example, the first electrode 206 and the second electrode 207 may be formed by metal deposition, photolithography, and etching processes; for another example, the first electrode 206 and the second electrode 207 may be formed by a metal stripping process, and are not limited to the examples listed herein.
Light in the peripheral silicon material region 203 enters the germanium absorption region 202 by direct coupling or evanescent coupling to reduce optical loss.
As shown in fig. 1, the dielectric material 201 is cylindrical and vertically penetrates the ge absorption region 202 and the peripheral silicon material region 203. The dielectric material 201 forms a resonant cavity with a periodic structure with the germanium absorption region 202 and the peripheral silicon material region 203. The dielectric material 201 may be silicon dioxide. Of course, the dielectric material 201 may be selected from other materials with refractive index such as air, vacuum, silicon oxynitride, etc., and is not limited to the examples listed herein. The dielectric material 201 penetrates the germanium absorption region 202, which effectively reduces the stress of the germanium absorption region 202.
As shown in fig. 1 and 2, in the present embodiment, the spacing between the dielectric materials 201 in the germanium absorption region 202 is larger than the spacing between the dielectric materials 201 in the peripheral silicon material region 203, so as to ensure the absorption effect of the germanium absorption region 202.
As shown in fig. 1, the second end of the germanium photodetector is connected to a reflective structure 30 having a photonic crystal structure, which can achieve a reflective effect, and further increase the absorption efficiency of the germanium photodetector 20.
The invention introduces a photonic crystal structure into the waveguide type germanium photoelectric detector 20, and because a resonant cavity formed by a periodic structure has a slow light effect, the group velocity can be greatly reduced when the guided mode of the photonic crystal is subjected to the periodic structure dispersion of the photonic crystal, thereby realizing the slow light effect of the photonic crystal. The photonic crystal has the advantages of flexible structural design, small volume, convenience for integration with the existing optical communication device and easiness in control, and can realize optical cache, thereby improving the absorption efficiency of the detector, reducing the size of the detector and more easily realizing the preparation of the photoelectric detector with low dark current, low capacitance and high responsivity. Meanwhile, the periodic germanium/dielectric layer (such as silicon dioxide) structure can effectively reduce the stress of the germanium material and is beneficial to improving the quality of the germanium material.
As shown in fig. 1 to 4, this embodiment further provides a method for manufacturing a waveguide type germanium photodetector based on a photonic crystal, where the method includes the steps of:
as shown in fig. 4, step 1) S11 is performed first, and a SOI substrate is provided, and the silicon waveguide structure 10 is etched on the top silicon layer 212 of the SOI substrate.
Specifically, the SOI substrate specifically includes a bottom silicon layer 210, an insulating layer 211, and a top silicon layer 212. The silicon waveguide structure 10 is formed in the top silicon layer 212 by a photolithography and etching process.
As shown in fig. 4, step 2) S12 is then performed to etch a germanium-based material selective epitaxial region in the top silicon layer 212 of the SOI substrate, wherein a bottom layer of the top silicon layer is left at the bottom of the germanium-based material selective epitaxial region for a partial thickness.
For example, a dielectric layer may be deposited on the top silicon layer 212 of the SOI substrate as a hard mask, a transfer window may be formed in the dielectric layer by photolithography and etching processes, and the top silicon layer 212 may be further etched to etch a germanium-based material selective epitaxial region in the top silicon layer 212. The germanium-based material selectively leaves a bottom layer of the top silicon layer at the bottom of the epitaxial region of partial thickness to facilitate subsequent epitaxial growth of the germanium-absorbing region 202.
As shown in fig. 4, step 3) S13 is performed to selectively epitaxially grow a germanium absorption region 202 in the germanium-based material selective epitaxial region, and a first contact layer 204 and a second contact layer 205 are formed in the peripheral silicon material region 203 at the periphery of the germanium absorption region 202 by ion implantation and annealing.
The germanium absorption region 202 may be one of SiGe, Ge, GeSn, and GePb. For example, in the present embodiment, the material of the germanium absorption region 202 may be selected to be SiGe, so as to reduce lattice mismatch between the germanium absorption region 202 and the top silicon layer 212, and improve the material quality of the germanium absorption region 202.
The height of the germanium absorption region 202 is greater than the depth of the selective epitaxial region of germanium-based material to further improve the absorption efficiency of the germanium absorption region 202 without increasing the length of the germanium absorption region.
Specifically, the first contact layer 204 may be formed by performing P-type ion implantation on the peripheral silicon material region 203 on the first side of the germanium absorption region 202 to form heavily doped P-type silicon as the first contact layer 204; the second contact layer 205 may be formed by N-type ion implantation into the peripheral silicon material region 203 on the second side of the germanium absorption region 202 to form heavily doped N-type silicon as the second contact layer 205, and both the first contact layer 204 and the second contact layer 205 are in direct contact with the germanium absorption region 202.
As shown in fig. 4, step 4) S14 is then performed, wherein periodically arranged grooves are formed in the germanium absorption region 202 and the peripheral silicon material region 203 through photolithography and etching processes, and the grooves are filled with a dielectric material 201, so as to form a photonic crystal structure with a slow light effect.
As shown in fig. 1, the recess and the dielectric material 201 are cylindrically shaped and vertically penetrate the germanium absorption region 202 and the peripheral silicon material region 203. The dielectric material 201 forms a resonant cavity with a periodic structure with the germanium absorption region 202 and the peripheral silicon material region 203. The dielectric material 201 may be silicon dioxide. Of course, the dielectric material 201 may also be selected from other materials with refractive index such as silicon oxynitride, and is not limited to the examples listed herein. The dielectric material 201 penetrates the germanium absorption region 202, and the stress of the germanium absorption region can be released in the process of forming the periodically arranged grooves, so that the stress of the germanium absorption region 202 is effectively reduced.
As shown in fig. 4, step 5) S15 is finally performed, a first electrode 206 region and a second electrode 207 region are defined in the first contact layer 204 and the second contact layer 205 by photolithography and etching methods, and the first electrode 206 and the second electrode 207 are formed.
For example, the first electrode 206 and the second electrode 207 may be formed by metal deposition, photolithography, and etching processes; for another example, the first electrode 206 and the second electrode 207 may be formed by a metal stripping process, and are not limited to the examples listed herein.
The first electrode 206 and the second electrode 207 may form ohmic contacts with the first contact layer 204 and the second contact layer 205 by thermal annealing, etc. to reduce the resistance and the parasitic capacitance.
As described above, the waveguide type germanium photodetector based on photonic crystal and the manufacturing method thereof of the present invention have the following beneficial effects:
the invention introduces a photonic crystal structure into the waveguide type germanium photoelectric detector, and the resonant cavity formed by the periodic structure has the effect of slow light, so that the absorption efficiency of the detector can be improved, the size of the detector is reduced, and the preparation of the photoelectric detector with low dark current, low capacitance and high responsivity is easier to realize. Meanwhile, the periodic germanium/dielectric layer (such as silicon dioxide) structure can effectively reduce the stress of the germanium material and is beneficial to improving the quality of the germanium material.
Compared with the traditional waveguide type germanium photoelectric detector, the invention can realize more efficient light absorption efficiency, and can realize the preparation of the photoelectric detector with low dark current, low capacitance and high responsivity by reducing the size of the device.
Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. A photonic crystal based waveguide type germanium photodetector, comprising:
a silicon waveguide structure;
the germanium photoelectric detector is connected with the silicon waveguide structure, and periodically arranged dielectric materials are arranged in a germanium absorption region of the germanium photoelectric detector and a peripheral silicon material region at the periphery of the germanium absorption region to form a photonic crystal structure with a slow light effect.
2. The photonic crystal based waveguide type germanium photodetector of claim 1, wherein: the silicon waveguide structure is connected with the peripheral silicon material region of the photonic crystal structure, and the germanium absorption region is opposite to the silicon waveguide structure.
3. The photonic crystal based waveguide type germanium photodetector of claim 1, wherein: the light of the peripheral silicon material region enters the germanium absorption region through direct coupling or evanescent coupling.
4. The photonic crystal based waveguide type germanium photodetector of claim 1, wherein: the germanium photodetector includes:
a germanium absorbing region having a peripheral silicon material region at a periphery thereof, the germanium absorbing region having opposite first and second ends and opposite first and second sides, the first end of the germanium absorbing region being disposed opposite to the silicon waveguide structure;
a first contact layer and a second contact layer formed in the peripheral silicon material region on the first side and the second side of the germanium absorption region, respectively;
and the first electrode and the second electrode are respectively formed on the first contact layer and the second contact layer.
5. The photonic crystal based waveguide type germanium photodetector of claim 1, wherein: the germanium absorption region is made of one of SiGe, Ge, GeSn and GePb.
6. The photonic crystal based waveguide type germanium photodetector of claim 1, wherein: the dielectric material is cylindrical and vertically penetrates through the germanium absorption region and the peripheral silicon material region.
7. The photonic crystal based waveguide type germanium photodetector of claim 1, wherein: the dielectric material, the germanium absorption region and the peripheral silicon material region form a resonant cavity with a periodic structure.
8. The photonic crystal based waveguide type germanium photodetector of claim 1, wherein: the dielectric material comprises air or silicon dioxide.
9. The method for preparing a waveguide type germanium photodetector based on photonic crystal according to any one of claims 1 to 8, wherein the method comprises the steps of:
step 1), providing an SOI substrate, and etching a silicon waveguide structure on a top silicon layer of the SOI substrate;
step 2), etching a germanium-based material selective epitaxial region on the top silicon layer of the SOI substrate, wherein a top silicon layer bottom layer with partial thickness is reserved at the bottom of the germanium-based material selective epitaxial region;
step 3), selectively epitaxially growing a germanium absorption region in the germanium-based material selective epitaxial region, and forming a first contact layer and a second contact layer in a peripheral silicon material region at the periphery of the germanium absorption region by adopting an ion implantation and annealing method;
step 4), forming periodically arranged grooves in the germanium absorption region and the peripheral silicon material region through photoetching and etching processes, and filling dielectric materials in the grooves to form a photonic crystal structure with a slow light effect;
and 5) defining a first electrode area and a second electrode area in the first contact layer and the second contact layer by photoetching and etching methods, and forming a first electrode and a second electrode.
10. The method for preparing a waveguide type germanium photodetector based on photonic crystal as claimed in claim 9, wherein: the height of the germanium absorption region is greater than the depth of the selective epitaxial region of the germanium-based material.
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