WO2021022576A1 - Waveguide-type germanium photoelectric detector employing photonic crystal, and preparation method - Google Patents

Waveguide-type germanium photoelectric detector employing photonic crystal, and preparation method Download PDF

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WO2021022576A1
WO2021022576A1 PCT/CN2019/100559 CN2019100559W WO2021022576A1 WO 2021022576 A1 WO2021022576 A1 WO 2021022576A1 CN 2019100559 W CN2019100559 W CN 2019100559W WO 2021022576 A1 WO2021022576 A1 WO 2021022576A1
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germanium
photonic crystal
silicon
region
waveguide
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PCT/CN2019/100559
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French (fr)
Chinese (zh)
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汪巍
方青
涂芝娟
曾友宏
蔡艳
余明斌
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上海新微技术研发中心有限公司
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Priority claimed from CN201921254955.4U external-priority patent/CN210040212U/en
Priority claimed from CN201910717527.9A external-priority patent/CN112331725A/en
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Publication of WO2021022576A1 publication Critical patent/WO2021022576A1/en

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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • 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
    • H01L31/08—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
    • H01L31/09—Devices sensitive to infrared, visible or ultraviolet radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • 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
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the invention belongs to the field of semiconductor manufacturing and optical communication, and particularly relates to a waveguide type germanium photodetector based on a photonic crystal and a preparation method thereof.
  • Photodetectors are widely used in various fields of military and national economy. In the visible or near-infrared band, it is mainly used for optical communication, ray measurement and detection, industrial automatic control, photometry, etc.; in the infrared band, it is mainly used for missile guidance, infrared thermal imaging, and infrared remote sensing.
  • Germanium (Ge) photodetectors because of their easy integration with silicon (Si), have a wide range of applications in the fields of optical communications, optical interconnection, and optical sensing.
  • germanium (Ge) materials and silicon (Si) materials, and it is extremely challenging to epitaxially grow high-quality germanium (Ge) materials.
  • Recent research shows that in the narrow channel epitaxial growth of germanium (Ge) material, linear dislocations will be annihilated on the sidewall of the channel, thereby ensuring the epitaxial growth of high-quality germanium (Ge) material.
  • the detector Limited by the relatively low absorption coefficient of germanium (Ge) materials in the C and L communication bands, in order to achieve high responsivity, the detector must be long enough, which makes it difficult to further optimize the high-speed characteristics and dark current of the detector.
  • the purpose of the present invention is to provide a photonic crystal-based waveguide type germanium photodetector and a preparation method for solving the problem of the capacitance and dark current of the germanium photodetector in the prior art. Optimization.
  • the present invention provides a waveguide type germanium photodetector based on a photonic crystal.
  • the germanium photodetector includes: a silicon waveguide structure; a germanium photodetector connected to the silicon waveguide structure, The germanium absorption area of the germanium photodetector and the peripheral silicon material area on the periphery of the germanium absorption area have dielectric materials arranged periodically to form a photonic crystal structure with a slow light effect.
  • the silicon waveguide structure is connected to a peripheral silicon material region of the photonic crystal structure, and the germanium absorption region is directly opposite to the silicon waveguide structure.
  • the light in the peripheral silicon material region enters the germanium absorption region through direct coupling or evanescent wave coupling.
  • the germanium photodetector includes: a germanium absorption region with a peripheral silicon material region on the periphery of the germanium absorption region, the germanium absorption region having opposite first and second ends, and opposite first sides And the second side, the first end of the germanium absorption region is opposite to the silicon waveguide structure; the first contact layer and the second contact layer are respectively formed on the first side and the second side of the germanium absorption region In the peripheral silicon material area; a first electrode and a second electrode are formed on the first contact layer and the second contact layer, respectively.
  • the material of the germanium absorption region includes one of SiGe, Ge, GeSn, and GePb.
  • the dielectric material is cylindrical and vertically penetrates the germanium absorption zone and the peripheral silicon material zone.
  • the dielectric material, the germanium absorption region and the peripheral silicon material region form a resonant cavity with a periodic structure.
  • the dielectric material includes silicon dioxide.
  • the present invention also provides a method for preparing a waveguide type germanium photodetector based on photonic crystals.
  • the preparation method includes the steps: step 1), providing an SOI substrate, and etching on the top silicon layer of the SOI substrate A silicon waveguide structure; step 2), etching a germanium-based material selective epitaxial region on the top silicon layer of the SOI substrate, and a part of the top silicon layer bottom layer is left at the bottom of the germanium-based material selective epitaxial region; Step 3), selectively epitaxially grow a germanium absorption region in the germanium-based material selective epitaxial region, and use ion implantation and annealing methods to form a first contact layer and a second contact in the peripheral silicon material region on the periphery of the germanium absorption region Layer; step 4), forming periodically arranged grooves in the germanium absorption area and the surrounding silicon material area by photolithography and etching processes, and filling the grooves with a dielectric material to form a slow light
  • the height of the germanium absorption region is greater than the depth of the germanium-based material selective epitaxial region.
  • the waveguide type germanium photodetector based on photonic crystal and the preparation method of the present invention have the following beneficial effects:
  • the invention introduces the photonic crystal structure into the waveguide type germanium photodetector. Since the resonant cavity formed by the periodic structure has the effect of slow light, the absorption efficiency of the detector can be improved, the size of the detector can be reduced, and low dark current and low Capacitive and highly responsive photodetectors are prepared. At the same time, the periodic germanium/dielectric layer (such as silicon dioxide, etc.) structure can effectively reduce the stress of the germanium material and help improve the quality of the germanium material.
  • the periodic germanium/dielectric layer such as silicon dioxide, etc.
  • the invention can realize more efficient light absorption efficiency, and realizes the preparation of low dark current, low capacitance and high responsivity photodetectors by reducing the size of the device.
  • Figures 1 to 3 show schematic structural diagrams of waveguide type germanium photodetectors based on photonic crystals according to embodiments of the present invention.
  • Figure 2 shows a schematic cross-sectional structure at AA' of Figure 1 and
  • Figure 3 shows Figure 1 is a schematic cross-sectional structure at B-B'.
  • FIG. 4 is a schematic diagram showing the structure of each step of the preparation method of the waveguide type germanium photodetector based on the photonic crystal according to the embodiment of the present invention.
  • spatial relation words such as “below”, “below”, “below”, “below”, “above”, “up”, etc. may be used herein to describe an element or The relationship between a feature and other elements or features. It will be understood that these spatial relationship terms are intended to encompass directions other than the directions depicted in the drawings of the device in use or operation.
  • a layer when referred to as being “between” two layers, it may be the only layer between the two layers, or one or more intervening layers may also be present.
  • the described structure where the first feature is "above" the second feature may include an embodiment in which the first and second features are formed in direct contact, or may include other features formed on the first and second features.
  • the embodiment between the second feature, so that the first and second features may not be in direct contact.
  • Fig. 2 is a schematic cross-sectional structure diagram of Fig. 1 at A-A'
  • Fig. 3 is a schematic cross-sectional structure diagram of Fig. 1 at B-B'.
  • This embodiment provides a waveguide type germanium photodetector based on a photonic crystal.
  • the waveguide type germanium photodetector includes a silicon waveguide structure 10 and a germanium photodetector 20.
  • the silicon waveguide structure 10 and the germanium photodetector 20 are prepared based on an SOI substrate.
  • the top silicon layer 212 of the SOI substrate is partially removed to form a germanium-based material selective epitaxial region.
  • a partial thickness of the top silicon layer and bottom layer remains at the bottom of the epitaxial region, and the germanium-based material selective epitaxial region is used for the epitaxial preparation of the germanium absorption 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 surrounding the germanium absorption region 202 have dielectric materials arranged periodically 201 to form a photonic crystal structure with slow light effect.
  • the germanium photodetector 20 includes a germanium absorption region 202, a first contact layer 204 and a second contact layer 205, and a first electrode 206 and a second electrode 207.
  • 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 on the periphery.
  • the germanium absorption region 202 has opposite first and second ends, and opposite first and second sides, and 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 is facing the silicon waveguide structure 10.
  • the material of the germanium absorption region 202 may be one of SiGe, Ge, GeSn, and GePb.
  • the material of the germanium absorption region 202 can be selected as SiGe to reduce the 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 respectively formed in the peripheral silicon material region 203 on the first side and the second side of the germanium absorption region 202.
  • the first contact layer 204 can be heavily doped with P-type silicon by performing P-type ion implantation on the peripheral silicon material region 203 on the first side of the germanium absorption region 202 to serve as the first contact layer 204;
  • the second contact layer 205 can form heavily doped N-type silicon by performing N-type ion implantation on the peripheral silicon material region 203 on the second side of the germanium absorption region 202 to serve as the second contact layer 205.
  • Both a 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.
  • the first electrode 206 and the second electrode 207 can be formed by metal deposition, photolithography and etching processes; for another example, the first electrode 206 and the second electrode 207 can be formed by a metal lift-off process without Limited to the examples listed here.
  • the light in the peripheral silicon material region 203 enters the germanium absorption region 202 through direct coupling or evanescent wave coupling to reduce light loss.
  • the dielectric material 201 is cylindrical and vertically penetrates the germanium absorption region 202 and the peripheral silicon material region 203.
  • the dielectric material 201, the germanium absorption region 202 and the peripheral silicon material region 203 form a resonant cavity with a periodic structure.
  • the dielectric material 201 may be silicon dioxide.
  • the dielectric material 201 can also be selected as air, vacuum or silicon oxynitride and other refractive index materials, and is not limited to the examples listed here.
  • the dielectric material 201 penetrates the germanium absorption region 202, which can effectively reduce the stress of the germanium absorption region 202.
  • the spacing between the dielectric materials 201 in the germanium absorption region 202 is greater than the spacing between the dielectric materials 201 in the peripheral silicon material region 203, so that The absorption effect of the germanium absorption region 202 is ensured.
  • a reflective structure 30 having a photonic crystal structure is connected to the second end of the germanium photodetector, which can achieve a reflection effect and further increase the absorption efficiency of the germanium photodetector 20.
  • the present invention introduces a photonic crystal structure in the waveguide type germanium photodetector 20. Since the resonant cavity formed by the periodic structure has a slow light effect, in the photonic crystal, the guided mode is dispersed by the periodic structure of the photonic crystal, and the group velocity will be greatly increased. Reduce to achieve the slow light effect of photonic crystals.
  • the photonic crystal of the present invention has the advantages of flexible structure design, small size, easy integration with existing optical communication devices, and easy control. It can realize optical buffering, thereby improving the absorption efficiency of the detector, reducing the size of the detector, and making it easier to achieve low darkness. Preparation of current, low capacitance and high responsivity photodetectors.
  • the periodic germanium/dielectric layer such as silicon dioxide, etc.
  • the periodic germanium/dielectric layer can effectively reduce the stress of the germanium material and help improve the quality of the germanium material.
  • this embodiment also provides a method for preparing a waveguide type germanium photodetector based on a photonic crystal, and the preparation method includes the steps:
  • step 1) S11 is performed, an SOI substrate is provided, and the silicon waveguide structure 10 is etched on the top silicon layer 212 of the SOI substrate.
  • 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 through photolithography and etching processes.
  • step 2) S12 is then performed.
  • a germanium-based material selective epitaxial region is etched on the top silicon layer 212 of the SOI substrate, and a part of the thickness of the germanium-based material selective epitaxial region remains at the bottom The top silicon layer and the bottom layer.
  • a dielectric layer may be first deposited on the top silicon layer 212 of the SOI substrate as a hard mask, and then a transfer window may be formed in the dielectric layer through a photolithography and etching process, and then the top may be further etched.
  • the silicon layer 212 is used to etch a germanium-based material selective epitaxial region in the top silicon layer 212. A part of the thickness of the bottom layer of the top silicon layer remains at the bottom of the germanium-based material selective epitaxial region to facilitate the subsequent epitaxial growth of the germanium absorption region 202.
  • the germanium absorption region 202 is selectively epitaxially grown on the germanium-based material selective epitaxial region, and ion implantation and annealing methods are used to form a silicon material on the periphery of the germanium absorption region 202 A first contact layer 204 and a second contact layer 205 are formed in the region 203.
  • the material of the germanium absorption region 202 may be one of SiGe, Ge, GeSn, and GePb.
  • the material of the germanium absorption region 202 can be selected as SiGe to reduce the 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 germanium-based material selective epitaxial region, so as to further improve the absorption efficiency of the germanium absorption region 202 without increasing the length of the germanium absorption region.
  • the first contact layer 204 can be heavily doped with P-type silicon by performing P-type ion implantation on the peripheral silicon material region 203 on the first side of the germanium absorption region 202 to serve as the first contact layer 204;
  • the second contact layer 205 can form heavily doped N-type silicon by performing N-type ion implantation on the peripheral silicon material region 203 on the second side of the germanium absorption region 202 to serve as the second contact layer 205.
  • Both a contact layer 204 and the second contact layer 205 are in direct contact with the germanium absorption region 202.
  • step 4) S14 is then performed.
  • Periodically arranged grooves are formed in the germanium absorption region 202 and the surrounding silicon material region 203 through photolithography and etching processes, and dielectric is filled in the grooves Material 201 to form a photonic crystal structure with slow light effect.
  • the groove and the dielectric material 201 are cylindrical and vertically penetrate the germanium absorption region 202 and the peripheral silicon material region 203.
  • the dielectric material 201, the germanium absorption region 202 and the peripheral silicon material region 203 form a resonant cavity with a periodic structure.
  • the dielectric material 201 may be silicon dioxide.
  • the dielectric material 201 can also be selected as other refractive index materials such as silicon oxynitride, and is not limited to the examples listed here.
  • the dielectric material 201 penetrates the germanium absorption region 202, and during the process of forming the periodically arranged grooves, the stress of the germanium absorption region can be released, thereby effectively reducing the stress of the germanium absorption region 202.
  • step 5 S15 is finally performed to define a first electrode 206 area and a second electrode 207 area 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.
  • first electrode 206 and the second electrode 207 can be formed by metal deposition, photolithography and etching processes; for another example, the first electrode 206 and the second electrode 207 can be formed by a metal lift-off process without Limited to the examples listed here.
  • the first electrode 206 and the second electrode 207 may respectively form an ohmic contact with the first contact layer 204 and the second contact layer 205 through thermal annealing or the like, so as to reduce the resistance and the parasitic capacitance.
  • the waveguide type germanium photodetector based on photonic crystal and the preparation method of the present invention have the following beneficial effects:
  • the invention introduces the photonic crystal structure into the waveguide type germanium photodetector. Since the resonant cavity formed by the periodic structure has the effect of slow light, the absorption efficiency of the detector can be improved, the size of the detector can be reduced, and low dark current and low Capacitive and highly responsive photodetectors are prepared. At the same time, the periodic germanium/dielectric layer (such as silicon dioxide, etc.) structure can effectively reduce the stress of the germanium material and help improve the quality of the germanium material.
  • the periodic germanium/dielectric layer such as silicon dioxide, etc.
  • the present invention can realize more efficient light absorption efficiency, and can realize the preparation of low dark current, low capacitance and high response photodetector by reducing the size of the device.
  • the present invention effectively overcomes various shortcomings in the prior art and has high industrial value.

Abstract

A waveguide-type germanium photoelectric detector employing a photonic crystal, comprising: a silicon waveguide structure (10); and a germanium photoelectric detector (20) connected to the silicon waveguide structure (10), wherein dielectric materials (201) are periodically disposed in a germanium absorption region (202) of the germanium photoelectric detector (20) and in a peripheral silicon material region (203) at the periphery of the germanium absorption region (202), so as to form a photonic crystal structure having a slow-light effect. When compared with conventional waveguide-type germanium photoelectric detectors, the waveguide-type germanium photoelectric detector employing a photonic crystal provides improved light absorption efficiency, and facilitates reduction of the device size so as to achieve a photoelectric detector having low dark currents, low capacitance, and high responsivity.

Description

基于光子晶体的波导型锗光电探测器及制备方法Waveguide type germanium photodetector based on photonic crystal and preparation method 技术领域Technical field
本发明属于半导体制造领域及光通讯领域，特别是涉及一种基于光子晶体的波导型锗光电探测器及制备方法。The invention belongs to the field of semiconductor manufacturing and optical communication, and particularly relates to a waveguide type germanium photodetector based on a photonic crystal and a preparation method thereof.
背景技术Background technique
光电探测器在军事和国民经济的各个领域有广泛用途。在可见光或近红外波段主要用于光通信、射线测量和探测、工业自动控制、光度计量等；在红外波段主要用于导弹制导、红外热成像、红外遥感等方面。Photodetectors are widely used in various fields of military and national economy. In the visible or near-infrared band, it is mainly used for optical communication, ray measurement and detection, industrial automatic control, photometry, etc.; in the infrared band, it is mainly used for missile guidance, infrared thermal imaging, and infrared remote sensing.
锗(Ge)光电探测器，因其容易实现与硅(Si)的集成，在光通信、光互联和光传感等领域有着广泛的应用。然而，锗(Ge)材料与硅(Si)材料之间存在着大的晶格失配，外延生长高质量锗(Ge)材料极具挑战。最近的研究表面，在窄的沟道中外延生长锗(Ge)材料，线性位错会在沟道侧壁湮灭，从而保证高质量锗(Ge)材料外延生长。受限于锗(Ge)材料在C、L通信波段相对较低的吸收系数，为了实现高的响应度，探测器必须足够长，这使得探测器的高速特性和暗电流难以进一步优化。Germanium (Ge) photodetectors, because of their easy integration with silicon (Si), have a wide range of applications in the fields of optical communications, optical interconnection, and optical sensing. However, there is a large lattice mismatch between germanium (Ge) materials and silicon (Si) materials, and it is extremely challenging to epitaxially grow high-quality germanium (Ge) materials. Recent research shows that in the narrow channel epitaxial growth of germanium (Ge) material, linear dislocations will be annihilated on the sidewall of the channel, thereby ensuring the epitaxial growth of high-quality germanium (Ge) material. Limited by the relatively low absorption coefficient of germanium (Ge) materials in the C and L communication bands, in order to achieve high responsivity, the detector must be long enough, which makes it difficult to further optimize the high-speed characteristics and dark current of the detector.
发明内容Summary of the invention
鉴于以上所述现有技术的缺点，本发明的目的在于提供一种基于光子晶体的波导型锗光电探测器及制备方法，用于解决现有技术中锗光电探测器的电容和暗电流难以进一步优化问题。In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a photonic crystal-based waveguide type germanium photodetector and a preparation method for solving the problem of the capacitance and dark current of the germanium photodetector in the prior art. Optimization.
为实现上述目的及其他相关目的，本发明提供一种基于光子晶体的波导型锗光电探测器，所述锗光电探测器包括：硅波导结构；锗光电探测器，连接于所述硅波导结构，所述锗光电探测器的锗吸收区及所述锗吸收区外围的周边硅材料区中具有周期性排列的介质材料，以形成具有慢光效应的光子晶体结构。In order to achieve the above objects and other related objects, the present invention provides a waveguide type germanium photodetector based on a photonic crystal. The germanium photodetector includes: a silicon waveguide structure; a germanium photodetector connected to the silicon waveguide structure, The germanium absorption area of the germanium photodetector and the peripheral silicon material area on the periphery of the germanium absorption area have dielectric materials arranged periodically to form a photonic crystal structure with a slow light effect.
可选地，所述硅波导结构与所述光子晶体结构的周边硅材料区连接，且所述锗吸收区正对于所述硅波导结构。Optionally, the silicon waveguide structure is connected to a peripheral silicon material region of the photonic crystal structure, and the germanium absorption region is directly opposite to the silicon waveguide structure.
可选地，所述周边硅材料区的光通过直接耦合或消逝波耦合方式进入所述锗吸收区。Optionally, the light in the peripheral silicon material region enters the germanium absorption region through direct coupling or evanescent wave coupling.
可选地，所述锗光电探测器包括：锗吸收区，所述锗吸收区外围具有周边硅材料区，所述锗吸收区具有相对的第一端及第二端，以及相对的第一侧及第二侧，所述锗吸收区的第一端与所述硅波导结构相对设置；第一接触层及第二接触层，分别形成于所述锗吸收区的第一 侧及第二侧的所述周边硅材料区中；第一电极及第二电极，分别形成于所述第一接触层及第二接触层上。Optionally, the germanium photodetector includes: a germanium absorption region with a peripheral silicon material region on the periphery of the germanium absorption region, the germanium absorption region having opposite first and second ends, and opposite first sides And the second side, the first end of the germanium absorption region is opposite to the silicon waveguide structure; the first contact layer and the second contact layer are respectively formed on the first side and the second side of the germanium absorption region In the peripheral silicon material area; a first electrode and a second electrode are formed on the first contact layer and the second contact layer, respectively.
可选地，所述锗吸收区的材料包括SiGe、Ge、GeSn及GePb中的一种。Optionally, the material of the germanium absorption region includes one of SiGe, Ge, GeSn, and GePb.
可选地，所述介质材料呈圆柱形垂直贯穿所述锗吸收区及所述周边硅材料区。Optionally, the dielectric material is cylindrical and vertically penetrates the germanium absorption zone and the peripheral silicon material zone.
可选地，所述介质材料与所述锗吸收区及所述周边硅材料区形成具有周期性结构的谐振腔。Optionally, the dielectric material, the germanium absorption region and the peripheral silicon material region form a resonant cavity with a periodic structure.
可选地，所述介质材料包括二氧化硅。Optionally, the dielectric material includes silicon dioxide.
本发明还提供一种基于光子晶体的波导型锗光电探测器的制备方法，所述制备方法包括步骤：步骤1)，提供一SOI衬底，在所述SOI衬底的顶硅层上刻蚀出硅波导结构；步骤2)，在所述SOI衬底的顶硅层以刻蚀出锗基材料选择性外延区域，所述锗基材料选择性外延区域底部保留部分厚度的顶硅层底层；步骤3)，在所述锗基材料选择性外延区域选择性外延生长锗吸收区，采用离子注入及退火方法在所述锗吸收区外围的周边硅材料区中形成第一接触层及第二接触层；步骤4)，通过光刻及刻蚀工艺在所述锗吸收区及周边硅材料区形成周期性排列的凹槽，并在所述凹槽中填充介质材料，以形成具有慢光效应的光子晶体结构；步骤5)，通过光刻及刻蚀方法在所述第一接触层及所述第二接触层中定义第一电极区域及第二电极区域，并形成第一电极及第二电极。The present invention also provides a method for preparing a waveguide type germanium photodetector based on photonic crystals. The preparation method includes the steps: step 1), providing an SOI substrate, and etching on the top silicon layer of the SOI substrate A silicon waveguide structure; step 2), etching a germanium-based material selective epitaxial region on the top silicon layer of the SOI substrate, and a part of the top silicon layer bottom layer is left at the bottom of the germanium-based material selective epitaxial region; Step 3), selectively epitaxially grow a germanium absorption region in the germanium-based material selective epitaxial region, and use ion implantation and annealing methods to form a first contact layer and a second contact in the peripheral silicon material region on the periphery of the germanium absorption region Layer; step 4), forming periodically arranged grooves in the germanium absorption area and the surrounding silicon material area by photolithography and etching processes, and filling the grooves with a dielectric material to form a slow light effect Photonic crystal structure; step 5), defining a first electrode area and a second electrode area in the first contact layer and the second contact layer by photolithography and etching methods, and forming the first electrode and the second electrode .
可选地，所述锗吸收区的高度大于所述锗基材料选择性外延区域的深度。Optionally, the height of the germanium absorption region is greater than the depth of the germanium-based material selective epitaxial region.
如上所述，本发明的基于光子晶体的波导型锗光电探测器及制备方法，具有以下有益效果：As mentioned above, the waveguide type germanium photodetector based on photonic crystal and the preparation method of the present invention have the following beneficial effects:
本发明在波导型锗光电探测器中引入光子晶体结构，由于周期性结构构成的谐振腔具有慢光的效应，可以提高探测器吸收效率，减小探测器尺寸，更容易实现低暗电流、低电容和高响应度光电探测器制备。同时，周期性锗/介质层(如二氧化硅等)结构可以有效降低锗材料的应力，有利于提高锗材料质量。The invention introduces the photonic crystal structure into the waveguide type germanium photodetector. Since the resonant cavity formed by the periodic structure has the effect of slow light, the absorption efficiency of the detector can be improved, the size of the detector can be reduced, and low dark current and low Capacitive and highly responsive photodetectors are prepared. At the same time, the periodic germanium/dielectric layer (such as silicon dioxide, etc.) structure can effectively reduce the stress of the germanium material and help improve the quality of the germanium material.
本发明与传统波导型锗光电探测器相比，可以实现更高效的光吸收效率，通过减小器件尺寸，实现低暗电流、低电容和高响应度光电探测器制备。Compared with the traditional waveguide type germanium photodetector, the invention can realize more efficient light absorption efficiency, and realizes the preparation of low dark current, low capacitance and high responsivity photodetectors by reducing the size of the device.
附图说明Description of the drawings
如图1～图3显示为本发明实施例的基于光子晶体的波导型锗光电探测器的结构示意图，其中，图2显示为图1在A-A’处的截面结构示意图，图3显示为图1在B-B’处的截面结构示意图。Figures 1 to 3 show schematic structural diagrams of waveguide type germanium photodetectors based on photonic crystals according to embodiments of the present invention. Figure 2 shows a schematic cross-sectional structure at AA' of Figure 1 and Figure 3 shows Figure 1 is a schematic cross-sectional structure at B-B'.
图4显示为本发明实施例的基于光子晶体的波导型锗光电探测器的制备方法各步骤所呈现的结构示意图。4 is a schematic diagram showing the structure of each step of the preparation method of the waveguide type germanium photodetector based on the photonic crystal according to the embodiment of the present invention.
元件标号说明Component label description
10                     硅波导结构10 Silicon waveguide structure
20                     锗光电探测器20 Germanium photodetector
201                    介质材料201 Media materials
202                    锗吸收区202 Germanium absorption zone
203                    周边硅材料区203 Surrounding silicon material area
204                    第一接触层204 The first contact layer
205                    第二接触层205 The second contact layer
206                    第一电极206 First electrode
207                    第二电极207 Second electrode
210                    底硅层210 Bottom silicon layer
211                    绝缘层211 Insulation layer
212                    顶硅层212 Top silicon layer
30                     反射结构30 Reflective structure
S11～S15               步骤1)～步骤5)S11～S15 Step 1)～Step 5)
具体实施方式detailed description
以下通过特定的具体实例说明本发明的实施方式，本领域技术人员可由本说明书所揭露的内容轻易地了解本发明的其他优点与功效。本发明还可以通过另外不同的具体实施方式加以实施或应用，本说明书中的各项细节也可以基于不同观点与应用，在没有背离本发明的精神下进行各种修饰或改变。The following describes the implementation of the present invention through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
如在详述本发明实施例时，为便于说明，表示器件结构的剖面图会不依一般比例作局部放大，而且所述示意图只是示例，其在此不应限制本发明保护的范围。此外，在实际制作中应包含长度、宽度及深度的三维空间尺寸。For example, when describing the embodiments of the present invention in detail, for ease of description, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic diagram is only an example, which should not limit the scope of protection of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual production.
为了方便描述，此处可能使用诸如“之下”、“下方”、“低于”、“下面”、“上方”、“上”等的空间关系词语来描述附图中所示的一个元件或特征与其他元件或特征的关系。将理解到，这些空间关系词语意图包含使用中或操作中的器件的、除了附图中描绘的方向之外的其他方向。此外，当一层被称为在两层“之间”时，它可以是所述两层之间仅有的层，或者也可以存在一 个或多个介于其间的层。For the convenience of description, spatial relation words such as "below", "below", "below", "below", "above", "up", etc. may be used herein to describe an element or The relationship between a feature and other elements or features. It will be understood that these spatial relationship terms are intended to encompass directions other than the directions depicted in the drawings of the device in use or operation. In addition, when a layer is referred to as being "between" two layers, it may be the only layer between the two layers, or one or more intervening layers may also be present.
在本申请的上下文中，所描述的第一特征在第二特征“之上”的结构可以包括第一和第二特征形成为直接接触的实施例，也可以包括另外的特征形成在第一和第二特征之间的实施例，这样第一和第二特征可能不是直接接触。In the context of the present application, the described structure where the first feature is "above" the second feature may include an embodiment in which the first and second features are formed in direct contact, or may include other features formed on the first and second features. The embodiment between the second feature, so that the first and second features may not be in direct contact.
需要说明的是，本实施例中所提供的图示仅以示意方式说明本发明的基本构想，遂图示中仅显示与本发明中有关的组件而非按照实际实施时的组件数目、形状及尺寸绘制，其实际实施时各组件的型态、数量及比例可为一种随意的改变，且其组件布局型态也可能更为复杂。It should be noted that the illustrations provided in this embodiment only illustrate the basic idea of the present invention in a schematic manner, so the figures only show the components related to the present invention instead of the actual implementation of the number, shape and For size drawing, the type, quantity, and ratio of each component can be changed at will during actual implementation, and the component layout type may also be more complicated.
如图1～图3所示，其中，图2显示为图1在A-A’处的截面结构示意图，图3显示为图1在B-B’处的截面结构示意图。本实施例提供一种基于光子晶体的波导型锗光电探测器，所述波导型锗光电探测器包括硅波导结构10及锗光电探测器20。As shown in Figs. 1 to 3, Fig. 2 is a schematic cross-sectional structure diagram of Fig. 1 at A-A', and Fig. 3 is a schematic cross-sectional structure diagram of Fig. 1 at B-B'. This embodiment provides a waveguide type germanium photodetector based on a photonic crystal. The waveguide type germanium photodetector includes a silicon waveguide structure 10 and a germanium photodetector 20.
所述硅波导结构10及所述锗光电探测器20基于SOI衬底制备，所述SOI衬底的顶硅层212被部分去除以形成锗基材料选择性外延区域，所述锗基材料选择性外延区域底部保留部分厚度的顶硅层底层，所述锗基材料选择性外延区域用于锗吸收区202的外延制备。The silicon waveguide structure 10 and the germanium photodetector 20 are prepared based on an SOI substrate. The top silicon layer 212 of the SOI substrate is partially removed to form a germanium-based material selective epitaxial region. A partial thickness of the top silicon layer and bottom layer remains at the bottom of the epitaxial region, and the germanium-based material selective epitaxial region is used for the epitaxial preparation of the germanium absorption region 202.
所述锗光电探测器20连接于所述硅波导结构10，所述锗光电探测器20的锗吸收区202及所述锗吸收区202外围的周边硅材料区203中具有周期性排列的介质材料201，以形成具有慢光效应的光子晶体结构。所述锗光电探测器20包括：锗吸收区202、第一接触层204及第二接触层205、及第一电极206及第二电极207。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 surrounding the germanium absorption region 202 have dielectric materials arranged periodically 201 to form a photonic crystal structure with slow light effect. The germanium photodetector 20 includes a germanium absorption region 202, a first contact layer 204 and a second contact layer 205, and a first electrode 206 and a second electrode 207.
如图2及图3所示，所述锗吸收区202形成于所述锗基材料选择性外延区域，所述锗吸收区202外围具有周边硅材料区203。所述锗吸收区202具有相对的第一端及第二端，以及相对的第一侧及第二侧，所述锗吸收区202的第一端与所述硅波导结构10相对设置，具体地，如图1所示，所述硅波导结构10与所述光子晶体结构的周边硅材料区203连接，且所述锗吸收区202正对于所述硅波导结构10。所述锗吸收区202的材料可以为SiGe、Ge、GeSn及GePb中的一种。例如，在本实施例中，所述锗吸收区202的材料可以选用为SiGe，以降低锗吸收区202与所述顶硅层212之间的晶格失配，提高锗吸收区202的材料质量。As shown in FIGS. 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 on the periphery. The germanium absorption region 202 has opposite first and second ends, and opposite first and second sides, and 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 is facing the silicon waveguide structure 10. The material of the germanium absorption region 202 may be one of SiGe, Ge, GeSn, and GePb. For example, in this embodiment, the material of the germanium absorption region 202 can be selected as SiGe to reduce the 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 .
所述第一接触层204及第二接触层205分别形成于所述锗吸收区202的第一侧及第二侧的所述周边硅材料区203中。具体地，所述第一接触层204可以通过对锗吸收区202的第一侧的所述周边硅材料区203进行P型离子注入形成重掺杂P型硅，以作为第一接触层204；所述第二接触层205可以通过对锗吸收区202的第二侧的所述周边硅材料区203进行N型离子注入形成重掺杂N型硅，以作为第二接触层205，所述第一接触层204与所述第二接触层205均与所述锗吸收区202直接接触。The first contact layer 204 and the second contact layer 205 are respectively formed in the peripheral silicon material region 203 on the first side and the second side of the germanium absorption region 202. Specifically, the first contact layer 204 can be heavily doped with P-type silicon by performing P-type ion implantation on the peripheral silicon material region 203 on the first side of the germanium absorption region 202 to serve as the first contact layer 204; The second contact layer 205 can form heavily doped N-type silicon by performing N-type ion implantation on the peripheral silicon material region 203 on the second side of the germanium absorption region 202 to serve as the second contact layer 205. Both a contact layer 204 and the second contact layer 205 are in direct contact with the germanium absorption region 202.
所述第一电极206及第二电极207分别形成于所述第一接触层204及第二接触层205上。例如，可以通过金属沉积、光刻及刻蚀工艺形成所述第一电极206及第二电极207；又如，可以通过金属剥离工艺形成所述第一电极206及第二电极207，且并不限于此处所列举的示例。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 can be formed by metal deposition, photolithography and etching processes; for another example, the first electrode 206 and the second electrode 207 can be formed by a metal lift-off process without Limited to the examples listed here.
所述周边硅材料区203的光通过直接耦合或消逝波耦合方式进入所述锗吸收区202，以降低光损耗。The light in the peripheral silicon material region 203 enters the germanium absorption region 202 through direct coupling or evanescent wave coupling to reduce light loss.
如图1所示，所述介质材料201呈圆柱形垂直贯穿所述锗吸收区202及所述周边硅材料区203。所述介质材料201与所述锗吸收区202及所述周边硅材料区203形成具有周期性结构的谐振腔。所述介质材料201可以为二氧化硅。当然，所述介质材料201也可选用为空气、真空或氮氧化硅等其他折射率的材料，并不限于此处所列举的示例。所述介质材料201贯穿所述锗吸收区202，可以有效降低所述锗吸收区202的应力。As shown in FIG. 1, the dielectric material 201 is cylindrical and vertically penetrates the germanium absorption region 202 and the peripheral silicon material region 203. The dielectric material 201, the germanium absorption region 202 and the peripheral silicon material region 203 form a resonant cavity with a periodic structure. The dielectric material 201 may be silicon dioxide. Of course, the dielectric material 201 can also be selected as air, vacuum or silicon oxynitride and other refractive index materials, and is not limited to the examples listed here. The dielectric material 201 penetrates the germanium absorption region 202, which can effectively reduce the stress of the germanium absorption region 202.
如图1及图2所示，在本实施例中，位于所述锗吸收区202中的所述介质材料201间的间距大于位于所述周边硅材料区203的介质材料201间的间距，以保证所述锗吸收区202的吸收效果。As shown in Figures 1 and 2, in this embodiment, the spacing between the dielectric materials 201 in the germanium absorption region 202 is greater than the spacing between the dielectric materials 201 in the peripheral silicon material region 203, so that The absorption effect of the germanium absorption region 202 is ensured.
如图1所示，所述锗光电探测器的第二端连接的有具有光子晶体结构的反射结构30，可以起到反射的效果，进一步增加锗光电探测器20的吸收效率。As shown in FIG. 1, a reflective structure 30 having a photonic crystal structure is connected to the second end of the germanium photodetector, which can achieve a reflection effect and further increase the absorption efficiency of the germanium photodetector 20.
本发明在波导型锗光电探测器20中引入光子晶体结构，由于周期性结构构成的谐振腔具有慢光的效应，在光子晶体，导模受到光子晶体的周期性结构色散，群速度会大幅度降低，从而实现光子晶体的慢光效应。本发明的光子晶体具有结构设计灵活、体积小、便于与现有的光通信器件集成、易于控制优点，可实现光缓存，从而提高探测器吸收效率，减小探测器尺寸，更容易实现低暗电流、低电容和高响应度光电探测器制备。同时，周期性锗/介质层(如二氧化硅等)结构可以有效降低锗材料的应力，有利于提高锗材料质量。The present invention introduces a photonic crystal structure in the waveguide type germanium photodetector 20. Since the resonant cavity formed by the periodic structure has a slow light effect, in the photonic crystal, the guided mode is dispersed by the periodic structure of the photonic crystal, and the group velocity will be greatly increased. Reduce to achieve the slow light effect of photonic crystals. The photonic crystal of the present invention has the advantages of flexible structure design, small size, easy integration with existing optical communication devices, and easy control. It can realize optical buffering, thereby improving the absorption efficiency of the detector, reducing the size of the detector, and making it easier to achieve low darkness. Preparation of current, low capacitance and high responsivity photodetectors. At the same time, the periodic germanium/dielectric layer (such as silicon dioxide, etc.) structure can effectively reduce the stress of the germanium material and help improve the quality of the germanium material.
如图1～图4所示，本实施例还提供一种基于光子晶体的波导型锗光电探测器的制备方法，所述制备方法包括步骤：As shown in Figures 1 to 4, this embodiment also provides a method for preparing a waveguide type germanium photodetector based on a photonic crystal, and the preparation method includes the steps:
如图4所示，首先进行步骤1)S11，提供一SOI衬底，在所述SOI衬底的顶硅层212上刻蚀出硅波导结构10。As shown in FIG. 4, firstly, step 1) S11 is performed, an SOI substrate is provided, and the silicon waveguide structure 10 is etched on the top silicon layer 212 of the SOI substrate.
具体地，所述SOI衬底具体包括底硅层210、绝缘层211以及顶硅层212。所述硅波导结构10通过光刻及刻蚀工艺在所述顶硅层212中形成。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 through photolithography and etching processes.
如图4所示，然后进行步骤2)S12，在所述SOI衬底的顶硅层212以刻蚀出锗基材料选择性外延区域，所述锗基材料选择性外延区域底部保留部分厚度的顶硅层底层。As shown in FIG. 4, step 2) S12 is then performed. A germanium-based material selective epitaxial region is etched on the top silicon layer 212 of the SOI substrate, and a part of the thickness of the germanium-based material selective epitaxial region remains at the bottom The top silicon layer and the bottom layer.
例如，可以先在所述SOI衬底的顶硅层212上沉积介质层，作为硬掩膜，然后通过光刻及刻蚀工艺在所述介质层中形成转移窗口，接着进一步刻蚀所述顶硅层212，以在所述顶硅层212中刻蚀出锗基材料选择性外延区域。所述锗基材料选择性外延区域底部保留部分厚度的顶硅层底层，以有利于后续锗吸收区202的外延生长。For example, a dielectric layer may be first deposited on the top silicon layer 212 of the SOI substrate as a hard mask, and then a transfer window may be formed in the dielectric layer through a photolithography and etching process, and then the top may be further etched. The silicon layer 212 is used to etch a germanium-based material selective epitaxial region in the top silicon layer 212. A part of the thickness of the bottom layer of the top silicon layer remains at the bottom of the germanium-based material selective epitaxial region to facilitate the subsequent epitaxial growth of the germanium absorption region 202.
如图4所示，接着进行步骤3)S13，在所述锗基材料选择性外延区域选择性外延生长锗吸收区202，采用离子注入及退火方法在所述锗吸收区202外围的周边硅材料区203中形成第一接触层204及第二接触层205。As shown in FIG. 4, proceed to step 3) S13, the germanium absorption region 202 is selectively epitaxially grown on the germanium-based material selective epitaxial region, and ion implantation and annealing methods are used to form a silicon material on the periphery of the germanium absorption region 202 A first contact layer 204 and a second contact layer 205 are formed in the region 203.
所述锗吸收区202的材料可以为SiGe、Ge、GeSn及GePb中的一种。例如，在本实施例中，所述锗吸收区202的材料可以选用为SiGe，以降低锗吸收区202与所述顶硅层212之间的晶格失配，提高锗吸收区202的材料质量。The material of the germanium absorption region 202 may be one of SiGe, Ge, GeSn, and GePb. For example, in this embodiment, the material of the germanium absorption region 202 can be selected as SiGe to reduce the 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 .
所述锗吸收区202的高度大于所述锗基材料选择性外延区域的深度，以在不增加锗吸收区长度的情况下，进一步提高锗吸收区202的吸收效率。The height of the germanium absorption region 202 is greater than the depth of the germanium-based material selective epitaxial region, so as to further improve the absorption efficiency of the germanium absorption region 202 without increasing the length of the germanium absorption region.
具体地，所述第一接触层204可以通过对锗吸收区202的第一侧的所述周边硅材料区203进行P型离子注入形成重掺杂P型硅，以作为第一接触层204；所述第二接触层205可以通过对锗吸收区202的第二侧的所述周边硅材料区203进行N型离子注入形成重掺杂N型硅，以作为第二接触层205，所述第一接触层204与所述第二接触层205均与所述锗吸收区202直接接触。Specifically, the first contact layer 204 can be heavily doped with P-type silicon by performing P-type ion implantation on the peripheral silicon material region 203 on the first side of the germanium absorption region 202 to serve as the first contact layer 204; The second contact layer 205 can form heavily doped N-type silicon by performing N-type ion implantation on the peripheral silicon material region 203 on the second side of the germanium absorption region 202 to serve as the second contact layer 205. Both a contact layer 204 and the second contact layer 205 are in direct contact with the germanium absorption region 202.
如图4所示，然后进行步骤4)S14，通过光刻及刻蚀工艺在所述锗吸收区202及周边硅材料区203形成周期性排列的凹槽，并在所述凹槽中填充介质材料201，以形成具有慢光效应的光子晶体结构。As shown in FIG. 4, step 4) S14 is then performed. Periodically arranged grooves are formed in the germanium absorption region 202 and the surrounding silicon material region 203 through photolithography and etching processes, and dielectric is filled in the grooves Material 201 to form a photonic crystal structure with slow light effect.
如图1所示，所述凹槽及所述介质材料201呈圆柱形垂直贯穿所述锗吸收区202及所述周边硅材料区203。所述介质材料201与所述锗吸收区202及所述周边硅材料区203形成具有周期性结构的谐振腔。所述介质材料201可以为二氧化硅。当然，所述介质材料201也可选用为如氮氧化硅等其他折射率的材料，并不限于此处所列举的示例。所述介质材料201贯穿所述锗吸收区202，在形成所述周期性排列的凹槽的过程中，锗吸收区的应力可以获得释放，从而有效降低所述锗吸收区202的应力。As shown in FIG. 1, the groove and the dielectric material 201 are cylindrical and vertically penetrate the germanium absorption region 202 and the peripheral silicon material region 203. The dielectric material 201, the germanium absorption region 202 and the peripheral silicon material region 203 form a resonant cavity with a periodic structure. The dielectric material 201 may be silicon dioxide. Of course, the dielectric material 201 can also be selected as other refractive index materials such as silicon oxynitride, and is not limited to the examples listed here. The dielectric material 201 penetrates the germanium absorption region 202, and during the process of forming the periodically arranged grooves, the stress of the germanium absorption region can be released, thereby effectively reducing the stress of the germanium absorption region 202.
如图4所示，最后进行步骤5)S15，通过光刻及刻蚀方法在所述第一接触层204及所述第二接触层205中定义第一电极206区域及第二电极207区域，并形成第一电极206及第二电极207。As shown in FIG. 4, step 5) S15 is finally performed to define a first electrode 206 area and a second electrode 207 area 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.
例如，可以通过金属沉积、光刻及刻蚀工艺形成所述第一电极206及第二电极207；又 如，可以通过金属剥离工艺形成所述第一电极206及第二电极207，且并不限于此处所列举的示例。For example, the first electrode 206 and the second electrode 207 can be formed by metal deposition, photolithography and etching processes; for another example, the first electrode 206 and the second electrode 207 can be formed by a metal lift-off process without Limited to the examples listed here.
所述第一电极206及所述第二电极207可以通过热退火等方式与所述第一接触层204及所述第二接触层205分别形成欧姆接触，以降低其电阻，同时降低寄生电容。The first electrode 206 and the second electrode 207 may respectively form an ohmic contact with the first contact layer 204 and the second contact layer 205 through thermal annealing or the like, so as to reduce the resistance and the parasitic capacitance.
如上所述，本发明的基于光子晶体的波导型锗光电探测器及制备方法，具有以下有益效果：As mentioned above, the waveguide type germanium photodetector based on photonic crystal and the preparation method of the present invention have the following beneficial effects:
本发明在波导型锗光电探测器中引入光子晶体结构，由于周期性结构构成的谐振腔具有慢光的效应，可以提高探测器吸收效率，减小探测器尺寸，更容易实现低暗电流、低电容和高响应度光电探测器制备。同时，周期性锗/介质层(如二氧化硅等)结构可以有效降低锗材料的应力，有利于提高锗材料质量。The invention introduces the photonic crystal structure into the waveguide type germanium photodetector. Since the resonant cavity formed by the periodic structure has the effect of slow light, the absorption efficiency of the detector can be improved, the size of the detector can be reduced, and low dark current and low Capacitive and highly responsive photodetectors are prepared. At the same time, the periodic germanium/dielectric layer (such as silicon dioxide, etc.) structure can effectively reduce the stress of the germanium material and help improve the quality of the germanium material.
与传统波导型锗光电探测器相比，本发明可以实现更高效的光吸收效率，可以通过减小器件尺寸，实现低暗电流、低电容和高响应度光电探测器制备。Compared with the traditional waveguide type germanium photodetector, the present invention can realize more efficient light absorption efficiency, and can realize the preparation of low dark current, low capacitance and high response photodetector by reducing the size of the device.
所以，本发明有效克服了现有技术中的种种缺点而具高度产业利用价值。Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial value.
上述实施例仅例示性说明本发明的原理及其功效，而非用于限制本发明。任何熟悉此技术的人士皆可在不违背本发明的精神及范畴下，对上述实施例进行修饰或改变。因此，举凡所属技术领域中具有通常知识者在未脱离本发明所揭示的精神与技术思想下所完成的一切等效修饰或改变，仍应由本发明的权利要求所涵盖。The above-mentioned embodiments only exemplarily illustrate the principles and effects of the present invention, and are not used to limit the present invention. Anyone familiar with this technology can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (10)

  1. 一种基于光子晶体的波导型锗光电探测器，其特征在于，所述锗光电探测器包括：A photonic crystal-based waveguide type germanium photodetector, characterized in that, the germanium photodetector comprises:
    硅波导结构；Silicon waveguide structure;
    锗光电探测器，连接于所述硅波导结构，所述锗光电探测器的锗吸收区及所述锗吸收区外围的周边硅材料区中具有周期性排列的介质材料，以形成具有慢光效应的光子晶体结构。The germanium photodetector is connected to the silicon waveguide structure, and the germanium absorption area of the germanium photodetector and the peripheral silicon material area around the germanium absorption area have dielectric materials arranged periodically to form a slow light effect Photonic crystal structure.
  2. 根据权利要求1所述的基于光子晶体的波导型锗光电探测器，其特征在于：所述硅波导结构与所述光子晶体结构的周边硅材料区连接，且所述锗吸收区正对于所述硅波导结构。The waveguide type germanium photodetector based on photonic crystal according to claim 1, wherein the silicon waveguide structure is connected to the peripheral silicon material area of the photonic crystal structure, and the germanium absorption area is facing the Silicon waveguide structure.
  3. 根据权利要求1所述的基于光子晶体的波导型锗光电探测器，其特征在于：所述周边硅材料区的光通过直接耦合或消逝波耦合方式进入所述锗吸收区。The waveguide type germanium photodetector based on photonic crystal according to claim 1, wherein the light in the peripheral silicon material area enters the germanium absorption area through direct coupling or evanescent wave coupling.
  4. 根据权利要求1所述的基于光子晶体的波导型锗光电探测器，其特征在于：所述锗光电探测器包括：The waveguide type germanium photodetector based on photonic crystal according to claim 1, wherein the germanium photodetector comprises:
    锗吸收区，所述锗吸收区外围具有周边硅材料区，所述锗吸收区具有相对的第一端及第二端，以及相对的第一侧及第二侧，所述锗吸收区的第一端与所述硅波导结构相对设置；The germanium absorption region has a peripheral silicon material area on the periphery of the germanium absorption region. The germanium absorption region has opposite first and second ends, and opposite first and second sides. One end is arranged opposite to the silicon waveguide structure;
    第一接触层及第二接触层，分别形成于所述锗吸收区的第一侧及第二侧的所述周边硅材料区中；The first contact layer and the second contact layer are respectively formed in the peripheral silicon material area on the first side and the second side of the germanium absorption area;
    第一电极及第二电极，分别形成于所述第一接触层及第二接触层上。The first electrode and the second electrode are respectively formed on the first contact layer and the second contact layer.
  5. 根据权利要求1所述的基于光子晶体的波导型锗光电探测器，其特征在于：所述锗吸收区的材料包括SiGe、Ge、GeSn及GePb中的一种。The waveguide type germanium photodetector based on photonic crystal according to claim 1, wherein the material of the germanium absorption region includes one of SiGe, Ge, GeSn, and GePb.
  6. 根据权利要求1所述的基于光子晶体的波导型锗光电探测器，其特征在于：所述介质材料呈圆柱形垂直贯穿所述锗吸收区及所述周边硅材料区。The waveguide type germanium photodetector based on photonic crystal according to claim 1, wherein the dielectric material is cylindrical and vertically penetrates the germanium absorption region and the peripheral silicon material region.
  7. 根据权利要求1所述的基于光子晶体的波导型锗光电探测器，其特征在于：所述介质材料与所述锗吸收区及所述周边硅材料区形成具有周期性结构的谐振腔。The waveguide type germanium photodetector based on photonic crystal according to 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. 根据权利要求1所述的基于光子晶体的波导型锗光电探测器，其特征在于：所述介质材料包括空气或二氧化硅。The waveguide type germanium photodetector based on photonic crystal according to claim 1, wherein the dielectric material includes air or silicon dioxide.
  9. 一种如权利要求1～8任意一项所述的基于光子晶体的波导型锗光电探测器的制备方法，其特征在于，所述制备方法包括步骤：A method for manufacturing a photonic crystal-based waveguide type germanium photodetector according to any one of claims 1 to 8, wherein the manufacturing method comprises the steps:
    步骤1)，提供一SOI衬底，在所述SOI衬底的顶硅层上刻蚀出硅波导结构；Step 1) providing an SOI substrate, and etching a silicon waveguide structure on the top silicon layer of the SOI substrate;
    步骤2)，在所述SOI衬底的顶硅层以刻蚀出锗基材料选择性外延区域，所述锗基材料选择性外延区域底部保留部分厚度的顶硅层底层；Step 2), etching a germanium-based material selective epitaxial region on the top silicon layer of the SOI substrate, and a part of the top silicon layer bottom layer is left at the bottom of the germanium-based material selective epitaxial region;
    步骤3)，在所述锗基材料选择性外延区域选择性外延生长锗吸收区，采用离子注入及退火方法在所述锗吸收区外围的周边硅材料区中形成第一接触层及第二接触层；Step 3), selectively epitaxially grow a germanium absorption region in the germanium-based material selective epitaxial region, and use ion implantation and annealing methods to form a first contact layer and a second contact in the peripheral silicon material region around the germanium absorption region Floor;
    步骤4)，通过光刻及刻蚀工艺在所述锗吸收区及周边硅材料区形成周期性排列的凹槽，并在所述凹槽中填充介质材料，以形成具有慢光效应的光子晶体结构；Step 4), forming periodically arranged grooves in the germanium absorption area and the surrounding silicon material area through photolithography and etching processes, and filling the grooves with dielectric material to form a photonic crystal with slow light effect structure;
    步骤5)，通过光刻及刻蚀方法在所述第一接触层及所述第二接触层中定义第一电极区域及第二电极区域，并形成第一电极及第二电极。Step 5), defining a first electrode area and a second electrode area in the first contact layer and the second contact layer by photolithography and etching methods, and forming the first electrode and the second electrode.
  10. 根据权利要求9所述的基于光子晶体的波导型锗光电探测器的制备方法，其特征在于：所述锗吸收区的高度大于所述锗基材料选择性外延区域的深度。The method for manufacturing a photonic crystal-based waveguide type germanium photodetector according to claim 9, wherein the height of the germanium absorption region is greater than the depth of the germanium-based material selective epitaxial region.
PCT/CN2019/100559 2019-08-05 2019-08-14 Waveguide-type germanium photoelectric detector employing photonic crystal, and preparation method WO2021022576A1 (en)

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