WO2021129356A1 - 一种光电探测器 - Google Patents

一种光电探测器 Download PDF

Info

Publication number
WO2021129356A1
WO2021129356A1 PCT/CN2020/134067 CN2020134067W WO2021129356A1 WO 2021129356 A1 WO2021129356 A1 WO 2021129356A1 CN 2020134067 W CN2020134067 W CN 2020134067W WO 2021129356 A1 WO2021129356 A1 WO 2021129356A1
Authority
WO
WIPO (PCT)
Prior art keywords
waveguide
region
layer
germanium layer
silicon
Prior art date
Application number
PCT/CN2020/134067
Other languages
English (en)
French (fr)
Inventor
胡晓
肖希
王磊
陈代高
张宇光
李淼峰
Original Assignee
武汉光谷信息光电子创新中心有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CN201911379861.4A external-priority patent/CN111129168B/zh
Priority claimed from CN201911382677.5A external-priority patent/CN111129201B/zh
Priority claimed from CN201911382842.7A external-priority patent/CN111129202B/zh
Application filed by 武汉光谷信息光电子创新中心有限公司 filed Critical 武汉光谷信息光电子创新中心有限公司
Priority to EP20906646.3A priority Critical patent/EP4084091B1/en
Priority to US17/789,934 priority patent/US20230042376A1/en
Publication of WO2021129356A1 publication Critical patent/WO2021129356A1/zh

Links

Images

Classifications

    • 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
    • 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
    • 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
    • G02B6/12004—Combinations of two or more optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/125—Bends, branchings or intersections
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • 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
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4206—Optical features
    • 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
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4295—Coupling light guides with opto-electronic elements coupling with semiconductor devices activated by light through the light guide, e.g. thyristors, phototransistors
    • 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
    • H01L31/0248—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 characterised by their semiconductor bodies
    • H01L31/0256—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 characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/028—Inorganic materials including, apart from doping material or other impurities, only elements of Group IV of the Periodic Table
    • 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
    • H01L31/0248—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 characterised by their semiconductor bodies
    • H01L31/0256—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 characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/0312—Inorganic materials including, apart from doping materials or other impurities, only AIVBIV compounds, e.g. SiC
    • 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
    • H01L31/10—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 characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
    • H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
    • H01L31/105—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the PIN type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12035—Materials
    • G02B2006/12061—Silicon
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12083—Constructional arrangements
    • G02B2006/12123—Diode
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12133—Functions
    • G02B2006/1215—Splitter

Definitions

  • the embodiments of the present application relate to the technical field of photodetectors, in particular to a photodetector.
  • Silicon photonics technology is a new generation of optical device development and integration based on silicon and silicon-based substrate materials (such as SiGe/Si, silicon-on-insulator, etc.), using the existing Complementary Metal Oxide Semiconductor (CMOS) process technology.
  • CMOS Complementary Metal Oxide Semiconductor
  • Silicon photonics technology combines the characteristics of ultra-large-scale and ultra-high-precision manufacturing of integrated circuit technology with the advantages of ultra-high speed and ultra-low power consumption of photonic technology. It is a disruptive technology to deal with the failure of Moore's Law. This combination is due to the scalability of semiconductor wafer manufacturing, which can reduce costs.
  • the photodetector has the function of realizing the conversion of optical signals to electrical signals.
  • III-V semiconductor materials are more suitable for photodetectors, III-V semiconductor materials are incompatible with silicon processes and cannot be used with silicon. Effective monolithic integration; taking into account the compatibility of germanium materials and CMOS processes, this field proposes the use of germanium materials as the light absorbing layer material to form a silicon germanium photodetector technology.
  • the current silicon germanium photodetectors have the disadvantages of low responsivity and cannot meet the requirements of high optical power detection, so further improvements are needed.
  • the embodiments of the present application provide a pulse signal generating device and method in order to solve at least one problem existing in the prior art.
  • an embodiment of the present application provides a photodetector, including:
  • a silicon nitride waveguide the silicon nitride waveguide is arranged around the germanium layer along the extension direction of at least three sidewalls of the germanium layer;
  • the silicon nitride waveguide is used to transmit an optical signal and couple the optical signal to the germanium layer, and the germanium layer is used to detect the optical signal and convert the optical signal into an electrical signal.
  • the silicon nitride waveguide includes a first waveguide region and a second waveguide region, and the germanium layer is disposed between the first waveguide region and the second waveguide region.
  • the projection of the sidewall of the germanium layer on the silicon layer has a first shape, and the length of the first shape in the first direction is greater than the length in the second direction;
  • the silicon nitride waveguide further includes: a third waveguide region; the third waveguide region connects the first waveguide region and the second waveguide region in a second direction.
  • the optical splitting waveguide connected to the silicon nitride waveguide is used to divide the received optical signal into at least two optical signals, and output the two optical signals to the first waveguide area and the The second waveguide area.
  • the optical signal transmitted by the silicon nitride waveguide propagates in a direction from the first waveguide region to the third waveguide region to the second waveguide region;
  • the distance between the first waveguide region and the germanium layer is greater than the distance between the second waveguide region and the germanium layer.
  • the silicon nitride waveguide and the light splitting waveguide enclose a closed area along the transmission direction of the optical signal, and the germanium layer is located in the closed area.
  • the silicon nitride waveguide includes a first-layer waveguide and a second-layer waveguide; the first-layer waveguide includes a fourth waveguide region disposed above the germanium layer, and the first layer waveguide
  • the two-layer waveguide includes a first waveguide region, a second waveguide region, and a third waveguide region arranged on the side of the germanium layer;
  • the first-layer waveguide and the second-layer waveguide couple the optical signal to the germanium layer through the fourth waveguide region, the first waveguide region, the second waveguide region, and the third waveguide region, respectively.
  • the first-layer waveguide further includes a first interlayer coupling region connected to the fourth waveguide region;
  • the second layer waveguide further includes a second interlayer coupling region connected to the first waveguide region and the second waveguide region;
  • Optical signal transmission is realized between the first layer waveguide and the second layer waveguide through the interlayer coupling of the first interlayer coupling region and the second interlayer coupling region; the first interlayer coupling region
  • the optical signals with the second interlayer coupling region are respectively transmitted to the fourth waveguide region, the first waveguide region, the second waveguide region, and the third waveguide region.
  • the first layer waveguide is used to receive optical signals, and the received optical signals are transferred to the second layer waveguide through the interlayer coupling in the first interlayer coupling zone.
  • the second interlayer coupling region is used to transfer optical signals to the first layer waveguide through the interlayer coupling in the first interlayer coupling zone.
  • the distance between the first interlayer coupling region and the second interlayer coupling region is 50 nm to 1500 nm.
  • the cross-sectional area of the first inter-layer coupling region becomes smaller, and the cross-sectional area of the second inter-layer coupling region becomes larger.
  • the orthographic projections of the first interlayer coupling region and the second interlayer coupling region on the silicon layer at least partially overlap.
  • the second layer waveguide further includes a splitting waveguide region located between the second interlayer coupling region and the first waveguide region and the second waveguide region, and the The optical splitting waveguide area is used for dividing the optical signal transmitted from the second interlayer coupling area into at least two paths, and outputting two of the optical signals to the first waveguide area and the second waveguide area respectively.
  • the first-layer waveguide further includes an isolated waveguide region located between the first interlayer coupling region and the fourth waveguide region; the isolated waveguide region and the light splitting region
  • the orthographic projections of the waveguide area on the silicon layer are staggered, so that the optical signal on the first-layer waveguide does not occur between the second-layer waveguide when it is transmitted to the position corresponding to the optical splitting waveguide area. Coupling between layers.
  • the extension direction of the fourth waveguide region of the first layer of waveguide is parallel to the contact plane between the silicon layer and the germanium layer, and the fourth waveguide region and the The distance between the upper surfaces of the germanium layer is 60nm-1000nm.
  • the first waveguide region and the second waveguide region are straight waveguide regions
  • the third waveguide area is a curved waveguide area.
  • the distance between the first waveguide region and the second waveguide region and the germanium layer is 50 nm-1000 nm.
  • the extending direction of the silicon nitride waveguide is parallel to the contact plane between the silicon layer and the germanium layer, and the distance between the silicon nitride waveguide and the silicon layer is 100nm-1200nm.
  • the length of the germanium layer in the first direction is 5 ⁇ m-100 ⁇ m.
  • a first metal electrode and a second metal electrode are respectively provided on the doped region of the first doping type and the doped region of the second doping type;
  • the first doping type is P-type
  • the second doping type is N-type to form a photodetector with a PIN structure
  • the first doping type is N-type
  • the second doping type is P-type to form a photodetector with a NIP structure.
  • An embodiment of the present application provides a photodetector, including: a silicon layer including a doped region of a first doping type; a germanium layer in contact with the silicon layer, the germanium layer including a second doping Impurity type doped region; silicon nitride waveguide, the silicon nitride waveguide is arranged around the germanium layer along the extension direction of at least three sidewalls of the germanium layer; wherein, the silicon nitride waveguide is used for transmission And couple the optical signal to the germanium layer, and the germanium layer is used to detect the optical signal and convert the optical signal into an electrical signal.
  • a silicon nitride material is used to form a silicon nitride waveguide, and the silicon nitride waveguide is arranged around the germanium layer, so that the optical signal in the silicon nitride waveguide can be coupled with the germanium layer at least twice;
  • the high optical power detection reduces the propagation loss of the optical signal and avoids the appearance of saturated absorption effect.
  • the response of the detector can be improved without increasing the length of the coupling region of the detector (that is, the length of the germanium layer).
  • Figure 1 is a side cross-sectional view of an implementation of a photodetector provided by an embodiment of the application;
  • FIG. 2 is a top view of an implementation manner of a photodetector provided by an embodiment of the application
  • FIG. 3 is a side cross-sectional view of another implementation of the photodetector provided by the embodiment of the application;
  • FIG. 4 is a top view of another implementation of the photodetector provided by the embodiment of the application.
  • FIG. 5 is a side cross-sectional view of another implementation of the photodetector provided by the embodiment of the application.
  • FIG. 6 is a side cross-sectional view of another implementation of the photodetector provided by the embodiment of the application.
  • FIG. 7 is a top view of another implementation manner of a photodetector provided by an embodiment of the application.
  • FIG. 8 is a top view of another implementation manner of a photodetector provided by an embodiment of the application.
  • first element, component, region, layer or section discussed below may be represented as a second element, component, region, layer or section.
  • second element, component, region, layer or section it does not mean that the first element, component, region, layer or section is necessarily present in the present application.
  • Spatial relation terms such as “under", “below”, “below”, “below”, “above”, “above”, etc., can be used here for convenience The description is used to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatial relationship terms are intended to include different orientations of devices in use and operation. For example, if the device in the figure is turned over, then elements or features described as “under” or “below” or “under” other elements will be oriented “on” the other elements or features. Therefore, the exemplary terms “below” and “below” may include both an orientation of up and down. The device can be otherwise oriented (rotated by 90 degrees or other orientation) and the spatial descriptors used here are interpreted accordingly.
  • a germanium material compatible with the CMOS process can be used to realize photodetection.
  • the germanium material is used to absorb photons and then generate carriers.
  • the silicon slab waveguide is usually used to transmit the optical signal into the structure, and then the light carrying the signal is coupled into the germanium layer; this structure has the following shortcomings: First, the silicon slab waveguide is used as the transmission light The structure of the signal, in the case of high optical power density, will have obvious nonlinear effects, resulting in two-photon absorption, so it is difficult to support high optical power detection; secondly, due to the small refractive index difference between silicon and germanium materials, silicon The optical signal transmitted in the slab waveguide is easier to couple to the germanium layer, which will cause the saturation absorption effect of the detector to appear, and then reduce the responsivity of the detector; the third aspect, the entire silicon slab waveguide is generally doped with P-
  • FIG. 1 is a side cross-sectional view of an embodiment of a photodetector provided by an embodiment of the application
  • FIG. 2 is a top view of an embodiment of a photodetector provided by an embodiment of the application. It should be noted that FIG. The side cross-sectional view in the direction of the dotted line in Fig. 2, as shown in Figs. 1 and 2, the photodetector provided by the embodiment of the present application includes:
  • a silicon layer 110 the silicon layer 110 includes a doped region 111 of a first doping type; a germanium layer 120 in contact with the silicon layer 110, the germanium layer 120 includes a doped region 121 of a second doping type;
  • the silicon nitride waveguide 130 is arranged around the germanium layer 120 along the extension direction of at least three sidewalls of the germanium layer 120;
  • the silicon nitride waveguide 130 is used to transmit optical signals and couple the optical signals to the germanium layer 120, and the germanium layer 120 is used to detect the optical signals and convert the optical signals into electric signal.
  • the photodetector further includes: a substrate, the substrate may be a substrate of elemental semiconductor material (for example, a silicon (Si) substrate, a germanium (Ge) substrate, etc.), a compound semiconductor Material substrate (for example, silicon germanium (SiGe) substrate, etc.), or silicon-on-insulator (SOI) substrate, germanium-on-insulator (GeOI) substrate, etc.
  • the embodiment of the present application is described by taking the substrate as an SOI substrate as an example.
  • the photodetector further includes an underlying substrate 140.
  • the underlying substrate 140 is, for example, an underlying silicon material; Oxygen layer (not shown in the figure);
  • the silicon layer 110 is formed on the buried oxide layer.
  • the germanium layer 120 is formed on the silicon layer 110, the silicon nitride waveguide 130 is arranged around the germanium layer 120 along the extension direction of at least three sidewalls of the germanium layer 120, and the silicon nitride
  • a silicon dioxide material is provided between the waveguide 130 and the germanium layer 120, and a silicon dioxide material is provided between the silicon nitride waveguide 130 and the silicon layer 110.
  • the silicon dioxide material 150 covers the silicon layer 110 and the germanium layer 120, and the silicon nitride waveguide 130 is disposed in the silicon dioxide material 150 and is in contact with the silicon layer.
  • the silicon dioxide material is used to support and fix the silicon nitride waveguide 130, and the silicon dioxide material has a lower refractive index, so that it can resist transmission
  • the optical signal is optically constrained.
  • the difference between the refractive index of the silicon nitride waveguide 130 and the refractive index of the germanium layer 120 is relatively large, and the silicon nitride waveguide 130 is arranged around the germanium layer 120, which can ensure that the optical signal is transmitted from
  • the high coupling efficiency of the silicon nitride waveguide 130 to the germanium layer 120 enables the optical signal to be evenly distributed in the germanium layer 120, thereby avoiding the overshoot of the detector formed by the accumulation of photo-generated carriers caused by the strong local optical field of the germanium layer 120.
  • the silicon nitride optical waveguide 130 is not only used to realize the propagation and direction change of the optical signal, but also couples with the germanium layer 120 to form a built-in electric field and generate carriers.
  • a low-nonlinear silicon nitride material is used as the transmission optical waveguide, the silicon nitride waveguide does not exhibit the two-photon absorption effect, and the silicon nitride waveguide supports low-loss optical transmission with high optical power density and large optical bandwidth.
  • the projection of the sidewall of the germanium layer 120 on the silicon layer 110 has a first shape, and the length of the first shape in the first direction is greater than the length in the second direction;
  • the silicon nitride waveguide 130 includes: a first waveguide region 131, a second waveguide region 132, and a third waveguide region 133; the first waveguide region 131 and the second waveguide region 132 are respectively located on the germanium layer 120 The outer sides of the first side wall and the second side wall surround the germanium layer 120, and the first side wall and the second side wall are respectively opposite sides of the germanium layer 120 that are parallel to the first direction Wall; the third waveguide region 133 connects the first waveguide region 131 and the second waveguide region 132 in the second direction.
  • the projection of the sidewall of the germanium layer 120 on the silicon layer 110 has a first shape, as shown in FIG. 2, where the dashed line direction in the figure is the second direction, which is perpendicular to the dashed line direction. Is the first direction.
  • the first shape may be a rectangle having a long side extending in the first direction and a short side extending in the second direction; wherein, the first shape
  • the length in the first direction is the length of the long side of the rectangle
  • the length of the first shape in the second direction is the length of the short side of the rectangle. It can be understood in conjunction with FIG. 2 that the length of the coupling region is the length of the first shape in the first direction.
  • the first side wall and the second side wall of the germanium layer 120 are the left side wall and the right side wall of the germanium layer 120 (in the first direction).
  • the first waveguide region 131 and the second waveguide region 132 are straight waveguide regions
  • the third waveguide region 133 is a curved waveguide region.
  • the first waveguide region 131 and the second waveguide region 132 are respectively located outside the first sidewall and the second sidewall of the germanium layer 120, that is, In other words, the first waveguide region 131 and the second waveguide region 132 are respectively located on the left and right sides of the germanium layer 120 (in the first direction).
  • the third waveguide region 133 is used to transfer the optical signal of the first waveguide region 131 to the second waveguide region 132 after being turned by 180°.
  • the first waveguide region 131 is an optical input waveguide region as an example for description.
  • the optical signal transmitted by the silicon nitride waveguide 130 propagates along the direction from the first waveguide region 131 to the third waveguide region 133 to the second waveguide region 132;
  • the distance between the first waveguide region 131 and the germanium layer 120 is greater than the distance between the second waveguide region 132 and the germanium layer 120.
  • the optical signal transmitted by the silicon nitride waveguide 130 is routed from the first waveguide region 131 to the third waveguide region 133. If the direction of the second waveguide region 132 propagates, the intensity of the optical signal transmitted in the first waveguide region 131 is greater than the intensity of the optical signal transmitted in the second waveguide region 132 (because the optical signal transmitted in the first waveguide region 131 After the signal is partially absorbed by the germanium layer 120, it is transmitted to the second waveguide region 132 through the third waveguide region 133, and then the optical signal transmitted by the second waveguide region 132 is transmitted through the germanium layer.
  • the first waveguide region 131 can be arranged at a position farther from the germanium layer 120 than the second waveguide region 132 Therefore, when the intensity of the optical signal transmitted by the first waveguide region 131 is relatively strong, the coupling speed between the optical signal transmitted by the first waveguide region 131 and the germanium layer 120 is controlled to prevent the germanium layer 120 from overshooting.
  • the phenomenon of early saturation, and when the intensity of the optical signal transmitted by the second waveguide region 132 is weak enables all the remaining optical signals in the second waveguide region 132 to be coupled to the germanium layer 120, thereby improving the coupling efficiency.
  • the first waveguide region 131 and the second waveguide region 132 are respectively located on both sides of the germanium layer 120, and the first waveguide region 131 and the second waveguide region 132 pass through the germanium layer 120.
  • the third waveguide region 133 is connected so that the optical signal transmitted in the silicon nitride waveguide 130 couples with the germanium layer 120 at least twice, so that the length of the germanium layer 120 can be increased without increasing the length of the germanium layer 120.
  • the responsivity of the photodetector will not reduce the 3dB optical bandwidth of the photodetector at the same time.
  • the cross-sectional area of the silicon nitride waveguide 130 along the input direction perpendicular to the optical signal is 0.06 ⁇ m 2 -0.5 ⁇ m 2 . It should be noted that the cross section of the silicon nitride waveguide 130 along the direction perpendicular to the input direction of the optical signal may be rectangular or trapezoidal. In the embodiment of the present application, the cross section of the silicon nitride waveguide 130 along the input direction perpendicular to the optical signal is rectangular as an example for description.
  • the cross section of the silicon nitride waveguide 130 along the direction perpendicular to the input direction of the optical signal may also be a trapezoid (the length of the lower base of the trapezoid closer to the silicon layer 110 is longer than that away from the silicon layer 110).
  • the upper and bottom sides of layer 110 are long).
  • the distance between the portion of the silicon nitride waveguide 130 surrounding the germanium layer 120 and the germanium layer 120 is 50 nm-1000 nm.
  • the extension direction of the silicon nitride waveguide 130 is parallel to the contact plane between the silicon layer 110 and the germanium layer 120, and the distance between the silicon nitride waveguide 130 and the silicon layer 110 is 100 nm-1200 nm.
  • the length of the germanium layer 120 in the first direction is 5 ⁇ m-100 ⁇ m. That is, the length of the coupling region is 5 ⁇ m-100 ⁇ m. By controlling the length of the germanium layer 120 in the first direction, the length of the coupling region can be controlled.
  • the preferred size of the photodetector is: the cross section of the silicon nitride waveguide 130 along the direction perpendicular to the input direction of the optical signal (as shown in FIG.
  • the length of the cross section is 800 nm and the width is 300 nm; the length of the germanium layer 120 along the cross section perpendicular to the input direction of the optical signal (the cross section shown in FIG.
  • the length of the germanium layer 120 in the first direction (that is, the length of the coupling region) is 12 ⁇ m; the distance between the silicon nitride waveguide 130 and the silicon layer 110 is 150 nm; the first waveguide region 131 is The distance between the germanium layer 120 is 100 nm; the distance between the second waveguide region 132 and the germanium layer 120 is 80 nm.
  • the silicon layer 110 includes a doped region 111 of a first doping type; the germanium layer 120 includes a doped region 121 of a second doping type;
  • the doped region 111 and the doped region 121 of the second doping type are respectively provided with a first metal electrode 112 and a second metal electrode 122;
  • the first doping type is P-type, and the second doping type is P-type.
  • the type is N-type to form a photodetector with a PIN structure; or, the first doping type is an N-type and the second doping type is a P-type to form a photodetector with a NIP structure.
  • the upper surface of the silicon layer 110 is formed with a doped region 111 of the first doping type; it should be noted that the doping region 111 of the first doping type is formed on the upper surface of the silicon layer 110. There may be one or more doped regions 111.
  • FIGS. 1 and 2 only illustrate the case where two doped regions 111 of the first doping type are formed on the silicon layer 110.
  • a first metal electrode 112 is respectively provided on the two doped regions 111 of the first doping type.
  • a doped region 121 of the second doping type is formed on the upper surface of the germanium layer 120; a second metal electrode 122 is provided on the doped region of the second doping type.
  • the first doping type may be P-type or N-type.
  • the second doping type is N-type to form a photodetector with a PIN structure
  • the first doping type is N-type
  • the second doping type is P-type to form a photodetector with a NIP structure.
  • the undoped region between the silicon layer 110 and the germanium layer 120 serves as an intrinsic body in the PIN structure or the NIP structure.
  • the silicon layer 110 may also be a doped silicon layer.
  • the silicon layer 110 may be an overall P-type doped silicon layer.
  • the doping concentration of the doped region is greater than the overall doping concentration of the silicon layer 110;
  • the silicon layer 110 may be an overall N-type doped silicon layer, but The doping concentration of the doped region is greater than the overall doping concentration of the silicon layer 110.
  • the silicon nitride waveguide is used to transmit the optical signal, the adverse effect on the transmission of the optical signal when the doped silicon layer is used as the waveguide is avoided, thereby effectively reducing the transmission loss of the optical signal.
  • the germanium layer 120 is extracted by applying an external voltage between the first metal electrode 112 on the silicon layer 110 and the second metal electrode 122 on the germanium layer 120 to form an external electric field.
  • the electric field direction of the applied electric field is the same as the electric field direction of the built-in electric field formed in the germanium layer 120, so that the applied electric field can accelerate the moving speed of the carriers, thereby improving the photodetector’s Responsiveness.
  • the first metal electrodes 112 may be respectively connected with the second metal electrodes 122 to form an external electric field. In other words, when two first metal electrodes 112 are provided on the silicon layer 110, two external electric fields can be formed between the first metal electrode 112 and the second metal electrode 122.
  • the length of the metal electrodes (112 and 122) in the first direction is smaller than the length of the germanium layer 120 in the first direction.
  • the upper surface of the metal electrodes (112 and 122) is exposed on the upper surface of the photodetector.
  • the doped region structure of the germanium layer 120 and the silicon layer 110 can also be changed to realize avalanche gain detection (APD).
  • Specific implementation methods include: adding an avalanche zone on the germanium layer 120, or applying a reverse bias voltage greater than 6V to the formed NIP structure or PIN structure to achieve avalanche gain detection.
  • An embodiment of the present application provides a photodetector, including: a silicon layer including a doped region of a first doping type; a germanium layer in contact with the silicon layer, the germanium layer including a second doping Impurity type doped region; silicon nitride waveguide, the silicon nitride waveguide is arranged around the germanium layer along the extension direction of at least three sidewalls of the germanium layer; wherein, the silicon nitride waveguide is used for transmission And couple the optical signal to the germanium layer, and the germanium layer is used to detect the optical signal and convert the optical signal into an electrical signal.
  • the difference between the refractive index of the silicon nitride waveguide and the refractive index of the germanium layer is relatively large, and the silicon nitride waveguide is arranged around the germanium layer, so that high coupling efficiency of the optical signal from the silicon nitride waveguide to the germanium layer can be ensured , It can make the optical signal evenly distributed in the germanium layer, so as to avoid the premature saturation of the detector formed by the accumulation of photo-generated carriers caused by the strong local optical field of the germanium layer; it can be understood that the higher the coupling efficiency, the higher the coupling efficiency. The more photons enter the germanium layer, so that only a shorter coupling region length is needed to achieve a high response speed.
  • FIG. 3 is a side cross-sectional view of another embodiment of the photodetector provided by the embodiment of the application
  • FIG. 4 is another embodiment of the photodetector provided by the embodiment of the application
  • Fig. 3 is a side cross-sectional view along the direction of the dotted line in Fig. 4, as shown in Figs. 3 and 4, the photodetector provided by the embodiment of the present application includes:
  • a silicon layer 210 which includes a doped region 211 of the first doping type
  • a silicon nitride waveguide 230, the silicon nitride waveguide 230 includes a first waveguide region 231 and a second waveguide region 232, and the germanium layer 220 is disposed between the first waveguide region 231 and the second waveguide region 232 ;
  • the optical splitting waveguide 240 connected to the silicon nitride waveguide 230 is used to divide the received optical signal into at least two optical signals, and output two optical signals to the first waveguide area respectively 231 and the second waveguide region 232;
  • the silicon nitride waveguide 230 is used to transmit optical signals and couple the optical signals to the germanium layer 220, and the germanium layer 220 is used to detect the optical signals and convert the optical signals into electric signal.
  • the material of the light splitting waveguide 240 and the silicon nitride waveguide 230 are the same.
  • the optical splitting waveguide 240 divides the received optical signal into two optical signals as an example for description.
  • the light splitting waveguide 240 may be a silicon nitride light splitting waveguide. As shown in FIG. 3, the optical splitting waveguide 240 is rectangular. It should be noted that the optical splitting waveguide 240 may be any optical splitting waveguide that can divide the received optical signal into at least two optical signals. The shape of the optical splitting waveguide 240 is not described in this application. limited.
  • the photodetector further includes a bottom substrate 250, the bottom substrate 250 is, for example, a bottom silicon material; there is a buried oxygen layer on the bottom substrate 250 (not shown in the figure) ;
  • the silicon layer 210 is formed on the buried oxide layer.
  • the germanium layer 220 is formed on the silicon layer 210, the germanium layer 220 is disposed between the first waveguide region 231 and the second waveguide region 232, and the silicon nitride waveguide 230 is There is a silicon dioxide material between the germanium layer 220 and a silicon dioxide material between the silicon nitride waveguide 230 and the silicon layer 210. As shown in FIG.
  • the silicon dioxide material 260 covers the silicon layer 210 and the germanium layer 220, and the silicon nitride waveguide 230 is disposed in the silicon dioxide material 260 and is in contact with the silicon layer.
  • 210 and the germanium layer 220 are each separated by a certain distance, the silicon dioxide material is used to support and fix the silicon nitride waveguide 230, and the silicon dioxide material has a lower refractive index, so that it can resist transmission
  • the optical signal is optically constrained.
  • the difference between the refractive index of the silicon nitride waveguide 230 and the refractive index of the germanium layer 220 is relatively large, and the silicon nitride waveguide 230 is arranged around the germanium layer 220, which can ensure that the optical signal is transmitted from
  • the high coupling efficiency of the silicon nitride waveguide 230 to the germanium layer 220 enables the optical signal to be evenly distributed in the germanium layer 220, thereby avoiding the overshoot of the detector formed by the accumulation of photo-generated carriers caused by the strong local optical field of the germanium layer 220.
  • the optical splitting waveguide 240 is provided to split the input optical signal, and the split optical signal is output to the first waveguide region 231 and the second waveguide region 232, and the germanium layer 220 is provided in the first waveguide region 231 and the second waveguide region 232.
  • the optical signal in the silicon nitride waveguide 230 can be coupled with the germanium layer 220 at least twice. In this way, the length of the coupling region of the detector (that is, the length of the germanium layer 220) is not increased. ), the response of the detector can be improved.
  • the silicon nitride optical waveguide 230 is not only used to realize the propagation and direction change of the optical signal, but also couples with the germanium layer 220 to form a built-in electric field and generate carriers.
  • a low-nonlinear silicon nitride material is used as the transmission optical waveguide, the silicon nitride waveguide does not exhibit the two-photon absorption effect, and the silicon nitride waveguide supports low-loss optical transmission with high optical power density and large optical bandwidth.
  • the projection of the sidewall of the germanium layer 220 on the silicon layer 210 has a first shape, and the length of the first shape in the first direction is greater than the length in the second direction;
  • the first waveguide region 231 and the second waveguide region 232 surround the germanium layer 220 on the outer sides of the first and second sidewalls of the germanium layer 220, respectively, and the first sidewall and the The second sidewalls are two opposite sidewalls of the germanium layer 220 that are parallel to the first direction.
  • the projection of the sidewall of the germanium layer 220 on the silicon layer 210 has a first shape, as shown in FIG. 4, the dashed line direction in the figure is the second direction, which is a direction perpendicular to the dashed line direction. Is the first direction.
  • the first shape may be a rectangle having a long side extending in the first direction and a short side extending in the second direction; wherein, the first shape
  • the length in the first direction is the length of the long side of the rectangle
  • the length of the first shape in the second direction is the length of the short side of the rectangle. It can be understood in conjunction with FIG. 4 that the length of the coupling region is the length of the first shape in the first direction.
  • the first side wall and the second side wall of the germanium layer 220 are the left side wall and the right side wall of the germanium layer 220 (in the first direction).
  • the silicon nitride waveguide 230 further includes a third waveguide region 233, which connects the first waveguide region 231 and the second waveguide region 232 in a second direction;
  • the optical signal output from the light splitting waveguide 240 to the first waveguide area 231 is transmitted along the third waveguide area 233 to the second waveguide area 232, and output from the light splitting waveguide 240 to the second waveguide area
  • the optical signal 232 is transmitted to the first waveguide area 231 along the third waveguide area 233.
  • connection of the third waveguide area 233 to the first waveguide area 231 and the second waveguide area 232 is only a connection method provided in the embodiment of the present application, and the embodiment of the present application is not limited to all In the case where the first waveguide region 231 and the second waveguide region 232 are connected by the third waveguide region 233, the first waveguide region 231 and the second waveguide region 232 may not be connected.
  • both the first waveguide region 231 and the second waveguide region 232 may be optical input waveguide regions, and the optical signal output from the optical splitting waveguide 240 may be along the first waveguide region 231 to the third waveguide region.
  • the waveguide region 233 is transmitted in the direction from the second waveguide region 232, and the optical signal output from the optical splitting waveguide 240 can also be in the direction from the second waveguide region 232 to the third waveguide region 233 to the first waveguide region 231. Transmission, that is, at least two optical signals in the silicon nitride waveguide 230 in the embodiment of the present application are transmitted in opposite directions.
  • each optical signal can be coupled to the germanium layer 220 through the first waveguide region 231 and the second waveguide region 232 at least twice. Therefore, without increasing the length of the germanium layer 220, the responsivity of the photodetector can be improved without reducing the 3dB optical bandwidth of the photodetector.
  • the silicon nitride waveguide 230 and the light splitting waveguide 240 enclose a closed area along the transmission direction of the optical signal, and the germanium layer 220 is located in the closed area.
  • the light splitting waveguide 240 and the third waveguide region 233 are respectively located on the third sidewall and the fourth sidewall of the germanium layer 220, and the third sidewall
  • the and the fourth sidewalls are respectively two sidewalls of the germanium layer 220 that are parallel to the second direction and are opposite to each other.
  • the third side wall and the fourth side wall of the germanium layer 220 are the left side wall and the right side wall of the germanium layer 220 (in the second direction), that is, the light splitting waveguide 240 and the
  • the third waveguide regions 233 are respectively located on the left and right sides of the germanium layer 220 (in the second direction).
  • the light splitting waveguide 240 is not limited to being located on the side opposite to the third waveguide region 233, and the position of the light splitting waveguide 240 can be adjusted according to actual needs.
  • the optical splitting waveguide 240 in the embodiment of the present application may also split the received optical signal into two or more optical signals.
  • the optical splitting waveguide 240 divides the received optical signal into three optical signals, and two of them After the optical signals are respectively output to the first waveguide area 231 and the second waveguide area 232, the optical splitting waveguide 240 can also output the remaining optical signal to another waveguide area, such as located above the germanium layer 220 The waveguide area (not shown in the figure).
  • the light splitting waveguide 240 is connected to the first waveguide region 231 and the second waveguide region 232, so that the light splitting waveguide 240 is connected to the first waveguide region 231.
  • the second waveguide area 232 and the third waveguide area 233 enclose a closed area along the transmission direction of the optical signal, and the germanium layer 220 is located in the closed area.
  • the first waveguide region 231 and the second waveguide region 232 are straight waveguide regions
  • the third waveguide region 233 is a curved waveguide region.
  • the first waveguide region 231 and the second waveguide region 232 are respectively located outside the first sidewall and the second sidewall of the germanium layer 220, that is, In other words, the first waveguide region 231 and the second waveguide region 232 are located on the left and right sides of the germanium layer 220 (in the first direction), respectively.
  • the third waveguide region 233 is used to transfer the optical signal of the first waveguide region 231 to the second waveguide region 232 after being turned 180°, and to transfer the second waveguide region 232 The optical signal is turned by 180° and then transmitted to the first waveguide region 231.
  • the area of the silicon nitride waveguide 230 along the cross section perpendicular to the transmission direction of the optical signal is 0.06 ⁇ m 2 -0.5 ⁇ m 2 .
  • the cross section of the silicon nitride waveguide 230 along the direction perpendicular to the transmission direction of the optical signal may be rectangular or trapezoidal.
  • the cross section of the silicon nitride waveguide 230 along the direction perpendicular to the transmission direction of the optical signal is rectangular as an example for description.
  • the cross-section of the silicon nitride waveguide 230 along the direction perpendicular to the transmission direction of the optical signal may also be trapezoidal (the length of the lower base of the trapezoid closer to the silicon layer 210 is greater than that away from the silicon layer 210). The upper and bottom sides of layer 210 are long).
  • the distance between the first waveguide region 231 and the second waveguide region 232 and the germanium layer 220 is 50 nm-1000 nm.
  • the extension direction of the silicon nitride waveguide 230 is parallel to the contact plane between the silicon layer 210 and the germanium layer 220, and the distance between the silicon nitride waveguide 230 and the silicon layer 210 is 100 nm-1200 nm.
  • the length of the germanium layer 220 in the first direction is 5 ⁇ m-100 ⁇ m. That is, the length of the coupling region is 5 ⁇ m-100 ⁇ m. By controlling the length of the germanium layer 220 in the first direction, the length of the coupling region can be controlled.
  • the preferred size of the photodetector is: the cross section of the silicon nitride waveguide 230 along the direction perpendicular to the input direction of the optical signal (as shown in FIG. 3).
  • the length of the cross section is 800 nm and the width is 300 nm; the length of the germanium layer 220 along the cross section perpendicular to the input direction of the optical signal (the cross section shown in FIG.
  • the length of the germanium layer 220 in the first direction (that is, the length of the coupling region) is 12 ⁇ m; the distance between the silicon nitride waveguide 230 and the silicon layer 210 is 150 nm; the first waveguide region 231 is The distance between the germanium layer 220 is 100 nm; the distance between the second waveguide region 232 and the germanium layer 220 is 100 nm.
  • an optical input waveguide 241 may be connected to the other end of the optical splitting waveguide 240.
  • the optical input waveguide 241 is used to receive optical signals and transmit the optical signals to The light splitting waveguide 240.
  • the silicon layer 210 includes a doped region 211 of a first doping type; the germanium layer 220 includes a doped region 221 of a second doping type;
  • the doped region 211 and the doped region 221 of the second doping type are respectively provided with a first metal electrode 212 and a second metal electrode 222;
  • the first doping type is P type, and the second doping type
  • the type is N-type to form a photodetector with a PIN structure; or, the first doping type is an N-type and the second doping type is a P-type to form a photodetector with a NIP structure.
  • a doped region 211 of the first doping type is formed on the upper surface of the silicon layer 210; it should be noted that the doped region 211 of the first doping type is formed on the upper surface of the silicon layer 210.
  • the number of doped regions 211 may be one or more.
  • FIGS. 3 and 4 only illustrate the case where two doped regions 211 of the first doping type are formed on the silicon layer 210.
  • a first metal electrode 212 is respectively provided on the two doped regions 211 of the first doping type.
  • a doped region 121 of the second doping type is formed on the upper surface of the germanium layer 220; a second metal electrode 222 is provided on the doped region of the second doping type.
  • the first doping type may be P-type or N-type.
  • the second doping type is N-type to form a photodetector with a PIN structure;
  • the first doping type is N-type
  • the second doping type is P-type to form a photodetector with a NIP structure.
  • the undoped area between the silicon layer 210 and the germanium layer 220 serves as an intrinsic body in the PIN structure or the NIP structure.
  • the silicon layer 210 may also be a doped silicon layer.
  • the silicon layer 210 may be an overall P-type doped silicon layer.
  • the doping concentration of the doped region is greater than the overall doping concentration of the silicon layer 210;
  • the silicon layer 210 may be an overall N-type doped silicon layer, but The doping concentration of the doped region is greater than the overall doping concentration of the silicon layer 210.
  • the silicon nitride waveguide is used to transmit the optical signal, the adverse effect on the transmission of the optical signal when the doped silicon layer is used as the waveguide is avoided, thereby effectively reducing the transmission loss of the optical signal.
  • the germanium layer 220 is extracted by applying an external voltage between the first metal electrode 212 on the silicon layer 210 and the second metal electrode 222 on the germanium layer 220 to form an external electric field.
  • the electric field direction of the applied electric field is the same as the electric field direction of the built-in electric field formed in the germanium layer 220, so that the applied electric field can accelerate the moving speed of the carriers, thereby improving the photodetector’s Responsiveness.
  • the first metal electrodes 212 may be respectively connected with the second metal electrodes 222 to form an external electric field. In other words, when two first metal electrodes 212 are provided on the silicon layer 210, two external electric fields can be formed between the first metal electrode 212 and the second metal electrode 222.
  • the length of the metal electrodes (212 and 222) in the first direction is smaller than the length of the germanium layer 220 in the first direction.
  • the upper surface of the metal electrode is exposed on the upper surface of the photodetector.
  • the doped region structure of the germanium layer 220 and the silicon layer 210 can also be changed to realize avalanche gain detection (APD).
  • Specific implementation methods include: adding an avalanche zone on the germanium layer 220, or applying a reverse bias voltage greater than 6V to the formed NIP structure or PIN structure to achieve avalanche gain detection.
  • FIG. 5 is a side cross-sectional view of another embodiment of the photodetector provided by the embodiment of the present application.
  • a first layer is formed on the upper surface of the germanium layer 220.
  • a doped region 221 of two doping types and a doped region 223 of a first doping type, and a second metal electrode 222 is provided on the doped region 221 of the second doping type; the first doping type
  • a third metal electrode 224 is provided on the doped region 223 of the device.
  • the first doping type and the second doping type are different doping types.
  • a lateral built-in electric field can be formed between the doped region 221 of the second doping type and the doped region 223 of the first doping type on the germanium layer 220 (directed by the doped region 221 of the second doping type).
  • the direction of the doped region 223 of the first doping type or the direction of the doped region 223 of the first doping type pointing to the direction of the doped region 221 of the second doping type) generates carriers.
  • FIG. 6 is a side cross-sectional view of another implementation manner of the photodetector provided by the embodiment of the application
  • FIG. 7 is another implementation manner of the photodetector provided by the embodiment of the application
  • FIG. 6 is a side cross-sectional view along the direction of the dotted line in FIG. 7.
  • the structure in the dashed frame of Fig. 7 is not in a filled form, and the material of the structure in the dashed frame of Fig.
  • L1 represents the first-layer waveguide
  • L2 represents the second-layer waveguide.
  • L1 and L2 are only used to illustrate the first-layer waveguide and the second-layer waveguide, and are not used to limit the shape and length of the first-layer waveguide and the second-layer waveguide of the present application.
  • the photodetector provided by the embodiment of the present application includes:
  • a silicon layer 310, the silicon layer 310 includes a doped region 311 of the first doping type
  • Silicon nitride waveguide the silicon nitride waveguide includes a first-layer waveguide 330 and a second-layer waveguide 340; the first-layer waveguide 330, the first-layer waveguide 330 includes a fourth waveguide disposed above the germanium layer 320 Region 331; a second layer of waveguide 340, the second layer of waveguide 340 includes a first waveguide region 3411, a second waveguide region 3412, and a third waveguide region 3413 disposed on the side of the germanium layer 320;
  • the first-layer waveguide 330 and the second-layer waveguide 340 are used to transmit optical signals, and the first-layer waveguide 330 and the second-layer waveguide 340 pass through the fourth waveguide region 331 and the first waveguide region 331, respectively.
  • the waveguide region 3411, the second waveguide region 3412, and the third waveguide region 3413 couple the optical signal to the germanium layer 320; the germanium layer 320 is used to detect the optical signal and convert the optical signal into electrical signal.
  • the photodetector further includes a bottom substrate 350, the bottom substrate 350 is, for example, a bottom silicon material; there is a buried oxygen layer (not shown in the figure) on the bottom substrate 350 ; The silicon layer 310 is formed on the buried oxide layer.
  • the germanium layer 320 is formed on the silicon layer 310, the fourth waveguide region 331 is disposed above the germanium layer 320, the first waveguide region 3411, the second waveguide region 3412, and the third waveguide region 3413
  • the germanium layer 320 is arranged around the germanium layer 320 along the extension direction of at least three sidewalls of the germanium layer 320, and the fourth waveguide region 331, the first waveguide region 3411, the second waveguide region 3412, and the third waveguide region
  • the silicon dioxide material 360 covers the silicon layer 310 and the germanium layer 320, the fourth waveguide region 331, the first waveguide region 3411, the second waveguide region 3412, and the third waveguide region 331.
  • the waveguide region 3413 is arranged in the silicon dioxide material 360 and is spaced apart from the silicon layer 310 and the germanium layer 320 at a certain distance.
  • the silicon dioxide material is used to support and fix the fourth waveguide region 331
  • the first waveguide region 3411, the second waveguide region 3412, and the third waveguide region 3413, and the silicon dioxide material has a lower refractive index, so that the transmitted optical signal can be optically confined.
  • the fourth waveguide region 331 is located above the germanium layer 320, and the first waveguide region 3411, the second waveguide region 3412 and the third waveguide region 3413 are arranged around the sides of the germanium layer, so that the optical signal can be coupled with multiple sides of the germanium layer 320.
  • the detected optical signal can be transmitted to the coupling region through multiple coupling paths, which reduces
  • the optical power density in each coupling path can not only ensure the high coupling efficiency of the optical signal from the waveguide to the germanium layer 320, but also make the optical signal evenly distributed in the germanium layer 320, thereby avoiding the strong local optical field of the germanium layer 320 Premature saturation of the detector caused by the accumulation of photo-generated carriers; it is understandable that the higher the coupling efficiency, the more photons are coupled into the germanium layer 320, so that only a shorter coupling region is needed. High response speed, so there is no need to increase the length of the coupling area of the detector, which not only avoids the excessive size of the device, but also suppresses the transmission loss. It should be noted that the length of the coupling region is equal to the length of the germanium layer 320.
  • the fourth waveguide region 331, the first waveguide region 3411, the second waveguide region 3412, and the third waveguide region 3413 are not only used to realize the propagation and redirection of optical signals, but also interact with the
  • the germanium layer 320 is coupled to form a built-in electric field to generate carriers.
  • the first-layer waveguide 330 and the second-layer waveguide 340 realize optical signal transmission through interlayer coupling; specifically,
  • the first layer waveguide 330 may further include a first interlayer coupling region 332 connected to the fourth waveguide region 331;
  • the second layer waveguide 340 may further include a second interlayer coupling region 342 connected to the first waveguide region 3411 and the second waveguide region 3412;
  • the first layer waveguide 330 and the second layer waveguide 340 realize optical signal transmission through the interlayer coupling of the first interlayer coupling region 332 and the second interlayer coupling region 342;
  • the optical signals of the interlayer coupling region 332 and the second interlayer coupling region 342 are respectively transmitted to the fourth waveguide region 331, the first waveguide region 3411, the second waveguide region 3412, and the third waveguide region 3413.
  • the first-layer waveguide 330 and the second-layer waveguide 340 split the received (that is, the optical signal that needs to be detected) at the upper and lower layers through interlayer coupling.
  • the optical power density transmitted in each layer of the waveguide is reduced, so that the fourth waveguide area 331, the first waveguide area 3411, the second waveguide area 3412, and the third waveguide area are reduced.
  • the position of 3413 can couple the optical signal to the germanium layer 320 more effectively.
  • One of the first-layer waveguide 330 and the second-layer waveguide 340 is used to receive an optical signal from outside the photodetector, and then transmit the optical signal to the other waveguide through interlayer coupling.
  • the first layer waveguide 330 is used to receive optical signals, and in the first interlayer coupling region 332, the received optical signals are transmitted to the second layer waveguide 340 through interlayer coupling.
  • the optical signal is coupled into the second layer waveguide 340 via the first interlayer coupling region 332.
  • the second interlayer coupling region 342 the optical signal remaining after the first interlayer coupling region 332 is transmitted to the fourth waveguide region 331 after interlayer coupling, and the second interlayer coupling region 342 is after interlayer coupling
  • the obtained optical signal is transmitted to the first waveguide region 3411 and the second waveguide region 3412.
  • the cross-sectional area of the first inter-layer coupling region 332 becomes smaller, and the cross-sectional area of the second inter-layer coupling region 342 becomes larger.
  • the first interlayer coupling region 332 and the second interlayer coupling region 342 are, for example, inverted tapered waveguides, and the first interlayer coupling region 332 (along the vertical
  • the cross-sectional area of the second interlayer coupling region 342 (in the optical signal transmission direction) becomes smaller along the optical signal transmission direction; the cross-sectional area of the second interlayer coupling region 342 (along the optical signal transmission direction) becomes larger along the optical signal transmission direction.
  • the mode field of the optical signal gradually becomes larger as the cross-sectional area of the first interlayer coupling region 332 becomes smaller, and the diffuse mode field distribution is more beneficial to the interlayer Optical coupling
  • the optical signal is coupled from the first interlayer coupling region 332 Enter the second interlayer coupling region 342; since the cross-sectional area of the second interlayer coupling region 342 at the position corresponding to the narrow end of the first interlayer coupling region 332 is larger, the first layer
  • the coupling efficiency is higher and the coupling loss is lower.
  • the orthographic projections of the first interlayer coupling region 332 and the second interlayer coupling region 342 on the silicon layer 310 at least partially overlap.
  • the first interlayer coupling region 332 in the inverted cone shape and the second interlayer coupling region 342 in the inverted cone shape partially overlap. Adjust the length W of the interlayer coupling region between the first interlayer coupling region 332 and the second interlayer coupling region 342 to adjust the first interlayer coupling region 332 and the second interlayer coupling region 342 For example, the greater the W, the greater the coupling ratio between the first interlayer coupling region 332 and the second interlayer coupling region 342, that is, the coupling enters the second layer The more optical signals in the inter-coupling region 342, the less optical signals remaining in the first inter-layer coupling region 332. Therefore, W can be adjusted according to actual coupling ratio requirements.
  • the second layer waveguide 340 further includes a splitting waveguide region 343 located between the second interlayer coupling region 341 and the first waveguide region 3411 and the second waveguide region 3412.
  • the splitting waveguide region 343 is used for
  • the optical signal transmitted from the second interlayer coupling area 342 is divided into at least two paths, and two of the optical signals are output to the first waveguide area 3411 and the second waveguide area 3412 respectively.
  • the projection of the sidewall of the germanium layer 320 on the silicon layer 310 has a first shape, and the length of the first shape in the first direction is greater than the length in the second direction;
  • the first waveguide region 3411 and the second waveguide region 3412 surround the germanium layer 320 on the outer side of the first sidewall and the second sidewall of the germanium layer 320, respectively.
  • the first sidewall and the second sidewall The sidewalls are two opposite sidewalls of the germanium layer 320 that are parallel to the first direction.
  • the projection of the sidewall of the germanium layer 320 on the silicon layer 310 has a first shape, as shown in FIG.
  • the dotted line direction in the figure is the second direction, and the direction perpendicular to the dotted line direction Is the first direction.
  • the first shape may be a rectangle having a long side extending in the first direction and a short side extending in the second direction; wherein, the first shape
  • the length in the first direction is the length of the long side of the rectangle
  • the length of the first shape in the second direction is the length of the short side of the rectangle. It can be understood in conjunction with FIG. 7 that the length of the coupling region is the length of the first shape in the first direction.
  • the first side wall and the second side wall of the germanium layer 320 are the left side wall and the right side wall of the germanium layer 320 (in the first direction).
  • the third waveguide region 3413 connects the first waveguide region 3411 and the second waveguide region 3412 in the second direction; output from the splitting waveguide region 343 to the first waveguide
  • the optical signal of the area 3411 is transmitted along the third waveguide area 3413 to the second waveguide area 3412, and the optical signal output from the split optical waveguide area 343 to the second waveguide area 3412 is transmitted along the third waveguide area 3413.
  • connection of the third waveguide region 3413 to the first waveguide region 3411 and the second waveguide region 3412 is only a connection method provided in the embodiment of the present application, and the embodiment of the present application is not limited to all In the case where the first waveguide region 3411 and the second waveguide region 3412 are connected by the third waveguide region 3413, the first waveguide region 3411 and the second waveguide region 3412 may not be connected.
  • the first waveguide region 3411, the second waveguide region 3412, and the third waveguide region 3413 of the second layer waveguide 340 surround the side of the germanium layer 320 on the side of the germanium layer 320. Wall and set.
  • the first waveguide region 3411 and the second waveguide region 3412 may both be optical input waveguide regions, and the optical signal output from the optical splitting waveguide region 343 may be along the first waveguide region 3411 to the first waveguide region 3411.
  • the three waveguide region 3413 is transmitted in the direction from the second waveguide region 3412, and the optical signal output from the split optical waveguide region 343 can also travel along the second waveguide region 3412 to the third waveguide region 3413 to the first waveguide region 3411. That is to say, the first waveguide region, the second waveguide region, and the third waveguide region in the embodiment of the present application have at least two optical signals transmitted in opposite directions.
  • each optical signal can be coupled to the germanium layer 320 via the first waveguide region 3411 and the second waveguide region 3412 at least twice. Therefore, without increasing the length of the germanium layer 320, the responsivity of the photodetector can be improved without reducing the 3dB optical bandwidth of the photodetector.
  • the light splitting waveguide region 343 and the third waveguide region 3413 are respectively located on the third side wall and the fourth side wall of the germanium layer 320, and the third side The wall and the fourth side wall are respectively two opposite side walls of the germanium layer 320 parallel to the second direction.
  • the third side wall and the fourth side wall of the germanium layer 320 are the left side wall and the right side wall of the germanium layer 320 (in the second direction), that is, the light splitting waveguide region 343 and the The third waveguide regions 3413 are respectively located on the left and right sides of the germanium layer 320 (in the second direction).
  • the first, second, and third waveguide regions and the optical splitting waveguide region 343 enclose a closed region along the transmission direction of the optical signal, and the germanium layer 320 is located at all The enclosed area.
  • the light splitting waveguide region 343 is not limited to being located on the side opposite to the third waveguide region 3413, and the position of the light splitting waveguide region 343 can be adjusted according to actual needs.
  • the optical splitting waveguide area 343 may also split the received optical signal into more than two optical signals.
  • the optical splitting waveguide area 343 divides the received optical signal into three optical signals, and two of them are split. After the optical signals are output to the first waveguide area 3411 and the second waveguide area 3412, the split optical waveguide area 343 can also output the remaining optical signal to another waveguide area, such as located in the germanium layer.
  • 320 is the waveguide area on the sidewall side in the second direction (not shown in the figure).
  • the first layer waveguide 330 further includes an isolated waveguide region 333 located between the first interlayer coupling region 332 and the fourth waveguide region 331; the isolated waveguide region 333 and the fourth waveguide region 331
  • the orthographic projections of the light splitting waveguide area 343 on the silicon layer 310 are staggered, so that the optical signal on the first-layer waveguide 330 does not interact with the first layer at the position corresponding to the light splitting waveguide area 343. Interlayer coupling between the two-layer waveguides 340.
  • the optical signal in the first-layer waveguide 330 runs along the isolated waveguide region 333 It is transmitted to the fourth waveguide region 331 and thus is staggered from the splitting waveguide region 343 of the second-layer waveguide 340 to prevent the second-layer waveguide 340 from interfering with the splitting waveguide region 343.
  • the distance H between the first interlayer coupling region 332 and the second interlayer coupling region 342 is 50 nm-1500 nm.
  • the extension direction of the fourth waveguide region 331 of the first layer waveguide 330 is parallel to the contact plane between the silicon layer 310 and the germanium layer 320, and the fourth waveguide region 331 is connected to the upper surface of the germanium layer 320.
  • the distance between them is 60nm-1000nm.
  • the distance between the first, second, and third waveguide regions and the silicon layer 310 is 100 nm-1200 nm.
  • the distance between the first, second, and third waveguide regions of the second-layer waveguide 340 and the sidewall of the germanium layer 320 is 50 nm-1000 nm.
  • the area of the cross section of the fourth waveguide region, the first waveguide region, the second waveguide region, and the third waveguide region in a direction perpendicular to the transmission direction of the optical signal is 0.06 ⁇ m 2 -0.5 ⁇ m 2 .
  • the cross section of the fourth waveguide region, the first waveguide region, the second waveguide region, and the third waveguide region along the transmission direction perpendicular to the optical signal may be rectangular or trapezoidal.
  • the cross section of the fourth waveguide region, the first waveguide region, the second waveguide region, and the third waveguide region along the transmission direction perpendicular to the optical signal is rectangular as an example for description.
  • the cross section of the fourth waveguide region, the first waveguide region, the second waveguide region, and the third waveguide region along the transmission direction perpendicular to the optical signal may also be trapezoidal (the trapezoidal shape).
  • the length of the bottom side close to the silicon layer 310 is greater than the length of the top bottom side far away from the silicon layer 310).
  • the cross section of the germanium layer 320 along the direction perpendicular to the transmission direction of the optical signal may be rectangular or trapezoidal.
  • the cross section of the germanium layer 320 along the direction perpendicular to the transmission direction of the optical signal is a trapezoid as an example for description.
  • the target shape of the germanium layer 320 (the cross section perpendicular to the transmission direction of the optical signal) is rectangular, but due to the influence of the process, the final shape
  • the actual shape of the germanium layer 320 (a cross-section perpendicular to the transmission direction of the optical signal) may be a trapezoid, and the bottom side of the trapezoid near the silicon layer 310 is longer than the upper bottom far away from the silicon layer 310 Side length.
  • the length of the germanium layer 320 in the first direction is 5 ⁇ m-100 ⁇ m. By controlling the length of the germanium layer 320 in the first direction, the length of the coupling region can be controlled.
  • the preferred size of the photodetector is: the fourth waveguide region, the first waveguide region, the second waveguide region, and the third waveguide region are perpendicular to the light
  • the cross section in the signal input direction has a length of 800 nm and a width of 300 nm; the germanium layer 320 has a cross section perpendicular to the input direction of the optical signal (as shown in FIG. 6).
  • the length of the cross section shown) is 3 ⁇ m and the width is 500 nm; the length of the germanium layer 320 in the first direction (that is, the length of the coupling region) is 12 ⁇ m; the first waveguide region, the second waveguide region, and the second waveguide region The distance between the three waveguide region and the silicon layer 310 is 150 nm; the distance between the first waveguide region 3411 and the germanium layer 320 is 100 nm; the distance between the second waveguide region 3412 and the germanium layer 320 The distance therebetween is 100 nm; the distance between the fourth waveguide region 331 and the upper surface of the germanium layer 320 is 100 nm.
  • the silicon layer 310 includes a first doped type doped region 311; the germanium layer 320 includes a second doped type doped region 321; the first doped type doped region 311 and the second doped region A first metal electrode 312 and a second metal electrode 322 are respectively provided on the doped region 321 of the doping type; the first doping type is P-type, and the second doping type is N-type to form a PIN structure Or, the first doping type is N-type and the second doping type is P-type to form a photodetector with a NIP structure.
  • a doped region 311 of the first doping type is formed on the upper surface of the silicon layer 310, and the second doped region 311 is formed on the upper surface of the germanium layer 320.
  • the upper surface of the silicon layer 310 can also be formed with a doped region 313 of the second doping type, and the upper surface of the germanium layer 320 can also be formed with a first doped region.
  • the doped region 323 of the doping type is formed on the upper surface of the silicon layer 310, and the second doped region 311 is formed on the upper surface of the germanium layer 320.
  • 6 to 7 only illustrate that a doped region 311 of the first doping type and a doped region 313 of the second doping type are formed on the silicon layer 310, and the germanium layer 320 is formed with The case of one doped region 321 of the second doping type and one doped region 323 of the first doping type.
  • the doped region 311 of the first doping type on the silicon layer 310 is provided with a first metal electrode 312, and the doped region 313 of the second doping type on the silicon layer 310 is provided with The third metal electrode 314; the second metal electrode 322 is provided on the doped region 321 of the second doping type on the germanium layer 320, and the doping of the first doping type on the germanium layer 320
  • a fourth metal electrode 324 is provided on the miscellaneous region 323.
  • the first doping type may be P-type or N-type.
  • the second doping type is N-type, so that the doping of the first doping type A photodetector with a PIN structure is formed between the doped region 311 and the doped region 321 of the second doping type, and the doped region 313 of the second doping type and the doped region of the first doping type A photodetector with a NIP structure is formed between the regions 323; when the first doping type is N-type, the second doping type is P-type, so that the doping region 311 of the first doping type A photodetector with a NIP structure is formed between the doped region 321 of the second doping type and the doped region 313 of the second doping type and the doped region 323 of the first doping type. A photodetector with a PIN structure is formed between. It should be noted that the undoped area between the silicon layer 310 and the germanium layer 320 serves as an intrinsic body in the PIN structure or the NIP structure.
  • the upper surface of the germanium layer 320 is formed with a doped region 321 of the second doping type and a doped region 323 of the first doping type.
  • the second doping type is a different doping type.
  • a lateral built-in electric field can be formed between the doped region 321 of the second doping type and the doped region 323 of the first doping type on the germanium layer 320 (directed by the doped region 321 of the second doping type).
  • the direction of the doped region 323 of the first doping type or the direction of the doped region 323 of the first doping type to the doped region 321 of the second doping type generates carriers.
  • the silicon layer 310 when there is only one type of doped region on the silicon layer 310, the silicon layer 310 may also be a doped silicon layer, and when the first doping type is P-type The silicon layer 310 may be an overall P-type doped silicon layer, but the doping concentration of the doped region is greater than the overall doping concentration of the silicon layer 310; when the first doping type is N-type The silicon layer 310 may be an overall N-type doped silicon layer, but the doping concentration of the doped region is greater than the overall doping concentration of the silicon layer 310. Understandably, since the silicon nitride waveguide is used to transmit the optical signal, the adverse effect on the transmission of the optical signal when the doped silicon layer is used as the waveguide is avoided, thereby effectively reducing the transmission loss of the optical signal.
  • an external voltage is applied between the first metal electrode 312 on the silicon layer 310 and the second metal electrode 322 on the germanium layer 320 and/or a voltage is applied to the silicon layer 310.
  • An applied voltage is applied between the third metal electrode 314 and the fourth metal electrode 324 on the germanium layer 320 to form an applied electric field, the carriers generated in the germanium layer 320 are extracted, and the electric field direction of the applied electric field is the same as that of the The directions of the built-in electric fields formed in the germanium layer 320 are the same, so that the external electric field can accelerate the moving speed of carriers, thereby improving the responsivity of the photodetector.
  • the length of the metal electrodes (312, 314, 322, and 324) in the first direction is smaller than the length of the germanium layer 320 in the first direction.
  • the upper surface of the metal electrode is exposed on the upper surface of the photodetector.
  • the structure of the doped region of the germanium layer 320 and the silicon layer 310 can also be changed to realize avalanche gain detection (APD).
  • Specific implementation methods include: adding an avalanche zone on the germanium layer 320, or applying a reverse bias voltage greater than 6V to the formed NIP structure or PIN structure to achieve avalanche gain detection.
  • FIG. 8 is a top view of another implementation of the photodetector provided by the embodiment of the application. It should be noted that, in order to illustrate the positional relationship between the upper and lower layers of the first layer of waveguide and the second layer of waveguide, the dashed frame in FIG. 8 The structure is not in the form of filling.
  • the material of the structure in the dashed frame in Figure 8 should be understood as the same as the materials of other structures; in addition, in order to show the waveguide structure more clearly, the scale of the structure in the dashed frame in Figure 8 and the structure outside the dashed frame in Figure 8 It may be different (for example, the structure in the dashed frame is enlarged in the lateral direction in the figure), therefore, the size or scale of the structure in the figure should not be construed as a limitation of the corresponding feature in the present application.
  • L1 represents the first-layer waveguide
  • L2 represents the second-layer waveguide.
  • L1 and L2 are only used to illustrate the first-layer waveguide and the second-layer waveguide, and are not used to limit the shape and length of the first-layer waveguide and the second-layer waveguide of the present application.
  • the second layer waveguide 440 may not use the light splitting waveguide region 443 for light splitting.
  • the second interlayer coupling region 442 is connected to the first waveguide region 4411 and the second waveguide region 4411.
  • the waveguide region 4412 can be directly connected, the second interlayer coupling region 442 transmits the optical signal obtained by coupling to the first waveguide region 4411, and the first waveguide region 4411 transmits the optical signal through the third waveguide region 4413.
  • the optical signal propagates in the direction from the first waveguide region 4411 to the third waveguide region 4413 to the second waveguide region 4412.
  • the first waveguide region 4411 and the second waveguide region 4412 are respectively located on both sides of the germanium layer 420, and the first waveguide region 4411 and the second waveguide region 4412 pass through the first waveguide region 4411 and the second waveguide region 4412.
  • the three waveguide regions 4413 are connected, so that the optical signal couples with the germanium layer 420 at least twice, so that the responsivity of the photodetector can be improved without increasing the length of the germanium layer 420 without reducing 3dB photoelectric bandwidth of photodetector.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Power Engineering (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Light Receiving Elements (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

一种光电探测器，包括：硅层（110），硅层（110）包括第一掺杂类型的掺杂区（111）；与硅层（110）接触的锗层（120），锗层（120）包括第二掺杂类型的掺杂区（121）；氮化硅波导（130），氮化硅波导（130）沿锗层（120）的至少三个侧壁的延伸方向围绕锗层（120）设置；其中，氮化硅波导（130）用于传输光信号，并将光信号耦合至锗层（120），锗层（120）用于探测光信号，并将光信号转换为电信号。

Description

一种光电探测器
相关申请的交叉引用
本申请基于申请号为201911379861.4、201911382677.5和201911382842.7、申请日为2019年12月27日的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本申请实施例涉及光电探测器技术领域，特别涉及一种光电探测器。
背景技术
硅光子技术是基于硅和硅基衬底材料(如SiGe/Si、绝缘体上硅等)，利用现有互补金属氧化物半导体(Complementary Metal Oxide Semiconductor，CMOS)工艺进行光器件开发和集成的新一代技术。硅光子技术结合了集成电路技术的超大规模、超高精度制造的特性和光子技术超高速率、超低功耗的优势，是应对摩尔定律失效的颠覆性技术。这种结合得力于半导体晶圆制造的可扩展性，因而能够降低成本。光电探测器作为硅光子架构的核心器件之一，具有实现光信号到电信号转换的功能。但晶体硅材料的能带结构决定其在光通信波段探测效率很低，虽然III-V族半导体材料更适合用于光电探测器，但是III-V族半导体材料与硅工艺不兼容，无法与硅进行有效的单片集成；考虑到锗材料与CMOS工艺的兼容性，本领域提出了采用锗材料作为光吸收层材料而形成锗硅光电探测器的技术。然而，目前的锗硅光电探测器具有响应度较低且无法满足高光功率探测的需求的缺点，因此有待进一步的改进。
发明内容
有鉴于此，本申请实施例为解决现有技术中存在的至少一个问题而提供一种脉冲信号发生装置、方法。
为达到上述目的，本申请实施例的技术方案是这样实现的：
第一方面，本申请实施例提供一种光电探测器，包括：
硅层，所述硅层包括第一掺杂类型的掺杂区；
与所述硅层接触的锗层，所述锗层包括第二掺杂类型的掺杂区；
氮化硅波导，所述氮化硅波导沿所述锗层的至少三个侧壁的延伸方向围绕所述锗层设置；
其中，所述氮化硅波导用于传输光信号，并将所述光信号耦合至所述锗层，所述锗层用于探测所述光信号，并将所述光信号转换为电信号。
在一种可选的实施方式中，所述氮化硅波导包括第一波导区和第二波导区，所述锗层设置在所述第一波导区和所述第二波导区之间。
在一种可选的实施方式中，所述锗层的侧壁在硅层上的投影具有第一形状，所述第一形状在第一方向上的长度大于在第二方向上的长度；
所述氮化硅波导还包括：第三波导区；所述第三波导区在第二方向上连接所述第一波导区和所述第二波导区。
在一种可选的实施方式中，还包括：
与所述氮化硅波导连接的分光波导，所述分光波导用于将接收的光信号分为至少两路光信号，并将其中两路光信号分别输出至所述第一波导区和所述第二波导区。
在一种可选的实施方式中，所述氮化硅波导传输的光信号沿所述第一波导区至所述第三波导区至所述第二波导区的方向传播；
所述第一波导区与所述锗层之间的距离大于所述第二波导区与所述锗层之间的距离。
在一种可选的实施方式中，所述氮化硅波导和所述分光波导沿所述光信号的传输方向围成一封闭区域，所述锗层位于所述封闭区域内。
在一种可选的实施方式中，所述氮化硅波导包括第一层波导和第二层波导；所述第一层波导包括设置在所述锗层上方的第四波导区，所述第二层波导包括设置在所述锗层侧面的第一波导区、第二波导区和第三波导区；
所述第一层波导和所述第二层波导分别通过所述第四波导区和所述第一波导区、第二波导区、第三波导区将所述光信号耦合至所述锗层。
在一种可选的实施方式中，所述第一层波导还包括与所述第四波导区连接的第一层间耦合区；
所述第二层波导还包括与所述第一波导区和所述第二波导区连接的第二层间耦合区；
所述第一层波导和所述第二层波导之间通过所述第一层间耦合区和所述第二层间耦合区的层间耦合实现光信号传递；所述第一层间耦合区和所述第二层间耦合区的光信号分别传输至所述第四波导区、所述第一波导区、所述第二波导区和所述第三波导区。
在一种可选的实施方式中，所述第一层波导用于接收光信号，并在所述第一层间耦合区将接收的光信号通过层间耦合传递至所述第二层波导的所述第二层间耦合区。
在一种可选的实施方式中，所述第一层间耦合区和所述第二层间耦合区之间的距离为50nm-1500nm。
在一种可选的实施方式中，沿光信号的传输方向上，所述第一层间耦合区的横截面积变小，所述第二层间耦合区的横截面积变大。
在一种可选的实施方式中，所述第一层间耦合区和所述第二层间耦合区在所述硅层上的正投影至少部分重合。
在一种可选的实施方式中，所述第二层波导还包括位于所述第二层间 耦合区及所述第一波导区和所述第二波导区之间的分光波导区，所述分光波导区用于将从所述第二层间耦合区传输过来的光信号分为至少两路，并将其中两路光信号分别输出至所述第一波导区和所述第二波导区。
在一种可选的实施方式中，所述第一层波导还包括位于所述第一层间耦合区和所述第四波导区之间的隔离波导区；所述隔离波导区和所述分光波导区在所述硅层上的正投影彼此错开，以使所述第一层波导上的光信号在传输至与所述分光波导区对应的位置处不发生与所述第二层波导之间的层间耦合。
在一种可选的实施方式中，所述第一层波导的所述第四波导区的延伸方向平行于所述硅层与所述锗层的接触平面，所述第四波导区与所述锗层上表面之间的距离为60nm-1000nm。
在一种可选的实施方式中，所述第一波导区和所述第二波导区为直波导区；
所述第三波导区为弯曲波导区。
在一种可选的实施方式中，所述第一波导区和所述第二波导区与所述锗层之间的距离为50nm-1000nm。
在一种可选的实施方式中，所述氮化硅波导的延伸方向平行于所述硅层与所述锗层的接触平面，所述氮化硅波导与所述硅层之间的距离为100nm-1200nm。
在一种可选的实施方式中，所述锗层在第一方向上的长度为5μm-100μm。
在一种可选的实施方式中，所述氮化硅波导与所述锗层之间具有二氧化硅材料；
所述氮化硅波导与所述硅层之间具有二氧化硅材料。
在一种可选的实施方式中，所述第一掺杂类型的掺杂区和所述第二掺 杂类型的掺杂区上分别设有第一金属电极和第二金属电极；
所述第一掺杂类型为P型，所述第二掺杂类型为N型，以形成PIN结构的光电探测器；或者，
所述第一掺杂类型为N型，所述第二掺杂类型为P型，以形成NIP结构的光电探测器。
本申请实施例提供了一种光电探测器，包括：硅层，所述硅层包括第一掺杂类型的掺杂区；与所述硅层接触的锗层，所述锗层包括第二掺杂类型的掺杂区；氮化硅波导，所述氮化硅波导沿所述锗层的至少三个侧壁的延伸方向围绕所述锗层设置；其中，所述氮化硅波导用于传输光信号，并将所述光信号耦合至所述锗层，所述锗层用于探测所述光信号，并将所述光信号转换为电信号。本申请实施例中采用氮化硅材料形成氮化硅波导，且氮化硅波导围绕锗层设置，从而氮化硅波导中的光信号可以与锗层进行至少两次耦合；如此，不仅可以实现高光功率探测，而且降低了光信号的传播损耗，避免了饱和吸收效应的出现，同时，无需增加探测器的耦合区长度(即锗层长度)即可提高探测器的响应度。
附图说明
图1为本申请实施例提供的光电探测器的一种实施方式的侧面剖视图；
图2为本申请实施例提供的光电探测器的一种实施方式的俯视图；
图3为本申请实施例提供的光电探测器的另一种实施方式的侧面剖视图；
图4为本申请实施例提供的光电探测器的另一种实施方式的俯视图；
图5为本申请实施例提供的光电探测器的另一种实施方式的侧面剖视图；
图6为本申请实施例提供的光电探测器的另一种实施方式的侧面剖视图；
图7为本申请实施例提供的光电探测器的另一种实施方式的俯视图；
图8为本申请实施例提供的光电探测器的另一种实施方式的俯视图。
具体实施方式
下面将参照附图更详细地描述本申请公开的示例性实施方式。虽然附图中显示了本申请的示例性实施方式，然而应当理解，可以以各种形式实现本申请，而不应被这里阐述的具体实施方式所限制。相反，提供这些实施方式是为了能够更透彻地理解本申请，并且能够将本申请公开的范围完整的传达给本领域的技术人员。
在下文的描述中，给出了大量具体的细节以便提供对本申请更为彻底的理解。然而，对于本领域技术人员而言显而易见的是，本申请可以无需一个或多个这些细节而得以实施。在其他的例子中，为了避免与本申请发生混淆，对于本领域公知的一些技术特征未进行描述；即，这里不描述实际实施例的全部特征，不详细描述公知的功能和结构。
在附图中，为了清楚，层、区、元件的尺寸以及其相对尺寸可能被夸大。自始至终相同附图标记表示相同的元件。
应当明白，当元件或层被称为“在……上”、“与……相邻”、“连接到”或“耦合到”其它元件或层时，其可以直接地在其它元件或层上、与之相邻、连接或耦合到其它元件或层，或者可以存在居间的元件或层。相反，当元件被称为“直接在……上”、“与……直接相邻”、“直接连接到”或“直接耦合到”其它元件或层时，则不存在居间的元件或层。应当明白，尽管可使用术语第一、第二、第三等描述各种元件、部件、区、层和/或部分，这些元件、部件、区、层和/或部分不应当被这些术语限制。这些术语仅仅用来区分一个元件、部件、区、层或部分与另一个元件、部件、区、层或部分。因此，在不脱离本申请教导之下，下面讨论的第一元件、部件、区、层或部分可表示为第二元件、部件、区、层或部分。而当讨论的第二元件、 部件、区、层或部分时，并不表明本申请必然存在第一元件、部件、区、层或部分。
空间关系术语例如“在……下”、“在……下面”、“下面的”、“在……之下”、“在……之上”、“上面的”等，在这里可为了方便描述而被使用从而描述图中所示的一个元件或特征与其它元件或特征的关系。应当明白，除了图中所示的取向以外，空间关系术语意图还包括使用和操作中的器件的不同取向。例如，如果附图中的器件翻转，然后，描述为“在其它元件下面”或“在其之下”或“在其下”元件或特征将取向为在其它元件或特征“上”。因此，示例性术语“在……下面”和“在……下”可包括上和下两个取向。器件可以另外地取向(旋转90度或其它取向)并且在此使用的空间描述语相应地被解释。
在此使用的术语的目的仅在于描述具体实施例并且不作为本申请的限制。在此使用时，单数形式的“一”、“一个”和“所述/该”也意图包括复数形式，除非上下文清楚指出另外的方式。还应明白术语“组成”和/或“包括”，当在该说明书中使用时，确定所述特征、整数、步骤、操作、元件和/或部件的存在，但不排除一个或更多其它的特征、整数、步骤、操作、元件、部件和/或组的存在或添加。在此使用时，术语“和/或”包括相关所列项目的任何及所有组合。
为了能够更加详尽地了解本申请实施例的特点与技术内容，下面结合附图对本申请实施例的实现进行详细阐述，所附附图仅供参考说明之用，并非用来限定本申请实施例。
硅光子集成芯片中可采用兼容CMOS工艺的锗材料实现光电探测，通过在硅平板波导上形成锗层，利用锗材料吸收光子继而产生载流子。目前锗硅光电探测器结构中通常利用硅平板波导将光信号传导入结构内部，继而将携带信号的光耦合至锗层内；这种结构存在以下不足：第一方面，硅 平板波导作为传输光信号的结构，在较高光功率密度的情况下，会有明显非线性效应，产生双光子吸收，因此难以支持高光功率探测；第二方面，由于硅材料和锗材料的折射率差较小，硅平板波导内传输的光信号比较容易耦合至锗层，将会导致探测器饱和吸收效应出现，继而降低探测器的响应度；第三方面，整个硅平板波导一般进行P型或N型掺杂，以形成电场、抽取载流子，然而，形成的P型或N型掺杂区域会对硅平板波导中光信号的传输产生影响，导致光的传播损耗，进一步降低探测器的响应度。
为此，提出了本申请实施例的以下技术方案。
图1为本申请实施例提供的光电探测器的一种实施方式的侧面剖视图，图2为本申请实施例提供的光电探测器的一种实施方式的俯视图，需要说明的是，图1为沿图2中虚线方向的侧面剖视图，如图1和图2所示，本申请实施例提供的光电探测器，包括：
硅层110，所述硅层110包括第一掺杂类型的掺杂区111；与所述硅层110接触的锗层120，所述锗层120包括第二掺杂类型的掺杂区121；
氮化硅波导130，所述氮化硅波导130沿所述锗层120的至少三个侧壁的延伸方向围绕所述锗层120设置；
其中，所述氮化硅波导130用于传输光信号，并将所述光信号耦合至所述锗层120，所述锗层120用于探测所述光信号，并将所述光信号转换为电信号。
在本申请实施例中，所述光电探测器还包括：衬底，所述衬底可以为单质半导体材料衬底(例如为硅(Si)衬底、锗(Ge)衬底等)、复合半导体材料衬底(例如为锗硅(SiGe)衬底等)，或绝缘体上硅(SOI)衬底、绝缘体上锗(GeOI)衬底等。本申请实施例以衬底为SOI衬底为例进行说明，所述光电探测器还包括底层衬底140，所述底层衬底140例如为底层硅材料；在所述底层衬底140上具有埋氧层(图中未示出)；所述硅层110形 成在所述埋氧层上。所述锗层120形成在所述硅层110上，所述氮化硅波导130沿所述锗层120的至少三个侧壁的延伸方向围绕所述锗层120设置，且所述氮化硅波导130与所述锗层120之间具有二氧化硅材料，所述氮化硅波导130与所述硅层110之间具有二氧化硅材料。如图1所示，所述二氧化硅材料150覆盖所述硅层110和所述锗层120，所述氮化硅波导130设置在所述二氧化硅材料150中，并与所述硅层110和所述锗层120各间隔一定距离，所述二氧化硅材料用于支撑和固定所述氮化硅波导130，且所述二氧化硅材料具有较低的折射率，从而可以对传输的光信号进行光约束。
在本申请实施例中，所述氮化硅波导130的折射率和所述锗层120的折射率的差较大，且氮化硅波导130围绕锗层120设置，如此既能够保证光信号从氮化硅波导130到锗层120的高耦合效率，又能够使得光信号均匀分布在锗层120中，从而能够避免锗层120局部光场较强造成的光生载流子堆积形成的探测器过早饱和现象；可以理解的是，耦合效率越高，耦合进入锗层120中的光子数就越多，这样仅需要较短的耦合区长度就可以实现高响应速度。需要说明的是，耦合区长度等于所述锗层120的长度。
在本申请实施例中，所述氮化硅光波导130不仅用于实现光信号的传播与变向，且与所述锗层120发生耦合作用，从而形成内建电场，产生载流子。
在本申请实施例中，使用低非线性氮化硅材料作为传输光波导，氮化硅波导不会出现双光子吸收效应，且氮化硅波导支持高光功率密度、大光学带宽的低损耗光传输。
所述锗层120的侧壁在硅层110上的投影具有第一形状，所述第一形状在第一方向上的长度大于在第二方向上的长度；
所述氮化硅波导130包括：第一波导区131、第二波导区132和第三波导区133；所述第一波导区131和所述第二波导区132分别在所述锗层120 的第一侧壁和第二侧壁的外侧围绕所述锗层120，所述第一侧壁和所述第二侧壁分别为所述锗层120的平行于第一方向的彼此相对的两侧壁；所述第三波导区133在第二方向上连接所述第一波导区131和所述第二波导区132。
在本申请实施例中，所述锗层120的侧壁在硅层110上的投影具有第一形状，如图2所示，图中虚线方向为所述第二方向，与虚线方向垂直的方向为所述第一方向。在图2所示实施例中，该第一形状可以为矩形，所述矩形具有沿所述第一方向延伸的长边和沿所述第二方向延伸的短边；其中，所述第一形状在第一方向上的长度为矩形长边的长度，所述第一形状在第二方向上的长度为矩形短边的长度。结合图2可以理解的是，耦合区长度即为所述第一形状在第一方向上的长度。
需要说明的是，如图1所示，所述锗层120的第一侧壁和第二侧壁即为所述锗层120(沿第一方向上)的左侧壁和右侧壁。
所述第一波导区131和所述第二波导区132为直波导区；
所述第三波导区133为弯曲波导区。
在本申请实施例中，如图2所示，所述第一波导区131和所述第二波导区132分别位于所述锗层120的第一侧壁和第二侧壁的外侧，也就是说，所述第一波导区131和所述第二波导区132分别位于所述锗层120(沿第一方向上)的左侧和右侧。
在本申请实施例中，所述第三波导区133用于将所述第一波导区131的光信号转折180°后传输至所述第二波导区132。需要说明的是，本申请实施例中以所述第一波导区131为光输入波导区为例进行说明。
所述氮化硅波导130传输的光信号沿所述第一波导区131至所述第三波导区133至所述第二波导区132的方向传播；
所述第一波导区131与所述锗层120之间的距离大于所述第二波导区 132与所述锗层120之间的距离。
在本申请实施例中，由于所述第一波导区131为光输入波导区，所述氮化硅波导130传输的光信号沿所述第一波导区131至所述第三波导区133至所述第二波导区132的方向传播，则在所述第一波导区131传输的光信号强度大于在所述第二波导区132传输的光信号强度(因为所述第一波导区131传输的光信号被所述锗层120吸收了部分后，经由所述第三波导区133传输至所述第二波导区132，则此时所述第二波导区132传输的光信号是经由所述锗层120耦合一次后剩余的光信号)，那么形成所述氮化硅波导130时，可以将所述第一波导区131设置在比所述第二波导区132距离所述锗层120更远的位置上，从而在所述第一波导区131传输的光信号强度较强时，控制所述第一波导区131传输的光信号与所述锗层120的耦合速度，避免出现所述锗层120过早饱和的现象，而在所述第二波导区132传输的光信号强度较弱时，使得所述第二波导区132剩余的光信号能够全部耦合进行所述锗层120，从而提高耦合效率。
在本申请实施例中，所述第一波导区131和所述第二波导区132分别位于所述锗层120的两侧，所述第一波导区131和所述第二波导区132通过所述第三波导区133连接，使得所述氮化硅波导130内传输的光信号与所述锗层120至少耦合作用两次，从而能够在不增加所述锗层120的长度的情况下，提高光电探测器的响应度，同时也不会降低光电探测器3dB光电带宽。
所述氮化硅波导130沿垂直于所述光信号的输入方向上的横截面面积为0.06μm 2-0.5μm 2。需要说明的是，所述氮化硅波导130沿垂直于所述光信号的输入方向上的横截面可以为矩形或梯形。本申请实施例中以所述氮化硅波导130沿垂直于所述光信号的输入方向上的横截面为矩形为例进行说明。在实际应用时，所述氮化硅波导130沿垂直于所述光信号的输入方向 上的横截面也可以为梯形(所述梯形靠近所述硅层110的下底边长大于远离所述硅层110的上底边长)。
所述氮化硅波导130围绕所述锗层120的部分与所述锗层120之间的距离为50nm-1000nm。
所述氮化硅波导130的延伸方向平行于所述硅层110与所述锗层120的接触平面，所述氮化硅波导130与所述硅层110之间的距离为100nm-1200nm。
所述锗层120在第一方向上的长度为5μm-100μm。也就是说，耦合区的长度为5μm-100μm。通过控制所述锗层120在第一方向上的长度，既可以控制耦合区的长度。
需要说明的是，本申请实施例提供的所述光电探测器的优选尺寸为：所述氮化硅波导130沿垂直于所述光信号的输入方向上的横截面(如图1所示的横截面)的长度为800nm，宽度为300nm；所述锗层120沿垂直于所述光信号的输入方向上的横截面(如图1所示的横截面)的长度为3μm，宽度为500nm；所述锗层120在第一方向上的长度(即耦合区的长度)为12μm；所述氮化硅波导130与所述硅层110之间的距离为150nm；所述第一波导区131与所述锗层120之间的距离为100nm；所述第二波导区132与所述锗层120之间的距离为80nm。
如图1和图2所示，所述硅层110包括第一掺杂类型掺杂区111；所述锗层120包括第二掺杂类型的掺杂区121；所述第一掺杂类型的掺杂区111和所述第二掺杂类型的掺杂区121上分别设有第一金属电极112和第二金属电极122；所述第一掺杂类型为P型，所述第二掺杂类型为N型，以形成PIN结构的光电探测器；或者，所述第一掺杂类型为N型，所述第二掺杂类型为P型，以形成NIP结构的光电探测器。
在本申请实施例中，所述硅层110的上表面形成有第一掺杂类型的掺 杂区111；需要说明的是，所述硅层110的上表面形成的第一掺杂类型的掺杂区111可以为一个或多个，图1和图2仅示例出了所述硅层110上形成有两个第一掺杂类型的掺杂区111的情况。两个所述第一掺杂类型的掺杂区111上分别设有第一金属电极112。所述锗层120的上表面形成有第二掺杂类型的掺杂区121；所述第二掺杂类型的掺杂区上设有第二金属电极122。所述第一掺杂类型可以为P型或N型，所述第一掺杂类型为P型时，则所述第二掺杂类型为N型，以形成PIN结构的光电探测器；所述第一掺杂类型为N型时，则所述第二掺杂类型为P型，以形成NIP结构的光电探测器。需要说明是，所述硅层110和所述锗层120之间未被掺杂的区域作为PIN结构或NIP结构中的本征体。
在本申请实施例中，所述硅层110还可以为掺杂硅层，在所述第一掺杂类型为P型时，所述硅层110可以为整体P型掺杂硅层，但所述掺杂区的掺杂浓度大于所述硅层110的整体掺杂浓度；在所述第一掺杂类型为N型时，所述硅层110可以为整体N型掺杂硅层，但所述掺杂区的掺杂浓度大于所述硅层110的整体掺杂浓度。可以理解地，由于采用氮化硅波导传输光信号，避免了以掺杂的硅层作为波导的情况下对光信号传输造成的不利影响，从而有效地降低了光信号的传输损耗。
在本申请实施例中，通过在所述硅层110上的第一金属电极112和所述锗层120上的第二金属电极122之间施加外加电压以形成外加电场，抽取所述锗层120内产生的载流子，且外加电场的电场方向与所述锗层120内形成的内建电场的电场方向相同，从而所述外加电场可以加快载流子的移动速度，从而提高光电探测器的响应度。需要说明的是，在所述硅层110上设置有两个第一金属电极112的情况下，第一金属电极112可以分别与第二金属电极122连接形成外加电场。也就是说，在所述硅层110上设置有两个第一金属电极112的情况下，第一金属电极112与第二金属电极122 之间可以形成两个外加电场。
在本申请实施例中，如图2所示，所述金属电极(112和122)沿所述第一方向上的长度小于所述锗层120的在第一方向的长度。所述金属电极(112和122)的上表面裸露于光电探测器的上表面。
在本申请实施例中，本申请实施例中还可以通过改变所述锗层120和所述硅层110的掺杂区结构，以实现雪崩增益探测(APD)。具体实现方式包括：在所述锗层120上增加一个雪崩区，或者在形成的NIP结构或PIN结构上施加一个大于6V的反偏电压以实现雪崩增益探测。
本申请实施例提供了一种光电探测器，包括：硅层，所述硅层包括第一掺杂类型的掺杂区；与所述硅层接触的锗层，所述锗层包括第二掺杂类型的掺杂区；氮化硅波导，所述氮化硅波导沿所述锗层的至少三个侧壁的延伸方向围绕所述锗层设置；其中，所述氮化硅波导用于传输光信号，并将所述光信号耦合至所述锗层，所述锗层用于探测所述光信号，并将所述光信号转换为电信号。所述氮化硅波导的折射率和所述锗层的折射率的差较大，且氮化硅波导围绕锗层设置，如此既能够保证光信号从氮化硅波导到锗层的高耦合效率，又能够使得光信号均匀分布在锗层中，从而能够避免锗层局部光场较强造成的光生载流子堆积形成的探测器过早饱和现象；可以理解的是，耦合效率越高，耦合进入锗层中的光子数就越多，这样仅需要较短的耦合区长度就可以实现高响应速度。
在本申请的另一实施例中，图3为本申请实施例提供的光电探测器的另一种实施方式的侧面剖视图，图4为本申请实施例提供的光电探测器的另一种实施方式的俯视图，需要说明的是，图3为沿图4中虚线方向的侧面剖视图，如图3和图4所示，本申请实施例提供的光电探测器，包括：
硅层210，所述硅层210包括第一掺杂类型的掺杂区211；
与所述硅层210接触的锗层220，所述锗层220包括第二掺杂类型的掺 杂区221；
氮化硅波导230，所述氮化硅波导230包括第一波导区231和第二波导区232，所述锗层220设置在所述第一波导区231和所述第二波导区232之间；
与所述氮化硅波导230连接的分光波导240，所述分光波导240用于将接收的光信号分为至少两路光信号，并将其中两路光信号分别输出至所述第一波导区231和所述第二波导区232；
其中，所述氮化硅波导230用于传输光信号，并将所述光信号耦合至所述锗层220，所述锗层220用于探测所述光信号，并将所述光信号转换为电信号。
所述分光波导240和所述氮化硅波导230的材料相同。
需要说明的是，本申请实施例以所述分光波导240将接收的光信号分为两路光信号为例进行说明。
在本申请实施例中，所述分光波导240可以为氮化硅分光波导。如图3所示，所述分光波导240为矩形，需要说明的是，所述分光波导240可以为任意能够将接收的光信号分为至少两路光信号的分光波导，本申请不对其形状进行限定。
在本申请实施例中，所述光电探测器还包括底层衬底250，所述底层衬底250例如为底层硅材料；在所述底层衬底250上具有埋氧层(图中未示出)；所述硅层210形成在所述埋氧层上。所述锗层220形成在所述硅层210上，所述锗层220设置在所述第一波导区231和所述第二波导区232之间，且所述氮化硅波导230与所述锗层220之间具有二氧化硅材料，所述氮化硅波导230与所述硅层210之间具有二氧化硅材料。如图3所示，所述二氧化硅材料260覆盖所述硅层210和所述锗层220，所述氮化硅波导230设置在所述二氧化硅材料260中，并与所述硅层210和所述锗层220各间隔 一定距离，所述二氧化硅材料用于支撑和固定所述氮化硅波导230，且所述二氧化硅材料具有较低的折射率，从而可以对传输的光信号进行光约束。
在本申请实施例中，所述氮化硅波导230的折射率和所述锗层220的折射率的差较大，且氮化硅波导230围绕锗层220设置，如此既能够保证光信号从氮化硅波导230到锗层220的高耦合效率，又能够使得光信号均匀分布在锗层220中，从而能够避免锗层220局部光场较强造成的光生载流子堆积形成的探测器过早饱和现象；可以理解的是，耦合效率越高，耦合进入锗层220中的光子数就越多，这样仅需要较短的耦合区长度就可以实现高响应速度。需要说明的是，耦合区长度等于所述锗层220的长度。
在本申请实施例中，通过设置分光波导240对输入的光信号进行分光，并将分光后的光信号分别输出至第一波导区231和第二波导区232，而锗层220设置在第一波导区231和第二波导区232之间，从而氮化硅波导230中的光信号可以与锗层220进行至少两次耦合，如此，在不增加探测器的耦合区长度(即锗层220长度)的情况下，即可提高探测器的响应度。
在本申请实施例中，所述氮化硅光波导230不仅用于实现光信号的传播与变向，且与所述锗层220发生耦合作用，从而形成内建电场，产生载流子。
在本申请实施例中，使用低非线性氮化硅材料作为传输光波导，氮化硅波导不会出现双光子吸收效应，且氮化硅波导支持高光功率密度、大光学带宽的低损耗光传输。
所述锗层220的侧壁在硅层210上的投影具有第一形状，所述第一形状在第一方向上的长度大于在第二方向上的长度；
所述第一波导区231和所述第二波导区232分别在所述锗层220的第一侧壁和第二侧壁的外侧围绕所述锗层220，所述第一侧壁和所述第二侧壁分别为所述锗层220的平行于第一方向的彼此相对的两侧壁。
在本申请实施例中，所述锗层220的侧壁在硅层210上的投影具有第一形状，如图4所示，图中虚线方向为所述第二方向，与虚线方向垂直的方向为所述第一方向。在图4所示实施例中，该第一形状可以为矩形，所述矩形具有沿所述第一方向延伸的长边和沿所述第二方向延伸的短边；其中，所述第一形状在第一方向上的长度为矩形长边的长度，所述第一形状在第二方向上的长度为矩形短边的长度。结合图4可以理解的是，耦合区长度即为所述第一形状在第一方向上的长度。
需要说明的是，如图3所示，所述锗层220的第一侧壁和第二侧壁即为所述锗层220(沿第一方向上)的左侧壁和右侧壁。
所述氮化硅波导230还包括第三波导区233，所述第三波导区233在第二方向上连接所述第一波导区231和所述第二波导区232；
从所述分光波导240输出至所述第一波导区231的光信号沿所述第三波导区233传输至所述第二波导区232，从所述分光波导240输出至所述第二波导区232的光信号沿所述第三波导区233传输至所述第一波导区231。
需要说明的是，所述第三波导区233连接所述第一波导区231和所述第二波导区232仅为本申请实施例中提供的一种连接方式，本申请实施例中不限于所述第一波导区231和所述第二波导区232通过所述第三波导区233连接的情况，所述第一波导区231和所述第二波导区232之间也可以不进行连接。
在本申请实施例中，所述第一波导区231和所述第二波导区232均可以为光输入波导区，从所述分光波导240输出的光信号可以沿第一波导区231至第三波导区233至所述第二波导区232的方向传输，同时从所述分光波导240输出的光信号还可以沿第二波导区232至第三波导区233至所述第一波导区231的方向传输，也就是说，本申请实施例中所述氮化硅波导230中至少具有两路光信号沿相反方向传输。可以理解的是，每路光信号可 以经由所述第一波导区231和所述第二波导区232与锗层220进行至少两次耦合。从而能够在不增加所述锗层220的长度的情况下，提高光电探测器的响应度，同时也不会降低光电探测器3dB光电带宽。
所述氮化硅波导230和所述分光波导240沿所述光信号的传输方向围成一封闭区域，所述锗层220位于所述封闭区域内。
在本申请实施例中，如图4所示，所述分光波导240和所述第三波导区233分别位于所述锗层220的第三侧壁和第四侧壁，所述第三侧壁和所述第四侧壁分别为所述锗层220的平行于第二方向的彼此相对的两侧壁。所述锗层220的第三侧壁和第四侧壁即为所述锗层220(沿第二方向上)的左侧壁和右侧壁，也就是说，所述分光波导240和所述第三波导区233分别位于所述锗层220(沿第二方向上)的左侧和右侧。
需要说明的是，所述分光波导240不限于位于与所述第三波导区233相对的一侧，所述分光波导240的位置可以根据实际需要而进行调整。且本申请实施例中所述分光波导240还可以将接收的光信号分光为两路以上的光信号，例如，所述分光波导240将接收的光信号分为三路光信号，将其中两路光信号分别输出至所述第一波导区231和所述第二波导区232后，所述分光波导240还可以将剩余的一路光信号输出至另外的波导区，如位于所述锗层220上方的波导区(图中并未示出)。
在本申请实施例中，如图3所示，所述分光波导240与所述第一波导区231和所述第二波导区232连接，从而所述分光波导240与所述第一波导区231、所述第二波导区232和所述第三波导区233沿所述光信号的传输方向围成一封闭区域，而所述锗层220位于该封闭区域内。
所述第一波导区231和所述第二波导区232为直波导区；
所述第三波导区233为弯曲波导区。
在本申请实施例中，如图4所示，所述第一波导区231和所述第二波 导区232分别位于所述锗层220的第一侧壁和第二侧壁的外侧，也就是说，所述第一波导区231和所述第二波导区232分别位于所述锗层220(沿第一方向上)的左侧和右侧。
在本申请实施例中，所述第三波导区233用于将所述第一波导区231的光信号转折180°后传输至所述第二波导区232，以及将所述第二波导区232的光信号转折180°后传输至所述第一波导区231。
所述氮化硅波导230沿垂直于所述光信号的传输方向上的横截面的面积为0.06μm 2-0.5μm 2。
需要说明的是，所述氮化硅波导230沿垂直于所述光信号的传输方向上的横截面可以为矩形或梯形。本申请实施例中以所述氮化硅波导230沿垂直于所述光信号的传输方向上的横截面为矩形为例进行说明。在实际应用时，所述氮化硅波导230沿垂直于所述光信号的传输方向上的横截面也可以为梯形(所述梯形靠近所述硅层210的下底边长大于远离所述硅层210的上底边长)。
所述第一波导区231和所述第二波导区232与所述锗层220之间的距离为50nm-1000nm。
所述氮化硅波导230的延伸方向平行于所述硅层210与所述锗层220的接触平面，所述氮化硅波导230与所述硅层210之间的距离为100nm-1200nm。
所述锗层220在第一方向上的长度为5μm-100μm。也就是说，耦合区的长度为5μm-100μm。通过控制所述锗层220在第一方向上的长度，既可以控制耦合区的长度。
需要说明的是，本申请实施例提供的所述光电探测器的优选尺寸为：所述氮化硅波导230沿垂直于所述光信号的输入方向上的横截面(如图3所示的横截面)的长度为800nm，宽度为300nm；所述锗层220沿垂直于 所述光信号的输入方向上的横截面(如图3所示的横截面)的长度为3μm，宽度为500nm；所述锗层220在第一方向上的长度(即耦合区的长度)为12μm；所述氮化硅波导230与所述硅层210之间的距离为150nm；所述第一波导区231与所述锗层220之间的距离为100nm；所述第二波导区232与所述锗层220之间的距离为100nm。
在本申请实施例中，如图4所示，所述分光波导240的另一端还可以连接有光输入波导241，所述光输入波导241用于接收光信号，并将所述光信号传输至所述分光波导240。
如图3和图4所示，所述硅层210包括第一掺杂类型掺杂区211；所述锗层220包括第二掺杂类型的掺杂区221；所述第一掺杂类型的掺杂区211和所述第二掺杂类型的掺杂区221上分别设有第一金属电极212和第二金属电极222；所述第一掺杂类型为P型，所述第二掺杂类型为N型，以形成PIN结构的光电探测器；或者，所述第一掺杂类型为N型，所述第二掺杂类型为P型，以形成NIP结构的光电探测器。
在本申请实施例中，所述硅层210的上表面形成有第一掺杂类型的掺杂区211；需要说明的是，所述硅层210的上表面形成的第一掺杂类型的掺杂区211可以为一个或多个，图3和图4仅示例出了所述硅层210上形成有两个第一掺杂类型的掺杂区211的情况。两个所述第一掺杂类型的掺杂区211上分别设有第一金属电极212。所述锗层220的上表面形成有第二掺杂类型的掺杂区121；所述第二掺杂类型的掺杂区上设有第二金属电极222。所述第一掺杂类型可以为P型或N型，所述第一掺杂类型为P型时，则所述第二掺杂类型为N型，以形成PIN结构的光电探测器；所述第一掺杂类型为N型时，则所述第二掺杂类型为P型，以形成NIP结构的光电探测器。需要说明是，所述硅层210和所述锗层220之间未被掺杂的区域作为PIN结构或NIP结构中的本征体。
在本申请实施例中，所述硅层210还可以为掺杂硅层，在所述第一掺杂类型为P型时，所述硅层210可以为整体P型掺杂硅层，但所述掺杂区的掺杂浓度大于所述硅层210的整体掺杂浓度；在所述第一掺杂类型为N型时，所述硅层210可以为整体N型掺杂硅层，但所述掺杂区的掺杂浓度大于所述硅层210的整体掺杂浓度。可以理解地，由于采用氮化硅波导传输光信号，避免了以掺杂的硅层作为波导的情况下对光信号传输造成的不利影响，从而有效地降低了光信号的传输损耗。
在本申请实施例中，通过在所述硅层210上的第一金属电极212和所述锗层220上的第二金属电极222之间施加外加电压以形成外加电场，抽取所述锗层220内产生的载流子，且外加电场的电场方向与所述锗层220内形成的内建电场的电场方向相同，从而所述外加电场可以加快载流子的移动速度，从而提高光电探测器的响应度。需要说明的是，在所述硅层210上设置有两个第一金属电极212的情况下，第一金属电极212可以分别与第二金属电极222连接形成外加电场。也就是说，在所述硅层210上设置有两个第一金属电极212的情况下，第一金属电极212与第二金属电极222之间可以形成两个外加电场。
在本申请实施例中，如图3所示，所述金属电极(212和222)沿所述第一方向上的长度小于所述锗层220的在第一方向的长度。所述金属电极的上表面裸露于光电探测器的上表面。
在本申请实施例中，本申请实施例中还可以通过改变所述锗层220和所述硅层210的掺杂区结构，以实现雪崩增益探测(APD)。具体实现方式包括：在所述锗层220上增加一个雪崩区，或者在形成的NIP结构或PIN结构上施加一个大于6V的反偏电压以实现雪崩增益探测。
在本申请的另一实施例中，图5为本申请实施例提供的光电探测器的另一种实施方式的侧面剖视图，如图5所示，所述锗层220的上表面形成 有一个第二掺杂类型的掺杂区221和一个第一掺杂类型的掺杂区223，所述第二掺杂类型的掺杂区221上设有第二金属电极222；所述第一掺杂类型的掺杂区223上设有第三金属电极224。所述第一掺杂类型和所述第二掺杂类型为不同的掺杂类型。所述锗层220上的第二掺杂类型的掺杂区221和第一掺杂类型的掺杂区223之间可以形成侧向内建电场(由第二掺杂类型的掺杂区221指向第一掺杂类型的掺杂区223的方向或由第一掺杂类型的掺杂区223指向第二掺杂类型的掺杂区221的方向)，产生载流子。
在本申请的另一实施例中，图6为本申请实施例提供的光电探测器的另一种实施方式的侧面剖视图，图7为本申请实施例提供的光电探测器的另一种实施方式的俯视图，需要说明的是，图6为沿图7中虚线方向的侧面剖视图。还需要说明的是，为了示意出第一层波导和第二层波导的上下层位置关系，图7虚线框内的结构未采用填充的形式，应将图7虚线框内结构的材料理解为和其他结构的材料相同；此外，为了更加清晰地示出波导结构，图7虚线框内结构与虚线框外结构的比例尺可能不同(例如，虚线框内结构在图中横向方向进行了放大)，因此，图中结构尺寸或比例大小不应理解为对本申请中对应特征的限制。其中，L1表示第一层波导，L2表示第二层波导。L1和L2仅用于示意第一层波导和第二层波导，不用于限制本申请第一层波导和第二层波导的形状和长度。
如图6和图7所示，本申请实施例提供的光电探测器，包括：
硅层310，所述硅层310包括第一掺杂类型的掺杂区311；
与所述硅层310接触的锗层320，所述锗层320包括第二掺杂类型的掺杂区321；
氮化硅波导，所述氮化硅波导包括第一层波导330和第二层波导340；第一层波导330，所述第一层波导330包括设置在所述锗层320上方的第四波导区331；第二层波导340，所述第二层波导340包括设置在所述锗层320 侧面的第一波导区3411、第二波导区3412和第三波导区3413；
其中，所述第一层波导330和所述第二层波导340用于传输光信号，所述第一层波导330和所述第二层波导340分别通过所述第四波导区331、第一波导区3411、第二波导区3412和第三波导区3413将所述光信号耦合至所述锗层320；所述锗层320用于探测所述光信号，并将所述光信号转换为电信号。
在本申请实施例中，所述光电探测器还包括底层衬底350，所述底层衬底350例如为底层硅材料；在所述底层衬底350上具有埋氧层(图中未示出)；所述硅层310形成在所述埋氧层上。所述锗层320形成在所述硅层310上，所述第四波导区331设置在所述锗层320的上方，所述第一波导区3411、第二波导区3412和第三波导区3413沿所述锗层320的至少三个侧壁的延伸方向围绕所述锗层320设置，且所述第四波导区331、所述第一波导区3411、第二波导区3412和第三波导区3413与所述锗层320之间具有二氧化硅材料，所述第四波导区331、所述第一波导区3411、第二波导区3412和第三波导区3412与所述硅层310之间具有二氧化硅材料。如图6所示，所述二氧化硅材料360覆盖所述硅层310和所述锗层320，所述第四波导区331、所述第一波导区3411、第二波导区3412和第三波导区3413设置在所述二氧化硅材料360中，并与所述硅层310和所述锗层320各间隔一定距离，所述二氧化硅材料用于支撑和固定所述第四波导区331、所述第一波导区3411、第二波导区3412和第三波导区3413，且所述二氧化硅材料具有较低的折射率，从而可以对传输的光信号进行光约束。
在本申请实施例中，通过设置所述第一层波导330和所述第二层波导340，所述第四波导区331位于锗层320上方，所述第一波导区3411、第二波导区3412和第三波导区3413围绕锗层的侧面而设置，从而光信号可以与锗层320的多个面进行耦合，如此，被探测的光信号可以通过多条耦合 路径传递至耦合区，降低了每条耦合路径内的光功率密度，既能够保证光信号从波导到锗层320的高耦合效率，又能够使得光信号均匀分布在锗层320中，从而能够避免锗层320局部光场较强造成的光生载流子堆积形成的探测器过早饱和现象；可以理解的是，耦合效率越高，耦合进入锗层320中的光子数就越多，这样仅需要较短的耦合区就可以实现高响应速度，因此无需增加探测器的耦合区的长度，既避免了器件尺寸过大，又抑制了传输损耗。需要说明的是，耦合区长度等于所述锗层320的长度。
在本申请实施例中，所述第四波导区331、所述第一波导区3411、第二波导区3412和第三波导区3413不仅用于实现光信号的传播与变向，且与所述锗层320发生耦合作用，从而形成内建电场，产生载流子。
在一个可选实施例中，所述第一层波导330和所述第二层波导340之间通过层间耦合实现光信号传递；具体地，
所述第一层波导330还可以包括与所述第四波导区331连接的第一层间耦合区332；
所述第二层波导340还可以包括与所述第一波导区3411和第二波导区3412连接的第二层间耦合区342；
所述第一层波导330和所述第二层波导340之间通过所述第一层间耦合区332和所述第二层间耦合区342的层间耦合实现光信号传递；所述第一层间耦合区332和所述第二层间耦合区342的光信号分别传输至所述第四波导区331、第一波导区3411、第二波导区3412和第三波导区3413。
可以理解地，由于所述第一层波导330和所述第二层波导340之间通过层间耦合将接收到的(即需要被探测的)光信号进行了上、下层分光，如此，在被探测的光信号的总量不变的情况下，每层波导内传输的光功率密度得到了降低，从而在第四波导区331、第一波导区3411、第二波导区3412和第三波导区3413的位置处可以更有效地将光信号耦合至所述锗层 320。
所述第一层波导330和所述第二层波导340中的一个波导用于从所述光电探测器外部接收光信号，然后通过层间耦合将光信号传递给另一波导。
在一个可选实施例中，所述第一层波导330用于接收光信号，并在所述第一层间耦合区332将接收的光信号通过层间耦合传递至所述第二层波导340的所述第二层间耦合区342。
在本实施例中，如图7所示，光信号进入所述第一层波导330后，所述光信号经由所述第一层间耦合区332耦合进入所述第二层波导340的所述第二层间耦合区342，所述第一层间耦合区332经层间耦合后剩余的光信号传输至所述第四波导区331，所述第二层间耦合区342经层间耦合后得到的光信号传输至所述第一波导区3411和第二波导区3412。
在一个可选实施例中，沿光信号的传输方向上，所述第一层间耦合区332的横截面积变小，所述第二层间耦合区342的横截面积变大。
在本实施例中，如图7所示，所述第一层间耦合区332和所述第二层间耦合区342例如为倒锥形波导，所述第一层间耦合区332(沿垂直于光信号传输方向上)的横截面积沿光信号传输方向变小；所述第二层间耦合区342(沿垂直于光信号传输方向上)的横截面积沿光信号传输方向变大。光信号进入所述第一层间耦合区332后，光信号的模场随着所述第一层间耦合区332横截面积的变小而逐渐变大，弥散的模场分布更利于层间的光耦合，在所述第一层间耦合区332的窄端(可以视为所述第一层间耦合区332横截面积最小处)，光信号从所述第一层间耦合区332耦合进入所述第二层间耦合区342；由于所述第一层间耦合区332的窄端对应的位置上所述第二层间耦合区342的横截面积较大，则所述第一层间耦合区332的光信号耦合进入所述第二层间耦合区342时，耦合效率较高，且耦合损耗较低。
所述第一层间耦合区332和所述第二层间耦合区342在所述硅层310 上的正投影至少部分重合。
在本申请实施例中，如图7所示，倒锥形的所述第一层间耦合区332和倒锥形的所述第二层间耦合区342部分重合，在实际应用时，可以通过调整所述第一层间耦合区332和所述第二层间耦合区342之间的层间耦合区长度W来调整所述第一层间耦合区332和所述第二层间耦合区342之间的耦合比例，例如，W越大，所述第一层间耦合区332和所述第二层间耦合区342之间的耦合比例越大，也就是说，耦合进入所述第二层间耦合区342中的光信号越多，所述第一层间耦合区332中剩余的光信号越少。因此，可以根据实际的耦合比例需求而对W进行调整。
所述第二层波导340还包括位于所述第二层间耦合区341及所述第一波导区3411和所述第二波导区3412之间的分光波导区343，所述分光波导区343用于将从所述第二层间耦合区342传输过来的光信号分为至少两路，并将其中两路光信号分别输出至所述第一波导区3411和所述第二波导区3412。
在本申请实施例中，所述锗层320的侧壁在硅层310上的投影具有第一形状，所述第一形状在第一方向上的长度大于在第二方向上的长度；所述第一波导区3411和所述第二波导区3412分别在所述锗层320的第一侧壁和第二侧壁的外侧围绕所述锗层320，所述第一侧壁和所述第二侧壁分别为所述锗层320的平行于第一方向的彼此相对的两侧壁。在本申请实施例中，所述锗层320的侧壁在硅层310上的投影具有第一形状，如图7所示，图中虚线方向为所述第二方向，与虚线方向垂直的方向为所述第一方向。在图7所示实施例中，该第一形状可以为矩形，所述矩形具有沿所述第一方向延伸的长边和沿所述第二方向延伸的短边；其中，所述第一形状在第一方向上的长度为矩形长边的长度，所述第一形状在第二方向上的长度为矩形短边的长度。结合图7可以理解的是，耦合区长度即为所述第一形状 在第一方向上的长度。
需要说明的是，如图6所示，所述锗层320的第一侧壁和第二侧壁即为所述锗层320(沿第一方向上)的左侧壁和右侧壁。
在本申请实施例中，所述第三波导区3413在第二方向上连接所述第一波导区3411和所述第二波导区3412；从所述分光波导区343输出至所述第一波导区3411的光信号沿所述第三波导区3413传输至所述第二波导区3412，从所述分光波导区343输出至所述第二波导区3412的光信号沿所述第三波导区3413传输至所述第一波导区3411。
需要说明的是，所述第三波导区3413连接所述第一波导区3411和所述第二波导区3412仅为本申请实施例中提供的一种连接方式，本申请实施例中不限于所述第一波导区3411和所述第二波导区3412通过所述第三波导区3413连接的情况，所述第一波导区3411和所述第二波导区3412之间也可以不进行连接。
在本申请实施例中，所述第二层波导340的所述第一波导区3411、第二波导区3412和第三波导区3413在所述锗层320的侧面围绕所述锗层320的侧壁而设置。
在本申请实施例中，所述第一波导区3411和所述第二波导区3412均可以为光输入波导区，从所述分光波导区343输出的光信号可以沿第一波导区3411至第三波导区3413至所述第二波导区3412的方向传输，同时从所述分光波导区343输出的光信号还可以沿第二波导区3412至第三波导区3413至所述第一波导区3411的方向传输，也就是说，本申请实施例中所述第一波导区、第二波导区和第三波导区中至少具有两路光信号沿相反方向传输。可以理解的是，每路光信号可以经由所述第一波导区3411和所述第二波导区3412与锗层320进行至少两次耦合。从而能够在不增加所述锗层320的长度的情况下，提高光电探测器的响应度，同时也不会降低光电探测 器3dB光电带宽。
在本申请实施例中，如图7所示，所述分光波导区343和所述第三波导区3413分别位于所述锗层320的第三侧壁和第四侧壁，所述第三侧壁和所述第四侧壁分别为所述锗层320的平行于第二方向的彼此相对的两侧壁。所述锗层320的第三侧壁和第四侧壁即为所述锗层320(沿第二方向上)的左侧壁和右侧壁，也就是说，所述分光波导区343和所述第三波导区3413分别位于所述锗层320(沿第二方向上)的左侧和右侧。如图7所示，所述第一波导区、第二波导区和第三波导区和所述分光波导区343沿所述光信号的传输方向围成一封闭区域，所述锗层320位于所述封闭区域内。
需要说明的是，所述分光波导区343不限于位于与所述第三波导区3413相对的一侧，所述分光波导区343的位置可以根据实际需要而进行调整。
本申请实施例中所述分光波导区343还可以将接收的光信号分光为两路以上的光信号，例如，所述分光波导区343将接收的光信号分为三路光信号，将其中两路光信号分别输出至所述第一波导区3411和所述第二波导区3412后，所述分光波导区343还可以将剩余的一路光信号输出至另外的波导区，如位于所述锗层320在第二方向上的侧壁侧的波导区(图中并未示出)。
如图7所示，所述第一层波导330还包括位于所述第一层间耦合区332和所述第四波导区331之间的隔离波导区333；所述隔离波导区333和所述分光波导区343在所述硅层310上的正投影彼此错开，以使所述第一层波导330上的光信号在传输至与所述分光波导区343对应的位置处不发生与所述第二层波导340之间的层间耦合。
在本申请实施例中，在所述第一层波导330和所述第二层波导340之间的层间耦合完毕后，所述第一层波导330中的光信号沿所述隔离波导区333传输至所述第四波导区331，由此与第二层波导340的所述分光波导区 343错开，以避免所述第二层波导340对所述分光波导区343产生干扰。
所述第一层间耦合区332和所述第二层间耦合区342之间的距离H为50nm-1500nm。
所述第一层波导330的所述第四波导区331的延伸方向平行于所述硅层310与所述锗层320的接触平面，所述第四波导区331与所述锗层320上表面之间的距离为60nm-1000nm。所述第一波导区、第二波导区和第三波导区与所述硅层310之间的距离为100nm-1200nm。
所述第二层波导340的所述第一波导区、第二波导区和第三波导区与所述锗层320侧壁之间的距离为50nm-1000nm。
所述第四波导区、所述第一波导区、第二波导区和第三波导区沿垂直于所述光信号的传输方向上的横截面的面积为0.06μm 2-0.5μm 2。
需要说明的是，所述第四波导区、所述第一波导区、第二波导区和第三波导区沿垂直于所述光信号的传输方向上的横截面可以为矩形或梯形。本申请实施例中以所述第四波导区、所述第一波导区、第二波导区和第三波导区沿垂直于所述光信号的传输方向上的横截面为矩形为例进行说明。在实际应用时，所述第四波导区、所述第一波导区、第二波导区和第三波导区沿垂直于所述光信号的传输方向上的横截面也可以为梯形(所述梯形靠近所述硅层310的下底边长大于远离所述硅层310的上底边长)。
还需要说明的是，所述锗层320沿垂直于所述光信号的传输方向上的横截面可以为矩形或梯形。本申请实施例中以所述锗层320沿垂直于所述光信号的传输方向上的横截面为梯形为例进行说明。在实际应用时，在形成所述锗层320时，所述锗层320的目标形状(沿垂直于所述光信号的传输方向上的横截面)为矩形，但是由于工艺的影响，最终形成的锗层320的实际形状(沿垂直于所述光信号的传输方向上的横截面)可能为梯形，所述梯形靠近所述硅层310的下底边长大于远离所述硅层310的上底边长。
所述锗层320在第一方向上的长度为5μm-100μm。通过控制所述锗层320在第一方向上的长度，可以控制耦合区的长度。
需要说明的是，本申请实施例提供的所述光电探测器的优选尺寸为：所述第四波导区、所述第一波导区、第二波导区和第三波导区沿垂直于所述光信号的输入方向上的横截面(如图6所示的横截面)的长度为800nm，宽度为300nm；所述锗层320沿垂直于所述光信号的输入方向上的横截面(如图6所示的横截面)的长度为3μm，宽度为500nm；所述锗层320在第一方向上的长度(即耦合区的长度)为12μm；所述第一波导区、第二波导区和第三波导区与所述硅层310之间的距离为150nm；所述第一波导区3411与所述锗层320之间的距离为100nm；所述第二波导区3412与所述锗层320之间的距离为100nm；所述第四波导区331与所述锗层320上表面之间的距离为100nm。
所述硅层310包括第一掺杂类型掺杂区311；所述锗层320包括第二掺杂类型的掺杂区321；所述第一掺杂类型的掺杂区311和所述第二掺杂类型的掺杂区321上分别设有第一金属电极312和第二金属电极322；所述第一掺杂类型为P型，所述第二掺杂类型为N型，以形成PIN结构的光电探测器；或者，所述第一掺杂类型为N型，所述第二掺杂类型为P型，以形成NIP结构的光电探测器。
在本申请实施例中，如图6和图7所示，所述硅层310的上表面形成有第一掺杂类型的掺杂区311，所述锗层320的上表面形成的第二掺杂类型的掺杂区321；需要说明的是，所述硅层310的上表面还可以形成有第二掺杂类型的掺杂区313，所述锗层320的上表面还可以形成有第一掺杂类型的掺杂区323。图6至图7仅示例出了所述硅层310上形成有一个第一掺杂类型的掺杂区311和一个第二掺杂类型的掺杂区313，以及所述锗层320上形成有一个第二掺杂类型的掺杂区321和一个第一掺杂类型的掺杂区323的 情况。所述硅层310上的所述第一掺杂类型的掺杂区311上设有第一金属电极312，所述硅层310上的所述第二掺杂类型的掺杂区313上设有第三金属电极314；所述锗层320上的所述第二掺杂类型的掺杂区321上设有第二金属电极322，所述锗层320上的所述第一掺杂类型的掺杂区323上设有第四金属电极324。所述第一掺杂类型可以为P型或N型，所述第一掺杂类型为P型时，则所述第二掺杂类型为N型，以在所述第一掺杂类型的掺杂区311和所述第二掺杂类型的掺杂区321之间形成PIN结构的光电探测器，在所述第二掺杂类型的掺杂区313和所述第一掺杂类型的掺杂区323之间形成NIP结构的光电探测器；所述第一掺杂类型为N型时，则所述第二掺杂类型为P型，以在所述第一掺杂类型的掺杂区311和所述第二掺杂类型的掺杂区321之间形成NIP结构的光电探测器、在所述第二掺杂类型的掺杂区313和所述第一掺杂类型的掺杂区323之间形成PIN结构的光电探测器。需要说明是，所述硅层310和所述锗层320之间未被掺杂的区域作为PIN结构或NIP结构中的本征体。
在本申请实施例中，所述锗层320的上表面形成有一个第二掺杂类型的掺杂区321和一个第一掺杂类型的掺杂区323，所述第一掺杂类型和所述第二掺杂类型为不同的掺杂类型。所述锗层320上的第二掺杂类型的掺杂区321和第一掺杂类型的掺杂区323之间可以形成侧向内建电场(由第二掺杂类型的掺杂区321指向第一掺杂类型的掺杂区323的方向或由第一掺杂类型的掺杂区323指向第二掺杂类型的掺杂区321的方向)，产生载流子。
在本申请实施例中，所述硅层310上仅有一种类型的掺杂区的情况下，所述硅层310还可以为掺杂硅层，在所述第一掺杂类型为P型时，所述硅层310可以为整体P型掺杂硅层，但所述掺杂区的掺杂浓度大于所述硅层310的整体掺杂浓度；在所述第一掺杂类型为N型时，所述硅层310可以为整体N型掺杂硅层，但所述掺杂区的掺杂浓度大于所述硅层310的整体 掺杂浓度。可以理解地，由于采用氮化硅波导传输光信号，避免了以掺杂的硅层作为波导的情况下对光信号传输造成的不利影响，从而有效地降低了光信号的传输损耗。
在本申请实施例中，通过在所述硅层310上的第一金属电极312和所述锗层320上的第二金属电极322之间施加外加电压和/或在所述硅层310上的第三金属电极314和所述锗层320上的第四金属电极324之间施加外加电压以形成外加电场，抽取所述锗层320内产生的载流子，且外加电场的电场方向与所述锗层320内形成的内建电场的电场方向相同，从而所述外加电场可以加快载流子的移动速度，从而提高光电探测器的响应度。
在本申请实施例中，如图7所示，所述金属电极(312、314、322和324)沿所述第一方向上的长度小于所述锗层320的在第一方向的长度。所述金属电极的上表面裸露于光电探测器的上表面。
在本申请实施例中，本申请实施例中还可以通过改变所述锗层320和所述硅层310的掺杂区结构，以实现雪崩增益探测(APD)。具体实现方式包括：在所述锗层320上增加一个雪崩区，或者在形成的NIP结构或PIN结构上施加一个大于6V的反偏电压以实现雪崩增益探测。
本申请还提供了光电探测器的另一实施方式。图8为本申请实施例提供的光电探测器的另一种实施方式的俯视图，需要说明的是，为了示意出第一层波导和第二层波导的上下层位置关系，图8虚线框内的结构未采用填充的形式，应将图8虚线框内结构的材料理解为和其他结构的材料相同；此外，为了更加清晰地示出波导结构，图8虚线框内结构与虚线框外结构的比例尺可能不同(例如，虚线框内结构在图中横向方向进行了放大)，因此，图中结构尺寸或比例大小不应理解为对本申请中对应特征的限制。其中，L1表示第一层波导，L2表示第二层波导。L1和L2仅用于示意第一层波导和第二层波导，不用于限制本申请第一层波导和第二层波导的形状和 长度。
如图8所示，本实施方式中所述第二层波导440也可以不采用分光波导区443进行分光，所述第二层间耦合区442与所述第一波导区4411和所述第二波导区4412可以直接连接，所述第二层间耦合区442将耦合得到的光信号传输至所述第一波导区4411，所述第一波导区4411将光信号经由所述第三波导区4413传输至所述第二波导区4412。所述光信号沿所述第一波导区4411至所述第三波导区4413至所述第二波导区4412的方向传播。本申请实施例中所述第一波导区4411和所述第二波导区4412分别位于所述锗层420的两侧，所述第一波导区4411和所述第二波导区4412通过所述第三波导区4413连接，使得光信号与所述锗层420至少耦合作用两次，从而能够在不增加所述锗层420的长度的情况下，提高光电探测器的响应度，同时也不会降低光电探测器3dB光电带宽。
应理解，说明书通篇中提到的“一个实施例”或“一实施例”意味着与实施例有关的特定特征、结构或特性包括在本申请的至少一个实施例中。因此，在整个说明书各处出现的“在一个实施例中”或“在一实施例中”未必一定指相同的实施例。此外，这些特定的特征、结构或特性可以任意适合的方式结合在一个或多个实施例中。应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。上述本申请实施例序号仅仅为了描述，不代表实施例的优劣。
本申请所提供的几个产品实施例中所揭露的特征，在不冲突的情况下可以任意组合，得到新的产品实施例。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请 的保护范围应以所述权利要求的保护范围为准。

Claims (21)

  1. 一种光电探测器，其中，包括：
    硅层，所述硅层包括第一掺杂类型的掺杂区；
    与所述硅层接触的锗层，所述锗层包括第二掺杂类型的掺杂区；
    氮化硅波导，所述氮化硅波导沿所述锗层的至少三个侧壁的延伸方向围绕所述锗层设置；
    其中，所述氮化硅波导用于传输光信号，并将所述光信号耦合至所述锗层，所述锗层用于探测所述光信号，并将所述光信号转换为电信号。
  2. 根据权利要求1所述的光电探测器，其中，
    所述氮化硅波导包括第一波导区和第二波导区，所述锗层设置在所述第一波导区和所述第二波导区之间。
  3. 根据权利要求2所述的光电探测器，其中，
    所述锗层的侧壁在硅层上的投影具有第一形状，所述第一形状在第一方向上的长度大于在第二方向上的长度；
    所述氮化硅波导还包括：第三波导区；所述第三波导区在第二方向上连接所述第一波导区和所述第二波导区。
  4. 根据权利要求3所述的光电探测器，其中，还包括：
    与所述氮化硅波导连接的分光波导，所述分光波导用于将接收的光信号分为至少两路光信号，并将其中两路光信号分别输出至所述第一波导区和所述第二波导区。
  5. 根据权利要求3所述的光电探测器，其中，
    所述氮化硅波导传输的光信号沿所述第一波导区至所述第三波导区至所述第二波导区的方向传播；
    所述第一波导区与所述锗层之间的距离大于所述第二波导区与所述锗 层之间的距离。
  6. 根据权利要求4所述的光电探测器，其中，
    所述氮化硅波导和所述分光波导沿所述光信号的传输方向围成一封闭区域，所述锗层位于所述封闭区域内。
  7. 根据权利要求1所述的光电探测器，其中，
    所述氮化硅波导包括第一层波导和第二层波导；所述第一层波导包括设置在所述锗层上方的第四波导区，所述第二层波导包括设置在所述锗层侧面的第一波导区、第二波导区和第三波导区；
    所述第一层波导和所述第二层波导分别通过所述第四波导区和所述第一波导区、第二波导区、第三波导区将所述光信号耦合至所述锗层。
  8. 根据权利要求7所述的光电探测器，其中，
    所述第一层波导还包括与所述第四波导区连接的第一层间耦合区；
    所述第二层波导还包括与所述第一波导区和所述第二波导区连接的第二层间耦合区；
    所述第一层波导和所述第二层波导之间通过所述第一层间耦合区和所述第二层间耦合区的层间耦合实现光信号传递；所述第一层间耦合区和所述第二层间耦合区的光信号分别传输至所述第四波导区、所述第一波导区、所述第二波导区和所述第三波导区。
  9. 根据权利要求8所述的光电探测器，其中，
    所述第一层波导用于接收光信号，并在所述第一层间耦合区将接收的光信号通过层间耦合传递至所述第二层波导的所述第二层间耦合区。
  10. 根据权利要求8所述的光电探测器，其中，
    所述第一层间耦合区和所述第二层间耦合区之间的距离为50nm-1500nm。
  11. 根据权利要求8所述的光电探测器，其中，
    沿光信号的传输方向上，所述第一层间耦合区的横截面积变小，所述第二层间耦合区的横截面积变大。
  12. 根据权利要求8所述的光电探测器，其中，
    所述第一层间耦合区和所述第二层间耦合区在所述硅层上的正投影至少部分重合。
  13. 根据权利要求8所述的光电探测器，其中，
    所述第二层波导还包括位于所述第二层间耦合区及所述第一波导区和所述第二波导区之间的分光波导区，所述分光波导区用于将从所述第二层间耦合区传输过来的光信号分为至少两路，并将其中两路光信号分别输出至所述第一波导区和所述第二波导区。
  14. 根据权利要求13所述的光电探测器，其中，
    所述第一层波导还包括位于所述第一层间耦合区和所述第四波导区之间的隔离波导区；所述隔离波导区和所述分光波导区在所述硅层上的正投影彼此错开，以使所述第一层波导上的光信号在传输至与所述分光波导区对应的位置处不发生与所述第二层波导之间的层间耦合。
  15. 根据权利要求8所述的光电探测器，其中，
    所述第一层波导的所述第四波导区的延伸方向平行于所述硅层与所述锗层的接触平面，所述第四波导区与所述锗层上表面之间的距离为60nm-1000nm。
  16. 根据权利要求3或7所述的光电探测器，其中，
    所述第一波导区和所述第二波导区为直波导区；
    所述第三波导区为弯曲波导区。
  17. 根据权利要求2或7所述的光电探测器，其中，
    所述第一波导区和所述第二波导区与所述锗层之间的距离为50nm-1000nm。
  18. 根据权利要求1所述的光电探测器，其中，
    所述氮化硅波导的延伸方向平行于所述硅层与所述锗层的接触平面，所述氮化硅波导与所述硅层之间的距离为100nm-1200nm。
  19. 根据权利要求3所述的光电探测器，其中，
    所述锗层在第一方向上的长度为5μm-100μm。
  20. 根据权利要求1所述的光电探测器，其中，
    所述氮化硅波导与所述锗层之间具有二氧化硅材料；
    所述氮化硅波导与所述硅层之间具有二氧化硅材料。
  21. 根据权利要求1所述的光电探测器，其中，所述第一掺杂类型的掺杂区和所述第二掺杂类型的掺杂区上分别设有第一金属电极和第二金属电极；
    所述第一掺杂类型为P型，所述第二掺杂类型为N型，以形成PIN结构的光电探测器；或者，
    所述第一掺杂类型为N型，所述第二掺杂类型为P型，以形成NIP结构的光电探测器。
PCT/CN2020/134067 2019-12-27 2020-12-04 一种光电探测器 WO2021129356A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP20906646.3A EP4084091B1 (en) 2020-12-04 Photoelectric detector
US17/789,934 US20230042376A1 (en) 2019-12-27 2020-12-04 Photoelectric detector

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
CN201911379861.4 2019-12-27
CN201911379861.4A CN111129168B (zh) 2019-12-27 2019-12-27 一种光电探测器
CN201911382842.7 2019-12-27
CN201911382677.5A CN111129201B (zh) 2019-12-27 2019-12-27 一种光电探测器
CN201911382842.7A CN111129202B (zh) 2019-12-27 2019-12-27 一种光电探测器
CN201911382677.5 2019-12-27

Publications (1)

Publication Number Publication Date
WO2021129356A1 true WO2021129356A1 (zh) 2021-07-01

Family

ID=76573154

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/134067 WO2021129356A1 (zh) 2019-12-27 2020-12-04 一种光电探测器

Country Status (2)

Country Link
US (1) US20230042376A1 (zh)
WO (1) WO2021129356A1 (zh)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150129752A1 (en) * 2011-02-17 2015-05-14 Cornell University Polysilicon photodetector, methods and applications
CN109148619A (zh) * 2018-08-21 2019-01-04 南通赛勒光电科技有限公司 一种氮化硅耦合锗探测器结构及制备方法
US20190386159A1 (en) * 2017-07-28 2019-12-19 Cisco Technology, Inc. Germanium photodetector with extended responsivity
CN111129201A (zh) * 2019-12-27 2020-05-08 武汉光谷信息光电子创新中心有限公司 一种光电探测器
CN111129168A (zh) * 2019-12-27 2020-05-08 武汉光谷信息光电子创新中心有限公司 一种光电探测器
CN111129202A (zh) * 2019-12-27 2020-05-08 武汉光谷信息光电子创新中心有限公司 一种光电探测器

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150129752A1 (en) * 2011-02-17 2015-05-14 Cornell University Polysilicon photodetector, methods and applications
US20190386159A1 (en) * 2017-07-28 2019-12-19 Cisco Technology, Inc. Germanium photodetector with extended responsivity
CN109148619A (zh) * 2018-08-21 2019-01-04 南通赛勒光电科技有限公司 一种氮化硅耦合锗探测器结构及制备方法
CN111129201A (zh) * 2019-12-27 2020-05-08 武汉光谷信息光电子创新中心有限公司 一种光电探测器
CN111129168A (zh) * 2019-12-27 2020-05-08 武汉光谷信息光电子创新中心有限公司 一种光电探测器
CN111129202A (zh) * 2019-12-27 2020-05-08 武汉光谷信息光电子创新中心有限公司 一种光电探测器

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4084091A4 *

Also Published As

Publication number Publication date
EP4084091A4 (en) 2023-06-14
US20230042376A1 (en) 2023-02-09
EP4084091A1 (en) 2022-11-02

Similar Documents

Publication Publication Date Title
CN108474973B (zh) 光电子部件
CN111129168B (zh) 一种光电探测器
US6897498B2 (en) Polycrystalline germanium-based waveguide detector integrated on a thin silicon-on-insulator (SOI) platform
WO2022021741A1 (zh) 一种侧向结构雪崩光电探测器及其制备方法
CN111129201B (zh) 一种光电探测器
WO2017148098A1 (zh) 光波导探测器与光模块
US9978890B1 (en) Germanium multi-directional detector
US9735296B2 (en) Semiconductor light receiving device
JP6318468B2 (ja) 導波路型半導体受光装置及びその製造方法
WO2022041550A1 (zh) 一种雪崩光电探测器及其制备方法
CA2995668C (en) Photodetector using germanium on a silicon substrate
US20220350090A1 (en) Photodetector with resonant waveguide structure
CN103489953A (zh) 一种双步消逝场耦合的雪崩光电探测器
Benedikovic et al. Silicon-germanium avalanche receivers with fJ/bit energy consumption
CN109786497A (zh) 单行载流子光电探测器
CN111129202B (zh) 一种光电探测器
US10067305B2 (en) Temperature control of a component on an optical device
CN101661137B (zh) 制作用于1.55微米通信波段硅波导光电转换器的方法
WO2021129356A1 (zh) 一种光电探测器
JP2020053444A (ja) 半導体受光素子、及び光電融合モジュール
EP4084091B1 (en) Photoelectric detector
TW201543644A (zh) 全集成主被動積體光學於矽基積體電路及其製作方法
CN114335207A (zh) 一种基于双层亚波长光栅的锗硅光电探测器
Li et al. Influence of photonic crystals on the performance parameters of GeSn vertical-structure photodiodes
Li et al. Enhancement of responsivity and speed in waveguide Ge/Si avalanche photodiode with separate vertical Ge absorption, lateral Si charge and multiplication configuration

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20906646

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2020906646

Country of ref document: EP

Effective date: 20220725