WO2023168987A1 - 光电探测结构及光电集成芯片 - Google Patents

光电探测结构及光电集成芯片 Download PDF

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WO2023168987A1
WO2023168987A1 PCT/CN2022/132887 CN2022132887W WO2023168987A1 WO 2023168987 A1 WO2023168987 A1 WO 2023168987A1 CN 2022132887 W CN2022132887 W CN 2022132887W WO 2023168987 A1 WO2023168987 A1 WO 2023168987A1
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main electrode
layer
waveguide
germanium layer
photoelectric detection
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PCT/CN2022/132887
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English (en)
French (fr)
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曾治国
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苏州湃矽科技有限公司
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Publication of WO2023168987A1 publication Critical patent/WO2023168987A1/zh

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    • 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
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components 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
    • H01L27/144—Devices controlled by radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components 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
    • H01L27/144—Devices controlled by radiation
    • H01L27/1443—Devices controlled by radiation with at least one potential jump or surface barrier
    • 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
    • H01L31/0224—Electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—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
    • 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

Definitions

  • This application relates to the field of optical communication technology, and specifically to a photoelectric detection structure and an optoelectronic integrated chip.
  • High-performance photodetector (Photo Detector, PD) is one of the core devices of high-speed optical communication.
  • Waveguide optical receiving devices have great advantages for high integration, especially monitoring photodetectors (monitor PD, MPD). It is used at the transmitting end (TX) and converts the monitored optical signal into an electrical signal and feeds it back to the optical chip (Photonic Integrated Circuit Chip, PIC). Therefore, the responsivity and dark current of the device itself must have good performance so that relatively low light intensity (uW) can be measured. Coupled with long-term use, its reliability issues have brought greater challenges to MPD, such as process stability and device reproducibility.
  • the purpose of this application is to provide a photoelectric detection structure and an optoelectronic integrated chip that can have higher sensitivity and responsiveness.
  • an embodiment of the present application provides a photoelectric detection structure, including a substrate, a waveguide layer provided on the substrate, and a germanium layer provided on the waveguide layer.
  • the waveguide layer It includes a silicon base part and a first doping body and a second doping body disposed in the silicon base part, the first doping body and the second doping body have different doping types, and the third doping body
  • a doping body includes a first main electrode and a plurality of first finger electrodes electrically connected to the first main electrode
  • the second doping body includes a second main electrode and a plurality of first finger electrodes electrically connected to the second main electrode.
  • the first main electrode and the second main electrode are arranged oppositely, and the plurality of first finger-shaped electrodes and the plurality of second finger-shaped electrodes are mutually connected in a comb-tooth shape.
  • the germanium layers are arranged at intervals in a plug-in manner to form a waveguide region; the germanium layer is located on the waveguide region and in contact with the plurality of first finger electrodes and the plurality of second finger electrodes.
  • a light receiving portion is provided on one edge of the germanium layer, and the light receiving portion is used for optical coupling and alignment with an external light conductor to receive light waves.
  • the main extension direction of the germanium layer is the same as the propagation direction of light waves in the waveguide region.
  • the projection of the germanium layer at least partially covers the waveguide area.
  • the projection of the germanium layer does not overlap with the projection of the first main electrode and the second main electrode.
  • the waveguide layer is protruding from a portion of the germanium layer as a light receiving portion, and the light receiving portion is located in the same film layer as the first dopant and the second dopant.
  • the light receiving part further includes a template converter for introducing optical signals.
  • the photodetection structure further includes a first metal contact electrically connected to the first main electrode, and a second metal contact electrically connected to the second main electrode.
  • the electrodes are electrically connected, and the first metal contact and the second metal contact are used to derive the photocurrent generated by the germanium layer.
  • the photodetection structure further includes a passivation layer covering the germanium layer and the waveguide layer.
  • an embodiment of the present application provides an optoelectronic integrated chip as described in any embodiment of the present application.
  • Embodiments of the present application provide a photoelectric detection structure and an optoelectronic integrated chip, aiming to achieve photoelectric conversion by arranging a first dopant and a second dopant in the silicon-based part of the waveguide layer, wherein the first dopant includes A plurality of first finger-shaped electrodes, the second dopant body includes a plurality of second finger-shaped electrodes, and the plurality of first finger-shaped electrodes and the plurality of second finger-shaped electrodes are arranged at intervals in a comb-tooth shape, To form a waveguide region, the germanium layer is located on the waveguide region and is in contact with a plurality of first finger electrodes and a plurality of second finger electrodes to effectively extract the photocurrent flowing into the germanium layer, thereby making the photodetection structure Has high sensitivity and responsiveness.
  • Figure 1 is a schematic plan view of a photoelectric detection structure provided by common technology.
  • Figure 2 is a schematic cross-sectional structural diagram along the A-A’ direction of Figure 1.
  • FIG. 3 is a schematic plan view of a photoelectric detection structure provided by an embodiment of the present application.
  • Figure 4 is a schematic cross-sectional structural diagram along the B-B' direction of Figure 3.
  • FIG. 5 is a schematic structural diagram of the germanium layer in FIG. 3 .
  • FIG. 6 is a schematic plan view of a photodetection structure provided by another embodiment of the present application.
  • first and second in this article are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Thus, features defined as “first” and “second” may explicitly or implicitly include one or more of the described features. In the description of this application, “plurality” means two or more than two, unless otherwise explicitly and specifically limited.
  • connection should be understood in a broad sense.
  • connection or integral connection; it can be mechanical connection, electrical connection or mutual communication; it can be direct connection, or indirect connection through an intermediary, it can be internal connection of two elements or interaction of two elements relation.
  • Figure 1 is a schematic plan view of a photoelectric detection structure provided by common technology.
  • Figure 2 is a schematic cross-sectional structural diagram along the A-A’ direction of Figure 1.
  • a photodetection structure 1000' provided in common technology includes a waveguide layer 200', P-type dopants and N-type dopants located on both sides of the waveguide layer 200', and a germanium layer 400'.
  • the germanium layer 400' is located on the P-type dopant, the N-type dopant and one side surface of the waveguide layer 200', and in the direction perpendicular to the plane where the waveguide layer 200' is located, the germanium layer 400' The projection of partially overlaps with the projection of the P-type dopant and the projection of the N-type dopant.
  • the P-type doping In a photodetector (PD) in common technology, since the lateral electric field formed between the P-type dopant and the N-type dopant is used to extract the photocurrent inside the germanium layer 400', the P-type doping must be strictly controlled.
  • the doping concentration of the dopant and the N-type dopant and the overlapping area between the germanium layer 400' and the P-type dopant and the N-type dopant are controlled to ensure that the P-type dopant and the N-type dopant
  • the strong electric field effect formed between them can be used to extract as much photocurrent as possible inside the germanium layer 400' to improve the output efficiency of the photodetection structure 1000'. Therefore, in this case, the width of the germanium layer 400' needs to be strictly controlled to be more than several hundred nanometers.
  • FIG. 3 is a schematic plan view of a photoelectric detection structure provided by an embodiment of the present application.
  • Figure 4 is a schematic cross-sectional structural diagram along the B-B' direction of Figure 3.
  • FIG. 5 is a schematic structural diagram of the germanium layer in FIG. 3 .
  • FIG. 6 is a schematic plan view of a photodetection structure provided by another embodiment of the present application.
  • an embodiment of the present application provides a photoelectric detection structure 1000, which includes a waveguide layer 200, in which the optical signal to be detected is transmitted in a given direction (such as the X direction) and is limited to Wherein; the waveguide layer 200 includes a silicon-based part 201 and a first doping body 210 and a second doping body 220 disposed in the silicon-based part 201, the first doping body 210 and the second doping body 220.
  • the doping body 220 has different doping types.
  • the first dopant 210 includes a first main electrode 211 and a plurality of first finger electrodes 212 electrically connected to the first main electrode 211 .
  • the second doped body 220 includes a second main electrode 221 and a plurality of second finger electrodes 222 electrically connected to the second main electrode 221 .
  • the first main electrode 211 and the second main electrode 221 are respectively located on both sides of the waveguide layer 200, and the first main electrode 211 and the second main electrode 221 are arranged oppositely.
  • the plurality of first finger electrodes 212 and the plurality of second finger electrodes 222 are arranged at intervals in a comb-tooth shape and interleaved with each other to form the waveguide region 300 .
  • the photodetection structure 1000 further includes a germanium layer 400 located above the waveguide region 300 and in contact with the plurality of first finger electrodes 212 and the plurality of second finger electrodes 222, such that The fading tail of the optical signal transmitted in the waveguide layer 200 is coupled into the germanium layer 400 .
  • the photodetection structure 1000 further includes: a substrate (not shown), the substrate is used to support the waveguide layer 200 and the germanium layer 400 located on the waveguide layer 200 .
  • the first doping body 210 is a P-type doping body
  • the second doping body 210 is an N-type doping body.
  • the first doping body 210 is an N-type doping body.
  • Dopant, the second dopant 210 is a P-type dopant.
  • the embodiments of the present application are not limited here, as long as the doping types of the first doping body 210 and the second doping body 210 are different.
  • the photodetection structure 1000 described in this application uses a plurality of first finger electrodes 212 and a plurality of second finger electrodes 222 arranged in a comb-shaped interleaved manner in the waveguide layer 200 .
  • the ends of each first finger electrode 212 in the first doped body 210 and each second finger electrode 222 in the second doped body 220 are alternately arranged along the transmission direction of the optical signal to form a periodic arrangement.
  • the depletion layer increases the effective length of the PN junction depletion layer in the waveguide layer; on the other hand, through each first finger electrode 212 in the first doped body 210 and each second second doped body 220
  • the built-in fringe field formed by the finger electrodes 222 can effectively extract the photocurrent flowing into the germanium layer 400 and transfer the photocurrent through the first main electrode 211 and the second main electrode 221 .
  • the electrical signal is transmitted out of the photodetector.
  • the photoelectric detection structure 1000 has higher sensitivity and responsivity.
  • the plurality of first finger electrodes 212 and the plurality of second finger electrodes 222 are spaced apart in a comb-like interleaved manner, which can also allow a waveguide layer with a wider cross-sectional width perpendicular to the optical signal transmission direction. 200, thereby improving the yield of the photodetection structure 1000 and the performance of the device.
  • the photodetection structure 1000 described in this application is a horizontal structure without a metal layer. Therefore, it has more advantages than the traditional vertical electrode structure in that it has higher responsivity and lower dark current.
  • the energy gap (bandgap) of the material has always been the main cause of the dark current. Therefore, the above-mentioned germanium The layer 400 is in direct contact with the silicon-based part 201 in the waveguide layer 200, that is, the germanium is in contact with silicon (Si-contact), and the energy gap of silicon is higher than the energy gap of germanium to reduce the dark current of the device and increase The responsiveness of the device.
  • the waveguide layer 200 is used to transmit optical signals between optical devices and optoelectronic devices.
  • Single-mode waveguides and multi-mode waveguides are widely used in photonic integrated circuits or optical chips (photonic integrated circuit chips, PICs).
  • the optical chip uses photons as an information carrier to process information and transmit data, and may be a silicon-based optical chip.
  • the term "single-mode waveguide” may be used for waveguide forms that support only transverse electric modes (TE) or only transverse magnetic modes (TM).
  • the single-mode waveguide may be, for example, a silicon-based strip waveguide or a ridge waveguide. Single-mode operation enables Connect directly to optical signal processing and networking components.
  • multimode waveguide refers to a waveguide form that supports both transverse electric mode (TE) and transverse magnetic mode (TM).
  • the multimode waveguide can be, for example, a through waveguide and a cross waveguide formed on a silicon base. Sampling and separation of multiplexed optical signals.
  • the germanium layer 400 using the above design can be compatible with both single-mode waveguide and multi-mode waveguide.
  • the main extension direction of the germanium layer 400 is the same as the propagation direction of light waves in the waveguide region 300 (for example, the optical signal transmission direction is along the X direction).
  • the germanium layer 400 includes a mesa having a length L along the optical signal transmission direction (X direction) and a length L along a direction (Z direction) substantially perpendicular to the optical signal transmission direction (X direction). Width W, wherein the width W of the mesa is less than its length L.
  • the main extending direction of the germanium layer 400 refers to the direction of the length L of the germanium layer 400 , and is generally consistent with the extending direction of the waveguide layer 200 .
  • the projection of the germanium layer 400 covers the waveguide area 300, so that the light propagating in the waveguide area 300 can be completely absorbed by the germanium layer 400, and Photocurrent is generated to improve the output efficiency of the photodetection structure 1000.
  • the width of the germanium layer 400 is also tolerant to the first doping body 210 and the second doping body 220.
  • the width of the germanium layer 400 is perpendicular to the waveguide layer 200. In the direction, the projection of the germanium layer 400 does not overlap with the projection of the first main electrode 211 and the second main electrode 221 , that is, the first main electrode 211 and the second main electrode
  • the width of the gap between 221 is greater than the cross-sectional width of the germanium layer 400 perpendicular to its extending direction.
  • the germanium layer 400 does not need to be in contact with the first main electrode 211 and the second main electrode 221 , that is, there is no need to set the germanium layer 400 with the first main electrode 211 and the second main electrode 221 Since the width of the germanium layer 400 is not limited, the manufacturing process of germanium epitaxy on silicon is relatively simple, and strict alignment is not required during the manufacturing process.
  • the first main electrode 211 and the second main electrode 221 can be used to transmit the electrical signal out of the photodetector, so the first main electrode 211 and the second main electrode
  • the upper surface of 221 has no contact with the germanium layer 400, which is also beneficial to the derivation of subsequent electrical signals.
  • a light receiving portion 501 is provided on one edge of the germanium layer.
  • the light receiving portion 501 is used for optical coupling and alignment with an external photoconductor to receive light wave signals.
  • a portion of the waveguide layer 200 can be protruded from the germanium layer 400 as the light receiving portion 501 for optical coupling alignment to optimize coupling efficiency.
  • the manufacturing process can also be saved and the manufacturing cost can be reduced.
  • the thickness of the germanium layer 400 and the spacing between the doped first finger electrodes 212 and the doped second finger electrodes 222 are simultaneously considered to calculate the spacing generated at the top of the germanium layer 400 All the photocurrent is extracted, so that even if slow carriers pass through diffusion, the optical power extraction of the photodetection structure 1000 will not be affected.
  • the thickness of the germanium layer 400 has almost no impact on the photodetection structure 1000.
  • a thicker thickness can improve the optimal conditions for evanescent wave coupling.
  • conditions such as the threshold size of the operating voltage of the first doping body 210 and the second doping body 220 can also be adjusted by adjusting the doping width and doping concentration of the first doping body 210 and the second doping body 220 changes without being restricted by specific manufacturing processes.
  • the photodetection structure 1000 further includes a passivation layer (not shown), the passivation layer covering the germanium layer 400 and the waveguide layer 200 superior.
  • the passivation layer has a surface passivation effect and can be used to reduce dark current of the photodetector device.
  • the passivation layer is also scratch-resistant and can protect its internal film structure from being damaged. It is also used to prevent the germanium layer 400 and the waveguide layer 200 from being polluted by the external environment and water vapor corrosion. .
  • the photodetection structure 1000 further includes a first metal contact (not shown), the first metal contact is electrically connected to the first main electrode 211, and A second metal contact (not shown), the second metal contact is electrically connected to the second main electrode 221 , and the first metal contact and the second metal contact are used to collect particles from the germanium layer 400 The light absorbs the generated electrons to derive the generated photocurrent.
  • the first metal contact is disposed on the first main electrode 211, and the second metal contact is disposed on the second main electrode 221. Since in the direction perpendicular to the waveguide layer 200, the projection of the germanium layer 400 is different from the projection of the germanium layer 400.
  • the projections of the first main electrode 211 and the second main electrode 221 do not overlap, so the first metal contact and the second metal contact can avoid direct contact with the germanium layer 400, thereby avoiding the germanium layer 400.
  • There is a metal layer under layer 400 which causes electrons to be absorbed by the metal layer, affecting the responsivity of the device.
  • the first main electrode 211 and the second main electrode 221 are heavily doped P regions and N regions respectively, the first metal contact can form a relatively close relationship with the first main electrode 211 .
  • the above-mentioned second metal contact can form a better ohmic contact with the second main electrode 221 to apply the required bias and inject and extract the generated current, and can overcome the resistance of the silicon layer. There is an adverse effect on the electrical characteristics of the device.
  • Another embodiment of the present application provides an optoelectronic integrated chip, which includes the photodetection structure described in the previous embodiment.
  • Embodiments of the present application provide a photoelectric detection structure and an optoelectronic integrated chip, aiming to achieve photoelectric conversion by arranging a first dopant and a second dopant in the silicon-based part of the waveguide layer, wherein the first dopant includes A plurality of first finger-shaped electrodes, the second dopant body includes a plurality of second finger-shaped electrodes, and the plurality of first finger-shaped electrodes and the plurality of second finger-shaped electrodes are arranged at intervals in a comb-tooth shape, To form a waveguide region, the germanium layer is located on the waveguide region and is in contact with a plurality of first finger electrodes and a plurality of second finger electrodes to effectively extract the photocurrent flowing into the germanium layer, thereby making the photodetection structure Has high sensitivity and responsiveness.

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Abstract

本申请公开了一种光电探测结构及光电集成芯片，其旨在通过在波导层的硅基部分内设置第一掺杂体和第二掺杂体以实现光电转换，其中，第一掺杂体包括多个第一指状电极，第二掺杂体包括多个第二指状电极，并且多个第一指状电极和多个第二指状电极以梳齿状互插的形式间隔排布，以构成波导区域，锗层位于波导区域之上并且与多个第一指状电极以及与多个第二指状电极接触，以有效提取出流入锗层内部的光电流，从而使得光电探测结构具有较高的灵敏度和响应度。

Description

光电探测结构及光电集成芯片 技术领域
本申请涉及光通信技术领域，具体涉及一种光电探测结构及光电集成芯片。
 背景技术
高性能的光电探测器（Photo Detector，PD）是高速光通讯的核心器件之一，波导式光接收器件对于高度集成化有很大的优势，尤其是监控用光电探测器（monitor PD, MPD）在发射端（TX）的使用，并将监控到的光信号转换成电信号反馈至光芯片（光子集成电路芯片，PIC）中。故其器件本身的响应度和暗电流都必须有良好的表现，以便于能够测到相对低的光强度（uW）。加上长时间使用，其可靠性问题给MPD带来了更大的挑战，譬如工艺的稳定性和器件的再现性等。
因此，对于硅上锗的光电探测器，亟需提出改进。
 技术问题
本申请的目的在于，本申请实施例提供一种光电探测结构及光电集成芯片，能够具有较高的灵敏度和响应度。
 技术解决方案
根据本申请的一方面，本申请一实施例提供了一种光电探测结构，包括衬底、设于所述衬底上的波导层以及设于所述波导层上的锗层，所述波导层包括硅基部分以及设置在所述硅基部分内的第一掺杂体和第二掺杂体，所述第一掺杂体和所述第二掺杂体的掺杂类型不同，所述第一掺杂体包括第一主电极以及与所述第一主电极电连接的多个第一指状电极，所述第二掺杂体包括第二主电极以及与所述第二主电极电连接的多个第二指状电极，所述第一主电极和所述第二主电极相对设置，并且所述多个第一指状电极和所述多个第二指状电极以梳齿状互插的形式间隔排布，以构成波导区域；所述锗层位于所述波导区域之上并且与所述多个第一指状电极以及与所述多个第二指状电极接触。
可选地，所述锗层的一侧边缘设置有光接收部，所述光接收部用于与外部的光导体进行光耦合对位以接收光波。
可选地，所述锗层的主延伸方向与所述波导区域上光波的传导方向相同。
可选地，在垂直于所述波导层的方向上，所述锗层的投影至少部分覆盖所述波导区域。
可选地，在垂直于所述波导层的方向上，所述锗层的投影与所述第一主电极以及与所述第二主电极的投影均不交叠。
可选地，所述波导层凸设于所述锗层的一部分作为光接收部，所述光接收部与所述第一掺杂体和所述第二掺杂体位于同一膜层。
可选地，所述光接收部还包括模板转换器，以用于光信号的导入。
可选地，所述光电探测结构还包括第一金属接触，所述第一金属接触与所述第一主电极电连接，以及第二金属接触，所述第二金属接触与所述第二主电极电连接，所述第一金属接触以及所述第二金属接触用于导出所述锗层产生的光电流。
可选地，所述光电探测结构还包括钝化层，所述钝化层覆盖在所述锗层以及所述波导层之上。
根据本申请的另一方面，本申请一实施例提供了一种采用如本申请任意一实施例所述光电集成芯片。
 有益效果
本申请实施例提供了光电探测结构及光电集成芯片，旨在通过在波导层的硅基部分内设置第一掺杂体和第二掺杂体以实现光电转换，其中，第一掺杂体包括多个第一指状电极，第二掺杂体包括多个第二指状电极，并且多个第一指状电极和多个第二指状电极以梳齿状互插的形式间隔排布，以构成波导区域，锗层位于波导区域之上并且与多个第一指状电极以及与多个第二指状电极接触，以实现有效提取出流入锗层内部的光电流，从而使得光电探测结构具有较高的灵敏度和响应度。
 附图说明
下面结合附图，通过对本申请的具体实施方式详细描述，将使本申请的技术方案及其它有益效果显而易见。
图1为常用技术所提供的一种光电探测结构的平面结构示意图。
图2为图1沿A-A’方向的截面结构示意图。
图3为本申请一实施例所提供的一种光电探测结构的平面结构示意图。
图4为图3沿B-B’方向的截面结构示意图。
图5为图3中的锗层的结构示意图。
图6为本申请又一实施例所提供的一种光电探测结构的平面结构示意图。
 本发明的实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
文中的术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个所述特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接或可以相互通讯；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
下文的公开提供了许多不同的实施方式或例子用来实现本申请的不同结构。为了简化本申请的公开，下文中对特定例子的部件和设置进行描述。当然，它们仅仅为示例，并且目的不在于限制本申请。此外，本申请可以在不同例子中重复参考数字和/或参考字母，这种重复是为了简化和清楚的目的，其本身不指示所讨论各种实施方式和/或设置之间的关系。
图1为常用技术所提供的一种光电探测结构的平面结构示意图。图2为图1沿A-A’方向的截面结构示意图。
参阅图1至图2，常用技术中提供的光电探测结构1000’，其包括波导层200’，以及位于波导层200’两侧的P型掺杂体和N型掺杂体，锗层400’，所述锗层400’位于P型掺杂体、N型掺杂体以及波导层200’的一侧表面之上，并且，在垂直于波导层200’所在的平面方向上，锗层400’的投影与P型掺杂体的投影以及N型掺杂体的投影部分交叠。
常用技术中的光电探测器（PD）中，由于P型掺杂体和N型掺杂体之间形成的侧向电场用于提取锗层400’内部的光电流，所以必须严格控制P型掺杂体和N型掺杂体的掺杂浓度以及控制锗层400’与P型掺杂体、N型掺杂体之间的交叠面积，以确保P型掺杂体与N型掺杂体之间形成的强电场效应能够尽可能多的用于提取锗层400’内部的光电流，以提高光电探测结构1000’的输出效率。因此，在此情形下，锗层400’的宽度需要被严格控制在数百纳米以上。
图3为本申请一实施例所提供的一种光电探测结构的平面结构示意图。图4为图3沿B-B’方向的截面结构示意图。图5为图3中的锗层的结构示意图。图6为本申请又一实施例所提供的一种光电探测结构的平面结构示意图。
参阅图3至图6，本申请一实施例提供了一种光电探测结构1000，其包括波导层200，其中，待探测的光信号在给定方向（例如X方向）上传输，并被限制在其中；所述波导层200包括硅基部分201以及设置在所述硅基部分201内的第一掺杂体210和第二掺杂体220，所述第一掺杂体210和所述第二掺杂体220的掺杂类型不同。所述第一掺杂体210包括第一主电极211以及与所述第一主电极211电连接的多个第一指状电极212。所述第二掺杂体220包括第二主电极221以及与所述第二主电极221电连接的多个第二指状电极222。在本申请实施例中，第一主电极211和第二主电极221分别位于波导层200的两侧，所述第一主电极211和所述第二主电极221相对设置。并且所述多个第一指状电极212和所述多个第二指状电极222以梳齿状互插的形式间隔排布，以构成波导区域300。光电探测结构1000还包括锗层400，所述锗层400位于所述波导区域300之上并且与所述多个第一指状电极212以及所述多个第二指状电极222接触，使得在所述波导层200中传输的光信号的逐渐消失的尾部耦合入所述锗层400中。
可选地，所述光电探测结构1000还包括：衬底（图未示出），所述衬底用于支撑所述波导层200以及位于所述波导层200之上的所述锗层400。
可选地，所述第一掺杂体210为P型掺杂体，所述第二掺杂体210为N型掺杂体，也可以是，所述第一掺杂体210为N型掺杂体，所述第二掺杂体210为P型掺杂体。本申请实施例在此不做限制，只要所述第一掺杂体210和所述第二掺杂体210的掺杂类型不同即可。
本申请所述的光电探测结构1000在波导层200中采用多个第一指状电极212和所述多个第二指状电极222以梳齿状互插的形式间隔排布。一方面，使得第一掺杂体210内的各第一指状电极212和第二掺杂体220内的各第二指状电极222的末端沿光信号的传输方向交替排列形成周期性排列的耗尽层，增加了波导层中PN结耗尽层的有效长度；另一方面，通过第一掺杂体210内的各第一指状电极212和第二掺杂体220内的各第二指状电极222形成的内建边缘电场（fringe field）的形式，可以有效提取出流入锗层400内部的光电流，并经由所述第一主电极211和所述第二主电极221将所述电信号传送出光电探测器。从而使得该光电探测结构1000具有较高的灵敏度和响应度。此外，多个第一指状电极212和所述多个第二指状电极222以梳齿状互插的形式间隔排布还能够允许在垂直于光信号传输方向的截面宽度较宽的波导层200的设计，从而能够提高该光电探测结构1000的良率以及器件的性能。
本申请所述的光电探测结构1000为不具有金属层的水平结构，因此，相比于传统的垂直电极结构更加具有优势，具有较高的响应度以及具有较低的暗电流。
为了降低器件的暗电流，通常除了控制锗层400的外延生长以及保证光电探测结构1000的制造工艺的准确性以外，材料的能隙（bandgap）一直是主导暗电流的主因，因此，将上述锗层400与波导层200中的硅基部分201直接接触，即将锗与硅接触（Si-contact），利用硅的能隙比锗的能隙要高的缘故，以降低器件的暗电流，并增加器件的响应度。
在本实施例中，波导层200用于在光学器件和光电子器件之间传送光信号，单模波导和多模波导被广泛应用于光子集成电路或者光芯片（光子集成电路芯片，PIC）中，其中，所述光芯片是用光子为信息载体进行信息的处理与数据的传送，其可以是基于硅的光芯片。术语“单模波导”可用于仅支持横电模（TE）或者仅支持横磁模（TM）的波导形式，该单模波导例如可以是基于硅的条波导或者脊波导，单模操作使得能够直接连接至光信号处理和联网元件。术语“多模波导”即既支持横电模（TE），又支持横磁模（TM）的波导形式，该多模波导例如可以是在硅基上形成的直通波导和交叉波导，以用于合波光信号的取样与分离。在本实施例中，采用上述设计的锗层400能够既兼容单模波导的形式，又兼容多模波导形式。
进一步地，如图3-图5所示，所述锗层400的主延伸方向与所述波导区域300上光波的传导方向（例如光信号传输方向沿X方向）相同。示例性地，所述锗层400包括一台面，所述台面具有沿光信号传输方向（X方向）的长度L和沿基本上垂直于光信号传输方向（X方向）的方向（Z方向）的宽度W，其中，所述台面的宽度W小于其长度L。所述锗层400的主延伸方向既是指的是锗层400的长度L的方向，通常与波导层200的延伸方向保持一致。
进一步地，在垂直于所述波导层200的方向上，所述锗层400的投影覆盖所述波导区域300，以使得在所述波导区域300内传播的光线能够完全被锗层400吸收，并产生光电流，以提高光电探测结构1000的输出效率。
基于波导层200的宽度较宽的情形下，锗层400的宽度对于第一掺杂体210和第二掺杂体220的容忍度也较高，可选地，在垂直于所述波导层200的方向上，锗层400的投影与所述第一主电极211以及与所述第二主电极221的投影均不交叠，也即，所述第一主电极211与所述第二主电极221之间的间隙宽度大于所述锗层400垂直于其延伸方向的截面宽度。使得锗层400无需与所述第一主电极211以及与所述第二主电极221之间进行接触，即无需设置锗层400与所述第一主电极211以及与所述第二主电极221之间的交叠宽度，由于锗层400的宽度不受限制，使得硅上锗外延的工艺制造相对比较简单，在工艺制造过程中无需严苛的对位等。在本实施例中，所述第一主电极211与所述第二主电极221能够用于将所述电信号传送出光电探测器，故所述第一主电极211与所述第二主电极221的上表面没有锗层400的接触，也有利于后续电信号的导出。
进一步地，在所述锗层的一侧边缘设置有光接收部501，所述光接收部501用于与外部的光导体进行光耦合对位以接收光波信号。可选地，可将所述波导层200凸设于所述锗层400的一部分作为光接收部501，用于光耦合对位，以优化耦合效率。此外，采用将所述波导层200凸设于所述锗层400的一部分作为光接收部501，也能够节省制造工艺，降低制造成本。
进一步地，将锗层400的厚度、被掺杂的第一指状电极212与被掺杂的第二指状电极222之间的间隙（spacing）同时考虑，以将位于锗层400顶部产生的光电流全部萃取下来，从而能够实现：即使透过扩散（diffusion）的慢速载子(slow carrier)依然不影响光电探测结构1000的光功率提取。
在本实施例中，锗层400的厚度对此光电探测结构1000几乎没有影响，厚度较厚反而可以提升消逝波耦合的最佳条件。
此外，第一掺杂体210和第二掺杂体220操作电压的阈值大小等条件也可以通过调节第一掺杂体210和第二掺杂体220的掺杂宽度以及掺杂的浓度来进行改变，而不受具体工艺制造的限制。
可选地，在本申请的一实施例中，所述光电探测结构1000还包括钝化层（图未示出），所述钝化层覆盖在所述锗层400以及所述波导层200之上。所述钝化层具有表面钝化的作用，能够用于降低光电探测器件的暗电流。此外，所述钝化层还具有耐刮擦性，能够保护其内部膜层结构不被损伤，同时还用于防止所述锗层400以及所述波导层200不被外部环境污染以及水汽腐蚀等。
可选地，在本申请的一实施例中，所述光电探测结构1000还包括第一金属接触（图未示出），所述第一金属接触与所述第一主电极211电连接，以及第二金属接触（图未示出），所述第二金属接触与所述第二主电极221电连接，所述第一金属接触以及所述第二金属接触用于收集由所述锗层400的光吸收产生的电子以导出产生的光电流。上述第一金属接触设置在第一主电极211之上，上述第二金属接触设置在第二主电极221之上，由于在垂直于所述波导层200的方向上，锗层400的投影与所述第一主电极211以及与所述第二主电极221的投影均不交叠，故上述第一金属接触与上述第二金属接触能够避开与锗层400进行直接接触，由此可以避免锗层400之下有金属层所导致的电子被金属层吸收，影响器件的响应度。此外，由于所述第一主电极211和所述第二主电极221分别为重掺杂的P区和N区，因此，上述第一金属接触可与所述第一主电极211之间形成较佳的欧姆接触，上述第二金属接触可与所述第二主电极221之间形成较佳的欧姆接触，以应用所需要的偏置并且注入和提取所产生的电流，并能够克服硅层的存在对器件的电气特性的不利影响。
本申请另一实施例提供了一种光电集成芯片，其包括前述实施例所述的光电探测结构。
本申请实施例提供了光电探测结构及光电集成芯片，旨在通过在波导层的硅基部分内设置第一掺杂体和第二掺杂体以实现光电转换，其中，第一掺杂体包括多个第一指状电极，第二掺杂体包括多个第二指状电极，并且多个第一指状电极和多个第二指状电极以梳齿状互插的形式间隔排布，以构成波导区域，锗层位于波导区域之上并且与多个第一指状电极以及与多个第二指状电极接触，以实现有效提取出流入锗层内部的光电流，从而使得光电探测结构具有较高的灵敏度和响应度。
在上述实施例中，对各个实施例的描述都各有侧重，某个实施例中没有详述的部分，可以参见其他实施例的相关描述。
以上对本申请实施例所提供的一种光电探测结构及光电集成芯片进行了详细介绍，本文中应用了具体个例对本申请的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本申请的技术方案及其核心思想；本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例的技术方案的范围。

Claims (10)

  1. 一种光电探测结构，其特征在于，包括：
    衬底、设于所述衬底上的波导层以及设于所述波导层上的锗层；
    所述波导层包括硅基部分以及设置在所述硅基部分内的第一掺杂体和第二掺杂体，所述第一掺杂体和所述第二掺杂体的掺杂类型不同，所述第一掺杂体包括第一主电极以及与所述第一主电极电连接的多个第一指状电极，所述第二掺杂体包括第二主电极以及与所述第二主电极电连接的多个第二指状电极，所述第一主电极和所述第二主电极相对设置，并且所述多个第一指状电极和所述多个第二指状电极以梳齿状互插的形式间隔排布，以构成波导区域；
    所述锗层位于所述波导区域之上并且与所述多个第一指状电极以及与所述多个第二指状电极接触。
  2. 根据权利要求1所述的光电探测结构，其特征在于，
    所述锗层的一侧边缘设置有光接收部，所述光接收部用于与外部的光导体进行光耦合对位以接收光波。
  3. 根据权利要求2所述的光电探测结构，其特征在于，
    所述锗层的主延伸方向与所述波导区域上光波的传导方向相同。
  4. 根据权利要求3所述的光电探测结构，其特征在于，
    在垂直于所述波导层的方向上，所述锗层的投影至少部分覆盖所述波导区域。
  5. 根据权利要求4所述的光电探测结构，其特征在于，
    在垂直于所述波导层的方向上，所述锗层的投影与所述第一主电极以及与所述第二主电极的投影均不交叠。
  6. 根据权利要求2所述的光电探测结构，其特征在于，
    所述波导层凸设于所述锗层的一部分作为光接收部，所述光接收部与所述第一掺杂体和所述第二掺杂体位于同一膜层。
  7. 根据权利要求2所述的光电探测结构，其特征在于，
    所述光接收部还包括模板转换器，以用于光信号的导入。
  8. 根据权利要求1所述的光电探测结构，其特征在于，
    所述光电探测结构还包括第一金属接触，所述第一金属接触与所述第一主电极电连接，以及第二金属接触，所述第二金属接触与所述第二主电极电连接，所述第一金属接触以及所述第二金属接触用于导出所述锗层产生的光电流。
  9. 根据权利要求1所述的光电探测结构，其特征在于，所述光电探测结构还包括钝化层，所述钝化层覆盖在所述锗层以及所述波导层之上。
  10. 一种光电集成芯片，其特征在于，所述光电集成芯片包括如权利要求1所述的光电探测结构。
PCT/CN2022/132887 2022-03-10 2022-11-18 光电探测结构及光电集成芯片 WO2023168987A1 (zh)

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CN110212053A (zh) * 2019-05-29 2019-09-06 哈尔滨工业大学（深圳） 一种硅基叉指型光电探测器
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