WO2023103444A1 - 光电探测器 - Google Patents

光电探测器 Download PDF

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Publication number
WO2023103444A1
WO2023103444A1 PCT/CN2022/113315 CN2022113315W WO2023103444A1 WO 2023103444 A1 WO2023103444 A1 WO 2023103444A1 CN 2022113315 W CN2022113315 W CN 2022113315W WO 2023103444 A1 WO2023103444 A1 WO 2023103444A1
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Prior art keywords
layer
waveguide layer
light
photodetector
waveguide
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PCT/CN2022/113315
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English (en)
French (fr)
Inventor
吴昊
郑学哲
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苏州旭创科技有限公司
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Priority to EP22902878.2A priority Critical patent/EP4447127A1/en
Publication of WO2023103444A1 publication Critical patent/WO2023103444A1/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
    • H01L31/0248—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
    • H01L31/0352—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 their shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • 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

  • the present application relates to the technical field of integrated circuits, in particular to a photodetector.
  • Photodetectors are devices that convert high-speed optical signals into electrical signals, and their technical indicators such as bandwidth, responsivity, and saturated optical power have also been improved accordingly.
  • bandwidth bandwidth
  • responsivity bandwidth
  • saturated optical power bandwidth
  • the bandwidth of a common PIN photodetector is limited by two factors: 1. The parasitic capacitance and resistance of the detector; 2. The transit time of photogenerated carriers in the intrinsic region of the detector. In order to reduce the parasitic capacitance and increase the bandwidth without affecting the responsivity, the photodetector must reduce the area of the PIN junction region and increase the width of the region.
  • the widening of the intrinsic region leads to the weakening of the internal electric field, the drift speed of photo-generated carriers in the electric field slows down, and the transit time increases; what is more serious is that when the incident light power increases, the number of photo-generated carriers increases and the PIN Accumulated in the junction, the electric field generated by the carriers weakens the drift electric field in the PIN junction, which further increases the transit time of the photogenerated carriers.
  • the performance of the photodetector is that when the incident light power increases and exceeds a certain threshold, the detector bandwidth decreases, and when the light continues to increase, the detector responsivity decreases.
  • the present invention provides a photodetector comprising:
  • an absorbing layer located on the upper surface of the waveguide layer or at least partially embedded within the waveguide layer;
  • a cladding material covering the top and sidewalls of the waveguide layer and absorber layer
  • At least one end surface of the photodetector is a light incident surface, and the thickness of the absorbing layer on the end surface adjacent to the light incident surface is smaller than the thickness of other parts.
  • the thickness of the waveguide layer is greater than the thickness of the cladding material.
  • the width of the end face of the absorbing layer adjacent to the light incident surface is smaller than the width of other parts of the absorbing layer.
  • the width of the end surface of the waveguide layer adjacent to the light incident surface is greater than the width of other parts of the waveguide layer.
  • the orthographic projection of the absorbing layer on the upper surface of the waveguide layer is at least partially located within the upper surface of the waveguide layer.
  • the orthographic projection of the absorption layer on the upper surface of the waveguide layer is located within the upper surface of the waveguide layer, and the centerline of the absorption layer deviates from the centerline of the waveguide layer.
  • the orthographic projection of the absorbing layer on the upper surface of the waveguide layer is located within the upper surface of the waveguide layer, and the centerline of the absorbing layer deviates from the centerline of the waveguide layer.
  • the waveguide layer is inclined at a preset angle compared to the extending direction of the absorbing layer.
  • the end surface of the waveguide layer adjacent to the light incident surface is stepped.
  • the absorbent layer includes:
  • first absorbing layer and a second absorbing layer, the first absorbing layer is integrally connected to the second absorbing layer, and the first absorbing layer is located between the second absorbing layer and the light incident surface;
  • the light energy absorption rate of the first absorption layer is smaller than the light energy absorption rate of the second absorption layer.
  • the light energy absorption rate of the absorbing layer increases gradually from the light incident surface away from the light incident surface.
  • the waveguide layer includes:
  • a first waveguide layer and a second waveguide layer the second waveguide layer is embedded in the first waveguide layer, and the upper surface of the second waveguide layer is higher than the upper surface of the first waveguide layer, the absorption A layer is located on the upper surface of the second waveguide layer or is at least partially embedded in the second waveguide layer.
  • the absorption layer of the photodetector is located on the waveguide layer or at least partially embedded in the waveguide layer, and the cladding material covers the top and side walls of the waveguide layer and the absorption layer; wherein, at least one end surface of the photodetector is the light incident surface, and the absorption layer is in the The thickness of the end surface adjacent to the light incident surface is smaller than the thickness of other parts.
  • the thickness of the end face of the absorbing layer near the light incident surface is smaller than the thickness of other parts, so that the light energy absorbed by the part near the light incident surface is smaller than the light energy absorbed by other parts of the absorbing layer, thereby reducing the photogenerated carriers in the absorbing layer.
  • the aggregation degree of the intrinsic region of the photodetector increases the electric field intensity of the photogenerated carrier accumulation region, reduces the influence of large light input on the bandwidth and responsivity performance of the photodetector, and finally increases the large light input threshold of the photodetector.
  • Fig. 1 is a kind of detector structure schematic diagram
  • Fig. 2 is the comparative schematic diagram of the photodetector of the present application and the detector in Fig. 1 and the ideal detector along the light wave transmission direction absorption curve;
  • curve 1 is the photodetector of the present application along the light wave transmission direction absorption curve
  • curve 2 The absorption curve of the detector along the light wave transmission direction in Fig. 1, the curve 3 is the absorption curve of the ideal detector along the light wave transmission direction;
  • Fig. 3 to Fig. 6 are the longitudinal cross-sectional structural schematic diagrams of photodetectors provided in different embodiments of the present application;
  • FIG. 7 to 21 are schematic cross-sectional structural diagrams of photodetectors provided in different embodiments of the present application.
  • Cladding material 200. Waveguide layer; 201. Second gradient portion; 202. Second straight line portion; 203. Second waveguide layer; 204. First waveguide layer; 300. Absorption layer; 301. First gradient portion ; 302, the first straight portion; 303, the first absorption layer; 304, the second absorption layer.
  • first doping type becomes the second doping type
  • second doping type can be referred to as the first doping type
  • first doping type and the second doping type are different doping types, for example,
  • the first doping type can be P-type and the second doping type can be N-type, or the first doping type can be N-type and the second doping type can be P-type.
  • Embodiments of the invention are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention such that variations in the shapes shown as a result, for example, of manufacturing techniques and/or tolerances are contemplated.
  • embodiments of the invention should not be limited to the particular shapes of regions shown herein but are to include deviations in shapes that result, for example, from manufacturing techniques.
  • an implanted region illustrated as a rectangle will, typically, have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from implanted to non-implanted region.
  • a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation was performed.
  • the regions shown in the figures are schematic in nature and their shapes do not indicate the actual shape of a region of a device and are not intended to limit the scope of the invention.
  • One solution to solve the large optical bandwidth and responsivity attenuation is to increase the bias voltage loaded on the PIN detector, thereby increasing the electric field intensity in the intrinsic region, so as to weaken the influence of a large number of photogenerated carriers on the electric field.
  • the problems with this method are: 1. For TIA (Trans-impedance Amplifier, transimpedance amplifier) or external power supply requirements are increased. In order to meet the bandwidth requirements under large light, SiGe detectors are required to provide bias voltages above 3V, and InP even requires more than 5V, which is inconsistent with the future development trend of CMOS integration; 2. Large Under the bias voltage, the dark current of the detector increases, and the generated noise also increases accordingly. At the same time, the high electric field makes more defects in SiGe or InP materials excited, which accelerates aging during continuous operation and shortens the life of the device.
  • Another solution to solve the large optical bandwidth and responsivity attenuation is to divide the received light into several beams and input them into several different detectors, or different areas of the detectors, so as to reduce the generation of light in the incident area of the detectors.
  • the number of photogenerated carriers can reduce the influence of the electric field on the intrinsic region; the incident light is divided into 2 beams and 4 beams, and input into 1 and 2 detectors, which can increase the attenuation threshold of the detector's large light input by 3dB and 6dB.
  • the problems of this scheme are: 1.
  • a solution to simultaneously solve large optical bandwidth attenuation and multi-detector signal time delay Multiple detectors are connected in parallel by using electrodes of transmission line structure, and the signal time delay is controlled by the length of the input waveguide, so as to realize the electrical signal of multiple detectors. full synchronization.
  • the problem with this solution is that the design of the electrode structure is complex, the process requirements are strict, and the application remains unchanged. Similarly, this solution cannot solve the problem of return loss at the receiving end caused by the incomplete absorption of light by the detector, and the problem caused by the increase in the number of detectors. The problem of reduced yield and reliability.
  • the present invention provides a kind of photodetector
  • Fig. 3 Fig. 4 and Fig. 5 are the longitudinal cross-sectional structure diagrams of photodetector of the present invention
  • photodetector comprises: waveguide layer 200 , the absorbing layer 300 and the cladding material 100 .
  • the absorption layer 300 is located on the upper surface of the waveguide layer 200 or at least partially embedded in the waveguide layer 200; the cladding material 100 covers the top and sidewalls of the waveguide layer 200 and the absorption layer 300; wherein, at least one end surface of the photodetector is a light incident surface, The thickness of the absorbing layer 300 at the end surface adjacent to the light incident surface is smaller than that of other parts.
  • the waveguide layer 200 is used to guide the transmission of light waves, and the absorbing layer 300 is located on the upper surface of the waveguide layer 200, as shown in Figure 3(a); in another example, the absorbing layer 300 can also be partially embedded in the waveguide layer 200 , as shown in FIG. 3( b ); in another example, the absorbing layer 300 can also be completely embedded in the waveguide layer 200 , as shown in FIG. 3( c ).
  • the absorbing layer 300 absorbs light waves and generates carriers to form photocurrent; the cladding material 100 covers the top and sidewalls of the waveguide layer 200 and the absorbing layer 300 to protect the waveguide layer 200 and the absorbing layer 300 .
  • the thickness of the absorbing layer 300 at the end surface adjacent to the light incident surface is smaller than that of other parts.
  • the waveguide layer 200 is used to guide the transmission of light waves, and the absorption layer 300 is located on the upper surface of the waveguide layer 200, as shown in Figure 4(a); in another example, the absorption layer 300 can also be partially embedded in the waveguide layer 200 , as shown in FIG. 4( b ); in yet another example, the absorbing layer 300 can also be completely embedded in the waveguide layer 200 , as shown in FIG. 4( c ).
  • the schematic diagram of the longitudinal section structure is shown in FIG. 6 .
  • the present invention provides a photodetector by changing the thickness of the end surface of the absorbing layer 300 near the light-incident surface, thereby changing the transmission and absorption distribution of light waves in the photodetector, and reducing the absorption at the front end of the photodetector.
  • the light energy as shown by the solid line in Figure 2, reduces the degree of aggregation of photogenerated carriers in the local area and reduces its influence on the electric field, thereby increasing the large light input threshold of the detector.
  • the thickness of the waveguide layer 200 may be greater than the thickness of the cladding material 100 .
  • the absorbing layer 300 may be located on the upper surface of the waveguide layer 200 or at least partially embedded in the waveguide layer 200, and the absorbing layer 300 may be The thickness of the end surface adjacent to the light incident surface is smaller than the thickness of other parts.
  • the width of the end surface of the absorbing layer 300 adjacent to the light incident surface is smaller than the width of other parts of the absorbing layer 300 .
  • the width of the end surface of the absorbing layer 300 adjacent to the light incident surface is smaller than the width of other parts of the absorbing layer 300, and the absorbing layer 300 can be divided into a first gradient portion 301 and a first straight line portion 302, and the first gradient portion 301 and the second linear portion 302.
  • the straight line portion 302 is an integral structure.
  • the width of the first gradient portion 301 gradually increases from the end surface close to the light incident surface along the direction away from the light incident surface until it is equal to the width of the first straight line portion 302 .
  • At least one end surface of the photodetector is a light incident surface
  • the absorption layer 300 can be divided into a first gradient portion 301 and a first straight line portion 302, as shown in FIG. 7 ;
  • first gradient portions 301 are provided at both ends of the first linear portion 302 of the absorbing layer 300 , as shown in FIG. 8 .
  • the shape of the absorbing layer 300 adjacent to the light-incident surface of the light-variable detector is changed, and a smaller width of the absorbing layer 300 is used at the light-incident surface that first contacts the light wave, so that the light absorbed by the adjacent light-incident surface The energy is reduced, and the distribution of photogenerated carriers is reduced.
  • the width of the absorbing layer 300 is widened to increase absorption, so that the distribution of light absorbed and generated carriers is uniform on the light wave transmission path. , to increase the large light input threshold of the photodetector.
  • the width of the end face of the waveguide layer 200 adjacent to the light incident surface is greater than the width of other parts of the waveguide layer 200 .
  • the width of the end face of the waveguide layer 200 adjacent to the light incident surface is greater than the width of other parts of the waveguide layer 200, and the waveguide layer 200 can be divided into a second gradient portion 201 and a second straight line portion 202, and the second gradient portion 201 and the second straight line portion
  • the part 202 is an integral structure.
  • the width of the end surface of the second gradient portion 201 decreases gradually from the end surface close to the light incident surface along the direction away from the light incident surface until it is the same as the width of the second straight line portion 202 .
  • At least one end surface of the photodetector is a light incident surface
  • the waveguide layer 200 can be divided into a second gradient portion 201 and a second straight line portion 202, as shown in FIG. 9 ;
  • first gradient portions 301 are provided at both ends of the second linear portion 202 of the waveguide layer 200 , as shown in FIG. 10 .
  • the shape of the waveguide layer 200 adjacent to the light-incident surface of the photodetector is changed, and the front end that first touches the light wave is used to use a larger width of the waveguide material to reduce the contact between the light field and the absorbing material, so that the adjacent light-incoming surface The light energy absorbed by the light surface is reduced, and the distribution of photogenerated carriers is reduced.
  • the width of the waveguide material is reduced to increase the absorption, so that on the transmission path, the light absorption and generated current carriers The sub-distribution is uniform, and the detector's large light input threshold is increased.
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is at least partly located within the upper surface of the waveguide layer 200 .
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is entirely located within the upper surface of the waveguide layer 200 as shown in FIG. 11 , or partly located within the upper surface of the waveguide layer 200 as shown in FIG. 12 .
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is located within the upper surface of the waveguide layer 200, and the centerline of the absorbing layer 300 deviates from the centerline of the waveguide layer 200, as shown in FIG. 11 .
  • the central line of the absorbent layer 300 refers to along the central axis of the absorbent layer 300 .
  • the centerline of the waveguide layer 200 refers to the central axis of the waveguide layer 200 .
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is all located inside the upper surface of the waveguide layer 200 , and the centerline of the absorbing layer 300 deviates upward or downward from the centerline of the waveguide layer 200 .
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is located inside the upper surface of the waveguide layer 200 , the centerline of the absorbing layer 300 deviates upward or downward from the centerline of the waveguide layer 200 .
  • the effect of the light wave and the absorbing layer 300 can be reduced, so that the light energy absorbed by the light incident surface of the photodetector is reduced, the distribution quantity of the photogenerated carriers is reduced, and the total energy of the light at the rear end is reduced, so that on the light wave transmission path , light absorption and generated carriers are evenly distributed, and the large light input threshold of the detector is improved.
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is located within the upper surface of the waveguide layer 200, and the centerline of the absorbing layer 300 deviates from the centerline of the waveguide layer 200, as shown in FIG. 12 .
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is located inside the upper surface of the waveguide layer 200 , and the centerline of the absorbing layer 300 deviates upward or downward from the centerline of the waveguide layer 200 .
  • the orthographic projection of the absorbing layer 300 on the upper surface of the waveguide layer 200 is located inside the upper surface of the waveguide layer 200 , the centerline of the absorbing layer 300 deviates upward or downward from the centerline of the waveguide layer 200 .
  • the effect of the light wave and the absorbing layer 300 can be reduced, so that the light energy absorbed by the light incident surface of the photodetector is reduced, the distribution quantity of the photogenerated carriers is reduced, and the total energy of the light at the rear end is reduced, so that on the light wave transmission path , light absorption and generated carriers are evenly distributed, and the large light input threshold of the detector is improved.
  • the positions of the absorbing layer 300 and the waveguide layer 200 and the shape of the waveguide layer 200 can be changed at the same time to control the transmission path of the input light wave at the front end of the detector and reduce the interaction with the absorbing material, so that the light energy absorbed by the front end Reduced, the distribution of photo-generated carriers is reduced, and the light-absorbed and generated carriers are evenly distributed on the transmission path, which increases the detector's large light input threshold.
  • the waveguide layer 200 is inclined at a preset angle compared to the extending direction of the absorbing layer 300 .
  • the waveguide layer 200 is inclined at a preset angle compared to the extending direction of the absorbing layer 300, so that by changing the relative positions of the input waveguide layer 200 and the absorbing layer 300, the incident light waves do not directly irradiate on the absorbing material, but It is gradually absorbed during the transmission process, so that the light energy absorbed by the front end is reduced, and the distribution of photogenerated carriers is reduced.
  • the carrier distribution of light absorption and generation is uniform, so as to improve the maximum light input threshold of the detector.
  • the angle at which the waveguide layer 200 is inclined relative to the extending direction of the absorbing layer 300 may be 5° to 45°, specifically, it may be 10°, 15°, 20°, 25°, 30°, 35° or 40° and so on.
  • the positions of the absorbing layer 300 and the waveguide layer 200 and the shape of the waveguide layer 200 can be changed at the same time, the transmission path of the input light wave at the front end of the photodetector can be controlled, and the interaction with the absorbing material can be reduced, so that the light energy absorbed by the front end Reduced, the distribution of photo-generated carriers is reduced, and the light-absorbed and generated carriers are evenly distributed on the transmission path, which increases the detector's large light input threshold.
  • the end surface of the waveguide layer 200 adjacent to the light incident surface is stepped.
  • At least one end surface of the photodetector is the incident surface, and the end surface of the waveguide layer 200 adjacent to the light incident surface is stepped.
  • the end surface of the waveguide layer 200 adjacent to the light incident surface is stepped, as shown in Figure 14; when both ends of the photodetector are incident surfaces, the waveguide layer 200 is adjacent to the light incident surface
  • the two end surfaces of both are stepped, as shown in Figure 15.
  • the stepped end surface of the waveguide layer 200 adjacent to the light incident surface here means that the end surface of the waveguide layer 200 adjacent to the light incident surface is stepped in the width direction, so that different parts of the waveguide layer 200 along the width direction have different lengths.
  • the end surface of the waveguide layer 200 adjacent to the light-incident surface is stepped, and the waveguide layer 200 is inclined at a certain angle compared with the extending direction of the absorbing layer 300 .
  • the incident light wave is not directly irradiated on the absorbing material, but is gradually absorbed during the transmission process, so that the light energy absorbed by the front end is reduced, and the distribution of photogenerated carriers is reduced. On the transmission path, light absorption and generated The uniform distribution of carriers increases the detector's large light input threshold.
  • the absorbing layer 300 includes: a first absorbing layer 303 and a second absorbing layer 304, the first absorbing layer 303 and The second absorbing layer 304 is integrally connected and located between the second absorbing layer 304 and the light incident surface; the light energy absorption rate of the first absorbing layer 303 is smaller than the light energy absorbing rate of the second absorbing layer 304 .
  • the absorption layer 300 of the photodetector is located on the waveguide layer 200 or at least partially embedded in the waveguide layer 200 ; the cladding material 100 covers the top and sidewalls of the waveguide layer 200 and the absorption layer 300 .
  • the absorbing layer 300 includes: a first absorbing layer 303 and a second absorbing layer 304 .
  • the first absorbing layer 303 and the second absorbing layer 304 are integrally connected, and the first absorbing layer 303 is located between the second absorbing layer 304 and the light incident surface, so that the first absorbing layer 303 is disposed close to the light incident surface.
  • the light energy absorption rate of the first absorption layer 303 is smaller than the light energy absorption rate of the second absorption layer 304 .
  • the absorbing layer 300 when one end surface of the photodetector is the light incident surface, the absorbing layer 300 includes: a first absorbing layer 303 and a second absorbing layer 304 connected in sequence, and the first absorbing layer 303 and the second absorbing layer 304 are integrated connected, and the first absorbing layer 303 is located between the second absorbing layer 304 and the light incident surface, so that the first absorbing layer 303 is arranged close to the light incident surface, that is, one end of the second absorbing layer 304 is connected with the first absorbing layer 303, such as Figure 16 shows.
  • the absorbing layer 300 includes: the first absorbing layer 303, the second absorbing layer 304, and the first absorbing layer 303 connected in sequence, and the first absorbing layer 303 and the second absorbing layer
  • the layers 304 are integrally connected, and the first absorbing layer 303 is located at both ends of the second absorbing layer 304, so that the first absorbing layer 303 is respectively adjacent to the light incident surfaces at both ends of the photodetector; that is, the opposite ends of the second absorbing layer 304 are A first sacrificial layer 303 is connected, as shown in FIG. 17 .
  • the first absorbent layer 303 and the second absorbent layer 304 are made of absorbent materials with different absorption coefficients, and the first absorbent layer 303 is located at both ends of the second absorbent layer 304, so that the first absorbent layer 303 are respectively adjacent to the light incident surfaces at both ends of the photodetector.
  • the first absorbing layer 303 adopts a material with a low absorption rate
  • the second absorbing layer 304 uses a material with a high absorbing rate, so that the light energy absorbed by the front end of the photodetector is reduced, and the distribution number of photogenerated carriers is reduced.
  • light absorption And the distribution of the generated carriers is uniform, which improves the large light input threshold of the detector.
  • the light energy absorptivity of the absorbing layer 300 increases gradually from the light incident surface away from the light incident surface.
  • the absorption layer 300 of the photodetector is located on the waveguide layer 200 or at least partially embedded in the waveguide layer 200 ; the cladding material 100 covers the top and sidewalls of the waveguide layer 200 and the absorption layer 300 .
  • the light energy absorptivity of the absorbing layer 300 gradually increases from the light-incident plane to the direction away from the light-incident plane.
  • the light energy absorption rate of the absorbing layer 300 gradually increases from the light incident surface to the other end surface away from the light incident surface, as shown in FIG. 18 .
  • both ends of the photodetector are light incident surfaces, the light energy absorption rate of the absorbing layer 300 increases gradually from the light incident surfaces at both ends towards the middle of the photodetector, as shown in FIG. 19 .
  • the absorbing layer 300 is made of a material with a gradual change in absorption rate, and the light energy absorption rate of the absorbing layer 300 gradually increases from the light incident surface to the direction away from the light incident surface.
  • the light energy absorbed by the front end is reduced, and the distribution of photogenerated carriers is reduced.
  • the light absorbed and generated carriers are evenly distributed, and the detector's large light input threshold is increased.
  • the waveguide layer 200 includes: a first waveguide layer 204 and a second waveguide layer 203, the second waveguide layer 203 is embedded In the first waveguide layer 204 , and the upper surface of the second waveguide layer 203 is higher than the upper surface of the first waveguide layer 204 , the absorbing layer 300 is located on the upper surface of the second waveguide layer 203 or at least partially embedded in the second waveguide layer 203 .
  • the absorption layer 300 of the photodetector is located on the waveguide layer 200 or at least partially embedded in the waveguide layer 200 ; the cladding material 100 covers the top and sidewalls of the waveguide layer 200 and the absorption layer 300 .
  • the waveguide layer 200 includes: a first waveguide layer 204 and a second waveguide layer 203 .
  • the second waveguide layer 203 is embedded in the first waveguide layer 204, and the upper surface of the second waveguide layer 203 is higher than the upper surface of the first waveguide layer 204, and the absorption layer 300 is located on the upper surface of the second waveguide layer 203 or is at least partially embedded in the second waveguide layer 203.
  • waveguide layer 203 includes: a first waveguide layer 204 and a second waveguide layer 203 .
  • the second waveguide layer 203 is embedded in the first waveguide layer 204, and the upper surface of the second waveguide layer 203 is higher than the upper surface of the first waveguide layer 204, and the absorption layer 300 is located on
  • the materials of the first waveguide layer 204 and the second waveguide layer 203 can be the same or different, and the uniform absorption distribution of the incident light can be controlled through the multi-layer waveguide material structure of different heights, thereby improving the large light input of the detector. threshold.
  • the width of the end surface of the first waveguide layer 204 adjacent to the light incident surface is greater than the width of other parts of the first waveguide layer 204, and the width of the end surface of the second waveguide layer 205 adjacent to the light incident surface is greater than that of other parts of the second waveguide layer 205.
  • the width of the first waveguide layer 204 and the minimum width of the second waveguide layer 205 are both greater than the width of the absorbing layer 300 .
  • the schematic diagram of the vertical section structure of the photodetector in this embodiment refers to the schematic diagram of the cross-sectional structure taken along the thickness direction of the photodetector
  • the schematic diagram of the cross-sectional structure of the photodetector refers to the section along the direction parallel to the photodetector. Schematic diagram of the cross-sectional structure taken from the surface.

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  • Light Receiving Elements (AREA)

Abstract

本申请涉及集成电路技术领域，特别是涉及一种光电探测器。一种光电探测器包括：波导层；吸收层，所述吸收层位于所述波导层上表面或至少部分嵌入所述波导层内；包层材料，所述包层材料覆盖所述波导层及吸收层的顶部及侧壁；其中，所述光电探测器至少一端面为入光面，所述吸收层在临近所述入光面的端面的厚度小于其他部分的厚度。本申请通过吸收层在临近入光面的端面的厚度小于其他部分的厚度，进而使临近入光面部分的吸收的光能量小于吸收层其他部分吸收的光能量，进而减小光生载流子在光电探测器的本征区域的聚集程度，增加光生载流子聚集区域的电场强度，减小大光输入对光电探测器带宽和响应度性能的影响，最终提升光电探测器的大光输入阈值。

Description

光电探测器 技术领域
本申请涉及集成电路技术领域，特别是涉及一种光电探测器。
 背景技术
当前互联网的发展、海量内容的涌现以及5G网络的部署和应用，对通信速率和通信容量要求日益增高。光电探测器是将高速光信号转化为电信号的器件，对其带宽、响应度、饱和光功率等技术指标也相应提升。一方面，根据香农定理，更高的通信速率要求更大的探测器带宽；另一方面，不同的应用场景和不同的发射端互通，要求接收端工作于一定的输入光功率范围。
常见的PIN型光电探测器的带宽由两个因素共同限制：1. 探测器的寄生电容和电阻大小；2. 光生载流子在探测器本征区的渡越时间。为减小寄生电容提升带宽，同时不影响响应度，光电探测器必须减小PIN结区的面积和增大区的宽度。本征区加宽导致了内部电场的减弱，光生载流子在电场中的漂移速度减慢，渡越时间增长；更严重的是当入射光功率增大，光生载流子数量增多并在PIN结中累积，载流子产生的电场减弱了PIN结中的漂移电场，使得光生载流子的渡越时间进一步增长。表现到光电探测器的性能是，当入射光功率增大并超过某一阈值时，探测器带宽减小，同时当光继续增强时，探测器响应度下降。
综上，如何提高探测器的大光输入阈值，成为本技术领域人员丞待解决的技术问题。
 技术问题
基于此，有必要针对现有技术中的问题提供一种减小大光输入对探测器带宽和响应度性能影响，最终提升探测器的大光输入阈值的光电探测器。
 技术解决方案
为了实现上述目的，本发明提供了一种光电探测器，所述光电探测器包括：
波导层；
吸收层，所述吸收层位于所述波导层的上表面或至少部分嵌入所述波导层内；
包层材料，所述包层材料覆盖所述波导层及吸收层的顶部及侧壁；
其中，所述光电探测器至少一端面为入光面，所述吸收层在临近所述入光面的端面的厚度小于其他部分的厚度。
在其中一个实施例中，所述波导层的厚度大于所述包层材料的厚度。
在其中一个实施例中，所述吸收层在临近所述入光面的端面宽度小于所述吸收层其他部分的宽度。
在其中一个实施例中，所述波导层在临近所述入光面的端面宽度大于所述波导层其他部分的宽度。
在其中一个实施例中，所述吸收层在所述波导层上表面的正投影至少部分位于所述波导层上表面内。
在其中一个实施例中，所述吸收层在所述波导层上表面的正投影位于所述波导层的上表面内，且所述吸收层的中心线偏离所述波导层的中心线。
在其中一个实施例中，所述吸收层在所述波导层上表面的正投影部分位于所述波导层的上表面内，且所述吸收层的中心线偏离所述波导层的中心线。
在其中一个实施例中，所述波导层相较于相较于所述吸收层延伸方向倾斜预设角度。
在其中一个实施例中，所述波导层临近所述入光面的端面呈台阶状。
在其中一个实施例中，所述吸收层包括：
第一吸收层及第二吸收层，所述第一吸收层与所述第二吸收层一体连接，且所述第一吸收层位于所述第二吸收层与所述入光面之间；所述第一吸收层的光能量吸收率小于第二吸收层的光能量吸收率。
在其中一个实施例中，所述吸收层的光能量吸收率自所述入光面向远离入光面的方向逐渐增大。
在其中一个实施例中，所述波导层包括：
第一波导层及第二波导层，所述第二波导层嵌入所述第一波导层内，且所述第二波导层的上表面高于所述第一波导层的上表面，所述吸收层位于所述第二波导层上表面或至少部分嵌入所述第二波导层。
 有益效果
上述光电探测器的吸收层位于波导层上或至少部分嵌入波导层内，包层材料覆盖波导层及吸收层的顶部及侧壁；其中，光电探测器至少一端面为入光面，吸收层在临近入光面的端面的厚度小于其他部分的厚度。本申请通过吸收层在临近入光面的端面的厚度小于其他部分的厚度，进而使临近入光面部分的吸收的光能量小于吸收层其他部分吸收的光能量，进而减小光生载流子在光电探测器的本征区域的聚集程度，增加光生载流子聚集区域的电场强度，减小大光输入对光电探测器带宽和响应度性能的影响，最终提升光电探测器的大光输入阈值。
 附图说明
为了更清楚地说明本申请实施例或传统技术中的技术方案，下面将对实施例或传统技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为一种探测器结构示意图；
图2为本申请的光电探测器与图1中的探测器及理想探测器沿光波传输方向吸收曲线的对比示意图；其中，曲线①为本申请的光电探测器沿光波传输方向吸收曲线，曲线②图1中的探测器沿光波传输方向吸收曲线，曲线③为理想探测器沿光波传输方向吸收曲线；
图3至图6为本申请不同实施例中提供的光电探测器的纵截面结构示意图；
图7至图21为本申请不同实施例中提供的光电探测器的横截面结构示意图。
 
附图标记说明：
100、包层材料；200、波导层； 201、第二渐变部；202、第二直线部；203、第二波导层；204、第一波导层；300、吸收层；301、第一渐变部；302、第一直线部；303、第一吸收层；304、第二吸收层。
 本发明的实施方式
为了便于理解本申请，下面将参照相关附图对本申请进行更全面的描述。附图中给出了本申请的实施例。但是，本申请可以以许多不同的形式来实现，并不限于本文所描述的实施例。相反地，提供这些实施例的目的是使本申请的公开内容更加透彻全面。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。本文中在本申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请。
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、掺杂类型和/或部分，这些元件、部件、区、层、掺杂类型和/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、掺杂类型或部分与另一个元件、部件、区、层、掺杂类型或部分。因此，在不脱离本发明教导之下，下面讨论的第一元件、部件、区、层、掺杂类型或部分可表示为第二元件、部件、区、层或部分；举例来说，可以将第一掺杂类型成为第二掺杂类型，且类似地，可以将第二掺杂类型成为第一掺杂类型；第一掺杂类型与第二掺杂类型为不同的掺杂类型，譬如，第一掺杂类型可以为P型且第二掺杂类型可以为N型，或第一掺杂类型可以为N型且第二掺杂类型可以为P型。
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，在这里可以用于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，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。此外，器件也可以包括另外地取向(譬如，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。
在此使用时，单数形式的“一”、“一个”和“所述/该”也可以包括复数形式，除非上下文清楚指出另外的方式。还应当理解的是，术语“包括/包含”或“具有”等指定所陈述的特征、整体、步骤、操作、组件、部分或它们的组合的存在，但是不排除存在或添加一个或更多个其他特征、整体、步骤、操作、组件、部分或它们的组合的可能性。同时，在本说明书中，术语“和/或”包括相关所列项目的任何及所有组合。
这里参考作为本发明的理想实施例(和中间结构)的示意图的横截面图来描述发明的实施例，这样可以预期由于例如制造技术和/或容差导致的所示形状的变化。因此，本发明的实施例不应当局限于在此所示的区的特定形状，而是包括由于例如制造技术导致的形状偏差。例如，显示为矩形的注入区在其边缘通常具有圆的或弯曲特征和/或注入浓度梯度，而不是从注入区到非注入区的二元改变。同样，通过注入形成的埋藏区可导致该埋藏区和注入进行时所经过的表面之间的区中的一些注入。因此，图中显示的区实质上是示意性的，它们的形状并不表示器件的区的实际形状，且并不限定本发明的范围。
解决大光带宽和响应度衰减的一种方案是提高加载在PIN探测器上的偏置电压，进而增强本征区的电场强度，以减弱大量光生载流子对电场的影响。此方法存在的问题是：1. 对TIA（Trans-impedance amplifier, 跨阻放大器）的或者外部供电要求提高，为满足大光下的带宽要求，SiGe探测器要求提供3V以上偏压，InP甚至要求5V以上，与未来CMOS集成发展的趋势不符；2. 大偏置电压下探测器的暗电流增加，产生的噪声也相应增加，同时高电场使得SiGe或者InP材料中的缺陷更多被激发，在持续工作中加速老化，缩短器件寿命。
解决大光带宽和响应度衰减的另一种方案是，将接收到的光分成几束，分别输入几个不同的探测器，或者探测器的不同区域，以减小在探测器的入射区域产生的光生载流子数量，减小对本征区域的电场影响；分别将入射光分成2束和4束，输入进1个和2个探测器，可以分别将探测器的大光输入衰减阈值提升3dB和6dB。该方案的问题是：1. 从探测器一端进入的光经过吸收区域，未被完全吸收时，会从另一端输出，沿着另一端的输入光路返回到传输链路，导致整个收端系统收端回损较低，影响整个传输链路；2. 当光被分为较多束，并联探测器较多时，不同探测器输出电信号之间易产生时延，同样会影响到探测器的整体带宽和收端系统性能；3. 当多个探测器并联时，收端芯片的良率和可靠性都会随着探测器数量的增加而降低。
一种同时解决大光带宽衰减和多探测器信号时延的方案，通过使用传输线结构的电极将多个探测器并联起来，并通过输入波导长度控制信号时延，从而实现多个探测器电信号的完全同步。这种方案的问题是，电极结构设计复杂度大，对工艺要求严格，应用不变，同样这个方案无法解决探测器对光不完全吸收导致的收端回损问题，以及由探测器数量增多带来的良率和可靠性降低的问题。如图1所示，普通光电探测器沿光的传输方向为一致的截面设计，因此，光在每一个截面上的吸收系数相同，导致光在进入到光电探测器中后，前端吸收光能量较多，后端随着总光功率衰减吸收到光能量较小。如图2中虚线所示，进而导致了光生载流子在探测器前端分布较多，在后端分布较少。本申请通过结构和材料设计，改变光波在光电探测器中的传输和吸收分布，减小在探测器前端吸收的光能量，如图2中实线所示，从而降低光生载流子在局部区域的聚集程度，减小其对电场影响，从而增大探测器的大光输入阈值。
如图3、图4和图5所示，本发明提供一种光电探测器，图3、图4和图5为本发明的光电探测器的纵截面结构示意图，光电探测器包括：波导层200、吸收层300和包层材料100。吸收层300位于波导层200的上表面或至少部分嵌入波导层200内；包层材料100覆盖波导层200及吸收层300的顶部及侧壁；其中，光电探测器至少一端面为入光面，吸收层300在临近入光面的端面的厚度小于其他部分的厚度。
在一个示例中，波导层200用于引导光波的传输，吸收层300位于波导层200的上表面，如图3（a）所示；在另一个示例中，吸收层300还可以部分嵌入波导层200内，如图3（b）所示；在又一个示例中，吸收层300还可以全部嵌入波导层200内，如图3（c）所示。
具体的，吸收层300吸收光波并产生载流子并形成光电流；包层材料100覆盖波导层200及吸收层300的顶部及侧壁，用于保护波导层200和吸收层300。吸收层300在临近入光面的端面的厚度小于其他部分的厚度。
更为具体的，波导层200用于引导光波的传输，吸收层300位于波导层200的上表面，如图4（a）所示；在另一个示例中，吸收层300还可以部分嵌入波导层200内，如图4（b）所示；在又一个示例中，吸收层300还可以全部嵌入波导层200内，如图4（c）所示。当光电探测器两端面均为入光面时的纵截面结构示意图如图6所示。
具体地，本发明提供一种光电探测器通过改变吸收层300在临近入光面的端面的厚度，进而改变了光波在光电探测器中的传输和吸收分布，减小在光电探测器前端吸收的光能量，如图 2中实线所示，从而降低光生载流子在局部区域的聚集程度，减小其对电场影响，从而增大探测器的大光输入阈值。避免了普通光电探测器沿光波的传输方向为一致的截面设计，使光波在每一个截面上吸收的光能量相同，导致光波在进入到光电探测器中后，前端吸收光能量较多，后端随着总光功率衰减吸收到光能量较小，进而导致了光生载流子在探测器前端分布较多，在后端分布较少。
如图6所示，在其中一个实施例中，波导层200的厚度可以大于包层材料100的厚度。
具体地，在波导层200的厚度可以大于包层材料100的厚度的实施例中，可以为吸收层300位于波导层200的上表面或至少部分嵌入波导层200内，且可以为吸收层300在临近入光面的端面的厚度小于其他部分的厚度。通过增加波导层200的厚度，使得光波入射到光电探测器后，光场的分布向下移动，当光波由波导层200进入到吸收层300时，由于波导层200的厚度增大，使波导层200与吸收层300的相互作用的距离增大而使作用减弱，因此前端吸收到的光能量降低，光生载流子的分布数量降低，在光波传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在图3至图6的基础上，如图7和图8所示，在其中一个实施例中，吸收层300临近入光面的端面的宽度小于吸收层300其他部分的宽度。
具体地，吸收层300临近入光面的端面的宽度小于吸收层300其他部分的宽度，吸收层300可分为第一渐变部301和第一直线部302，其第一渐变部301和第一直线部302为一体结构。第一渐变部301的宽度自临近入光面的端面沿远离入光面方向逐渐增大，直至与第一直线部302的宽度相同。
进一步地，光电探测器至少一端面为入光面，当探测器一端面为入光面时，吸收层300可分为第一渐变部301和第一直线部302，如图7所示；当探测器两端面为入光面时，吸收层300的第一直线部302的两端分别设有第一渐变部301，如图8所示。
上述实施例中，改光变探测器邻近入光面的吸收层300的形状，在最先接触到光波的入光面处用较小的吸收层300宽度，使得邻近入光面吸收到的光能量降低，进而光生载流子的分布数量降低，后端随着光总能量降低，加宽吸收层300的宽度以增加吸收，使得在光波传输路径上，光吸收和产生的载流子分布均匀，提升光电探测器大光输入阈值。
在图3至图6的基础上，如图9和图10所示，在其中一个实施例中，波导层200临近入光面的端面宽度大于波导层200其他部分的宽度。
具体地，波导层200临近入光面的端面宽度大于波导层200其他部分的宽度，波导层200可分为第二渐变部201和第二直线部202，其第二渐变部201和第二直线部202为整体结构。第二渐变部201的端面的宽度自临近入光面的端面沿远离入光面方向逐渐减小，直至与第二直线部202的宽度相同。
进一步地，光电探测器至少一端面为入光面，当探测器一端面为入光面时，波导层200可分为第二渐变部201和第二直线部202，如图9所示；当探测器两端面为入光面时，波导层200的第二直线部202的两端分别设有第一渐变部301，如图10所示。
上述实施例中，改变光电探测器邻近入光面的波导层200的形状，在最先接触到光波的前端，用较大的波导材料宽度，减小光场与吸收材料的接触，使得邻近入光面吸收到的光能量降低，进而光生载流子的分布数量降低，后端随着光总能量降低，减小波导材料宽度以增加吸收，使得在传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在图3至图6的基础上，如图11和图12所示，在其中一个实施例中，吸收层300在波导层200上表面的正投影至少部分位于波导层200上表面内。
具体地，吸收层300在波导层200上表面的正投影全部位于波导层200上表面内，如图11所示，或者部分位于波导层200上表面内，如图12所示。
在其中一个实施例中，吸收层300在波导层200上表面的正投影位于波导层200的上表面内，且吸收层300的中心线偏离波导层200的中心线，如图11所示。
其中，吸收层300的中心线是指沿吸收层300的中轴线。波导层200的中心线是指波导层200的中轴线。吸收层300在波导层200上表面的正投影全部位于波导层200上表面内，且吸收层300的中心线向上或向下偏离波导层200的中心线。
上述实施例中，由于光波在输入波导中主要分布在中间位置，通过改变吸收层300与波导层200的位置关系，吸收层300在波导层200上表面的正投影位于波导层200的上表面内，将吸收层300的中心线向上或向下偏离波导层200的中心线。如此可以减小光波与吸收层300的作用，使得光电探测器入光面吸收到的光能量降低，光生载流子的分布数量降低，后端随着光总能量降低，使得在光波传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在其中一个实施例中，吸收层300在波导层200上表面的正投影部分位于波导层200的上表面内，且吸收层300的中心线偏离波导层200的中心线，如图12所示。
具体地，吸收层300在波导层200上表面的正投影部分位于波导层200上表面内，且吸收层300的中心线向上或向下偏离波导层200的中心线。
上述实施例中，由于光波在输入波导中主要分布在中间位置，通过改变吸收层300与波导层200的位置关系，吸收层300在波导层200上表面的正投影部分位于波导层200上表面内，将吸收层300的中心线向上或向下偏离波导层200的中心线。如此可以减小光波与吸收层300的作用，使得光电探测器入光面吸收到的光能量降低，光生载流子的分布数量降低，后端随着光总能量降低，使得在光波传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在该实施例中，可以同时改变吸收层300与波导层200的位置以及波导层200的形状，控制输入光波在探测器前端的传输路径，减少与吸收材料相互作用，使得前端吸收到的光能量降低，光生载流子的分布数量降低，在传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在如图3至图6的基础上，如图13所示，在其中一个实施例中，波导层200相较于吸收层300的延伸方向倾斜预设角度。
具体地，波导层200相较于吸收层300的延伸方向倾斜预设角度，如此通过改变输入波导层200与吸收层300的相对位置，使入射光波并不直接照射到吸收材料上，而是在传输过程中被逐渐吸收，使得前端吸收到的光能量降低，进而光生载流子的分布数量降低。在光波传输的路径上，使光吸收和产生的载流子分布均匀，达到提升探测器大光输入阈值。
更为具体的，波导层200相较于吸收层300的延伸方向倾斜的角度可以为5°~45°，具体的，可以为10°、15°、20°、25°、30°、35°或40°等等。
上述实施例中，可以同时改变吸收层300与波导层200的位置以及波导层200的形状，控制输入光波在光电探测器前端的传输路径，减少与吸收材料相互作用，使得前端吸收到的光能量降低，光生载流子的分布数量降低，在传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在如图3至图6的基础上，如图14和图15所示，在其中一个实施例中，波导层200临近入光面的端面呈台阶状。
具体地，光电探测器至少一端面为入射面，波导层200临近入光面的端面呈台阶状。当光电探测器一端面为入射面时，波导层200临近入光面的一端面呈台阶状，如图14所示；当光电探测器两端均为入射面时，波导层200临近入光面的两端面均呈台阶状，如图15所示。需要说明的是，这里的波导层200临近入光面的端面呈台阶状是指波导层200临近入光面的端面沿宽度方向呈台阶状，这样会使得波导层200沿宽度方向的不同部分具有不同的长度。
在该实施例中，通过将波导层200临近入光面的端面呈台阶状，以及波导层200相较于吸收层300的延伸方向倾斜一定角度。使入射光波并不直接照射到吸收材料上，而是在传输过程中被逐渐吸收，使得前端吸收到的光能量降低，光生载流子的分布数量降低，在传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在如图3至图6的基础上，如图16和图17所示，在其中一个实施例中，吸收层300包括：第一吸收层303及第二吸收层304，第一吸收层303与第二吸收层304一体连接，且位于第二吸收层304与入光面之间；第一吸收层303的光能量吸收率小于第二吸收层304的光能量吸收率。
具体地，光电探测器的吸收层300位于波导层200上或至少部分嵌入波导层200内；包层材料100覆盖波导层200及吸收层300的顶部及侧壁。其中，吸收层300包括：第一吸收层303及第二吸收层304。并且第一吸收层303与第二吸收层304为一体连接，且第一吸收层303位于第二吸收层304与入光面之间，使第一吸收层303靠近入光面设置。第一吸收层303的光能量吸收率小于第二吸收层304的光能量吸收率。
具体地，当光电探测器的一端面为入光面时，吸收层300包括：依次连接的第一吸收层303及第二吸收层304，并且第一吸收层303与第二吸收层304为一体连接，且第一吸收层303位于第二吸收层304与入光面之间，使第一吸收层303靠近入光面设置，即第二吸收层304的一端连接有第一吸收层303，如图16所示。当光电探测器的两端均为入光面时，吸收层300包括：依次连接的第一吸收层303、第二吸收层304及第一吸收层303，并且第一吸收层303与第二吸收层304为一体连接，且第一吸收层303位于第二吸收层304的两端，使第一吸收层303分别邻近光电探测器两端的入光面；即第二吸收层304相对的两端均连接有第一牺牲层303，如图17所示。
在该实施例中，使第一吸收层303及第二吸收层304具有不同吸收系数的吸收材料制作而成，且第一吸收层303位于第二吸收层304的两端，使第一吸收层303分别邻近光电探测器两端的入光面。第一吸收层303采用低吸收率材料，第二吸收层304使用高吸收率材料，使得光电探测器前端吸收到的光能量降低，光生载流子的分布数量降低，在传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在如图3至图6的基础上，如图18和图19所示，在其中一个实施例中，吸收层300的光能量吸收率自入光面向远离入光面的方向逐渐增大。
具体地，光电探测器的吸收层300位于波导层200上或至少部分嵌入波导层200内；包层材料100覆盖波导层200及吸收层300的顶部及侧壁。其中，吸收层300的光能量吸收率自入光面向远离入光面的方向逐渐增大。
具体地，当光电探测器的一端面为入光面时，吸收层300的光能量吸收率自入光面向远离入光面的另一端面逐渐增大，如图18所示。当光电探测器的两端均为入光面时，吸收层300的光能量吸收率分别自两端的入光面向光电探测器中间的方向逐渐增大，如图19所示。
在该实施例中，吸收层300采用吸收率渐变的材料，吸收层300的光能量吸收率自入光面向远离入光面的方向逐渐增大。使得前端吸收到的光能量降低，光生载流子的分布数量降低，在传输路径上，光吸收和产生的载流子分布均匀，提升探测器大光输入阈值。
在如图3至图6的基础上，如图20和图21所示，在其中一个实施例中，波导层200包括：第一波导层204及第二波导层203，第二波导层203嵌入第一波导层204内，且第二波导层203的上表面高于第一波导层204的上表面，吸收层300位于第二波导层203上表面或至少部分嵌入第二波导层203。
具体地，光电探测器的吸收层300位于波导层200上或至少部分嵌入波导层200内；包层材料100覆盖波导层200及吸收层300的顶部及侧壁。其中，波导层200包括：第一波导层204及第二波导层203。第二波导层203嵌入第一波导层204内，且第二波导层203的上表面高于第一波导层204的上表面，吸收层300位于第二波导层203上表面或至少部分嵌入第二波导层203。
具体地，第一波导层204和第二波导层203的材料可以相同也可以不同，通过不同高度的多层波导材料结构，实现控制对入射光的均匀吸收分布，从而提升探测器的大光输入阈值。
更为具体的，第一波导层204临近入光面的端面的宽度大于第一波导层204其他部分的宽度，第二波导层205临近入光面的端面的宽度大于第二波导层205其他部分的宽度，且第一波导层204的宽度及第二波导层205的最小宽度均大于吸收层300的宽度。
需要说明的是，本实施例中光电探测器的纵截面结构示意图是指沿光电探测器的厚度方向截取的截面结构示意图，光电探测器的横截面结构示意图是指沿平行于光电探测器的上表面截取的截面结构示意图。
在本说明书的描述中，参考术语“有些实施例”、“其他实施例”、“理想实施例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特征包含于本发明的至少一个实施例或示例中。在本说明书中，对上述术语的示意性描述不一定指的是相同的实施例或示例。
上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对申请专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。

Claims (12)

  1. 一种光电探测器，其特征在于，所述光电探测器包括：
    波导层；
    吸收层，所述吸收层位于所述波导层的上表面或至少部分嵌入所述波导层内；
    包层材料，所述包层材料覆盖所述波导层及吸收层的顶部及侧壁；
    其中，所述光电探测器至少一端面为入光面，所述吸收层在临近所述入光面的端面的厚度小于其他部分的厚度。
  2. 根据权利要求1所述的光电探测器，其特征在于，所述波导层的厚度大于所述包层材料的厚度。
  3. 根据权利要求1所述的光电探测器，其特征在于，所述吸收层在临近所述入光面的端面宽度小于所述吸收层其他部分的宽度。
  4. 根据权利要求1所述的光电探测器，其特征在于，所述波导层在临近所述入光面的端面宽度大于所述波导层其他部分的宽度。
  5. 根据权利要求1所述的光电探测器，其特征在于，所述吸收层在所述波导层上表面的正投影至少部分位于所述波导层上表面内。
  6. 根据权利要求5所述的光电探测器，其特征在于，所述吸收层在所述波导层上表面的正投影位于所述波导层的上表面内，且所述吸收层的中心线偏离所述波导层的中心线。
  7. 根据权利要求5所述的光电探测器，其特征在于，所述吸收层在所述波导层上表面的正投影部分位于所述波导层的上表面内，且所述吸收层的中心线偏离所述波导层的中心线。
  8. 根据权利要求1所述的光电探测器，其特征在于，所述波导层相较于相较于所述吸收层延伸方向倾斜预设角度。
  9. 根据权利要求1所述的光电探测器，其特征在于，所述波导层临近所述入光面的端面呈台阶状。
  10. 根据权利要求1所述的光电探测器，其特征在于，所述吸收层包括：
    第一吸收层及第二吸收层，所述第一吸收层与所述第二吸收层一体连接，且所述第一吸收层位于所述第二吸收层与所述入光面之间；所述第一吸收层的光能量吸收率小于第二吸收层的光能量吸收率。
  11. 根据权利要求1所述的光电探测器，其特征在于，所述吸收层的光能量吸收率自所述入光面向远离入光面的方向逐渐增大。
  12. 根据权利要求1所述的光电探测器，其特征在于，所述波导层包括：
    第一波导层及第二波导层，所述第二波导层嵌入所述第一波导层内，且所述第二波导层的上表面高于所述第一波导层的上表面，所述吸收层位于所述第二波导层上表面或至少部分嵌入所述第二波导层。
PCT/CN2022/113315 2021-12-06 2022-08-18 光电探测器 WO2023103444A1 (zh)

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