A segmented bandwidth-enhanced high responsivity silicon germanium photodetector

Abstract

The present application relates to photoelectric detector, specifically to a segmented bandwidth enhancement high responsivity silicon germanium photodetector, solve the problem that the volume of the germanium absorption layer of the existing silicon germanium photodetector is large, which leads to large RC parameter of the whole device, and then leads to low photoelectric bandwidth, and reducing the size of the germanium absorption layer may not fully absorb light, resulting in reduced responsivity, the present application uses segmented germanium absorption layer, removes the germanium absorption layer without light field distribution by etching groove, reduces the volume of the germanium absorption layer, reduces the RC parameter, while maintaining the responsivity of the silicon germanium photodetector unchanged, effectively improves the photoelectric bandwidth of the detector, and improves the communication ability of the device. The distributed bragg reflector structure promotes the secondary absorption of light by the germanium absorption layer, further improves the responsivity of the detector, while not affecting the bandwidth, dark current and other performances.

Description

Technical Field

[0001] This invention relates to photodetectors, and more specifically to a segmented bandwidth-enhanced high-response silicon-germanium photodetector. Background Technology

[0002] With the rapid development of cloud computing, big data centers, and artificial intelligence technologies, the demands on data center information transmission capacity and speed are increasing dramatically. Traditional electrical interconnection solutions are gradually failing to meet the bandwidth and speed transmission requirements of massive amounts of data in these systems. Against this backdrop, silicon-based optoelectronic technology, compatible with CMOS (Complementary Metal-oxide Semiconductor) processes, has emerged. Among these technologies, silicon-based photodetectors, as one of the core components of receiver chips in optical interconnection systems, possess characteristics such as low dark current, high responsivity, and high bandwidth.

[0003] Silicon-based photodetectors convert optical signals into electrical signals during operation. However, due to the bandgap structure of silicon, pure silicon-based photodetectors cannot achieve effective detection in the communication band. To solve this problem, germanium is usually introduced into silicon. Germanium is compatible with CMOS technology and its cutoff wavelength covers the communication band. Therefore, silicon-germanium photodetectors with a silicon-germanium structure are generally used to achieve communication band detection.

[0004] The basic structure of commonly used silicon-germanium photodetectors is as follows: Figure 1As shown, the structure includes a silicon substrate layer 01, a buried oxide layer 02, and a silicon waveguide layer 03 arranged sequentially from bottom to top. The silicon waveguide layer 03 includes a silicon strip waveguide 031, a silicon tapered waveguide 032, and silicon waveguide regions. The silicon strip waveguide 031 is positioned near one end of the buried oxide layer 02 along its length, and the length direction of the silicon strip waveguide 031 is parallel to the length direction of the buried oxide layer 02. The silicon waveguide region is positioned near the other end of the buried oxide layer 02 along its length, and has two grooves on it. The length directions of the two grooves are parallel to the length direction of the silicon strip waveguide 03, and both are positioned along the width direction of the buried oxide layer 02, forming three protrusions on the silicon waveguide region. The three protrusions are the first silicon waveguide region 033, the second silicon waveguide region 034, and the third silicon waveguide region 035. The three silicon waveguide regions 035 are located between the second silicon waveguide region 034 and the third silicon waveguide region 035. The silicon tapered waveguide 032 has a tapered structure, with its small end connected to one end of the silicon strip waveguide 031 and its other end connected to one end of the first silicon waveguide region 033. The first silicon waveguide region 033, the second silicon waveguide region 034 and the third silicon waveguide region 035 are respectively provided with a first metal electrode plate 04, a second metal electrode plate 05 and a third metal electrode plate 06. All three are plate-shaped structures and are arranged accordingly. A germanium absorption layer 07 is provided between the first metal electrode plate 04 and the first silicon waveguide region 033. The germanium absorption layer 07 has a rectangular structure and its length is the same as that of the first silicon waveguide region 033.

[0005] In traditional silicon-germanium photodetectors, the germanium absorption layer 07 has a large volume, resulting in a large resistance-capacitance (RC) parameter for the entire device. This limits the RC and consequently leads to a low photoelectric bandwidth for traditional silicon-germanium photodetectors.

[0006] Furthermore, there is a certain constraint relationship between the bandwidth and responsivity of silicon-germanium photodetectors. In order to improve the bandwidth, it is usually necessary to increase the carrier transit time-limited bandwidth or RC-limited bandwidth of the device, that is, to reduce the intrinsic region width or the size of the germanium absorption layer 07. However, as the size of the germanium absorption layer 07 decreases, the light absorption may be insufficient, which may lead to a decrease in responsivity. Summary of the Invention

[0007] The purpose of this invention is to solve the technical problems of existing silicon-germanium photodetectors, which have a large germanium absorption layer, resulting in a large RC parameter of the entire device, which in turn leads to a low photoelectric bandwidth. Furthermore, reducing the size of the germanium absorption layer may result in insufficient light absorption and reduced responsivity. The invention provides a segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector.

[0008] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0009] A segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector includes, from bottom to top, a silicon substrate layer, a buried oxide layer, and a silicon waveguide layer. Both the silicon substrate layer and the buried oxide layer are rectangular structures. The silicon waveguide layer includes a silicon strip waveguide, a silicon tapered waveguide, and a silicon waveguide region. One end of the silicon strip waveguide is located at the middle of one end of the buried oxide layer along its length, and the two are parallel in their length directions. The silicon tapered waveguide has a tapered structure, with its smaller end connected to the other end of the silicon strip waveguide. The silicon waveguide region has a rectangular structure and is located near the other end of the buried oxide layer along its length. Two grooves are arranged side-by-side along the width direction of the buried oxide layer, forming three parallel protrusions on the rear silicon waveguide layer. These three protrusions are a second silicon waveguide region, a third silicon waveguide region, and a first silicon waveguide region located between them. The larger end of the silicon tapered waveguide is connected to one end of the first silicon waveguide region. Its special feature is that:

[0010] It also includes a segmented germanium absorption layer, metal electrodes, and a distributed Bragg reflector;

[0011] The segmented germanium absorption layer is disposed on the top of the first silicon waveguide region. The segmented germanium absorption layer includes a plurality of rectangular sub-germanium absorption layers arranged sequentially along the length direction of the first silicon waveguide region, and an etching groove is provided between two adjacent sub-germanium absorption layers.

[0012] The metal electrode includes a first metal electrode, a second metal electrode, and a third metal electrode. There are multiple first metal electrodes, which are respectively disposed on multiple sub-germanium absorption layers. The projections of all the first metal electrodes in a vertical plane perpendicular to the length direction of the buried oxide layer coincide, and their tops are connected through a first upper metal electrode.

[0013] There are multiple second metal electrodes disposed on top of the second silicon waveguide region along the length direction. The projections of all the second metal electrodes in a vertical plane perpendicular to the length direction of the buried oxide layer coincide, and the top is connected by a second upper metal electrode.

[0014] The third metal electrode is multiple and is disposed on the top of the third silicon waveguide region along the length direction. The projections of all the third metal electrodes in the vertical plane perpendicular to the length direction of the buried oxide layer coincide, and the top is connected by the third upper metal electrode.

[0015] The first upper metal electrode, the second upper metal electrode, and the third upper metal electrode are each connected to a solder pad;

[0016] One end of the distributed Bragg reflector is connected to the other end of the first silicon waveguide region, and the other end is flush with the other end face of the buried oxide layer along its length.

[0017] Furthermore, the first upper metal electrode is connected to the pad via a coiled wire inductor;

[0018] The coiled inductor includes an upper coil and a lower coil arranged coaxially. The lower coil has a first notch. The upper coil is formed by a first upper coil and a second upper coil of the same size and structure, which are arranged opposite to each other. The projection of the lower coil in the horizontal plane is located inside the upper coil.

[0019] One end of the lower coil at the first notch is connected to one end of the first upper coil via a first connecting line, and the other end is connected to one end of the second upper coil via a second connecting line, with the first connecting line and the second connecting line intersecting each other.

[0020] An electrode connection section is provided on the outer wall of the lower coil at a position opposite to the first notch, which is connected to the first upper metal electrode.

[0021] The other ends of the first upper coil and the second upper coil are respectively provided with inductor output sections, which are arranged in parallel. One of the inductor output sections is connected to the pad, and the other is grounded. The projection of the electrode connection section in the horizontal plane is located in the middle of the projections of the two inductor output sections in the horizontal plane, and the three are arranged in parallel.

[0022] Furthermore, the first silicon waveguide region is P-type doped, the upper part of the germanium sub-absorbing layer is N-type doped, the middle part is undoped, and the undoped part forms the intrinsic region;

[0023] The germanium absorption layer has a thickness of 0.01-2 μm, a width of 0.01-5 μm, and a length of 0.01-5 μm.

[0024] The width of the etching groove is 0.1-0.5 μm.

[0025] Furthermore, the width of the groove is 0.1-2 μm and the depth is 0.01-1 μm;

[0026] Both the second and third silicon waveguide regions are P-type doped.

[0027] Furthermore, the number of the second metal electrode and the third metal electrode are the same, and they are arranged in a one-to-one correspondence.

[0028] Furthermore, the distributed Bragg reflector is at least a first-order distributed Bragg reflector with 2-20 periods.

[0029] Furthermore, the first metal electrode, the second metal electrode, and the third metal electrode have the same structure, all being rectangular structures with a width of 0.01-5 μm and a length of 0.01-5 μm.

[0030] Furthermore, the end of the distributed Bragg reflector connected to the first silicon waveguide region has the same cross-sectional dimensions as the first silicon waveguide region.

[0031] Compared with the prior art, the present invention has the following beneficial technical effects:

[0032] 1. The present invention provides a segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector. By using a segmented germanium absorption layer, the germanium absorption layer without light field distribution is removed by etching grooves, thereby reducing the volume of the germanium absorption layer and lowering the RC parameter. While maintaining the responsivity of the silicon-germanium photodetector, the photoelectric bandwidth of the detector is effectively improved, enhancing the communication capability of the device. Furthermore, the distributed Bragg reflector promotes the secondary absorption of light by the segmented germanium absorption layer, further improving the detector responsivity without affecting other performance characteristics such as bandwidth and dark current.

[0033] 2. The present invention provides a segmented bandwidth-enhanced high-response silicon-germanium photodetector, which adopts a coiled wire-drawn inductor structure and utilizes gain peaking technology to compensate for the bandwidth degradation caused by junction capacitance at high frequency signals, thereby further improving the bandwidth of the photodetector. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of an existing silicon-germanium photodetector;

[0035] Figure 2 This is a schematic diagram of the structure of an embodiment of a segmented bandwidth-enhanced high-response silicon-germanium photodetector according to the present invention;

[0036] Figure 3 This is a graph showing the relationship between the reflectivity of the distributed Bragg reflector and wavelength in an embodiment of the present invention.

[0037] Figure 4 The diagrams show a comparison of the light field distribution between existing silicon-germanium photodetectors and embodiments of the present invention, where a is the light field distribution diagram of the embodiment of the present invention and b is the light field distribution diagram of existing silicon-germanium photodetectors.

[0038] Figure 5 This is a schematic diagram of the structure of the coiled inductor in an embodiment of the present invention;

[0039] Figure 6 This is an equivalent circuit diagram of an embodiment of the present invention;

[0040] Figure 7 This is a comparison chart of the photoelectric bandwidth curves of existing silicon-germanium photodetectors, embodiments of the present invention, and embodiments of the present invention without a coiled inductor.

[0041] The annotations in the attached figures are explained as follows:

[0042] 01-Silicon substrate layer, 02-Buried oxide layer, 03-Silicon waveguide layer, 031-Silicon strip waveguide, 032-Silicon tapered waveguide, 033-First silicon waveguide region, 034-Second silicon waveguide region, 035-Third silicon waveguide region, 04-First metal electrode plate, 05-Second metal electrode plate, 06-Third metal electrode plate, 07-Germanium absorption layer;

[0043] 1-Germanium absorption layer, 2-First metal electrode, 3-Second metal electrode, 4-Third metal electrode, 5-Distributed Bragg reflector, 6-First upper metal electrode, 7-Second upper metal electrode, 8-Third upper metal electrode, 9-Pad, 10-Draw-out inductor, 101-Lower coil, 102-First upper coil, 103-Second upper coil, 104-First connecting line, 105-Second connecting line, 106-Electrode connection section, 107-Inductor output section. Detailed Implementation

[0044] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0045] like Figures 2-7 As shown, this embodiment provides a segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector, comprising a silicon substrate layer 01, a buried oxide layer 02, and a silicon waveguide layer 03 arranged sequentially from bottom to top. Both the silicon substrate layer 01 and the buried oxide layer 02 are rectangular structures. The silicon waveguide layer 03 includes a silicon strip waveguide 031, a silicon tapered waveguide 032, and a silicon waveguide region. One end of the silicon strip waveguide 031 is located at the middle of one end of the buried oxide layer 02 along its length, and the two are parallel in their length directions. The silicon tapered waveguide 032 has a tapered structure, with its small end connected to the other end of the silicon strip waveguide 031. The waveguide region has a rectangular structure and is located near the other end of the buried oxide layer 02 along its length. Two grooves are arranged side-by-side along the width of the buried oxide layer 02, with their lengths parallel to the length of the buried oxide layer 02. The grooves have a width of 0.1-2 μm and a depth of 0.01-1 μm, resulting in three parallel protrusions on the rear silicon waveguide layer. These three protrusions are the second silicon waveguide region 034, the third silicon waveguide region 035, and the first silicon waveguide region 033 located between them. The larger end of the silicon tapered waveguide 032 is connected to one end of the first silicon waveguide region 033. All three silicon waveguide regions—the first silicon waveguide region 033, the second silicon waveguide region 034, and the third silicon waveguide region 035—are p-type doped.

[0046] The difference between this invention and traditional silicon-germanium photodetectors is that it includes a segmented germanium absorption layer, metal electrodes, and a distributed Bragg reflector 5.

[0047] The segmented germanium absorber layer is disposed on top of the first silicon waveguide region 033. The segmented germanium absorber layer includes multiple rectangular sub-germanium absorber layers 1 arranged sequentially along the length of the first silicon waveguide region 033. An etching trench is formed between adjacent sub-germanium absorber layers 1. The upper part of the sub-germanium absorber layer 1 is N-type doped, while the middle part is undoped, and the undoped portion forms the intrinsic region. The thickness of the sub-germanium absorber layer 1 is 0.01-2 μm, the width is 0.01-5 μm, and the length is 0.01-5 μm. The width of the etching trench is 0.1-0.5 μm. In fabricating a segmented germanium absorber layer, the traditional rectangular germanium absorber layer 07 is etched in segments to form multiple regularly arranged sub-germanium absorber layers 1. The arrangement and size of the etching trenches are related to the light field transmission. Generally, no light field is transmitted within the etching trenches, while light field transmission only occurs within the sub-germanium absorber layers 1. Thus, the light absorption efficiency of the entire segmented germanium absorber layer remains almost unchanged. Furthermore, the etching trenches reduce the volume of the traditional germanium absorber layer 07. By using etching trenches of different widths and sub-germanium absorber layers 1 of different sizes according to different light field distributions, the volume can be reduced by 20%-45%, thereby reducing the RC parameter of the photodetector and increasing the photoelectric bandwidth of the photodetector. Figure 4 The comparison between (a) and (b) shows that after etching the traditional germanium absorption layer 07 to form multiple sub-germanium absorption layers 1, the optical field distribution does not change drastically compared to the unetched structure.

[0048] The metal electrodes include a first metal electrode 2, a second metal electrode 3, and a third metal electrode 4. All three have the same structure, which is a rectangular structure with a width of 0.01-5 μm and a length of 0.01-5 μm.

[0049] There are multiple first metal electrodes 2, which are respectively disposed on multiple sub-germanium absorption layers 1. The projections of all first metal electrodes 2 in a vertical plane perpendicular to the length direction of the buried oxide layer 02 coincide, and their tops are connected by a first upper metal electrode 6.

[0050] Multiple second metal electrodes 3 are arranged sequentially along the length direction on the top of the second silicon waveguide region 034. The projections of all second metal electrodes 3 in a vertical plane perpendicular to the length direction of the buried oxide layer 02 coincide, and their tops are connected by a second upper metal electrode 7.

[0051] Multiple third metal electrodes 4 are sequentially arranged on top of the third silicon waveguide region 035 along its length. The projections of all third metal electrodes 4 in a vertical plane perpendicular to the length of the buried oxide layer 02 coincide, and their tops are connected by a third upper metal electrode 8. In this embodiment, the number of second metal electrodes 3 and third metal electrodes 4 are the same, and they are arranged in a one-to-one correspondence.

[0052] The first upper metal electrode 6, the second upper metal electrode 7, and the third upper metal electrode 8 are each connected to a solder pad 9. The solder pad 9 is used to connect with external components to achieve signal output.

[0053] One end of the distributed Bragg reflector 5 is connected to the other end of the first silicon waveguide region 033, and the other end is flush with the other end face of the buried oxide layer 02 along its length. It is used to reflect unabsorbed light back into the first silicon waveguide region 033, promote secondary absorption of light by the segmented germanium absorption layer, and improve responsivity. Figure 3 The diagram shows the reflectivity of the distributed Bragg reflector 5 in this embodiment of the invention as a function of wavelength. It can be seen that the reflectivity can reach a maximum of 95%-96%. Furthermore, the end of the distributed Bragg reflector 5 connected to the first silicon waveguide region 033 has the same cross-sectional dimensions as the first silicon waveguide region 033. Figure 4 The comparison between (a) and (b) shows that the addition of the distributed Bragg reflector 5 results in a stronger light field energy, which improves the light absorption efficiency of the germanium absorption layer compared to the existing structure.

[0054] Furthermore, the distributed Bragg reflector 5 is at least a first-order distributed Bragg reflector with 2-20 periods, and its duty cycle and number of periods vary with the detection band of the silicon-germanium photodetector.

[0055] To further broaden the bandwidth of the silicon-germanium photodetector and achieve a faster photoelectric response, a coiled wire inductor 10 is provided between the first upper metal electrode 6 and the pad 9, and the two are connected through the coiled wire inductor 10.

[0056] like Figure 5 As shown, the coiled inductor 10 includes an upper coil and a lower coil 101 arranged coaxially. The lower coil 101 has a first notch. The upper coil is formed by a first upper coil 102 and a second upper coil 103 of the same size. The two are arranged opposite to each other, and the projection of the lower coil 101 in the horizontal plane is located inside the upper coil.

[0057] One end of the lower coil 101 at the first notch is connected to one end of the first upper coil 102 via a first connecting line 104, and the other end is connected to one end of the second upper coil 103 via a second connecting line 105, with the first connecting line 104 and the second connecting line 105 intersecting. An electrode connecting section 106 is provided on the outer wall of the lower coil 101 at a position opposite to the first notch, and it is connected to the first upper metal electrode 6. Inductor output sections 107 are respectively provided at the other ends of the first upper coil 102 and the second upper coil 103, arranged parallel to each other, with one inductor output section 107 connected to the pad 9 and the other grounded. The projection of the electrode connecting section 106 in the horizontal plane is located between the projections of the two inductor output sections 107 in the horizontal plane, and all three are arranged parallel to each other.

[0058] In this embodiment, the coiled inductor 10 has a double-layer structure, with each layer having a coil radius of 3-100μm. The upper and lower coils 101 can be square, polygonal, or circular. In this embodiment, a circular shape is chosen. The line width of the upper and lower coils 101 is 0.5-5μm, and the lateral spacing between the two coil layers is 0-5μm. The inductance of the entire coiled inductor 10 varies with the above-mentioned dimensions, and the total inductance ranges from 20 to 800pH.

[0059] The coiled wire-drawn inductor 10 utilizes the inductance peaking effect to improve bandwidth and achieve a faster photoelectric response. The coiled wire-drawn inductor 10 is connected to the first upper-layer metal electrode 6 and the pad 9, respectively, resonating with the junction capacitance of the silicon-germanium photodetector. This generates a peaking effect in the high-frequency region, thereby changing the frequency response of the output impedance. This reduces the output impedance at high frequencies, effectively compensating for the high-frequency signal components that were originally attenuated due to the junction capacitance, thus expanding the bandwidth of the silicon-germanium photodetector and achieving a faster photoelectric response. Figure 7 It can be seen that the photoelectric bandwidth of the segmented silicon-germanium photodetector using a coiled inductor 10 is significantly improved.

[0060] The segmented bandwidth-enhanced high-response silicon-germanium photodetector of this embodiment is a silicon-germanium PIN photodetector or a silicon-germanium avalanche photodetector. In use, the optical signal is input from the silicon strip waveguide 031, coupled through the silicon tapered waveguide 032 into the first silicon waveguide region 033, and then enters the segmented germanium absorption layer via evanescent wave coupling. Absorption generates electron-hole pairs, forming a photocurrent under the influence of the built-in electric field. This photocurrent passes through the first metal electrode 2 and the first upper metal electrode 6, and then through the coiled inductor 10. Through its gain peaking effect, the photoelectric bandwidth of the device is enhanced, and the signal is then output from the pad 9, completing the conversion from optical signal to electrical signal. Simultaneously, light leaking from the end of the first silicon waveguide region 033 enters the distributed Bragg reflector 5 and is then reflected back into the first silicon waveguide region 033, causing secondary absorption of this light and enhancing the photoelectric response.

[0061] The equivalent circuit of the segmented bandwidth-enhanced high-response silicon-germanium photodetector in this embodiment is as follows: Figure 6 As shown, the parasitic electrical component consists of the PN junction capacitance Cd, the PN junction resistance Rd, the electrode parasitic resistance Rs, inductors L1 and L2, the parasitic series resistance R, and the inter-pad capacitance Cp. Based on the inductance peaking effect, the impedance variation characteristics with frequency are altered to further enhance its bandwidth. Furthermore, by designing different inductance values, inductance peaking effects are generated at different frequency points.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector, comprising a silicon substrate layer (01), a buried oxide layer (02), and a silicon waveguide layer (03) arranged sequentially from bottom to top. The silicon substrate layer (01) and the buried oxide layer (02) are both rectangular structures. The silicon waveguide layer (03) includes a silicon strip waveguide (031), a silicon tapered waveguide (032), and a silicon waveguide region. One end of the silicon strip waveguide (031) is located at the middle of one end of the buried oxide layer (02) along its length, and the two are parallel in their length directions. The silicon tapered waveguide (032) has a tapered structure, with its small end connected to the silicon strip waveguide (031). The other end of 031) is connected; the silicon waveguide region is a rectangular structure and is located near the other end of the buried oxide layer (02) along its length direction. Two grooves are arranged side by side along the width direction of the buried oxide layer (02), and their length directions are parallel to the length direction of the buried oxide layer (02), so that three parallel protrusions are formed on the rear silicon waveguide layer. The three protrusions are the second silicon waveguide region (034), the third silicon waveguide region (035), and the first silicon waveguide region (033) located between them. The large end of the silicon tapered waveguide (032) is connected to one end of the first silicon waveguide region (033); characterized in that: It also includes a segmented germanium absorption layer, metal electrodes, and a distributed Bragg reflector (5); The segmented germanium absorption layer is disposed on the top of the first silicon waveguide region (033). The segmented germanium absorption layer includes a plurality of rectangular sub-germanium absorption layers (1) arranged sequentially along the length direction of the first silicon waveguide region (033). An etching groove is provided between two adjacent sub-germanium absorption layers (1). The metal electrode includes a first metal electrode (2), a second metal electrode (3) and a third metal electrode (4). There are multiple first metal electrodes (2), which are respectively disposed on multiple sub-germanium absorption layers (1). The projections of all first metal electrodes (2) in a vertical plane perpendicular to the length direction of the buried oxide layer (02) coincide, and their tops are connected through a first upper metal electrode (6). There are multiple second metal electrodes (3) arranged sequentially on the top of the second silicon waveguide region (034) along the length direction. The projections of all the second metal electrodes (3) in the vertical plane perpendicular to the length direction of the buried oxide layer (02) coincide, and the top is connected by the second upper metal electrode (7). The third metal electrode (4) is multiple and is arranged sequentially on the top of the third silicon waveguide region (035) along the length direction. The projections of all the third metal electrodes (4) in the vertical plane perpendicular to the length direction of the buried oxide layer (02) coincide, and the top is connected by the third upper metal electrode (8). The first upper metal electrode (6), the second upper metal electrode (7) and the third upper metal electrode (8) are respectively connected to pads (9); One end of the distributed Bragg reflector (5) is connected to the other end of the first silicon waveguide region (033), and the other end is flush with the other end face of the buried oxide layer (02) along its length.

2. The segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector according to claim 1, characterized in that: The first upper metal electrode (6) is connected to the pad (9) through a coiled wire inductor (10); The coiled inductor (10) includes an upper coil and a lower coil (101) arranged coaxially. The lower coil (101) has a first notch. The upper coil is formed by a first upper coil (102) and a second upper coil (103) of the same size and structure, which are arranged opposite to each other. The projection of the lower coil (101) in the horizontal plane is located inside the upper coil. One end of the lower coil (101) at the first notch is connected to one end of the first upper coil (102) via the first connecting line (104), and the other end is connected to one end of the second upper coil (103) via the second connecting line (105), and the first connecting line (104) and the second connecting line (105) are arranged to cross each other; An electrode connection section (106) is provided on the outer wall of the lower coil (101) at a position opposite to the first notch, which is connected to the first upper metal electrode (6); The other ends of the first upper coil (102) and the second upper coil (103) are respectively provided with inductor output sections (107), which are arranged in parallel. One of the inductor output sections (107) is connected to the pad (9), and the other is grounded. The projection of the electrode connection section (106) in the horizontal plane is located in the middle of the projection of the two inductor output sections (107) in the horizontal plane, and the three are arranged in parallel.

3. The segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector according to claim 2, characterized in that: The first silicon waveguide region (033) is P-type doped, the upper part of the germanium absorption layer (1) is N-type doped, the middle part is undoped, and the undoped part forms the intrinsic region; The germanium absorption layer (1) has a thickness of 0.01-2 μm, a width of 0.01-5 μm, and a length of 0.01-5 μm; The width of the etching groove is 0.1-0.5 μm.

4. The segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector according to claim 3, characterized in that: The groove has a width of 0.1-2 μm and a depth of 0.01-1 μm; Both the second silicon waveguide region (034) and the third silicon waveguide region (035) are P-type doped.

5. The segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector according to claim 4, characterized in that: The number of the second metal electrode (3) and the third metal electrode (4) are the same, and they are set in a one-to-one correspondence.

6. The segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector according to claim 5, characterized in that: The distributed Bragg reflector (5) is at least a first-order distributed Bragg reflector with 2-20 periods.

7. The segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector according to claim 1, characterized in that: The first metal electrode (2), the second metal electrode (3) and the third metal electrode (4) have the same structure, all of which are rectangular structures with a width of 0.01-5μm and a length of 0.01-5μm.

8. The segmented bandwidth-enhanced high-responsivity silicon-germanium photodetector according to claim 1, characterized in that: The end of the distributed Bragg reflector (5) connected to the first silicon waveguide region (033) has the same cross-sectional dimensions as the first silicon waveguide region (033).

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