Photoelectric detector, optical receiver, optical module and manufacturing method of photoelectric detector

Abstract

The embodiment of the invention provides a photoelectric detector, an optical receiver, an optical module and a manufacturing method of the photoelectric detector, in the photoelectric detector, a transition layer is arranged between a collection layer and an absorption layer, so that the size of the collection layer can be reduced; and the transition layer can limit the electric field between the collection layer and the absorption layer within the size range of the collection layer, so that the junction capacitance of the photoelectric detector can be reduced, the size of the absorption layer is not influenced, and the photoelectric detector can simultaneously realize large bandwidth and high coupling tolerance. The photoelectric detector comprises an epitaxial structure; the epitaxial structure comprises a first contact layer, an absorption layer, a transition layer, a collection layer and a second contact layer which are stacked; the size of the collecting layer in the first direction is smaller than that of the transition layer in the first direction, and the first direction is perpendicular to the stacking direction; the edges of the transition layer and the collection layer form a first step; the doping concentration of the dopant in the transition layer is less than or equal to 1e16 atoms / cubic centimeter.

Description

Technical Field

[0001] This application relates to the field of optoelectronic devices, and particularly to a photodetector, an optical receiver, an optical module, and a manufacturing method of a photodetector. Background Art

[0002] In an optical communication system, a photodetector is usually provided in an optical receiver. The photodetector is used to convert the received optical signal into an electrical signal, so as to obtain transmission data. As the transmission rate of the optical signal in the optical communication system continues to increase, the bandwidth of the photodetector also needs to be increased accordingly. In addition, in order to ensure that the photodetector can receive optical signals in a larger range, the coupling tolerance of the photodetector also needs to be increased.

[0003] Among them, the bandwidth of the photodetector is negatively correlated with the junction capacitance of the photodetector. The junction capacitance is positively correlated with the area of the collection layer of the photodetector, and the junction capacitance is positively correlated with the area of the absorption layer of the photodetector. The coupling tolerance of the photodetector is positively correlated with the area of the absorption layer of the photodetector. The collection layer and the absorption layer of the existing photodetector are coupled together, making it difficult for the existing photodetector to simultaneously achieve a large bandwidth and a high coupling tolerance. Summary of the Invention

[0004] Embodiments of this application provide a photodetector, an optical receiver, an optical module, and a manufacturing method of a photodetector. In this photodetector, a transition layer is provided between the collection layer and the absorption layer. The transition layer separates the collection layer from the absorption layer, so that the size of the collection layer can be reduced, and the transition layer can limit the electric field between the collection layer and the absorption layer within the range of the size of the collection layer. Furthermore, the junction capacitance of the photodetector can be reduced without affecting the size of the absorption layer, enabling the photodetector to simultaneously achieve a large bandwidth and a high coupling tolerance.

[0005] In a first aspect, a photodetector is provided, including an epitaxial structure; the epitaxial structure includes a first contact layer, an absorption layer, a transition layer, a collection layer, and a second contact layer that are stacked; the size of the collection layer along a first direction is smaller than the size of the transition layer along the first direction, and the first direction is perpendicular to the stacking direction; a first step is formed at the edge between the transition layer and the collection layer; the doping concentration of the dopant in the transition layer is less than or equal to 1e16 atoms per cubic centimeter. In this photodetector, since a transition layer is provided between the collection layer and the absorption layer, the transition layer separates the collection layer from the absorption layer, so that the size of the collection layer can be reduced, and the doping concentration of the dopant in the transition layer is less than or equal to 1e16 atoms per cubic centimeter. Therefore, the transition layer can limit the electric field between the collection layer and the absorption layer within the range of the size of the collection layer, and further reduce the junction capacitance of the photodetector without affecting the size of the absorption layer, enabling the photodetector to simultaneously achieve a large bandwidth and a high coupling tolerance.

[0006] Optionally, the size of the absorption layer in the first direction is equal to the size of the transition layer in the first direction.

[0007] Optionally, the epitaxial structure further includes: a cliff layer disposed between the transition layer and the collection layer, and the size of the cliff layer in the first direction is equal to the size of the collection layer in the first direction. In this optional manner, the cliff layer can regulate the electric field between the absorption layer and the collection layer, so that electrons can be transported to the second contact layer faster, improving the response speed and responsivity of the photodetector.

[0008] Optionally, the cliff layer includes a dopant that provides N-type carriers, and the doping concentration of the dopant in the cliff layer is greater than or equal to 1e17 atoms / cm³ and less than or equal to 1e18 atoms / cm³.

[0009] Optionally, the absorption layer includes a first absorption layer and a second absorption layer. The first absorption layer is close to the first contact layer, and the second absorption layer is close to the transition layer. The first absorption layer includes a dopant that provides P-type carriers, and the doping concentration of the dopant in the first absorption layer is a Gaussian distribution along the stacking direction. The second absorption layer includes a dopant that provides N-type carriers, and the doping concentration of the dopant in the second absorption layer is less than or equal to 1e16 atoms / cm³. In this optional manner, the first absorption layer and the second absorption layer can improve the responsivity of the photodetector.

[0010] Optionally, the epitaxial structure further includes: a waveguide layer disposed between the first contact layer and the absorption layer, and the light input port of the waveguide layer is disposed on one side of the epitaxial structure along the stacking direction. In this optional manner, the optical signal received by the photodetector is transmitted in the waveguide layer, and the optical signal transmitted to the waveguide layer is coupled into the absorption layer through an evanescent wave. During this process, the absorption direction of the optical signal is different from the transport direction of the photo-generated electrons, which can improve the bandwidth and responsivity of the photodetector.

[0011] Optionally, the photodetector further includes a substrate and a lens. The substrate is disposed on the side of the first contact layer away from the absorption layer, and the lens is disposed on the side of the substrate away from the epitaxial structure. In this optional manner, the lens can focus the optical signal received by the photodetector, further increasing the coupling tolerance of the photodetector.

[0012] Optionally, the photodetector includes a substrate and an epitaxial structure arranged in an M×N array, where M is a positive integer greater than or equal to 1, N is a positive integer greater than or equal to 1, and the epitaxial structure arranged in the M×N array is disposed on the substrate. In this optional mode, the photodetector can be connected to a multi-core optical fiber, and the epitaxial structures arranged in the M×N array correspond one-to-one with multiple optical fibers in the multi-core optical fiber. For example, one epitaxial structure in the epitaxial structures arranged in the M×N array is used to receive the optical signal input by one optical fiber in the multi-core optical fiber. Alternatively, when the photodetector includes an epitaxial structure arranged in an M×N array, the photodetector can also convert the surface-incident optical signal into an electrical signal.

[0013] Optionally, the photodetector further includes a lens arranged in an M×N array; the lens arranged in the M×N array is disposed on a side of the substrate away from the epitaxial structure arranged in the M×N array, and the epitaxial structures arranged in the M×N array correspond one-to-one with the lens arranged in the M×N array.

[0014] Optionally, the epitaxial structure further includes: a dielectric layer, the dielectric layer is disposed between the first contact layer and the absorption layer; the size of the dielectric layer in the first direction is equal to the size of the absorption layer in the first direction; the dielectric layer includes a dopant that provides P-type carriers. In this optional mode, the photodetector is in a reverse bias state, and when the optical signal irradiates the photodetector, the dielectric layer can block the electrons in the absorption layer from being transported to the first contact layer and ensure that the electrons are transported to the second contact layer. This dielectric layer is also referred to as an electron blocking layer.

[0015] Optionally, the doping concentration of the dopant in the dielectric layer is greater than or equal to 1e18 atoms / cm³.

[0016] Optionally, the first contact layer includes a dopant that provides P-type carriers; the second contact layer includes a dopant that provides N-type carriers; the collection layer includes a dopant that provides N-type carriers.

[0017] Optionally, the doping concentration of the dopant in the first contact layer is greater than or equal to 1e19 atoms / cm³ and less than or equal to 3×1e19 atoms / cm³; the doping concentration of the dopant in the second contact layer is greater than or equal to 1e19 atoms / cm³ and less than or equal to 3×1e19 atoms / cm³; the doping concentration of the dopant in the collection layer is less than or equal to 1e16 atoms / cm³.

[0018] Optionally, the material of the transition layer includes indium gallium arsenide phosphide.

[0019] Optionally, the size of the absorption layer in the first direction is smaller than the size of the first contact layer in the first direction, and a second step is formed at the edge of the first contact layer and the absorption layer.

[0020] Optionally, the size of the second contact layer in the first direction is equal to the size of the collection layer in the first direction.

[0021] Optionally, the photodetector further includes an insulating structure, a first electrode, and a second electrode; the insulating structure covers the epitaxial structure; the first electrode is disposed on the second step, and the first electrode penetrates the insulating structure and is connected to the first contact layer; the second electrode is disposed on the second contact layer, and the second electrode penetrates the insulating structure and is connected to the second contact layer.

[0022] Optionally, the material of the substrate includes indium phosphide.

[0023] In a second aspect, an optical receiver is provided, including a signal receiving circuit and the photodetector according to any one of the first aspects described above; the photodetector is configured to receive an optical signal, convert the optical signal into an electrical signal, and transmit the electrical signal to the signal receiving circuit; the signal receiving circuit is configured to extract the transmitted data carried from the electrical signal.

[0024] In a third aspect, an optical module is provided, including an optical transmitter and the optical receiver according to the second aspect described above; the optical transmitter is configured to transmit an optical signal; the optical receiver is configured to receive an optical signal.

[0025] In a fourth aspect, a method for manufacturing a photodetector is provided, including: sequentially forming a first contact layer, an absorption layer, a transition layer, a collection layer, and a second contact layer that are stacked; the doping concentration of the dopant in the transition layer is less than or equal to 1e16 atoms / cm³; etching the second contact layer and the collection layer so that the size of the collection layer in the first direction is smaller than the size of the transition layer in the first direction to form a first step at the edge of the transition layer and the collection layer; the first direction is perpendicular to the stacking direction.

[0026] Optionally, the method further includes: etching the transition layer and the absorption layer so that the size of the absorption layer in the first direction is smaller than the size of the first contact layer in the first direction to form a second step at the edge of the absorption layer and the first contact layer.

[0027] Wherein, the technical effects brought by any possible implementation manner in the second aspect to the fourth aspect can refer to the technical effects brought by different implementation manners in the first aspect above, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic structural diagram of an optical communication system provided by an embodiment of the present application;

[0029] Figure 2 A cross-sectional view of a photodetector provided by an embodiment of the present application;

[0030] Figure 3 is Figure 2 A cross-sectional view along AA';

[0031] Figure 4 Cross-sectional view of a photodetector provided for another embodiment of the present application;

[0032] Figure 5 Top view of a photodetector provided for another embodiment of the present application;

[0033] Figure 6 Cross-sectional view of a photodetector provided for another embodiment of the present application;

[0034] Figure 7 Cross-sectional view of a photodetector provided for another embodiment of the present application;

[0035] Figure 8 Cross-section of the photodetector in the method for manufacturing a photodetector provided for an embodiment of the present application Figure 1 ;

[0036] Figure 9 Cross-section of the photodetector in the method for manufacturing a photodetector provided for an embodiment of the present application Figure 2 ;

[0037] Figure 10 Cross-section of the photodetector in the method for manufacturing a photodetector provided for an embodiment of the present application Figure 3 ;

[0038] Figure 11 Cross-section of the photodetector in the method for manufacturing a photodetector provided for an embodiment of the present application Figure 4 ;

[0039] Figure 12 Cross-section of the photodetector in the method for manufacturing a photodetector provided for an embodiment of the present application Figure 5 ;

[0040] Figure 13 Cross-section of the photodetector in the method for manufacturing a photodetector provided for an embodiment of the present application Figure 6 ;

[0041] Figure 14 Cross-section of the photodetector in the method for manufacturing a photodetector provided for an embodiment of the present application Figure 7 . Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0043] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those of ordinary skill in the art. In the embodiments of the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, or B exists alone, where A and B may be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one (item)" or similar expressions thereof refer to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b, or c may represent: a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be single or multiple. Additionally, in the embodiments of the present application, terms such as "first" and "second" do not limit the quantity and order.

[0044] In addition, in the embodiments of the present application, orientation terms such as "upper" and "lower" are defined relative to the orientation in which the components in the drawings are schematically placed. It should be understood that these directional terms are relative concepts, and they are used for relative description and clarification, and they may change accordingly with the change of the orientation in which the components in the drawings are placed.

[0045] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0046] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0047] The embodiments of the present application are applied to an optical communication system. The optical communication system may be, for example, an Ethernet, fibre to the home (FTTH), optical transport network (OTN), network storage, data center, coherent optical communication, free space optical communication, etc. The optical communication system includes an optical module and an optical fiber. Refer to Figure 1As shown, the optical communication system 10 includes an optical module 11, an optical module 12, and an optical fiber 13 connecting the optical module 11 and the optical module 12. The optical module 11 can emit a first optical signal, transmit the first optical signal to the optical module 12 through the optical fiber 13, and the optical module 12 receives the first optical signal to achieve communication. Alternatively, the optical module 12 can emit a second optical signal, transmit the second optical signal to the optical module 11 through the optical fiber 13, and the optical module 11 receives the second optical signal to achieve communication.

[0048] In the above optical communication system 10, the optical module 11 or the optical module 12 is mainly used in optical line terminal (OLT), optical network unit (ONU), optical network terminal (ONT), switch, fiber router, video optical terminal, fiber transceiver, fiber network card and other equipment. Among them, the optical module 11 or the optical module 12 supports different rate classifications, for example: 1G~10G low rate, 25G, 40G, 50G, 100G, 200G / 400G, etc.

[0049] For example, refer to Figure 1 As shown, the optical module 11 includes an optical transmitter 111 and an optical receiver 112, wherein the optical transmitter 111 transmits a first optical signal and the optical receiver 112 receives a second optical signal. Figure 1 The optical transmitter 111 and the optical receiver 112 may multiplex the optical fiber 13. Of course, the optical signals of the optical transmitter 111 and the optical receiver 112 may also be transmitted in two optical fibers respectively.

[0050] For example, Figure 1 As shown, the optical receiver 112 includes a photoelectric conversion device and a signal receiving circuit, the photoelectric conversion device is used to convert the received second optical signal into an electrical signal, and the signal receiving circuit is used to extract the carried transmission data from the electrical signal.

[0051] Exemplarily, the optical module 12 includes an optical transmitter and an optical receiver, and the optical receiver includes an optoelectronic conversion device and a signal receiving circuit. Generally, the optical module at the transmitting end converts the electrical signal into an optical signal, transmits it to the optical module at the receiving end through an optical fiber, and the optical module at the receiving end converts the optical signal into an electrical signal.

[0052] As the transmission rate of optical signals in optical communication systems continues to increase, the bandwidth of photodetectors also needs to be increased accordingly. In addition, in order to ensure that the photodetector can receive optical signals in a larger range, the coupling tolerance of the photodetector also needs to be increased. Among them, the bandwidth of the photodetector is negatively correlated with the junction capacitance of the photodetector, the junction capacitance is positively correlated with the area of ​​the collection layer of the photodetector, and the junction capacitance is positively correlated with the area of ​​the absorption layer of the photodetector. The coupling tolerance of the photodetector is positively correlated with the area of ​​the absorption layer of the photodetector. The collection layer and the absorption layer of the existing photodetector are coupled together, making it difficult for the existing photodetectors to achieve large bandwidth and high coupling tolerance at the same time.

[0053] For this purpose, refer to Figure 2 and Figure 3 As shown, Figure 2 A cross-sectional view of a photodetector 20 provided in an embodiment of the present application, Figure 3 for Figure 2 The cross-sectional view along AA' is shown, wherein the photodetector 20 provided in the embodiment of the present application includes: an epitaxial structure 30. The epitaxial structure 30 includes a contact layer 31 (also referred to as a first contact layer), an absorption layer 32, a transition layer 33, a collection layer 34 and a contact layer 35 (also referred to as a second contact layer) which are stacked. The stacking direction is the z-axis direction, the AA' direction can be any direction in the plane formed by the x-axis direction and the y-axis, the AA' direction is also referred to as the first direction, and the z-axis direction is perpendicular to the AA' direction. The size of the collection layer 34 along the AA' direction is smaller than the size of the transition layer 33 along the AA' direction. The edges of the transition layer 33 and the collection layer 34 form a step S1, also referred to as a first step, specifically, the transition layer 33 constitutes the bottom surface of the step S1, and the sidewalls of the collection layer 34 and the contact layer 35 constitute the side surfaces of the step S1. The doping concentration of the dopant in the transition layer 33 is less than or equal to 1e16 atoms / cm3. Exemplarily, no additional dopant is provided in the transition layer 33 , and the dopant in the transition layer 33 may be the dopant in the absorption layer 32 diffused into the transition layer 33 , or the dopant in the collection layer 34 diffused into the transition layer 33 .

[0054] For example, Figure 2 As shown, when the photodetector 20 is viewed downward from the z-axis, each layer in the epitaxial structure 30 is circular. In some examples, when the photodetector 20 is viewed downward from the z-axis, each layer in the epitaxial structure 30 may be polygonal. The shapes of any two layers in the epitaxial structure 30 may be the same or different.

[0055] exist Figure 2 and Figure 3In the photodetector 20 shown, the photodetector 20 further includes an insulating structure 40, an electrode 50 also referred to as a (first electrode) and an electrode 60 (also referred to as a second electrode), wherein the insulating structure 40 covers the epitaxial structure 30. The electrode 50 is disposed on the second step (step S2 shown in the figure), and the electrode 50 penetrates the insulating structure 40 and is connected to the contact layer 31. The electrode 60 is disposed on the contact layer 35, and the electrode 60 penetrates the insulating structure 40 and is connected to the contact layer 35. The material of the insulating structure 40 can be selected from any of the following: silicon dioxide (SiO2), silicon nitride (SiN), polyimide (English name: polyimide, abbreviated as PI), benzocyclobutene (English name: benzocyclobutene, molecular formula: C8H8), etc.

[0056] exist Figure 2 and Figure 3 In the photodetector 20 shown, the contact layer 31 specifically includes a dopant that provides P (positive) type carriers (i.e., holes); wherein the doping concentration of the dopant in the contact layer 31 is greater than or equal to 1e19 atoms / cm3 and less than or equal to 3×1e19 atoms / cm3. The electrode 50 connected to the contact layer 31 is specifically the anode of the photodetector 20. Exemplarily, the dopant that provides P type carriers includes at least one or more impurity elements of zinc Zn, beryllium Be, or carbon C.

[0057] The absorption layer 32 includes a first absorption layer 321 and a second absorption layer 322, wherein the first absorption layer 321 is close to the contact layer 31, and the second absorption layer 322 is close to the transition layer 33. The first absorption layer 321 includes dopants that provide P-type carriers, and the doping concentration of the dopants in the first absorption layer 321 is Gaussian distributed along the z-axis direction. The first absorption layer 321 is also called an undepleted absorption layer. The second absorption layer 322 includes dopants that provide N (negative) type carriers (i.e., electrons), and the doping concentration of the dopants in the second absorption layer 322 is less than or equal to 1e16 atoms / cubic centimeter. Specifically, the second absorption layer 322 is not additionally provided with dopants or the second absorption layer 322 is lightly doped. The second absorption layer 322 is also called a depleted absorption layer. Exemplarily, the dopants that provide N-type carriers include at least one or more impurity elements in silicon Si or tin Sn. When the absorption layer 32 includes the first absorption layer 321 and the second absorption layer 322 , the photoelectric conversion efficiency of the photodetector 20 can be improved.

[0058] Exemplarily, the dimension of the absorption layer 32 along the AA' direction is smaller than the dimension of the contact layer 31 along the AA' direction, and the edges of the contact layer 31 and the absorption layer 32 form a step S2, also called a second step, specifically, the contact layer 31 is the bottom surface of the step S2, and the side wall of the absorption layer 32 is the side surface of the step S2. The step S2 is formed here to facilitate the manufacture of the electrode 50 on the contact layer 31, so that the electrode 50 is connected to the contact layer 31, that is, the electrode 50 is disposed on the step S2.

[0059] The doping concentration of the dopant in the transition layer 33 is less than or equal to 1e16 atoms / cm3. Exemplarily, the material of the transition layer 33 includes InGaAsP.

[0060] The collection layer 34 includes dopants that provide N-type carriers, wherein the doping concentration of the dopants in the collection layer 34 is less than or equal to 1e16 atoms / cubic centimeter. Specifically, the collection layer 34 is not additionally provided with dopants or the collection layer 34 is lightly doped.

[0061] The contact layer 35 includes dopants that provide N-type carriers, wherein the doping concentration of the dopants in the contact layer 35 is greater than or equal to 1e19 atoms / cm3 and less than or equal to 3×1e19 atoms / cm3. The electrode 60 connected to the contact layer 35 is specifically a cathode of the photodetector 20.

[0062] Exemplarily, the dimension of the contact layer 35 along the AA′ direction is equal to the dimension of the collection layer 34 along the AA′ direction.

[0063] Exemplarily, the photodetector 20 further includes a substrate 70, which is disposed on a side of the contact layer 31 away from the absorption layer 32, wherein the material of the substrate 70 includes indium phosphide (InP). The substrate 70 including indium phosphide (InP) can support light signals with a wavelength range of 1310 nanometers (nm) to 1620 nm to penetrate with less loss.

[0064] Exemplarily, the size of the contact layer 31 along the AA' direction is smaller than the size of the substrate 70 along the AA' direction, and the edge of the substrate 70 and the contact layer 31 form a step S3, also called the third step. When other structures are provided on the substrate 70, the step S3 can isolate the epitaxial structure 30 from other structures provided on the substrate 70.

[0065] Exemplarily, the material of any one of the contact layer 31, the absorption layer 32, the collection layer 34 and the contact layer 35 in the epitaxial structure 30 includes one or more of the following: indium phosphide (InP), indium gallium arsenide (InGaAs), indium gallium arsenide phosphide (InGaAsP). Exemplarily, the material of the transition layer 33 specifically includes a quaternary compound of indium gallium arsenide phosphide (InGaAsP).

[0066] Exemplarily, when the photodetector 20 is in a reverse bias state, for example, the electrode 50 of the photodetector 20 is connected to the negative electrode of the power supply and the electrode 60 is connected to the positive electrode of the same power supply. When the light signal irradiates the photodetector 20 from the substrate 70, the absorption layer 32 is excited to generate electrons under the action of the light signal, and a photocurrent can be generated when the electrons are transported from the absorption layer 32 to the contact layer 35, and the direction of light signal absorption is the same as the direction of electron transport. In this process, since the doping concentration of the dopant in the transition layer 33 is less than or equal to 1e16 atoms / cubic centimeter, the transition layer 33 can reduce the barrier difference between the absorption layer 32 and the collection layer 34 from the energy band level, avoiding the need for a large step energy level when the electrons jump from the absorption layer 32 to the collection layer 34, wherein the collection layer 34 can accelerate the transport of electrons. In addition, since the doping concentration of the dopant in the transition layer 33 is less than or equal to 1e16 atoms / cubic centimeter, from the electric field level, the transition layer 33 can limit the electric field of the absorption layer 32 to the size occupied by the plane formed by the collection layer 34 in the x-axis and the y-axis, thereby making the junction capacitance of the photodetector 20 determined by the size occupied by the plane formed by the collection layer 34 in the x-axis and the y-axis.

[0067] In the photodetector 20, since a transition layer 33 is provided between the collection layer 34 and the absorption layer 32, the transition layer 33 separates the collection layer 34 from the absorption layer 32 so that the size of the collection layer 34 can be reduced, and the doping concentration of the dopant in the transition layer 33 is less than or equal to 1e16 atoms / cubic centimeter. Therefore, the transition layer 33 can limit the electric field between the collection layer 34 and the absorption layer 32 within the size range of the collection layer 34, thereby reducing the junction capacitance of the photodetector 20 without affecting the size of the absorption layer 32, so that the photodetector 20 can simultaneously achieve a large bandwidth and a high coupling tolerance.

[0068] For example, refer to Figure 2 and Figure 3 As shown, the size of the absorption layer 32 along the AA' direction is equal to the size of the transition layer 33 along the AA' direction. The size of the transition layer 33 and the absorption layer 32 in the AA' direction can be increased as much as possible to improve the coupling tolerance of the photodetector 20, and the size of the collection layer 34 and the contact layer 35 in the AA' direction can be reduced as much as possible to improve the bandwidth of the photodetector 20.

[0069] In some embodiments, reference Figure 2 and Figure 3As shown, the epitaxial structure 30 further includes: a cliff layer 36, the cliff layer 36 is arranged between the transition layer 33 and the collection layer 34, and the size of the cliff layer 36 along the AA' direction is equal to the size of the collection layer 34 along the AA' direction. The cliff layer 36 includes dopants that provide N-type carriers, and the doping concentration of the dopants in the cliff layer 36 is greater than or equal to 1e17 atoms / cubic centimeter and less than or equal to 1e18 atoms / cubic centimeter. Exemplarily, when the photodetector 20 is in a reverse bias state and the light signal reaches the substrate 70 and irradiates the photodetector 20, the cliff layer 36 can regulate the electric field of the absorption layer 32 and the collection layer 34, so that the electrons can be transported to the contact layer 35 faster, thereby improving the response speed and responsiveness of the photodetector 20.

[0070] In some examples, reference Figure 2 and Figure 3 As shown, the epitaxial structure 30 further includes: a dielectric layer 37, the dielectric layer 37 is disposed between the contact layer 31 and the absorption layer 32; the size of the dielectric layer 37 along the AA' direction is equal to the size of the absorption layer 32 along the AA' direction; the dielectric layer 37 includes dopants that provide P-type carriers, and the doping concentration of the dopants in the dielectric layer 37 is greater than or equal to 1e18 atoms / cubic centimeter. Exemplarily, when the photodetector 20 is in a reverse bias state and the light signal irradiates the photodetector 20 from the substrate 70, the dielectric layer 37 can block the electrons in the absorption layer 32 from being transmitted to the contact layer 31, and ensure that the electrons are transported to the contact layer 35, and the dielectric layer 37 is also called an electron blocking layer.

[0071] In some examples, reference Figure 4 As shown, compared to Figure 3 The photodetector 20 shown, Figure 4 The photodetector 20 shown further includes a lens 80, which is disposed on a side of the substrate 70 away from the epitaxial structure 30. For example, the epitaxial structure 30 is disposed on the substrate 70, and the lens 80 is disposed under the substrate 70. When the optical signal irradiates the photodetector 20 from the substrate 70, the lens 80 can focus the optical signal, further increasing the coupling tolerance of the photodetector 20.

[0072] In other examples, refer to Figure 5 and Figure 6 As shown, Figure 5 A top view of a photodetector 20 provided in an embodiment of the present application, Figure 6 for Figure 5 The photodetector 20 shown is a cross-sectional view along BB'. Figure 5 The cross-sectional view of the photodetector 20 along CC' may also be as shown in FIG. Figure 6 As shown. For example, Figure 5 and Figure 6The photodetector 20 shown includes epitaxial structures 30 arranged in an M×N array, where M is a positive integer greater than or equal to 1, and N is a positive integer greater than or equal to 1. The epitaxial structures 30 arranged in an M×N array are disposed on a substrate 70. Figure 6 As shown, any one of the epitaxial structures 30 arranged in an M×N array may be Figure 2 and Figure 3 The epitaxial structure 30 is shown. Figure 5 The photodetector 20 shown includes epitaxial structures 30 arranged in an M×N array, so that Figure 5 The photodetector 20 shown can be connected to a multi-core optical fiber, and the epitaxial structures 30 arranged in an M×N array correspond one to one to multiple optical fibers in the multi-core optical fiber. For example, one epitaxial structure 30 in the M×N array is used to receive an optical signal input from one optical fiber in the multi-core optical fiber. Figure 5 When the photodetector 20 shown includes the epitaxial structures 30 arranged in an M×N array, the photodetector 20 can also convert the surface-incident optical signal into an electrical signal.

[0073] For example, Figure 5 As shown, in Figure 5 When the photodetector 20 shown includes an M×N array of epitaxial structures 30, Figure 5 The photodetector 20 shown may also include a lens 80 arranged in an M*N array; the lens 80 arranged in an M*N array is disposed on a side of the substrate 70 away from the epitaxial structure 30 arranged in an M*N array, for example, the epitaxial structure 30 arranged in an M*N array is disposed on the substrate 70, and the lens 80 arranged in an M*N array is disposed under the substrate 70, and the epitaxial structure 30 arranged in an M*N array corresponds one to one to the lens 80 arranged in an M*N array, and the lens 80 focuses the received light signal into the epitaxial structure 30 corresponding to the lens 80.

[0074] In some examples, reference Figure 7 As shown, compared to Figure 3 The photodetector 20 shown, Figure 7 In the photodetector 20 shown, the epitaxial structure 30 further includes: a waveguide layer 38, the waveguide layer 38 is disposed between the contact layer 31 and the absorption layer 32, the light entrance of the waveguide layer 38 is disposed on one side of the epitaxial structure 30 along the z-axis direction, and the insulating structure 40 does not cover the light entrance of the waveguide layer 38. Figure 7 In the photodetector 20 shown, the optical signal is transmitted in the waveguide layer 38 along AA', and the optical signal transmitted to the waveguide layer 38 enters the absorption layer 32 through evanescent wave coupling. In this process, the direction of optical signal absorption is different from the direction of electron transport, which can improve the bandwidth and responsiveness of the photodetector 20.

[0075] In other examples,Figure 7 The photodetector 20 shown may include a plurality of epitaxial structures 30 arranged in a row or a column. The plurality of epitaxial structures 30 are disposed on a substrate 70 , and light entrances of the waveguide layers 38 in the plurality of epitaxial structures 30 face the same direction.

[0076] In some embodiments, the embodiments of the present application further provide a method for manufacturing a photodetector, the method comprising:

[0077] Step S101, sequentially forming a first contact layer, an absorption layer, a transition layer, a collection layer and a second contact layer that are stacked.

[0078] For example, refer to Figure 8 As shown, the first contact layer is specifically Figure 8 The contact layer 31 shown, the second contact layer is specifically Figure 8 The contact layer 35 shown, the absorption layer is specifically Figure 8 The absorption layer 32 shown, the transition layer is specifically Figure 8 The transition layer 33 shown, the collection layer is specifically Figure 8 The collection layer 34 is shown. Wherein, the doping concentration of the dopant in the transition layer 33 is less than or equal to 1e16 atoms / cubic centimeter.

[0079] Exemplarily, step S101 includes:

[0080] S1011 , forming a contact layer 31 through epitaxy and ion implantation processes.

[0081] Specifically, a substrate 70 is prepared first, and the material of the substrate 70 includes indium phosphide (InP).

[0082] Next, the material of the contact layer 31 is epitaxially grown on the substrate 70 to form a first epitaxial layer of a first thickness. The material of the contact layer 31 includes one or more of the following: indium phosphide (InP), indium gallium arsenide (InGaAs), indium gallium arsenide phosphide (InGaAsP).

[0083] Again, dopants providing P-type carriers are injected into the first epitaxial layer through an ion implantation process, and the doping concentration of the dopants in the first epitaxial layer is greater than or equal to 1e19 atoms / cubic centimeter and less than or equal to 3×1e19 atoms / cubic centimeter, thereby forming a contact layer 31.

[0084] S1012 , forming an absorption layer 32 on the contact layer 31 through epitaxy and ion implantation processes.

[0085] Specifically, the absorption layer 32 includes a first absorption layer 321 and a second absorption layer 322. Step S1012 includes:

[0086] Step 1: epitaxially grow the material of the absorption layer 32 on the contact layer 31 through an epitaxial process to form a second epitaxial layer of a second thickness. The material of the absorption layer 32 includes: indium gallium arsenide (InGaAs).

[0087] Step 2: Inject dopants that provide P-type carriers into the second epitaxial layer through an ion implantation process, and make the doping concentration of the dopants in the second epitaxial layer Gaussian distributed along the z-axis direction, to form a first absorption layer 321, which is also called an undepleted absorption layer.

[0088] Step 3: epitaxially grow the material of the absorption layer 32 on the first absorption layer 321 through an epitaxial process to form a third epitaxial layer with a third thickness.

[0089] Step 4: Inject dopants that provide N-type carriers into the third epitaxial layer through an ion implantation process, and make the doping concentration of the dopants in the third epitaxial layer less than or equal to 1e16 atoms / cubic centimeter to form a second absorption layer 322, which is also called a depletion absorption layer.

[0090] In some examples, the fourth step may not be performed to form an undoped second absorption layer 322 .

[0091] S1013 , forming a transition layer 33 on the absorption layer 32 through an epitaxial process.

[0092] Exemplarily, the material of the transition layer 33 is epitaxially grown on the absorption layer 32 through an epitaxial process to form the transition layer 33. The material of the transition layer 33 includes a quaternary compound of indium gallium arsenic phosphide (InGaAsP). Dopants are not actively injected into the transition layer 33. The doping concentration of the dopant in the transition layer 33 is less than or equal to 1e16 atoms / cubic centimeter, and the dopant in the transition layer 33 can be the dopant in the absorption layer 32 diffused into the transition layer 33, or the dopant in the collection layer 34 diffused into the transition layer 33.

[0093] S1014 , forming a collection layer 34 on the transition layer 33 by an epitaxial process.

[0094] Exemplarily, the material of the collection layer 34 is epitaxially grown on the transition layer 33 by an epitaxial process to form a fourth epitaxial layer with a fourth thickness. The material of the collection layer 34 includes: indium phosphide (InP).

[0095] Dopants providing N-type carriers are implanted into the fourth epitaxial layer through an ion implantation process, and the doping concentration of the dopants in the fourth epitaxial layer is less than or equal to 1e16 atoms / cubic centimeter, so as to form a collection layer 34 .

[0096] In some examples, the ion implantation process may not be performed, and the collection layer 34 may be directly formed by epitaxial growth, so that the collection layer 34 is undoped.

[0097] S1015 , forming a contact layer 35 on the collection layer 34 through epitaxial growth and ion implantation processes.

[0098] Exemplarily, the material of the contact layer 35 is epitaxially grown on the collection layer 34 by an epitaxial process to form a fifth epitaxial layer of a fifth thickness. The material of the contact layer 35 includes one or more of the following: indium phosphide (InP), indium gallium arsenide (InGaAs), indium gallium arsenide phosphide (InGaAsP).

[0099] Dopants providing N-type carriers are implanted into the fifth epitaxial layer through an ion implantation process, and the doping concentration of the dopants in the fifth epitaxial layer is greater than or equal to 1e19 atoms / cubic centimeter and less than or equal to 3×1e19 atoms / cubic centimeter, thereby forming a contact layer 35.

[0100] In some examples, reference Figure 8 As shown, a dielectric layer 37 is also provided between the contact layer 31 and the absorption layer 32. Then, after the above step S1011 and before step S1012, it also includes: forming a dielectric layer 37 on the contact layer 31 by epitaxy and ion implantation process. Specifically, the material of the dielectric layer 37 is epitaxially grown on the contact layer 31 by an epitaxy process to form a sixth epitaxial layer of a sixth thickness. Among them, the material of the dielectric layer 37 includes one or more of the following: indium phosphide (InP), indium gallium arsenic phosphide (InGaAsP). Dopants that provide P-type carriers are injected into the sixth epitaxial layer by an ion implantation process, and the doping concentration of the dopants in the sixth epitaxial layer is greater than or equal to 1e18 atoms / cubic centimeter, thereby forming a dielectric layer 37. Step S1012 specifically includes: epitaxially growing the material of the absorption layer 32 on the dielectric layer 37 by an epitaxy process.

[0101] In some examples, reference Figure 8 As shown, a cliff layer 36 is also provided between the transition layer 33 and the collection layer 34. Then, after the above step S1013 and before the step S1014, it also includes: forming a cliff layer 36 on the transition layer 33 by epitaxial and ion implantation processes. Specifically, the material of the cliff layer 36 is epitaxially grown on the transition layer 33 by an epitaxial process to form a seventh epitaxial layer of the seventh thickness. Wherein, the material of the cliff layer 36 includes: indium phosphide (InP). Dopants that provide N-type carriers are injected into the seventh epitaxial layer by an ion implantation process, and the doping concentration of the dopants in the seventh epitaxial layer is greater than or equal to 1e17 atoms / cubic centimeter and less than or equal to 1e18 atoms / cubic centimeter, thereby forming the cliff layer 36. Step S1014 specifically includes: epitaxially growing the material of the collection layer 34 on the cliff layer 36 by an epitaxial process.

[0102] Step S102: Etch the contact layer 35 and the collection layer 34 so that the size of the collection layer 34 in the first direction is smaller than the size of the transition layer 33 in the first direction, to form a first step at the edge between the transition layer 33 and the collection layer 34.

[0103] Exemplarily, referring to Figure 9 As shown, the stacking direction is the z-axis direction, and the AA' direction can be any direction in the plane formed by the x-axis and the y-axis. The AA' direction is also referred to as the first direction, and the z-axis direction is perpendicular to the AA' direction. Among them, the size of the etched collection layer 34 in the AA' direction is smaller than the size of the transition layer 33 in the AA' direction, and the size of the contact layer 35 in the AA' direction is equal to the size of the collection layer 34 in the AA' direction.

[0104] Referring to Figure 9 As shown, specifically, a photoresist is coated on the contact layer 35, photolithography is performed on the photoresist to form a first etching opening window, and the contact layer 35 and the collection layer 34 are etched from the first etching opening window to form a step S1, also referred to as the first step, at the edge between the transition layer 33 and the collection layer 34. At this time, the size of the bottom surface of the step S1 has not yet reached the requirement.

[0105] Exemplarily, when there is also a cliff layer 36 between the transition layer 33 and the collection layer 34, step S102 specifically includes: etching the contact layer 35, the collection layer 34, and the cliff layer 36 to form a step S1 at the edge between the transition layer 33 and the collection layer 34. And the size of the cliff layer 36 in the AA' direction is equal to the size of the collection layer 34 in the AA' direction.

[0106] In some examples, the manufacturing method of the photodetector further includes:

[0107] Step S103: Etch the absorption layer 32 and the transition layer 33 so that the size of the absorption layer 32 in the first direction is smaller than the size of the contact layer 31 in the first direction, to form a second step at the edge between the contact layer 31 and the absorption layer 32.

[0108] Exemplarily, referring to Figure 10 As shown, the size of the etched absorption layer 32 in the AA' direction is smaller than the size of the contact layer 31 in the AA' direction, and the size of the transition layer 33 in the AA' direction is equal to the size of the absorption layer 32 in the AA' direction.

[0109] Referring to Figure 10As shown, specifically, photoresist is coated on the contact layer 35 and the transition layer 33, photolithography is performed on the photoresist to form a second etching opening, the absorption layer 32 and the transition layer 33 are etched from the second etching opening, and a step S2, also known as the second step, is formed at the edge of the absorption layer 32 and the contact layer 31. At this time, the size of the bottom surface of the step S1 has reached the requirement, but the size of the bottom surface of the step S2 has not reached the requirement.

[0110] Exemplarily, when a dielectric layer 37 is further included between the contact layer 31 and the absorption layer 32, step S103 may be to etch the absorption layer 32, the transition layer 33 and the dielectric layer 37, and a step S2 is formed at the edge of the contact layer 31 and the absorption layer 32. The size of the dielectric layer 37 in the AA' direction is equal to the size of the absorption layer 32 in the AA' direction.

[0111] Step S104, etch the contact layer 31 so that the size of the contact layer 31 in the first direction is smaller than the size of the substrate 70 in the first direction, so as to form a third step at the edge of the substrate 70 and the contact layer 31.

[0112] Exemplarily, referring to Figure 11 As shown, the size of the etched contact layer 31 in the AA' direction is smaller than the size of the substrate 70 in the AA' direction, and the AA' direction is perpendicular to the z-axis direction.

[0113] Referring to Figure 11 As shown, specifically, photoresist is coated on the contact layer 35, the transition layer 33 and the contact layer 31, photolithography is performed on the photoresist to form a third etching opening, the contact layer 31 is etched from the third etching opening, and a step S3, also known as the third step, is formed at the edge of the substrate 70 and the contact layer 31. At this time, the size of the bottom surface of the step S2 has reached the requirement, and the size of the bottom surface of the step S3 has reached the requirement.

[0114] Exemplarily, Figure 11 In, an epitaxial structure 30 of the photodetector 20 has been formed, and the epitaxial structure 30 includes: a contact layer 31, an absorption layer 32, a transition layer 33, a collection layer 34, and a contact layer 35, and Figure 11 The epitaxial structure 30 in also includes a cliff layer 36 and a dielectric layer 37.

[0115] Step S105, form an insulating structure.

[0116] Referring to Figure 12 As shown, specifically, the insulating structure is specifically the Figure 12 Insulating structure 40 shown. Among them, in Figure 12The material of the insulating structure 40 can be deposited on the epitaxial structure 30 as shown to form the insulating structure 40. The material of the insulating structure 40 can be any of the following: silicon dioxide (SiO2), silicon nitride (SiN), polyimide (English name: polyimide, abbreviated as PI), benzocyclobutene (English name: benzocyclobutene, molecular formula: C8H8), etc. The insulating structure 40 is located on the contact layer 35, on the sidewalls of the collection layer 34 and the cliff layer 36, on the transition layer 33, on the sidewalls of the absorption layer 32 and the dielectric layer 37, on the contact layer 31, and on the sidewall of the contact layer 31.

[0117] Step S106: Form the first electrode.

[0118] Refer to Figure 12 As shown, on the bottom surface of the step S2, through photolithography and etching processes, part of the insulating structure 40 is etched away to fabricate the first electrode trench K1. Among them, the first electrode trench K1 is filled with electrode material by magnetron sputtering or evaporation methods to form the first electrode. The first electrode can be, for example, Figure 3 the electrode 50 as shown.

[0119] Step S107: Form the second electrode.

[0120] Refer to Figure 12 As shown, on the contact layer 35, through photolithography and etching processes, part of the insulating structure 40 is etched away to fabricate the second electrode trench K2. Among them, the second electrode trench K2 is filled with electrode material by magnetron sputtering or evaporation methods to form the second electrode. The second electrode can be, for example, Figure 3 the electrode 60 as shown.

[0121] So far, the Figure 2 and Figure 3 photodetector 20 as shown can be fabricated.

[0122] Exemplarily, when the photodetector 20 further includes a lens, the manufacturing method of the photodetector further includes: fabricating a lens on the side of the substrate away from the epitaxial structure.

[0123] In some examples, steps S102, S103, and S104 in the above manufacturing method of the photodetector can be replaced by the following steps S108, S109, and S110.

[0124] Step S108: Etch to form step S3.

[0125] Specifically, refer to Figure 13 As shown, specifically, the contact layer 35, the collection layer 34, the cliff layer 36, the transition layer 33, the absorption layer 32, and the contact layer 31 are etched to form step S3, and the size of the bottom surface of the formed step S3 meets the requirements.

[0126] Step S109: Etch to form step S2.

[0127] Specifically, referring to Figure 14 as shown, on the basis of Figure 13 , etch the contact layer 35, the collection layer 34, the cliff layer 36, the transition layer 33, and the absorption layer 32 to form step S2, and the size of the bottom surface of the formed step S2 meets the requirements.

[0128] Step S110: Etch to form step S1.

[0129] Specifically, on the basis of Figure 14 , etch the contact layer 35, the collection layer 34, and the cliff layer 36 to form step S1, and the size of the bottom surface of the formed step S1 meets the requirements, and then form the Figure 11 epitaxial structure 30 as shown.

[0130] In some other examples, when an epitaxial structure 30 arranged in an M×N array needs to be fabricated, in step S102 of the above method for manufacturing a photodetector, steps S103, and steps S104, steps S102, steps S103, and steps S104 specifically form steps S1, S2, and S3 arranged in an M×N array, respectively.

[0131] In some examples, in order to form the Figure 7 photodetector 20 as shown, in the above method for manufacturing a photodetector, after step S1011 and before step S1012, it further includes: forming a waveguide layer 38 on the contact layer 31 by epitaxy.

[0132] Although the present application has been described in conjunction with specific features and their embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of the present application. Accordingly, the present specification and the drawings are merely exemplary descriptions of the present application defined by the appended claims, and are considered to have covered any and all modifications, variations, combinations, or equivalents within the scope of the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these changes and modifications.

Claims

1. A photodetector, characterized in that, Comprising: An epitaxial structure; The epitaxial structure includes a first contact layer, an absorption layer, a transition layer, a collection layer, and a second contact layer that are stacked; The size of the collection layer in the first direction is smaller than the size of the transition layer in the first direction, and a first step is formed at the edge of the transition layer and the collection layer. The first direction is perpendicular to the stacking direction; The doping concentration of the dopant in the transition layer is less than or equal to 1e16 atoms / cm³.

2. The photodetector according to claim 1, wherein The size of the absorption layer in the first direction is equal to the size of the transition layer in the first direction.

3. The photodetector according to claim 1 or 2, wherein The epitaxial structure further includes: a cliff layer, the cliff layer is disposed between the transition layer and the collection layer, and the size of the cliff layer in the first direction is equal to the size of the collection layer in the first direction.

4. The photodetector according to claim 3, wherein The cliff layer includes a dopant that provides N-type carriers, and the doping concentration of the dopant in the cliff layer is greater than or equal to 1e17 atoms / cm³ and less than or equal to 1e18 atoms / cm³.

5. The photodetector according to any one of claims 1-4, wherein The absorption layer includes a first absorption layer and a second absorption layer. The first absorption layer is close to the first contact layer, and the second absorption layer is close to the transition layer; The first absorption layer includes a dopant that provides P-type carriers, and the doping concentration of the dopant in the first absorption layer is a Gaussian distribution along the stacking direction; The second absorption layer includes a dopant that provides N-type carriers, and the doping concentration of the dopant in the second absorption layer is less than or equal to 1e16 atoms / cm³.

6. The photodetector according to any one of claims 1-5, wherein The epitaxial structure further includes: a waveguide layer, the waveguide layer is disposed between the first contact layer and the absorption layer, and the light input port of the waveguide layer is disposed on one side of the epitaxial structure along the stacking direction.

7. The photodetector according to any one of claims 1-6, wherein The photodetector further includes a substrate and a lens. The substrate is disposed on the side of the first contact layer away from the absorption layer, and the lens is disposed on the side of the substrate away from the epitaxial structure.

8. The photodetector according to any one of claims 1-6, wherein The photodetector includes the M×N array arrangement of the epitaxial structures, M is a positive integer greater than or equal to 1, N is a positive integer greater than or equal to 1, and the M×N array arrangement of the epitaxial structures is disposed on the substrate.

9. The photodetector according to claim 8, wherein The photodetector further includes an M×N array arrangement of lenses; the M×N array arrangement of lenses is disposed on the side of the substrate away from the M×N array arrangement of the epitaxial structures, and the M×N array arrangement of the epitaxial structures corresponds to the M×N array arrangement of lenses one by one.

10. The photodetector according to any one of claims 1-9, characterized in that the epitaxial structure further comprises: a dielectric layer disposed between the first contact layer and the absorption layer; the size of the dielectric layer in the first direction is equal to the size of the absorption layer in the first direction; the dielectric layer includes a dopant that provides P-type carriers.

11. The photodetector according to any one of claims 1-10, characterized in that the first contact layer includes a dopant that provides P-type carriers; the second contact layer includes a dopant that provides N-type carriers; the collection layer includes a dopant that provides N-type carriers.

12. The photodetector according to any one of claims 1-11, characterized in that the material of the transition layer includes indium gallium arsenide phosphide.

13. The photodetector according to any one of claims 1-12, characterized in that the size of the absorption layer in the first direction is smaller than the size of the first contact layer in the first direction, and a second step is formed at the edge of the first contact layer and the absorption layer.

14. The photodetector according to any one of claims 1-13, characterized in that the size of the second contact layer in the first direction is equal to the size of the collection layer in the first direction.

15. The photodetector according to claim 13, characterized in that the photodetector further comprises an insulating structure, a first electrode and a second electrode; the insulating structure covers the epitaxial structure; the first electrode is disposed on the second step, and the first electrode penetrates the insulating structure and is connected to the first contact layer; the second electrode is disposed on the second contact layer, and the second electrode penetrates the insulating structure and is connected to the second contact layer.

16. An optical receiver, characterized in that, Comprising a signal receiving circuit and the photodetector according to any one of claims 1-15; the photodetector is configured to receive an optical signal, convert the optical signal into an electrical signal, and transmit the electrical signal to the signal receiving circuit; the signal receiving circuit is configured to extract the transmitted data carried from the electrical signal.

17. An optical module, characterized in that, Comprising an optical transmitter and the optical receiver according to claim 16; the optical transmitter is configured to transmit an optical signal; the optical receiver is configured to receive an optical signal.

18. A manufacturing method of a photodetector, characterized in that, Comprising: a first contact layer, an absorption layer, a transition layer, a collection layer and a second contact layer which are sequentially formed and stacked, and the doping concentration of the dopant in the transition layer is less than or equal to 1e16 atoms / cubic centimeter; etching the second contact layer and the collection layer to make the size of the collection layer in the first direction smaller than the size of the transition layer in the first direction, so as to form a first step at the edge of the transition layer and the collection layer; the first direction is perpendicular to the stacking direction.

19. The manufacturing method of the photodetector according to claim 18, characterized in that the method further comprises: etching the transition layer and the absorption layer to make the size of the absorption layer in the first direction smaller than the size of the first contact layer in the first direction, so as to form a second step at the edge of the absorption layer and the first contact layer.

Images