Photodetector, preparation method thereof, chip and optical device

Abstract

An optoelectronic detector (10), a method for manufacturing the same, a chip (100), and an optical device, wherein the optoelectronic detector (10) includes: a substrate (11), a first electrode contact layer (12), a photosensitive layer (13), a second electrode contact layer (14), a passivation layer (15), and a first electrode (161) and a second electrode (162) that are sequentially stacked on the substrate (11); the optoelectronic detector (10) further includes a through hole (V0) that at least penetrates through the photosensitive layer (13) and the second electrode contact layer (14); the first electrode contact layer (12) and the second electrode contact layer (14) are doped semiconductor layers with opposite polarities; the first electrode (161) and the second electrode (162) are insulated from each other, the first electrode (161) is electrically connected to the first electrode contact layer (12) through a first groove (V1), and the second electrode (162) is electrically connected to the second electrode contact layer (14) through a second groove (V2). In the optoelectronic detector (10), when the detected light passes through the through hole (V0), the photosensitive layer (13) can capture some photons passing through the through hole (V0), thereby converting the optical signal into an electrical signal, realizing the detection of the detected light, and ensuring that the detected light is not disturbed.

Description

Technical Field

[0001] The present application relates to the field of optical communication technologies, and particularly to a photodetector, a preparation method thereof, a chip and an optical device. Background Art

[0002] The working mechanism of a wavelength-selective switch (WSS) structure is that a color beam is incident from an input optical fiber into free space within the WSS structure, and then through the action of various optical elements arranged in the free space, the color beam is regularly dispersed into monochromatic beams of different wavelengths, and then through the action of geometric optics, the monochromatic beams of different wavelengths enter different output optical fibers. Therefore, the WSS structure can select different output wavelengths according to actual application needs, and can adjust the output optical power separately, etc.

[0003] Since the light beam is transmitted in free space in the WSS structure, and there are only optical fibers at the entrance and the exit, in order to realize the detection of optical signals, a fiber tap detection device needs to be installed on the input or output optical fiber of the WSS structure. Refer to Figure 1 , when the light beam in optical fiber 1 is transmitted to the optical fiber connection point, a small amount of the light beam will emit from the optical fiber cross-section, and the fiber tap detection device 2 installed at the optical fiber connection point of optical fiber 1 through the mechanical fixing member 3 captures the light emitted from the optical fiber cross-section of optical fiber 1, so that the detection of the optical signal transmitted in optical fiber 1 can be realized without damaging the original optical path of optical fiber 1. Refer to Figure 2 , since the input optical fiber and the output optical fiber of the WSS structure are usually a fiber array, a large number of fiber tap detection devices 2 need to be installed to meet the requirements of real-time detection. However, the use of a large number of fiber tap detection devices 2 requires a large installation space, which will lead to an increase in the volume of the optical fiber communication system, a complex structure, an increase in cost, etc. Summary of the Invention

[0004] The present application provides a photodetector, a preparation method thereof, a chip and an optical device, for providing a novel photodetector.

[0005] In a first aspect, a photodetector provided by the present application includes: a substrate, a first electrode contact layer, a photosensitive layer, a second electrode contact layer, and a passivation layer that are sequentially stacked on the substrate, and a first electrode and a second electrode located on the passivation layer; the first electrode contact layer and the second electrode contact layer are doped semiconductor layers with opposite polarities. For example, the first electrode contact layer is a P-type doped semiconductor layer, and the second electrode contact layer is an N-type doped semiconductor layer, or the first electrode contact layer is an N-type doped semiconductor layer, and the second electrode contact layer is a P-type doped semiconductor layer. The photodetector further includes a through hole that at least penetrates the photosensitive layer and the second electrode contact layer; the orthographic projections of the first electrode and the second electrode on the substrate are respectively located outside the orthographic projection of the through hole on the substrate. The first electrode and the second electrode are insulated from each other. The first electrode is electrically connected to the first electrode contact layer through a first groove that penetrates the film layer between the first electrode and the first electrode contact layer, and the second electrode is electrically connected to the second electrode contact layer through a second groove that penetrates the passivation layer.

[0006] In this photodetector, the first electrode contact layer and the second electrode contact layer form a PN junction. When the photosensitive layer captures the light passing through the through hole V0, the PN junction can convert the optical signal into an electrical signal, thereby realizing the detection of the optical signal. It should be noted that the structure of this photodetector is not limited to a photodiode (PD), an avalanche photodiode (APD), or a hetero junction photodiode (HPT), etc.

[0007] It should be noted that in the present application, the orthographic projections of the first electrode and the second electrode on the substrate are respectively located outside the orthographic projection of the through hole on the substrate in order to ensure that neither the orthographic projection of the first electrode on the substrate nor the orthographic projection of the second electrode on the substrate can cover the through hole, thus preventing the first electrode and the second electrode from blocking the light passing through the through hole.

[0008] The photodetector of the present application can be applied to various structures based on free-space optical transmission. Specifically, the photodetector can be arranged on the transmission path of monochromatic light in free space. Utilizing the monochromaticity, directivity, and Gaussian distribution characteristics of the light intensity of these light beams, when the monochromatic light beam passes through the photodetector, a small portion of photons at the beam edge will enter the photodetector, enabling real-time tap detection of the optical signal without interfering with optical transmission. For example, when applied to a WSS structure, the photodetector is arranged on the transmission path of monochromatic light in the free space of the WSS structure. Therefore, not only can the monochromatic light signal be ensured to be undisturbed, but also the volume of the WSS structure can be ensured not to increase. Moreover, since the photodetector can directly obtain photons from the transmission path of monochromatic light without relying on other devices, it can be fixed on the transmission path of monochromatic light without complex mechanical fixing parts. Compared with the existing fiber tap detection device, the overall structural complexity and cost can be reduced.

[0009] In practical applications, generally, the electrical contact performance between the P-type doped semiconductor layer and the metal electrode is not as good as that between the N-type doped semiconductor layer and the metal electrode. Therefore, for the P-type doped semiconductor layer, a metal contact electrode can be formed between the P-type doped semiconductor layer and the metal electrode first. Thus, in the present application, if the first electrode contact layer is a P-type doped semiconductor layer, a metal contact electrode can be arranged between the first electrode contact layer and the first electrode. If the second electrode contact layer is a P-type doped semiconductor layer, a metal contact electrode can be arranged between the second electrode contact layer and the second electrode. No limitation is made here.

[0010] In specific implementation, generally, the second electrode contact layer is set as a P-type doped semiconductor layer. Thus, in the present application, the second electrode contact layer is a P-type doped semiconductor layer, and the photodetector further includes a metal contact electrode located between the second electrode and the second electrode contact layer to improve the electrical contact performance between the second electrode and the second electrode contact layer.

[0011] The present application does not limit the shapes of the first electrode and the second electrode. However, considering the symmetry of the performance of the photodetector, the second electrode is in a closed annular structure surrounding the through hole; the first electrode is in an annular structure arranged around the second electrode and having an opening. The opening of the first electrode is to avoid short circuit between the first electrode and the second electrode, and the first electrode and the second electrode are respectively led out from both sides of the through hole.

[0012] Furthermore, in order to increase the contact area between the electrode and the electrode contact layer, the shape of the groove can be set to be similar to the shape of the electrode. Exemplarily, in the present application, the shape of the second groove is in a closed annular structure surrounding the through hole; the shape of the first groove is in an annular structure arranged around the second groove and having an opening.

[0013] In a specific implementation, in order to avoid the photodetector from affecting the light passing through the area where the through hole is located, the through hole can penetrate all film layers along the thickness direction of the substrate, that is, the through hole penetrates the passivation layer, the second electrode contact layer, the photosensitive layer, the first electrode contact layer and the substrate. When the absorption spectrum of the substrate does not overlap with the wavelength of the light to be detected, the through hole can only penetrate the second electrode contact layer, the photosensitive layer and the first electrode contact layer. Further, when the absorption spectrum of the substrate does not overlap with the wavelength of the light to be detected, and the epitaxial material of the first electrode contact layer and the substrate is the same, the through hole can only penetrate the second electrode contact layer and the photosensitive layer.

[0014] The present application does not limit the shape of the through hole, which can be any shape, such as regular polygonal, circular, elliptical, etc. When the through hole is circular, the distance from the center of the through hole to the boundary of the through hole can be ensured to be the same. In addition, circular through holes are easier to realize in terms of technology.

[0015] In the present application, when the second electrode contact layer is formed, a covering layer may be formed first, and then the covering layer may be doped. If the doped region covers the area where the through hole is located, then the remaining doped region after the through hole passes through the doped region is the second electrode contact layer. If the doped region does not cover the area where the through hole is located, then the doped region is the second electrode contact layer. Therefore, in the present application, the photodetector also includes a covering layer arranged in the same layer as the second electrode contact layer, the second electrode contact layer is in the shape of a ring, and the covering layer is arranged around the second electrode contact layer; the second electrode contact layer and the covering layer have the same intrinsic material, but different doping concentrations, the covering layer is generally lightly doped, and the second electrode contact layer is generally heavily doped. Alternatively, the second electrode contact layer and the covering layer have the same intrinsic material, and the two have different electrical doping types, for example, the covering layer is N-type doped and the second electrode contact layer is P-type doped, or the covering layer is P-type doped and the second electrode contact layer is N-type doped.

[0016] In a second aspect, the present application provides a chip, comprising a driving circuit and at least one photoelectric detector provided in any of the above embodiments of the present application connected to the driving circuit. The photoelectric detector can convert the captured light signal into an electrical signal, and the driving circuit can amplify the electrical signal and output it to achieve detection of the light signal.

[0017] In a third aspect, an optical device provided by the present application includes a wavelength selective switch structure and at least one photodetector, and the photodetector is disposed on the transmission path of monochromatic light in the free space of the wavelength selective switch structure. This can not only ensure that the monochromatic light signal is not interfered, but also ensure that the volume of the WSS structure will not increase. Moreover, since the photodetector can directly obtain photons from the transmission path of monochromatic light without relying on other devices, it can be fixed on the transmission path of monochromatic light without complex mechanical fixing parts. Compared with the existing optical fiber tap detection device, the overall cost and overall structural complexity can be reduced.

[0018] In a fourth aspect, a method for manufacturing a photodetector provided by the present application includes: First, a first electrode contact layer, a photosensitive layer, and a second electrode contact layer are sequentially formed on a substrate, and a through hole is formed that at least penetrates the photosensitive layer and the second electrode contact layer; Then, a first passivation layer is formed on the second electrode contact layer, and a first groove that penetrates the first passivation layer and reaches the surface of the first electrode contact layer and a second groove that penetrates the passivation layer are formed; Finally, a first electrode and a second electrode are formed on the first passivation layer; wherein, the orthographic projections of the first electrode and the second electrode on the substrate are respectively located outside the orthographic projection of the through hole on the substrate; the first electrode and the second electrode are insulated from each other, the first electrode is electrically connected to the first electrode contact layer through the first groove, and the second electrode is electrically connected to the second electrode contact layer through the second groove. Among them, the first electrode contact layer and the second electrode contact layer are doped semiconductor layers with opposite polarities. For example, the first electrode contact layer is a P-type doped semiconductor layer, and the second electrode contact layer is an N-type doped semiconductor layer, or the first electrode contact layer is an N-type doped semiconductor layer, and the second electrode contact layer is a P-type doped semiconductor layer.

[0019] For the photodetector formed by using the above manufacturing method provided by the present application, a PN junction is formed between the first electrode contact layer and the second electrode contact layer. When the photosensitive layer captures the light passing through the through hole V0, the PN junction can convert the optical signal into an electrical signal, thereby realizing the detection of the optical signal. It should be noted that the structure of this photodetector is not limited to a photodiode (PD), an avalanche photodiode (APD), or a hetero junction photodiode (HPT), etc.

[0020] In a possible implementation, a first electrode contact layer, a photosensitive layer, and a second electrode contact layer are sequentially formed on a substrate, and a via hole penetrating at least the photosensitive layer and the second electrode contact layer is formed, which may include: first, forming a first electrode contact layer, a photosensitive layer, and a covering layer on the substrate in sequence; then, forming a second passivation layer on the covering layer and forming a via hole penetrating the second passivation layer, so that the exposed covering layer is in an annular or circular shape; then, doping the exposed covering layer to form a second electrode contact layer; and then, forming a via hole penetrating at least the photosensitive layer and the second electrode contact layer.

[0021] Alternatively, in another possible implementation, a first electrode contact layer, a photosensitive layer, and a second electrode contact layer are sequentially formed on a substrate, and a via hole penetrating at least the photosensitive layer and the second electrode contact layer is formed, which may include: first, forming a first electrode contact layer, a photosensitive layer, and a covering layer on the region of the substrate except for the central region in sequence; then, forming a second passivation layer on the covering layer and forming a via hole penetrating the second passivation layer, so that the exposed covering layer is in an annular shape; and then, doping the exposed covering layer to form a second electrode contact layer.

[0022] In this application, after doping the exposed covering layer to form a second electrode contact layer, it further includes: removing the central region of the substrate, so that in the formed photodetector, there is no film layer in the region where the via hole is located.

[0023] In a possible implementation, a first passivation layer is formed on the second electrode contact layer, and a first groove penetrating the first passivation layer and reaching the surface of the first electrode contact layer and a second groove penetrating the passivation layer are formed, which may include: first, forming a third groove penetrating the second passivation layer, the covering layer, and the photosensitive layer; then, forming a first passivation layer on the second electrode contact layer, so that the first passivation layer coats the side wall of the third groove to protect the side wall of the third groove; then, forming a second groove penetrating the first passivation layer and forming a first groove penetrating the first passivation layer in the region where the third groove is located, so that the first groove penetrates the first passivation layer and reaches the surface of the first electrode contact layer.

[0024] It can be understood that since there are multiple film layers between the first electrode and the first electrode contact layer, the depth of the third groove is relatively deep. The first electrode needs to climb over the side wall of the third groove to be electrically connected to the first electrode contact layer. If the side wall depth is deep, the first electrode is likely to be open-circuited when climbing the side wall. Therefore, optionally, in this application, after sequentially forming a first electrode contact layer, a photosensitive layer, and a second electrode contact layer on the substrate and before forming a first passivation layer on the second electrode contact layer, it may further include: removing the second passivation layer, the covering layer, and the photosensitive layer in a preset region, so that the remaining covering layer and photosensitive layer are in an annular structure. Thus, the subsequent formed first electrode only needs to penetrate the first groove of the first passivation layer to be electrically connected to the first electrode contact layer.

[0025] As described above, in the present application, among the first electrode contact layer and the second electrode contact layer, one electrode contact layer is a P-type doped semiconductor layer, and the other electrode contact layer is an N-type doped semiconductor layer. Generally, the electrical contact performance between the P-type doped semiconductor layer and the metal electrode is not as good as that between the N-type doped semiconductor layer and the metal electrode. Therefore, for the P-type doped semiconductor layer, a metal contact electrode can be formed between the P-type doped semiconductor layer and the metal electrode first. Therefore, in the present application, if the first electrode contact layer is a P-type doped semiconductor layer, a metal contact electrode can be provided between the first electrode contact layer and the first electrode. If the second electrode contact layer is a P-type doped semiconductor layer, a metal contact electrode can be provided between the second electrode contact layer and the second electrode. This is not limited herein.

[0026] In specific implementation, generally the second electrode contact layer is set as a P-type doped semiconductor layer. Therefore, in the present application, after sequentially forming the first electrode contact layer, the photosensitive layer, and the second electrode contact layer on the substrate, before forming the first passivation layer on the second electrode contact layer, it may further include: forming an annular metal contact electrode on the second electrode contact layer and annealing the metal contact electrode, so that the to-be-formed second electrode is electrically connected to the second electrode contact layer through the metal contact electrode. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of detection by an optical fiber tap detection device in the related art;

[0028] Figure 2 It is a schematic structural diagram of an optical fiber tap detection device applied to a WSS structure in the related art;

[0029] Figure 3a It is a schematic top view structural diagram of a photodetector in an embodiment of the present application;

[0030] Figure 3b is Figure 3a a schematic cross-sectional structural diagram of the illustrated photodetector along the AA' direction;

[0031] Figure 3c is Figure 3a a schematic cross-sectional structural diagram of the illustrated photodetector along the BB' direction;

[0032] Figure 4 It is a schematic flow diagram of a method for manufacturing a photodetector provided in an embodiment of the present application;

[0033] Figure 5 It is a schematic flow diagram of a method for manufacturing a photodetector provided in another embodiment of the present application;

[0034] Figure 6a Top view of the structure formed after performing the steps of the preparation method in this application;

[0035] Figure 6b is Figure 6a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0036] Figure 7a Top view of the structure formed after performing the steps of the preparation method in this application;

[0037] Figure 7b is Figure 7a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0038] Figure 8a Top view of the structure formed after performing the steps of the preparation method in this application;

[0039] Figure 8b is Figure 8a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0040] Figure 9a Top view of the structure formed after performing the steps of the preparation method in this application;

[0041] Figure 9b is Figure 9a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0042] Figure 10a Top view of the structure formed after performing the steps of the preparation method in this application;

[0043] Figure 10b is Figure 10a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0044] Figure 11a Top view of the structure formed after performing the steps of the preparation method in this application;

[0045] Figure 11b is Figure 11a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0046] Figure 11c is Figure 11a Schematic cross-sectional structure diagram of the shown structure along the BB' direction;

[0047] Figure 12a Top view of the structure formed after performing the steps of the preparation method in this application;

[0048] Figure 12b is Figure 12a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0049] Figure 12c is Figure 12a a schematic cross-sectional structure diagram of the shown structure along the BB' direction;

[0050] Figure 13a is a top view of the structure formed after performing the steps of the preparation method in this application;

[0051] Figure 13b is Figure 13a a schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0052] Figure 13c is Figure 13a a schematic cross-sectional structure diagram of the shown structure along the BB' direction;

[0053] Figure 14a is a top view of the photodetector in another embodiment of this application;

[0054] Figure 14b is Figure 14a a schematic cross-sectional structure diagram of the shown photodetector along the AA' direction;

[0055] Figure 14c is Figure 14a a schematic cross-sectional structure diagram of the shown photodetector along the BB' direction;

[0056] Figure 15a is a top view of the photodetector in another embodiment of this application;

[0057] Figure 15b is Figure 15a a schematic cross-sectional structure diagram of the shown photodetector along the AA' direction;

[0058] Figure 15c is Figure 15a a schematic cross-sectional structure diagram of the shown photodetector along the BB' direction;

[0059] Figure 16 is a schematic flow diagram of the preparation method of the photodetector provided in another embodiment of this application;

[0060] Figure 17a is a top view of the structure formed after performing the steps of the preparation method in this application;

[0061] Figure 17b is Figure 17a a schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0062] Figure 18a is Figure 14a another schematic cross-sectional structure diagram of the shown photodetector along the AA' direction;

[0063] Figure 18b For Figure 14a Another schematic cross-sectional structure diagram of the photodetector shown along the BB' direction;

[0064] Figure 19a For Figure 15a Another schematic cross-sectional structure diagram of the photodetector shown along the AA' direction;

[0065] Figure 19b For Figure 15a Another schematic cross-sectional structure diagram of the photodetector shown along the BB' direction;

[0066] Figure 20 Schematic flow diagram of the preparation method of the photodetector provided by another embodiment of the present application;

[0067] Figure 21a Top view of the structure formed after performing the steps of the preparation method in the present application;

[0068] Figure 21b For Figure 21a Schematic cross-sectional structure diagram of the shown structure along the AA' direction;

[0069] Figure 22a For Figure 15a Another schematic cross-sectional structure diagram of the photodetector shown along the AA' direction;

[0070] Figure 22b For Figure 15a Another schematic cross-sectional structure diagram of the photodetector shown along the BB' direction;

[0071] Figure 23 Schematic flow diagram of the preparation method of the photodetector provided by another embodiment of the present application;

[0072] Figure 24a For Figure 15a Another schematic cross-sectional structure diagram of the photodetector shown along the AA' direction;

[0073] Figure 24b For Figure 15a Another schematic cross-sectional structure diagram of the photodetector shown along the BB' direction;

[0074] Figure 25 Schematic structure diagram of the chip provided by an embodiment of the present application;

[0075] Figure 26 Schematic diagram of the arrangement of multiple photodetectors in the chip provided by an embodiment of the present application;

[0076] Figure 27Schematic diagram of the arrangement of multiple photodetectors in the chip provided by another embodiment of the present application. Detailed implementation manners

[0077] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their repeated description will be omitted. The words expressing positions and directions described in the present application are all illustrated by taking the accompanying drawings as examples, but can be changed according to needs, and all the changes are included in the protection scope of the present application. The accompanying drawings of the present application are only used to illustrate the relative positional relationship and do not represent the actual ratio.

[0078] It should be noted that specific details are set forth in the following description to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application. Therefore, the present application is not limited by the specific implementation manners disclosed below. The subsequent description in the specification is the preferred implementation manner for implementing the present application, but the description is for the purpose of illustrating the general principles of the present application and is not intended to limit the scope of the present application. The protection scope of the present application shall be defined by the appended claims.

[0079] To facilitate the understanding of the photodetector provided by the embodiments of the present application, the following first describes its specific application scenarios. The photodetector provided by the embodiments of the present application can be widely applied to various structures based on free-space optical transmission. For example, it can be applied to a WSS structure, and the photodetector is arranged on the transmission path of monochromatic light in the free space of the WSS structure. When the monochromatic light beam passes through the photodetector, a small part of the photons at the beam edge will enter the photodetector, so that the optical signal can be tapped and detected in real time without interfering with the optical transmission.

[0080] In specific implementation, the photodetector can also be applied to the aerospace field. For example, some satellite equipment uses free-space optical communication technology for communication, and the photodetector can perform real-time detection on these optical communications.

[0081] To facilitate the understanding of the photodetector provided by the embodiments of the present application, the photodetector, its manufacturing method, chip and optical device provided by the present application will be specifically described below with reference to specific embodiments and the accompanying drawings.

[0082] Embodiment 1

[0083] Figure 3aExemplarily shown is a top view structural schematic diagram of a photodetector in an embodiment of the present application. Figure 3b is Figure 3a a cross-sectional structural schematic diagram of the shown photodetector along the AA' direction. Figure 3c is Figure 3a a cross-sectional structural schematic diagram of the shown photodetector along the BB' direction.

[0084] Referring to Figures 3a to 3c , the photodetector 10 provided by the present application includes: a substrate 11, a first electrode contact layer 12, a photosensitive layer 13, a second electrode contact layer 14, and a passivation layer 15 that are sequentially stacked on the substrate 11, and a first electrode 161 and a second electrode 162 located on the passivation layer 15; wherein, the first electrode contact layer 12 and the second electrode contact layer 14 are doped semiconductor layers with opposite polarities. For example, the first electrode contact layer 12 is a P-type doped semiconductor layer, and the second electrode contact layer 14 is an N-type doped semiconductor layer, or the first electrode contact layer 12 is an N-type doped semiconductor layer, and the second electrode contact layer 14 is a P-type doped semiconductor layer. The photodetector 10 further includes a through hole V0 that at least penetrates the photosensitive layer 13 and the second electrode contact layer 14; the orthographic projections of the first electrode 161 and the second electrode 162 on the substrate 11 are respectively located outside the orthographic projection of the through hole V0 on the substrate 11; the first electrode 161 and the second electrode 162 are insulated from each other, and the first electrode 161 is electrically connected to the first electrode contact layer 12 through a first groove V1 that penetrates the film layer between the first electrode 161 and the first electrode contact layer 12, and the second electrode 162 is electrically connected to the second electrode contact layer 14 through a second groove V2 that penetrates the passivation layer 15.

[0085] In this photodetector, the first electrode contact layer 12 and the second electrode contact layer 14 form a PN junction. When the photosensitive layer 13 captures the light passing through the through hole V0, the PN junction can convert the optical signal into an electrical signal, thereby realizing the detection of the optical signal and ensuring that the light passing through the through hole V0 is not disturbed. It should be noted that the structure of this photodetector is not limited to a photodiode (PD), an avalanche photodiode (APD), or a hetero junction photodiode (HPT), etc.

[0086] The photodetector of the present application can be applied to various structures based on free-space optical transmission. Specifically, the photodetector can be disposed on the transmission path of monochromatic light in free space. By utilizing the monochromaticity, directivity, and Gaussian distribution characteristics of the light intensity of these light beams, when the monochromatic light beam passes through the through-hole region of the photodetector, a small number of photons at the beam edge will enter the photodetector, enabling real-time tap detection of the optical signal without interfering with optical transmission. For example, when applied to a WSS structure, the photodetector is disposed on the transmission path of monochromatic light in the free space of the WSS structure. Therefore, not only can the monochromatic light signal be ensured to be undisturbed, but also the volume of the WSS structure can be ensured not to increase. Moreover, since the photodetector can directly obtain photons from the transmission path of monochromatic light without the need to rely on other devices, it can be fixed on the transmission path of monochromatic light without the need for complex mechanical fixing parts. Compared with the existing fiber tap detection device, the overall structural complexity and cost can be reduced.

[0087] Embodiment 2

[0088] Figure 4 The schematic flow chart of the manufacturing method of the photodetector provided by an embodiment of the present application is exemplarily shown.

[0089] As Figure 4 shown, the method mainly includes the following steps:

[0090] S401. Form a first electrode contact layer, a photosensitive layer, and a second electrode contact layer on the substrate in sequence, and form a through-hole that at least penetrates the photosensitive layer and the second electrode contact layer; the first electrode contact layer and the second electrode contact layer are doped semiconductor layers with opposite polarities.

[0091] S402. Form a first passivation layer on the second electrode contact layer, and form a first groove that penetrates the first passivation layer and reaches the surface of the first electrode contact layer and a second groove that penetrates the passivation layer.

[0092] S403. Form a first electrode and a second electrode on the first passivation layer; wherein, the orthographic projections of the first electrode and the second electrode on the substrate are respectively located outside the orthographic projection of the through-hole on the substrate; the first electrode and the second electrode are insulated from each other, the first electrode is electrically connected to the first electrode contact layer through the first groove, and the second electrode is electrically connected to the second electrode contact layer through the second groove.

[0093] In a possible implementation, step S401 of sequentially forming a first electrode contact layer, a photosensitive layer, and a second electrode contact layer on a substrate and forming a through hole that at least penetrates the photosensitive layer and the second electrode contact layer may include: first, sequentially forming a first electrode contact layer, a photosensitive layer, and a covering layer on the substrate; then forming a second passivation layer on the covering layer and forming a via hole that penetrates the second passivation layer, so that the exposed covering layer is annular or circular; then doping the exposed covering layer to form a second electrode contact layer; and thereafter forming a through hole that at least penetrates the photosensitive layer and the second electrode contact layer.

[0094] In another possible implementation, step S401 of sequentially forming a first electrode contact layer, a photosensitive layer, and a second electrode contact layer on a substrate and forming a through hole that at least penetrates the photosensitive layer and the second electrode contact layer may include: first, sequentially forming a first electrode contact layer, a photosensitive layer, and a covering layer on the region of the substrate except for the central region, so that while forming the first electrode contact layer, the photosensitive layer, and the covering layer, a through hole that penetrates the first electrode contact layer, the photosensitive layer, and the covering layer is formed in the central region; then forming a second passivation layer on the covering layer and forming a via hole that penetrates the second passivation layer, so that the exposed covering layer is annular; then doping the exposed covering layer to form a second electrode contact layer. Wherein, the central region is the region where the through hole is located and may be a circular region. Further, after doping the exposed covering layer to form a second electrode contact layer, it further includes: removing the central region of the substrate, so that the through hole also penetrates the substrate.

[0095] In a possible implementation, step S402 of forming a first passivation layer on the second electrode contact layer and forming a first groove that penetrates the first passivation layer and reaches the surface of the first electrode contact layer and a second groove that penetrates the passivation layer may include: first, forming a third groove that penetrates the second passivation layer, the covering layer, and the photosensitive layer; then forming a first passivation layer on the second electrode contact layer, so that the first passivation layer can coat the side wall of the third groove to protect the side wall of the third groove; then forming a second groove that penetrates the first passivation layer and forming a first groove that penetrates the first passivation layer in the region where the third groove is located, so that the first groove penetrates the first passivation layer and reaches the surface of the first electrode contact layer.

[0096] It can be understood that since there are multiple film layers between the first electrode and the first electrode contact layer, the depth of the third groove is relatively deep. The first electrode needs to climb over the sidewall of the third groove to be electrically connected to the first electrode contact layer. If the sidewall depth is deep, the first electrode is prone to open circuit when on the sidewall. Therefore, optionally, in the present application, after successively forming the first electrode contact layer, the photosensitive layer, and the second electrode contact layer on the substrate, before forming the first passivation layer on the second electrode contact layer, it may further include: removing the second passivation layer, the cover layer, and the photosensitive layer within a preset area, so that the remaining cover layer and photosensitive layer form an annular structure. Thus, the subsequently formed first electrode only needs to penetrate the first groove of the first passivation layer to be electrically connected to the first electrode contact layer.

[0097] As described above, in the present application, among the first electrode contact layer and the second electrode contact layer, one electrode contact layer is a P-type doped semiconductor layer, and the other electrode contact layer is an N-type doped semiconductor layer. Generally, the electrical contact performance between the P-type doped semiconductor layer and the metal electrode is not as good as that between the N-type doped semiconductor layer and the metal electrode. Therefore, for the P-type doped semiconductor layer, a metal contact electrode can be formed between the P-type doped semiconductor layer and the metal electrode first. Thus, in the present application, if the first electrode contact layer is a P-type doped semiconductor layer, a metal contact electrode can be provided between the first electrode contact layer and the first electrode. If the second electrode contact layer is a P-type doped semiconductor layer, a metal contact electrode can be provided between the second electrode contact layer and the second electrode. This is not limited herein.

[0098] In specific implementation, generally, the second electrode contact layer is set as a P-type doped semiconductor layer. Thus, in the present application, when the second electrode contact layer is a P-type doped semiconductor layer, after successively forming the first electrode contact layer, the photosensitive layer, and the second electrode contact layer on the substrate, before forming the first passivation layer on the second electrode contact layer, it may further include: forming an annular metal contact electrode on the second electrode contact layer and annealing the metal contact electrode, so that the to-be-formed second electrode is electrically connected to the second electrode contact layer through the metal contact electrode.

[0099] The following takes the first electrode contact layer as an N-type doped semiconductor layer, the second electrode contact layer as a P-type doped semiconductor layer, and a metal contact electrode is provided between the second electrode contact layer and the second electrode as an example, and the present application will be described in detail in combination with specific embodiments. It should be noted that this embodiment is for better explaining the present invention, but does not limit the present application.

[0100] Embodiment III

[0101] Figure 5 Exemplarily shows a schematic flow chart of a method for manufacturing a photodetector provided in another embodiment of the present application.

[0102] AsFigure 5 As shown, the method mainly includes the following steps:

[0103] S501. Sequentially form a first electrode contact layer, a photosensitive layer, and a cover layer on the substrate.

[0104] Refer to Figure 6a and Figure 6b , Figure 6a is a top view of the structure formed after performing the steps of the preparation method in the present application, Figure 6b is Figure 6a a schematic cross-sectional structure diagram of the structure shown along the AA' direction. First, a first electrode contact layer 12 can be epitaxially grown on the substrate 11, then a photosensitive layer 13 can be epitaxially grown on the first electrode contact layer 12, and then a cover layer 17 can be epitaxially grown on the photosensitive layer 13. In specific implementation, the materials of the first electrode contact layer 12, the photosensitive layer 13, and the cover layer 17 can be material systems such as InP / InGaAs, Ge / Si, GaN, GaAs, etc., but are not limited thereto.

[0105] S502. Form a second passivation layer on the cover layer and form a via hole penetrating the second passivation layer so that the exposed cover layer is annular or circular.

[0106] Refer to Figure 7a and Figure 7b , Figure 7a is a top view of the structure formed after performing the steps of the preparation method in the present application, Figure 7b is Figure 7a a schematic cross-sectional structure diagram of the structure shown along the AA' direction. To facilitate subsequent doping of the cover layer 17, a second passivation layer 152 can be first formed on the cover layer 17, and the second passivation layer 152 can be patterned to form a via hole penetrating the second passivation layer 152 so that the exposed cover layer 17 is annular or circular as shown in Figure 7a or regular polygons, etc., which is not limited herein.

[0107] S503. Dope the exposed cover layer to form a second electrode contact layer.

[0108] Refer to Figure 8a and Figure 8b , Figure 8a is a top view of the structure formed after performing the steps of the preparation method in the present application, Figure 8b is Figure 8aSchematic cross-sectional structure diagram of the shown structure along the AA' direction. The exposed capping layer 17 can be doped to form the second electrode contact layer 14 through a diffusion or ion implantation process. That is, the epitaxial material of the second electrode contact layer 14 is the same as that of the capping layer 17, and their intrinsic materials are the same, but the doping concentrations are different. The capping layer 17 is generally lightly doped, and the second electrode contact layer 14 is generally heavily doped. Alternatively, the intrinsic materials of the second electrode contact layer 14 and the capping layer 17 are the same, but their electrical doping types are different. For example, the capping layer 17 is N-type doped, and the second electrode contact layer 14 is P-type doped, or the capping layer 17 is P-type doped, and the second electrode contact layer 14 is N-type doped.

[0109] In this application, the boundary shape of the second electrode contact layer and the shape of the through hole formed subsequently can be designed to be the same, and the center of the second electrode contact layer and the center of the through hole formed subsequently can be designed to coincide, so as to ensure that the performance of the photodetector in the same plane perpendicular to the light passing direction is as centrosymmetric as possible.

[0110] S504. Form a ring-shaped metal contact electrode on the second electrode contact layer and anneal the metal contact electrode so that the second electrode to be formed is electrically connected to the second electrode contact layer through the metal contact electrode.

[0111] See Figure 9a and Figure 9b , Figure 9a is a top view of the structure formed after performing the steps of the preparation method in this application. Figure 9b is Figure 9a Schematic cross-sectional structure diagram of the shown structure along the AA' direction. A ring-shaped metal contact electrode 18 is formed on the second electrode contact layer 14, and the metal contact electrode 18 is annealed. The center of the metal contact electrode 18 can coincide with the center of the through hole to be formed.

[0112] S505. Form a through hole that at least penetrates the light-sensitive layer and the second electrode contact layer.

[0113] In specific implementation, see Figure 10a and Figure 10b , Figure 10a is a top view of the structure formed after performing the steps of the preparation method in this application. Figure 10b is Figure 10aSchematic diagram of the cross-sectional structure of the structure shown along the AA' direction. The through hole V0 can penetrate the second electrode contact layer 14, the photosensitive layer 13, the first electrode contact layer 12 and the substrate 11. When the absorption spectrum of the substrate does not overlap with the wavelength of the light to be detected, the through hole V0 can only penetrate the second electrode contact layer 14, the photosensitive layer 13 and the first electrode contact layer 12. Further, when the absorption spectrum of the substrate does not overlap with the wavelength of the light to be detected, and the epitaxial material of the first electrode contact layer and the substrate is the same, the through hole V0 can only penetrate the second electrode contact layer 14 and the photosensitive layer 13.

[0114] The present application does not limit the shape of the through hole, which can be any shape, such as regular polygonal, circular, elliptical, etc. When the through hole V0 is circular, the distance from the center of the through hole V0 to the boundary of the through hole V0 can be ensured to be the same. In addition, circular through holes are easier to realize in terms of technology.

[0115] Continue to see Figure 10a and Figure 10b After the through hole V0 is formed, the covering layer 17 is arranged around the second electrode contact layer 14, and the through hole V0 penetrates the second electrode contact layer 14, ensuring that the functional area of the photodetector (i.e., the facing area of the first electrode contact layer 12, the photosensitive layer 13 and the second electrode contact layer 14) is close to the edge of the through hole V0, so that the photons passing through the through hole V0 are easily captured, thereby improving the sensitivity.

[0116] S506 , forming a third groove penetrating the second passivation layer, the photosensitive layer and the cover layer.

[0117] See also Figures 11a to 11c , Figure 11a A top view of a structure formed after executing the steps of the preparation method in this application, Figure 11b for Figure 11a The schematic diagram of the cross-sectional structure of the structure shown along the AA' direction, Figure 11c for Figure 11a The schematic cross-sectional structure diagram of the structure shown is along the BB' direction. A third groove V3 penetrating the second passivation layer 152, the photosensitive layer 13 and the cover layer 17 is formed.

[0118] S507 , forming a first passivation layer on the metal contact electrode.

[0119] See also Figures 12a to 12c , Figure 12a A top view of a structure formed after executing the steps of the preparation method in this application, Figure 12b for Figure 12a The schematic diagram of the cross-sectional structure of the structure shown along the AA' direction, Figure 12c for Figure 12aSchematic cross-sectional structure diagram of the structure shown in the BB' direction. The first passivation layer 151 formed on the metal contact electrode 18 can cover the sidewalls of the through hole V0 and the sidewalls of the third groove V3, thereby protecting the epitaxial materials at the through hole V0 and the third groove V3.

[0120] S508. Form a second groove penetrating the first passivation layer, and form a first groove penetrating the first passivation layer in the area where the third groove is located, so that the first groove penetrates the first passivation layer and reaches the surface of the first electrode contact layer.

[0121] See Figures 13a to 13c , Figure 13a is a top view of the structure formed after performing the steps of the preparation method in this application. Figure 13b is Figure 13a schematic cross-sectional structure diagram of the structure shown in the AA' direction. Figure 13c is Figure 13a schematic cross-sectional structure diagram of the structure shown in the BB' direction. The second groove V2 penetrating the first passivation layer 151 can be formed by a photolithography process, and the first groove V1 penetrating the first passivation layer 151 can be formed by a photolithography process in the area where the third groove V3 is located, so that the first groove V1 penetrates the first passivation layer 151 and reaches the surface of the first electrode contact layer 12.

[0122] In specific implementation, the second groove V2 and the first groove V1 penetrating the first passivation layer 151 can be formed simultaneously by a single photolithography process.

[0123] S509. Form a first electrode and a second electrode on the first passivation layer.

[0124] See Figures 14a to 14c , Figure 14a is a top view of the structure formed after performing the steps of the preparation method in this application. Figure 14b is Figure 14a schematic cross-sectional structure diagram of the structure shown in the AA' direction. Figure 14c is Figure 14a schematic cross-sectional structure diagram of the structure shown in the BB' direction. The orthographic projections of the first electrode 161 and the second electrode 162 on the substrate 11 located on the first passivation layer 151 are located outside the orthographic projection of the through hole V0 on the substrate 11. The first electrode 161 and the second electrode 162 are insulated from each other. The first electrode 161 is electrically connected to the first electrode contact layer 12 through the first groove V1, and the second electrode 162 is electrically connected to the metal contact electrode 18 through the second groove V2.

[0125] In specific implementation, the shapes of the first electrode and the second electrode are not limited. However, considering the symmetry of the performance of the photodetector, such as Figure 14aAs shown, the second electrode 162 has a closed annular structure surrounding the via V0; the first electrode 161 is arranged around the second electrode 162 and has an annular structure with an opening. The opening of the first electrode 161 is to prevent short circuit between the first electrode 161 and the second electrode 162. The first electrode 161 and the second electrode 162 are respectively led out from both sides of the via.

[0126] Further, in order to increase the contact area between the electrode and the electrode contact layer, the shape of the groove can be set to be similar to the shape of the electrode. Refer to Figure 13a , the shape of the second groove V2 is a closed ring surrounding the via V0; the shape of the first groove V1 is an annular shape arranged around the second groove V2 and having an opening.

[0127] After the above steps S501 to S509, the photodetector in the present application is formed. In this photodetector, the passivation layer is formed by two passivation layers, namely the first passivation layer and the second passivation layer. For the case where the via V0 penetrates all the film layers, refer to Figures 14a to 14c . For the case where the via V0 does not penetrate all the film layers, refer to Figures 15a to 15c .

[0128] Embodiment 4

[0129] Figure 16 Exemplarily shows a schematic flow chart of a method for manufacturing a photodetector provided by another embodiment of the present application. As Figure 16 shown, this method mainly includes the following steps:

[0130] S1601. Sequentially form a first electrode contact layer, a photosensitive layer, and a cover layer on a substrate.

[0131] S1602. Form a second passivation layer on the cover layer and form a via penetrating the second passivation layer to make the exposed cover layer annular or circular.

[0132] S1603. Dope the exposed cover layer to form a second electrode contact layer.

[0133] S1604. Form an annular metal contact electrode on the second electrode contact layer and anneal the metal contact electrode to make the second electrode to be formed electrically connected to the second electrode contact layer through the metal contact electrode.

[0134] S1605. Form a via at least penetrating the photosensitive layer and the second electrode contact layer.

[0135] S1606. Remove the second passivation layer, the cover layer, and the photosensitive layer in a preset area to make the remaining cover layer and photosensitive layer have an annular structure.

[0136] In specific implementation, refer to Figure 17a andFigure 17b , Figure 17a is a top view of the structure formed after performing the steps of the preparation method in this application. Figure 17b is Figure 17a a schematic cross-sectional structure diagram of the structure shown in the direction of AA'. Remove the second passivation layer 152, the covering layer 17, and the photosensitive layer 13 within the preset area S1, so that the remaining covering layer 17 and photosensitive layer 13 form an annular structure.

[0137] S1607. Form a first passivation layer on the metal contact electrode.

[0138] S1608. Form a second groove penetrating the first passivation layer, and form a first groove penetrating the first passivation layer in the area where the third groove is located, so that the first groove penetrates the first passivation layer and reaches the surface of the first electrode contact layer.

[0139] S1609. Form a first electrode and a second electrode on the first passivation layer.

[0140] Compared with Embodiment 3, this example is only different in step S1506 and step S506 in Embodiment 3. Other steps can refer to Embodiment 3 and will not be elaborated here.

[0141] After the above steps S1601 to S1609, a photodetector in this application is formed. In this photodetector, the passivation layer is formed by two passivation layers, namely the first passivation layer and the second passivation layer. For the case where the through hole V0 penetrates all the film layers, reference can be made to Figure 14a and Figure 18a and Figure 18b , Figure 18a is Figure 14a a schematic cross-sectional structure diagram of the structure shown in the direction of AA'. Figure 18b is Figure 14a a schematic cross-sectional structure diagram of the structure shown in the direction of BB'. For the case where the through hole V0 does not penetrate all the film layers, reference can be made to Figure 15a and Figure 19a and Figure 19b , Figure 19a is Figure 15a a schematic cross-sectional structure diagram of the structure shown in the direction of AA'. Figure 19b is Figure 15a a schematic cross-sectional structure diagram of the structure shown in the direction of BB'.

[0142] Embodiment 5

[0143] Figure 20 Exemplarily shows a schematic flow chart of the preparation method of the photodetector provided by another embodiment of this application. As Figure 20 shown, this method mainly includes the following steps:

[0144] S2001. Form a first electrode contact layer, a photosensitive layer, and a covering layer in sequence on the area of the substrate except for the central area.

[0145] See Figure 21a and Figure 21b , Figure 21a is a top view of the structure formed after performing the steps of the preparation method in this application. Figure 21b is Figure 21a A schematic cross-sectional structure diagram of the structure shown in the direction of AA'. On the area of the substrate 11 except for the central area, a first electrode contact layer 12, a photosensitive layer 13, and a covering layer 17 are epitaxially grown in sequence. Thus, while forming the first electrode contact layer 12, the photosensitive layer 13, and the covering layer 17, a through hole V0 penetrating the first electrode contact layer 12, the photosensitive layer 13, and the covering layer 17 is formed in the central area. Among them, the central area is the area where the through hole is located and can be a circular area.

[0146] S2002. Form a second passivation layer on the covering layer and form a via hole penetrating the second passivation layer so that the exposed covering layer is annular.

[0147] S2003. Dope the exposed covering layer to form a second electrode contact layer.

[0148] S2004. Form an annular metal contact electrode on the second electrode contact layer and anneal the metal contact electrode so that the second electrode to be formed is electrically connected to the second electrode contact layer through the metal contact electrode.

[0149] S2005. Form a third groove penetrating the second passivation layer, the photosensitive layer, and the covering layer.

[0150] S2006. Form a first passivation layer on the metal contact electrode.

[0151] S2007. Form a second groove penetrating the first passivation layer and form a first groove penetrating the first passivation layer in the area where the third groove is located so that the first groove penetrates the first passivation layer and reaches the surface of the first electrode contact layer.

[0152] S2008. Form a first electrode and a second electrode on the first passivation layer.

[0153] Compared with Embodiment 3, this example is only different from step S501 in Embodiment 3 in step S2001. In addition, in step S2001 of this example, the through hole only penetrates the first electrode contact layer 12, the photosensitive layer 13, and the second electrode contact 17. Therefore, compared with Embodiment 3, step S505 is omitted, and other steps can refer to Embodiment 3 and will not be elaborated here.

[0154] After the above steps S2001 to S2008, the formed photodetector can be seen in Figure 15a , Figure 22a and Figure 22b , Figure 22a which is Figure 15a a schematic cross-sectional structure diagram of the structure shown in the AA' direction, Figure 22b and Figure 15a is a schematic cross-sectional structure diagram of the structure shown in the BB' direction.

[0155] Furthermore, in this example, after step 2004 and before step S2005, the central region of the substrate can also be removed. Thus, in the finally formed photodetector, the through holes penetrate all the film layers, and specifically, it can be seen in Figures 14a to 14c .

[0156] Example 6

[0157] Figure 23 Exemplarily shows a schematic flow chart of a method for manufacturing a photodetector provided in another embodiment of the present application. As Figure 23 shown, the method mainly includes the following steps:

[0158] S2301. Sequentially form a first electrode contact layer, a photosensitive layer, and a covering layer on the region of the substrate except for the central region.

[0159] S2302. Form a second passivation layer on the covering layer and form a via hole penetrating the second passivation layer to make the exposed covering layer annular.

[0160] S2303. Dope the exposed covering layer to form a second electrode contact layer.

[0161] S2304. Form an annular metal contact electrode on the second electrode contact layer and anneal the metal contact electrode to make the to-be-formed second electrode electrically connected to the second electrode contact layer through the metal contact electrode.

[0162] S2305. Remove the second passivation layer, the covering layer, and the photosensitive layer within a preset region to make the remaining covering layer and photosensitive layer in an annular structure.

[0163] S2306. Form a first passivation layer on the metal contact electrode.

[0164] S2307. Form a second groove penetrating the first passivation layer and form a first groove penetrating the first passivation layer in the region where the third groove is located, so that the first groove penetrates the first passivation layer and reaches the surface of the first electrode contact layer.

[0165] S2308. Form a first electrode and a second electrode on the first passivation layer.

[0166] This example is different from Example 5 only in that step S2305 is different from step S2005 in Example 5. For other steps, reference can be made to Example 5 and will not be elaborated here.

[0167] After the above steps S2301 to S2308, the formed photodetector can be seen in Figure 15a 、 Figure 24a and Figure 24b , Figure 24a is Figure 15a a schematic cross-sectional structure diagram of the structure shown along the AA' direction, Figure 24b is Figure 15a a schematic cross-sectional structure diagram of the structure shown along the BB' direction.

[0168] Further, in this example, after step S2304 and before step S2005, it may further include removing the central region of the substrate. Thus, in the finally formed photodetector, the through hole penetrates through all the film layers. For details, reference can be made to Figures 14a to 14c .

[0169] In the photodetector provided by the present application, a first electrode contact layer, a photosensitive layer, and a second electrode contact layer are stacked around the through hole. When the photosensitive layer captures the light passing through the through hole, the light signal can be converted into an electrical signal, thereby realizing the detection of the light signal.

[0170] Referring to Figure 25 , the present application also provides a chip 100, which includes a driving circuit 101 and at least one photodetector 10 provided in any of the above embodiments and connected to the driving circuit 101 ( Figure 25 One photodetector 10 is taken as an example for illustration). Among them, the photodetector 10 can convert the captured light signal into an electrical signal, and the driving circuit 101 can amplify and output the electrical signal to realize the detection of the light signal.

[0171] In specific implementation, the number and arrangement of the photodetectors 10 can be designed according to the actual application scenarios and are not limited here. For example, in one embodiment, as Figure 26 shown, multiple photodetectors 10 are arranged along the first direction. In another embodiment, as Figure 27 shown, multiple photodetectors 10 are arranged in a matrix.

[0172] The present application also provides an optical device, which includes a wavelength selective switch structure and at least one photodetector. The photodetector is disposed on the transmission path of the monochromatic light in the free space of the wavelength selective switch structure. This can not only ensure that the monochromatic light signal is not interfered, but also ensure that the volume of the WSS structure will not increase. Moreover, since the photodetector can directly obtain photons from the transmission path of the monochromatic light without relying on other devices, it can be fixed on the transmission path of the monochromatic light without complex mechanical fixing parts. Compared with the existing optical fiber tap detection device, the overall cost and overall structural complexity can be reduced.

[0173] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the protection 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 also intends to include these changes and modifications.

Claims

1. An optical device, characterized in that, Comprising a wavelength selective switch structure and at least one photodetector, the photodetector being disposed on the transmission path of monochromatic light in the free space of the wavelength selective switch structure; The photodetector includes: a substrate, a first electrode contact layer, a photosensitive layer, a second electrode contact layer, a passivation layer, and a first electrode and a second electrode, which are sequentially stacked on the substrate; The photodetector further includes through holes that at least penetrate through the photosensitive layer and the second electrode contact layer; the monochromatic light passes through the through holes; The first electrode contact layer and the second electrode contact layer are doped semiconductor layers with opposite polarities; The orthographic projections of the first electrode and the second electrode on the substrate are respectively located outside the orthographic projection of the through hole on the substrate; The first electrode and the second electrode are insulated from each other. The first electrode is electrically connected to the first electrode contact layer through a first groove that penetrates through the film layer between the first electrode and the first electrode contact layer, and the second electrode is electrically connected to the second electrode contact layer through a second groove that penetrates through the passivation layer.

2. The optical device according to claim 1, characterized in that The second electrode has a closed annular structure surrounding the through hole; The first electrode has an annular structure surrounding the second electrode and having an opening; 3. The optical device according to claim 2, wherein The shape of the second groove is a closed ring surrounding the through hole; The shape of the first groove is an annular shape surrounding the second groove and having an opening; 4. The optical device according to any one of claims 1 to 3, characterized in that, The through hole also penetrates through the first electrode contact layer; 5. The optical device according to claim 4, characterized in that, The through hole also penetrates through the substrate and the passivation layer; 6. The optical device according to any one of claims 1 to 3, characterized in that, The shape of the through hole is circular; 7. The optical device according to any one of claims 1 to 3, characterized in that, The shape of the second electrode contact layer is annular; The photodetector further includes a covering layer disposed on the same layer as the second electrode contact layer, and the covering layer surrounds the second electrode contact layer; The second electrode contact layer and the covering layer have the same intrinsic material, different doping concentrations, or different electrical doping types; 8. The optical device according to any one of claims 1 to 3, characterized in that The first electrode contact layer is an N-type doped semiconductor layer, and the second electrode contact layer is a P-type doped semiconductor layer; the photodetector further includes a metal contact electrode located between the second electrode and the second electrode contact layer.

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