Semiconductor photoelectric device

Abstract

The invention provides a semiconductor photoelectric device. The semiconductor photoelectric device at least comprises a substrate layer made of a first semiconductor material and an absorption layer made of a second semiconductor material, an avoiding space is formed between the absorption layer and the substrate layer and is used for arranging an anode electrically connected with the absorption layer; the substrate layer and the absorption layer are connected through a connecting part made of a third semiconductor material; the substrate layer is electrically connected with the cathode; the absorption layer forms an electron-hole pair under illumination, and electrons / holes separated under the action of an electric field enter the substrate layer through the connecting part. The anode is arranged on the back surface of the absorption layer, and the illumination surface of the absorption layer is not shielded, so that the filling factor of the photoelectric detector can be ensured to be 100%, and the problem of light loss caused by a bias electrode is effectively avoided.

Description

Technical Field

[0001] The invention relates to a semiconductor device, and in particular to a semiconductor photoelectric device with a filling factor of 100%. Background Art

[0002] Photodetectors, as important devices in the field of optoelectronics, have performance that is directly related to the efficiency and accuracy of converting optical signals into electrical signals. They are widely used in optical communications, spectral analysis, environmental monitoring, biomedical imaging, security monitoring, laser radar, etc. In practical applications, improving the ratio of its effective photosensitive area to the overall area, i.e., the fill factor (FF), is an important way for detectors to maintain high sensitivity and signal-to-noise ratio.

[0003] The introduction of PN junction structure provides a new way to improve the performance of photodetectors. PN junction is an interface structure formed by two or more semiconductor materials with different doping types, which can promote the effective separation and transmission of carriers by utilizing energy band differences. In photodetectors, by carefully designing the composition and structure of PN junctions, not only can the quantum efficiency and response speed of the detector be significantly improved, but also the dark current and noise can be effectively suppressed by optimizing the energy band matching, thereby improving the signal-to-noise ratio and stability of the detector. At the same time, PN can be homogeneous or heterogeneous, and heterogeneous PN junction integration can combine the advantages of multiple materials, such as integrating high-performance materials onto substrate materials to be used as absorption layer materials and avalanche layer materials respectively.

[0004] In PN junction photodetectors, bias voltage is indispensable. On the one hand, it promotes the separation of carriers. By applying an external electric field, photogenerated electrons and holes can be quickly separated and move to their respective electrodes, reducing the probability of recombination. On the other hand, it speeds up the transmission speed of carriers, improves the response speed of the detector, and improves the signal-to-noise ratio by suppressing dark current, thereby enhancing the overall performance of the detector.

[0005] In order to allow electrons to be smoothly transferred from the photosensitive layer to the electrode, electrodes are usually required at both ends of the photodetector. However, the presence of the electrode will block part of the incident light, resulting in light loss. This light loss reduces the effective light absorption area of ​​the detector, thereby affecting its performance. Summary of the invention

[0006] The purpose of the present invention is to provide a semiconductor photoelectric device to effectively avoid the light loss problem caused by electrodes in view of the deficiencies in the prior art.

[0007] The semiconductor photoelectric device described in the present invention at least includes a substrate layer composed of a first semiconductor material and an absorption layer composed of a second semiconductor material; the substrate layer and the absorption layer form a PN junction. There is an avoidance space between the absorption layer and the substrate layer, which is used to set a first electrode electrically connected to the absorption layer; the substrate layer and the absorption layer are connected through a connecting portion composed of a third semiconductor material; the substrate layer is electrically connected to the second electrode; the absorption layer forms electron-hole pairs under light, and the separated electrons / holes enter the substrate layer through the connecting portion under the action of the electric field. Since the first electrode is arranged on the back of the absorption layer, the light-exposed surface of the absorption layer is not blocked, which can ensure that the filling factor of the photodetector is 100%.

[0008] In some embodiments of the present invention, an isolation medium is further provided in the avoidance space to electrically isolate the first electrode from the connecting portion and the substrate layer.

[0009] In some embodiments of the present invention, the isolation medium is SiO2 material.

[0010] In some embodiments of the present invention, the connection area between the connection portion and the absorption layer is smaller than the absorption layer area; or, the connection area between the connection portion and the substrate layer is smaller than the substrate layer area. The small contact area will effectively reduce noise.

[0011] In some embodiments of the present invention, in order to effectively achieve electron-hole separation, the second semiconductor material constituting the absorption layer is a P-type semiconductor material, and the third semiconductor material constituting the connecting portion is an intrinsic semiconductor material or an N-type semiconductor material. Or the second semiconductor material constituting the absorption layer is an N-type semiconductor material, and the third semiconductor material constituting the connecting portion is an intrinsic semiconductor material or a P-type semiconductor material.

[0012] When the substrate layer is used as an avalanche layer, it forms an avalanche diode with the absorption layer. Based on the structural design of the present invention, the problem of light loss caused by the electrode on the surface of the absorption layer can be avoided, and the APD noise can be significantly reduced.

[0013] In certain embodiments of the present invention, the second semiconductor material constituting the absorption layer is P-type doped Si, GaN, GaO, InN, GaAs, InAs or graphene; the first semiconductor material constituting the substrate layer is N-type doped Si, InP, sapphire or glass.

[0014] In certain embodiments of the present invention, the connecting portion and the absorption layer are obtained by epitaxial growth on the substrate layer, especially by adopting the reported trench epitaxial growth strategy, which can reduce defect density and improve device performance.

[0015] In the present invention, the second electrode is located at the bottom of the substrate layer.

[0016] The beneficial effect of the present invention is that: since the first electrode is arranged on the back of the absorption layer, the light-illuminating surface of the absorption layer is not blocked, and the filling factor of the photodetector can be guaranteed to be 100%. This can improve the photosensitivity of the device, increase the sensitivity and signal-to-noise ratio. When it is applied to an avalanche diode, on the one hand, the detection efficiency and minimum sensitivity of the device can be improved, and on the other hand, the structure reduces the contact area of ​​the PN junction semiconductor, which can reduce the number of defect sites when the current flows through the interface, thereby significantly reducing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an example device structure in the prior art using the P region as an absorption layer; Figure 2 for Figure 1 The carrier flow mode when the P region is used as an absorption layer; the red circles in the figure represent electrons, the white circles represent holes, and the arrows represent the migration direction; Figure 3 The PN semiconductor optoelectronic device structure of the present invention uses the P region as the absorption layer; Figure 4 for Figure 3 The carrier flow mode when the P region is used as an absorption layer; the red circles in the figure represent electrons, the white circles represent holes, and the arrows represent the migration direction; Figure 5 This is one of the structural schematic diagrams of the PN photoelectric device of the present invention; Figure 6 The second schematic diagram of the structure of the PN photoelectric device of the present invention; Figure 7 This is the third structural schematic diagram of the PN photoelectric device of the present invention; Figure 8 A schematic diagram of the connection part and anode of the PN photoelectric device of the present invention; Fig. 9 This is one of the schematic diagrams of region A and region B of the PN photoelectric device of the present invention; Fig.10 This is the second schematic diagram of region A and region B of the PN photoelectric device of the present invention. DETAILED DESCRIPTION

[0018] The PN semiconductor photoelectric device described in the present invention refers to a type of semiconductor device that uses the photoelectric effect of the PN junction to achieve the mutual conversion between light energy and electrical energy. This type of device is usually composed of a P-type semiconductor and an N-type semiconductor. When these two materials are in contact, a special area, the PN junction, is formed at the interface. The PN junction has unidirectional conductivity, that is, when a positive voltage is applied to a P-type semiconductor and a negative voltage is applied to an N-type semiconductor, current can pass smoothly; conversely, when the voltage direction is opposite, current can hardly pass.

[0019] As is common knowledge in the art, P-type semiconductors are rich in holes, which is usually achieved by doping with trivalent elements (such as boron). N-type semiconductors are rich in free electrons, which is usually achieved by doping with pentavalent elements (such as phosphorus).

[0020] For PN optoelectronic devices, either the P region or the N region can serve as the absorption layer. Figure 1 An example device structure using the P region as the absorption layer 1 in the prior art is given. Figure 2 Shown Figure 1 The carrier flow mode when the P region is used as the absorption layer 1 is shown. Specifically, when the P region is used as the absorption layer, it means that the light is mainly concentrated on the P-type semiconductor material. If the energy of the photon is greater than or equal to the bandgap energy of the P-type semiconductor material, the photon will be absorbed. The absorbed photon energy will excite the electrons in the valence band to transition to the conduction band, thereby leaving holes in the valence band to form electron-hole pairs. The generated electron-hole pairs are separated under the action of the built-in electric field. The electrons move to the substrate layer 2 (i.e., the N-type region), while the holes remain in the P-type region. This is because the direction of the built-in electric field is from the N-type region to the P-type region, so the electrons will move to the N-type region, while the holes will move to the P-type region. The electrons flow to the P-type region through the external circuit, while the holes remain in the P-type region. Correspondingly, when the N region is used as the absorption layer 1, it means that the light is mainly concentrated on the N-type semiconductor material. If the energy of the photon is greater than or equal to the bandgap energy of the N-type semiconductor material, the photon will be absorbed. The absorbed photon energy will excite the electrons in the valence band to jump to the conduction band, leaving holes in the valence band and forming electron-hole pairs. The generated electron-hole pairs are separated under the action of the built-in electric field. The holes move to the substrate layer 2 (P-type region), while the electrons remain in the N-type region. This is because the direction of the built-in electric field is from the N-type region to the P-type region, so the holes will move to the P-type region, while the electrons will remain in the N-type region. The holes flow to the N-type region through the external circuit, while the electrons remain in the N-type region.

[0021] Different from the PN semiconductor optoelectronic device of the prior art, the present invention provides Figure 3 The PN semiconductor photoelectric device shown comprises a substrate layer 2 made of a first semiconductor material and an absorption layer 1 made of a second semiconductor material; the absorption layer 1 and the substrate layer 2 are connected by a connecting portion 3, so that an escape space 6 is formed between the substrate layer 2 and the absorption layer 1, for accommodating an anode 4 electrically connected to the absorption layer; that is, the anode 4 is located in the escape space 6 between the substrate layer 2 and the absorption layer 1, but not on the light-receiving surface of the absorption layer 1, and the light-receiving surface of the absorption layer 1 is not blocked, which can ensure that the filling factor of the photodetector is 100%. The substrate layer 2 is electrically connected to the cathode 5.

[0022] The anode 4 and the cathode 5 respectively constitute the first electrode and the second electrode described in the present application. Those skilled in the art should know that the first electrode and the second electrode are used to provide bias for the PN junction, and their positive and negative polarities can be adjusted according to actual conditions. When holes are needed to be used as carriers for migration, the substrate layer area needs to be P-type doped, and the absorption area needs to be N-type doped; when electrons are needed to be used as carriers for migration, the substrate layer area needs to be N-type doped, and the absorption area needs to be P-type doped.

[0023] The first semiconductor material and the second semiconductor material may be the same semiconductor material but with different types of doping; or they may be different semiconductor materials, usually a P-type semiconductor material and an N-type semiconductor material. They may even be different semiconductor materials and doped at the same time. For example, the second semiconductor material constituting the absorption layer is P-type doped Si, GaN, GaO, InN, GaAs, InAs or graphene; the first semiconductor material constituting the substrate layer is N-type doped Si, InP, sapphire or glass.

[0024] Figure 3 In the device structure shown, a P-type semiconductor material is used as the absorption layer 1, and an N-type semiconductor material is used as the substrate layer. Figure 4 The flow mode of carriers is given. When the energy of photons is greater than or equal to the bandgap energy of P-type semiconductor materials, the photons will be absorbed. The absorbed photon energy will excite the electrons in the valence band to transition to the conduction band, leaving holes in the valence band to form electron-hole pairs. The generated electron-hole pairs are separated under the action of the built-in electric field. The electrons move to the substrate layer 2 (i.e., the N-type region), while the holes remain in the P-type region. This is because the direction of the built-in electric field is from the N-type region-connection part-P-type region, so the electrons will move to the connection part-N-type region, while the holes will move to the P-type region. Electrons flow to the P-type region through an external circuit, while holes remain in the P-type region. Under the action of bias, holes migrate to the anode 4 position, and electrons migrate in the opposite direction, entering the substrate layer 2 and cathode 5 through the connection part 3, thereby forming a detection electrical signal.

[0025] In order to ensure a sufficient built-in electric field, the connection part 3 is preferably made of intrinsic semiconductor or N-type semiconductor material. When the connection part 3 is made of intrinsic semiconductor, a built-in electric field in the direction of N-type region-connection part-P-type region is formed, so that the electron holes in the absorption layer 1 are separated. When the connection part 3 is made of N-type semiconductor, a built-in electric field is directly formed in the connection part-P-type region, so that the electron holes in the absorption layer 1 are separated.

[0026] Correspondingly, an N-type semiconductor material can be used as the absorption layer 1 and a P-type semiconductor material can be used as the substrate layer. When the energy of the photon is greater than or equal to the bandgap energy of the N-type semiconductor material, the photon will be absorbed. The absorbed photon energy will excite the electrons in the valence band to transition to the conduction band, thereby leaving holes in the valence band to form electron-hole pairs. The generated electron-hole pairs are separated under the action of the built-in electric field. The holes move to the substrate layer 2 (P-type region), while the electrons remain in the N-type region. This is because the direction of the built-in electric field is from the N-type region to the P-type region, so the holes will move to the P-type region, while the electrons will remain in the N-type region. The holes flow to the N-type region through the external circuit, while the electrons remain in the N-type region.

[0027] In this case, in order to ensure a sufficient built-in electric field, the connection part 3 is preferably made of an intrinsic semiconductor or a P-type semiconductor material. When the connection part 3 is made of an intrinsic semiconductor, a built-in electric field in the direction of the N-type region-connection part-P-type region is formed, so that the electron holes in the absorption layer 1 are separated. When the connection part 3 is made of a P-type semiconductor, a built-in electric field is directly formed in the connection part-N-type region, so that the electron holes in the absorption layer 1 are separated.

[0028] The connecting portion 3 is used to structurally separate the absorption layer 1 and the substrate layer 2 and ensure effective electron transmission between the two. An escape space is formed between the structurally separated absorption layer 1 and the substrate layer 2, which can be used to set the anode 4. Therefore, it can be of any shape. Figure 5 The regular columns are shown in Figure 6 , Figure 7 The shaped structures are shown, the connection parts 3 of these shaped structures separate the absorption layer 1 and the substrate layer 2 and ensure efficient electron transport between the two.

[0029] In order to form a clearance space 6 where the anode 4 can be set, the connection area between the connection part 3 and the absorption layer 1 must be smaller than the area of ​​the absorption layer 1. It should be noted that under the same illumination conditions and the same absorption layer performance, the number of photogenerated electrons generated is the same, but the transmission channel is reduced, which increases the electron density. A higher electron transmission density will help electrons to be collected by the electrode more effectively and reduce system noise. Therefore, Figure 1 and Figure 2 Compared with the connection structure in Figure 3 The connection structure has lower noise.

[0030] As a carrier (electron or hole) transmission channel between the absorption layer and the substrate layer, the connection part 3 should have good transmission performance, and the potential barrier between it and the absorption layer and the substrate layer should be small.

[0031] In the above structure, the second semiconductor material used as the absorption layer 1 can be Si, Ge, III-V semiconductor, amorphous semiconductor, two-dimensional material, etc.; in the above structure, the first semiconductor material used as the substrate layer 2 can be selected as Si, sapphire substrate, InP substrate, etc.

[0032] The connection part 3 is connected to the bottom surface of the absorption layer 1, so that the anode 4 cannot completely occupy the bottom surface area of ​​the absorption layer; the area where the bottom surface of the absorption layer 1 is connected to the connection part 3 is defined as area A, and the area where the bottom surface of the absorption layer 1 is connected to the anode 4 is defined as area B. Both area A and area B can be of any shape. Regardless of the shape, the photogenerated electrons migrate to area B, and then enter the substrate layer 2 through the connection part 3; the holes migrate to area A. Figure 8 and 9 A shape combination of the anode 4 and the connecting part 3 is shown, wherein the connecting part 3 is a cubic column, and the area A where it connects to the absorption layer 1 is square; the anode 4 is a round cake, and the area B where it connects to the absorption layer 1 is circular.

[0033] Fig.10 Schematic diagram of another shape of the connection part and the anode, wherein the area A where the connection part 3 is connected to the absorption layer 1 is square; and the area B where the anode 4 is connected to the absorption layer 1 is C-shaped.

[0034] It should be emphasized that since the anode 4 is disposed on the back of the absorption layer 1, it is not limited to transparent electrode materials. The anode 4 and the cathode 5 can be conventional electrodes in the art, and any material with good conductivity can be used in this application, including but not limited to Au, Cu, Al or Al / Au, Ti / Au and other double-layer electrodes.

[0035] Considering factors such as structural stability, the avoidance space 6 can be fully filled with an isolation medium to form an integrated structure similar to the existing PN photoelectric detector. In addition, the filling of the isolation medium will help to achieve insulation between the anode 4 and the connecting part 3 and the substrate layer 2. Commonly used, this isolation medium can be SiO2 or Al2O3.

[0036] A PN avalanche diode (APD) is a highly sensitive photodetector that uses the avalanche effect to amplify weak light signals. This type of diode is widely used in applications that require high-sensitivity detection, such as fiber-optic communications, LiDAR systems, quantum computing, and other fields. When a reverse bias is applied to both ends of the PN junction, the photogenerated electrons and holes in the absorption layer are separated by the electric field to form a depletion region, in which electron-hole pairs are generated. Under the action of a strong electric field, these carriers are accelerated, and new electron-hole pairs are further generated when the substrate layer (avalanche layer) collides with atoms in the lattice, significantly amplifying the photocurrent, which is particularly suitable for occasions where weak light signals need to be detected. Although APD has the advantage of high gain, it also amplifies noise signals, for example, the dark current on the surface of the absorption layer is amplified.

[0037] In particular, according to the concept of the present invention, a PN avalanche diode is provided, which includes an avalanche layer (i.e., substrate layer 2) composed of a first semiconductor material and an absorption layer 1 composed of a second semiconductor material; the absorption layer 1 and the avalanche layer are connected by a connecting portion 3, so that a avoidance space 6 is formed between the avalanche layer and the absorption layer 1, which is used to accommodate an anode 4 electrically connected to the absorption layer; that is, the anode 4 is located in the avoidance space 6 between the avalanche layer and the absorption layer 1, but not on the light-receiving surface of the absorption layer 1, and the light-receiving surface of the absorption layer 1 is not blocked, which can ensure that the filling factor of the photodetector is 100%. The avalanche layer is electrically connected to the cathode 5. Under illumination, the absorption layer forms electron-hole pairs. Under the action of bias, holes migrate to the position of the P-type doped anode 4, and electrons migrate in the opposite direction, enter the avalanche layer through the connecting portion 3, and multiply, and finally connect to the external circuit through the cathode 5, thereby forming a detection electrical signal. It can be seen that the present invention can avoid the problem of light loss caused by the electrode on the surface of the absorption layer, and significantly reduce APD noise.

[0038] Preferably, the avalanche layer can be a Si substrate layer. In order to achieve the avalanche function, a 1-3um thick intrinsic Si portion is required, and N-type heavily doped Si is below the intrinsic Si to contact the cathode 5 to form an ohmic contact. When an avalanche occurs, the breakdown voltage is relatively high, generally between 10 and 100V, depending on the thickness of the intrinsic layer and the doping concentration.

[0039] The device structure may involve a variety of preparation methods.

[0040] Method 1: Assembly STP1: depositing a metal electrode on the back of the substrate layer composed of the first semiconductor material to form a cathode; STP2: depositing a local metal electrode on the back side of the absorption layer composed of the second semiconductor material to form an anode; STP3: Take the connection part made of the third semiconductor material, the upper end of which is connected to the area other than the metal electrode on the back of the absorption layer, and ensure that it does not directly contact the metal electrode; the lower end is connected to the front of the substrate layer. The connection method can be bonding.

[0041] Method 2: Epitaxial growth STP1: depositing a metal electrode on the back of the substrate layer composed of the first semiconductor material to form a cathode; STP2: Then a dielectric layer with a thickness of 1 μm is deposited on the other side of the substrate layer; STP3: The dielectric layer is then photolithographically processed and then a 200nm wide trench is etched.

[0042] STP4: Deposit metal electrode material on the top area of ​​the dielectric layer to form the anode.

[0043] STP5: Using an epitaxial growth strategy, a third semiconductor material is epitaxially grown in the trench to form a connecting portion, and a second semiconductor material is further epitaxially grown to form an absorption layer.

[0044] Method 3: Partial epitaxial growth STP1: depositing a metal electrode on the back of the substrate layer composed of the first semiconductor material to form a cathode; STP2: Then a dielectric layer with a thickness of 1 μm is deposited on the other side of the substrate layer; STP3: The dielectric layer is then photolithographically processed and then a 200nm wide trench is etched.

[0045] STP4: Deposit metal electrode material on the top area of ​​the dielectric layer to form the anode.

[0046] STP5: using an epitaxial growth strategy to epitaxially grow a third semiconductor material in the trench to form a connecting portion; STP6: Adsorb or stick the absorption layer material on the upper surface of the dielectric layer and the connecting part.

[0047] Method 4: Reverse preparation STP1: depositing a local metal electrode on the back side of the absorption layer composed of the second semiconductor material to form an anode; STP2: Deposit a 1um thick dielectric layer to cover the anode.

[0048] STP3: The dielectric layer is then photolithographically processed and then a 200nm wide trench is etched.

[0049] STP4: Using an epitaxial growth strategy, a third semiconductor material is epitaxially grown in the trench to form a connecting portion, and the first semiconductor material is further epitaxially grown to form a substrate layer.

[0050] STP5: Deposit metal material on top of the substrate layer. The final structure is reversed to prepare the device.

[0051] As is common knowledge in the art, in the above-mentioned epitaxial growth scheme, the third semiconductor material can be selected as the first semiconductor or the second semiconductor or a mixture of the first and second semiconductors or other materials with a lattice constant or thermal expansion coefficient similar to those of the first and second semiconductors, preferably a mixture of the first and second semiconductors, which can effectively reduce defects in the connection part and optimize device performance.

[0052] The above-mentioned epitaxial method is generally MBE, CVD or magnetron sputtering.

[0053] Based on the above method, the following devices are constructed: Device 1: The absorption layer is a P-type semiconductor made of Ge with a thickness of 1um, a doping source of boron, and a doping concentration of 1x10 15 cm -3 The upper surface is heavily doped with boron, with a doping concentration of 1x10 19 cm -3 ; The substrate layer is an N-type semiconductor, made of Si, with a thickness of 1.5um, a doping source of phosphorus, and a doping concentration of 1x10 15 cm -3 The lower surface is heavily doped with phosphorus, with a doping concentration of 1x10 19 cm -3 ; The anode is located on the upper surface of the absorption layer, and the cathode is located on the bottom surface of the substrate layer. Figure 1 The structure is complex.

[0054] Device 2: The absorption layer is a P-type semiconductor made of Ge with a thickness of 1um, a doping source of boron, and a doping concentration of 1x10 15 cm -3 The upper surface is heavily doped with boron, with a doping concentration of 1x10 19 cm -3 ; The substrate layer is an N-type semiconductor, made of Si, with a thickness of 1.5um, a doping source of phosphorus, and a doping concentration of 1x10 15 cm -3 The lower surface is heavily doped with phosphorus, with a doping concentration of 1x10 19 cm -3 ; The connecting part 3 is intrinsic Ge, cylindrical structure, with a diameter of 100nm and a height of 0.1um; The anode 4 is located on the lower surface of the absorption layer 1 and has a ring structure, surrounding the connecting portion 3; the cathode 5 is located on the bottom surface of the substrate layer.

[0055] A SiO2 dielectric layer is also filled between the absorption layer and the substrate layer.

[0056] Device 3: The absorption layer is a P-type semiconductor made of Ge with a thickness of 1um, a doping source of boron, and a doping concentration of 1x10 15 cm -3 The upper surface is heavily doped with boron, with a doping concentration of 1x10 19 cm -3 ; The substrate layer is an N-type semiconductor, made of Si, with a thickness of 1.5um, a doping source of phosphorus, and a doping concentration of 1x10 15 cm -3 The lower surface is heavily doped with phosphorus, with a doping concentration of 1x10 19 cm -3 ; The connecting part 3 is intrinsic Ge, cylindrical structure, with a diameter of 200nm and a height of 0.1um; The anode 4 is located on the lower surface of the absorption layer 1 and has a ring structure, surrounding the connecting portion 3; the cathode 5 is located on the bottom surface of the substrate layer.

[0057] A SiO2 dielectric layer is also filled between the absorption layer and the substrate layer.

[0058] Device 4: The absorption layer is a P-type semiconductor made of Ge with a thickness of 1um, a doping source of boron, and a doping concentration of 1x10 15 cm -3 The upper surface is heavily doped with boron, with a doping concentration of 1x10 19 cm -3 ; The substrate layer is an N-type semiconductor, made of Si, with a thickness of 1.5um, a doping source of phosphorus, and a doping concentration of 1x10 15 cm -3 The lower surface is heavily doped with phosphorus, with a doping concentration of 1x10 19 cm -3 ; The connecting part 3 is an N-type semiconductor, made of Ge, with a thickness of 0.5um, a doping source of phosphorus, and a doping concentration of 1x10 15 cm -3 ; It is a cylindrical structure with a diameter of 100nm and a height of 0.1um; The anode 4 is located on the lower surface of the absorption layer 1 and has a ring structure, surrounding the connecting portion 3; the cathode 5 is located on the bottom surface of the substrate layer.

[0059] A SiO2 dielectric layer is also filled between the absorption layer and the substrate layer.

[0060] Device 5: The absorption layer is a P-type semiconductor made of Ge with a thickness of 1um, a doping source of boron, and a doping concentration of 1x10 15 cm -3 The upper surface is heavily doped with boron, with a doping concentration of 1x10 19 cm -3 ; The substrate layer is an N-type semiconductor, made of Si, with a thickness of 1.5um, a doping source of phosphorus, and a doping concentration of 1x10 15 cm -3 The lower surface is heavily doped with phosphorus, with a doping concentration of 1x10 19 cm -3 ; The connecting part 3 is a P-type semiconductor, made of Ge, with a thickness of 0.5um, and a doping source of boron with a doping concentration of 1x10 15 cm -3 ; It is a cylindrical structure with a diameter of 100nm and a height of 0.1um; The anode 4 is located on the lower surface of the absorption layer 1 and has a ring structure, surrounding the connecting portion 3; the cathode 5 is located on the bottom surface of the substrate layer.

[0061] A SiO2 dielectric layer is also filled between the absorption layer and the substrate layer.

[0062] The above devices were tested IV using the optoelectronic performance test system, and the results are as follows: Dark Current Responsiveness Sensitivity Device 1 120MHz 0.6A / W 95lux Device 2 45 MHz 0.51A / W 23lux Device 3 37 MHz 0.47A / W 18lux Device 4 49 MHz 0.43A / W 31lux Device 5 42 MHz 0.45A / W 36lux It can be seen that device 2 to device 6 significantly reduce the dark current compared to device 1. In addition, device 2 to device 6 are only used to illustrate the technical solution of the present invention, rather than to limit it; although the present invention is described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that it is still possible to modify the technical solution described in the aforementioned device 1 to device 6, or to replace some of the technical features therein by equivalents, including but not limited to the aforementioned semiconductor materials, doping types, doping concentrations, electrode shape structures, connection shape structures, etc. These modifications or replacements do not deviate the essence of the corresponding technical solution from the spirit and scope of the technical solution of the embodiment of the present invention.

Claims

1. A semiconductor optoelectronic device, characterized in that: At least comprising a substrate layer, and an absorption layer forming a PN junction with the substrate layer; there is an escape space between the absorption layer and the substrate layer for arranging a first electrode electrically connected to the absorption layer; The substrate layer and the absorption layer are connected via a connecting portion; The substrate layer is electrically connected to the second electrode; The absorption layer generates photogenerated electrons under light, and the photogenerated electrons enter the substrate layer through the connecting portion under the bias voltage formed by the first electrode and the second electrode.

2. The semiconductor optoelectronic device according to claim 1, characterized in that: An isolation medium is also provided in the avoidance space to electrically isolate the first electrode from the connecting portion and the substrate layer.

3. The semiconductor optoelectronic device according to claim 2, characterized in that: The isolation medium is SiO2 material.

4. The semiconductor optoelectronic device according to claim 1, characterized in that: The connection area between the connection part and the absorption layer is smaller than the area of ​​the absorption layer; or, the connection area between the connection part and the substrate layer is smaller than the area of ​​the substrate layer.

5. The semiconductor optoelectronic device according to claim 1, characterized in that: The absorption layer is made of a P-type semiconductor material, and the connection portion is made of an intrinsic semiconductor material or an N-type semiconductor material.

6. The semiconductor optoelectronic device according to claim 1, characterized in that: The absorption layer is made of N-type semiconductor material, and the connection portion is made of intrinsic semiconductor material or P-type semiconductor material.

7. The semiconductor optoelectronic device according to claim 1, characterized in that: The substrate layer serves as an avalanche layer and forms an avalanche diode with the absorption layer.

8. The semiconductor optoelectronic device according to claim 5, characterized in that: The absorption layer is P-type doped Si, GaN, GaO, InN, GaAs, InAs or graphene; the substrate layer is N-type doped Si, InP, sapphire or glass.

9. The semiconductor optoelectronic device according to claim 1, characterized in that: The connecting portion and the absorption layer are obtained on the substrate layer by epitaxial growth.

10. The semiconductor optoelectronic device according to claim 1, characterized in that: The second electrode is located at the bottom of the substrate layer.

Images