Infrared detector and preparation method

Abstract

The invention provides an infrared detector and a preparation method, and relates to the technical field of semiconductors. The infrared detector comprises an N-type layer, a visible light absorption layer, a short wave absorption layer and a P-type layer which are stacked in sequence; the visible light absorption layer is configured to absorb visible light photons to generate first carriers; the short wave absorption layer is configured to absorb infrared photons to generate second current carriers; under the driving of a built-in electric field formed by the N-type layer and the P-type layer, electrons in the first carrier and electrons in the second carrier move towards the P-type layer, holes in the first carrier and holes in the second carrier move towards the N-type layer, and the movement of the electrons and the holes forms current.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and more particularly, to an infrared detector and a preparation method thereof. Background Art

[0002] Short-wave infrared detectors have wide application values in the civilian field, and can realize functions such as high-resolution observation, target recognition, surveillance and tracking in an almost dark or completely dark environment, and play a key role in scenarios such as unmanned driving, drone inspection, and security monitoring.

[0003] Short-wave infrared detection is divided into two modes: active and passive. The active mode uses a laser and a detector as the core optoelectronic devices for ranging, communication, etc.; the passive mode only relies on the detector and is mainly used for night vision. In practical applications, the active and passive modes are often integrated to construct an overall detection system, so as to obtain multi-faceted information of the target, improve the anti-interference performance and recognition ability, and reduce the false alarm rate. Since the short-wave radiation value is relatively low at the outdoor ambient temperature, the signal obtained by passive detection is weak, and short-wave infrared detection focuses more on the active mode.

[0004] During the active short-wave infrared detection process, the intensity ratio of the diffuse reflection and specular reflection of the target changes dynamically under the influence of the material, surface topography and incident angle, resulting in unstable signal contrast received by a single-band detector. Summary of the Invention

[0005] In view of this, the present disclosure provides an infrared detector and a preparation method thereof, which can at least partially solve the above technical problems.

[0006] On the one hand, the present disclosure provides an infrared detector, including: an N-type layer, a visible light absorption layer, a short-wave absorption layer and a P-type layer stacked in sequence; the visible light absorption layer is configured to absorb visible light photons to generate first carriers; the short-wave absorption layer is configured to absorb infrared photons to generate second carriers; wherein, under the driving of the built-in electric field formed by the N-type layer and the P-type layer, the electrons in the first carriers and the electrons in the second carriers move towards the P-type layer, and the holes in the first carriers and the holes in the second carriers move towards the N-type layer, and the movement of electrons and holes forms a current.

[0007] According to an embodiment of the present disclosure, it further includes: a first buffer layer disposed between the visible light absorption layer and the short-wave absorption layer, and configured to smooth the bandgap between the visible light absorption layer and the short-wave absorption layer.

[0008] According to an embodiment of the present disclosure, the materials of the N-type layer and the visible light absorption layer include GaAs; the material of the first buffer layer includes InAlAs; the materials of the short-wave absorption layer and the P-type layer include InGaAs.

[0009] According to an embodiment of the present disclosure, the bandgap width of GaAs is 1.98 eV, and the cut-off wavelength is 0.6 μm; the bandgap width of InAlAs is 2.05 eV - 2.09 eV, and the cut-off wavelength is 0.59 μm - 0.60 μm; the bandgap width of InGaAs is 0.46 eV - 0.47 eV, and the cut-off wavelength is 2.64 μm - 2.70 μm.

[0010] According to an embodiment of the present disclosure, a stepped structure is formed on another part of the N-type layer by a part of the N-type layer, a visible light absorption layer, a first buffer layer, a short-wave absorption layer, and a P-type layer.

[0011] According to an embodiment of the present disclosure, it further includes: a second buffer layer disposed on the surface of the N-type layer far from the visible light absorption layer; a substrate disposed on the surface of the second buffer layer far from the N-type layer; a P-type capping layer disposed on the P-type layer; an upper electrode disposed around the P-type capping layer; a lower electrode disposed around another part of the N-type layer; a passivation layer disposed on the outer regions of the N-type layer, the visible light absorption layer, the first buffer layer, the short-wave absorption layer, the P-type layer, and the P-type capping layer, and located in the region between the upper electrode and the lower electrode.

[0012] According to an embodiment of the present disclosure, it further includes: a light transmission hole disposed on the P-type capping layer and penetrating through the passivation layer on the P-type capping layer.

[0013] According to an embodiment of the present disclosure, the substrate includes an N-type GaAs substrate in the (001) direction, and the doping concentration of the N-type GaAs substrate is not less than 10 17 cm -3 。

[0014] According to an embodiment of the present disclosure, the doping element of the N-type layer includes Si, and the doping concentration of Si is not less than 10 18 cm -3 ; the doping element of the P-type layer includes Be, and the doping concentration of Be is not less than 10 18 cm -3 。

[0015] The second aspect of the present disclosure provides a method for manufacturing an infrared detector, including: epitaxially growing a stacked N-type layer, a visible light absorption layer, a short-wave absorption layer, and a P-type layer in sequence; wherein, the visible light absorption layer is configured to absorb visible light photons to generate first carriers; the short-wave absorption layer is configured to absorb infrared photons to generate second carriers; under the action of an externally applied electric field, the electrons in the first carriers and the electrons in the second carriers move towards the P-type layer, and the holes in the first carriers and the holes in the second carriers move towards the N-type layer, and the movement of electrons and holes forms a current.

[0016] The infrared detector provided according to an embodiment of the present disclosure has at least the following beneficial effects:

[0017] By setting up a dual-absorption region structure of a visible light absorption layer and a short-wave absorption layer, active infrared detection in the range of 500 nm - 2500 nm can be achieved, the multi-spectral reflection characteristics of the target can be obtained, the detection contrast can be improved, and detection with wide spectral response can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0019] Figure 1 Schematically shows the structural diagram of an infrared detector according to an embodiment of the present disclosure;

[0020] Figure 2 Schematically shows the schematic diagram of a preparation method of an infrared detector according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known systems and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0022] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0023] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used here should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0024] In the case of using expressions such as "at least one of A, B, and C", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but not be limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0025] During the active detection process, the light intensity ratio of target diffuse reflection and specular reflection can usually be regarded as a fixed value. If we want to improve the detection contrast, we can mainly start from the following three key aspects:

[0026] 1. Improve the optoelectronic performance of the device: Select a front cut-off wavelength that is short enough. Shorter wavelengths can effectively avoid the performance deterioration of narrow-bandgap devices caused by the influence of long-wave radiation, thereby enhancing the response ability of the detector to target signals and improving the detection accuracy.

[0027] 2. Reduce atmospheric loss: As much as possible, use a longer rear cut-off wavelength. When long wavelengths propagate in the atmosphere, compared with short wavelengths, their energy attenuation is relatively small, which can reduce the absorption and scattering losses of the atmosphere to the optical signal, thereby increasing the detection range and improving the detection efficiency.

[0028] 3. Reduce background radiation interference: Avoid using wavelengths that are the same as sunlight radiation. As the main background radiation source, if the working wavelength of the detector coincides with it, a large amount of background noise will be introduced, interfering with the detection of target signals. By avoiding this wavelength range, the background radiation interference can be effectively reduced, the signal-to-noise ratio of the detection system can be improved, and the target recognition ability can be enhanced.

[0029] Figure 1 Schematically shows the structural diagram of an infrared detector according to an embodiment of the present disclosure.

[0030] As Figure 1 shown, the infrared detector of this embodiment includes: an N-type layer 221, a visible light absorption layer 222, a short-wave absorption layer 224, and a P-type layer 225 stacked in sequence.

[0031] The visible light absorption layer 222 is configured to absorb visible light photons to generate first carriers; the short-wave absorption layer 224 is configured to absorb infrared photons to generate second carriers.

[0032] Wherein, driven by the built-in electric field formed between the N-type layer 221 and the P-type layer 225, the electrons in the first carriers and the electrons in the second carriers move towards the P-type layer 225, and the holes in the first carriers and the holes in the second carriers move towards the N-type layer 221, and the movement of electrons and holes forms a current.

[0033] In the embodiment of the present disclosure, by setting the short front cut-off wavelength design of the visible light absorption layer 222, the signal-to-noise ratio of the target signal can be improved. And by setting the long rear cut-off wavelength design of the short-wave absorption layer 224, it can cover the short-wave infrared and reduce the atmospheric loss. Using the structural design of the double absorption layer, it can cover the active infrared detection range of 500nm - 2500nm, effectively reduce the background radiation interference, and has a wide spectral response characteristic. At the same time, the built-in electric field formed by the N-type layer and the P-type layer can improve the separation efficiency of carriers and improve the quantum efficiency.

[0034] Continue as Figure 1 shown, the infrared detector of this embodiment further includes: a first buffer layer 223, disposed between the visible light absorption layer 222 and the short-wave absorption layer 224, and configured to smooth the bandgap between the visible light absorption layer 222 and the short-wave absorption layer 224.

[0035] In the embodiment of the present disclosure, by disposing the first buffer layer 223 between the visible light absorption layer 222 and the short-wave absorption layer 224, interface defects can be effectively reduced, the bandgap between the visible light absorption layer 222 and the short-wave absorption layer 224 can be smoothed, non-radiative recombination can be suppressed, and thus the quantum efficiency can be improved.

[0036] Furthermore, the materials of the N-type layer 221 and the visible light absorption layer 222 include GaAs. The material of the first buffer layer 223 includes InAlAs. The materials of the short-wave absorption layer 224 and the P-type layer 225 include InGaAs.

[0037] The bandgap width of GaAs is 1.98 eV, and the cut-off wavelength is 0.6 μm. The bandgap width of InAlAs is from 2.05 eV to 2.09 eV, and the cut-off wavelength is from 0.59 μm to 0.60 μm. The bandgap width of InGaAs is from 0.46 eV to 0.47 eV, and the cut-off wavelength is from 2.64 μm to 2.70 μm.

[0038] In the embodiment of the present disclosure, the N-type layer 221, the visible light absorption layer 222, the first buffer layer 223, the short-wave absorption layer 224, and the P-type layer 225 constitute the visible infrared unit 22. By setting the materials of each layer in the visible infrared unit 22, the InGaAs material is matched with the InAlAs material, thereby improving the quantum efficiency. The first buffer layer 223 uses the InAlAs material, which has a relatively wide bandgap and a low absorption coefficient, hardly absorbs incident light, does not interfere with the operation of the visible light absorption region and the short-wave infrared absorption region. At the same time, dark current can be reduced without affecting the absorption of incident light, and the epitaxial quality of InGaAs can be improved.

[0039] Continue as Figure 1 shown, a stepped structure is formed on another part of the N-type layer 221 by a part of the N-type layer 221, the visible light absorption layer 222, the first buffer layer 223, the short-wave absorption layer 224, and the P-type layer 225 in the infrared detector of this embodiment.

[0040] Furthermore, the infrared detector of this embodiment further includes: a second buffer layer 21, disposed on the surface of the N-type layer 221 away from the visible light absorption layer 222.

[0041] The substrate 1, disposed on the surface of the second buffer layer 21 away from the N-type layer 221.

[0042] The P-type cap layer 23 is disposed on the P-type layer 225.

[0043] The upper electrode 3 is disposed around the P-type cap layer 23.

[0044] The lower electrode 6 is disposed around another part of the N-type layer 221.

[0045] The passivation layer 5 is disposed on the outer regions of the N-type layer 221, the visible light absorption layer 222, the first buffer layer 223, the short-wave absorption layer 224, the P-type layer 225, and the P-type cap layer 23, and is located in the region between the upper electrode 3 and the lower electrode 6.

[0046] In an embodiment of the present disclosure, the second buffer layer 21 may be an N-type doped buffer layer, and the material includes GaAs doped with N-type using Si, where the doping concentration of Si ≥ 1018 cm -3 , and the thickness of the second buffer layer 21 is 350 nm to 500 nm. The second buffer layer 21 is used to smooth the surface of the substrate 1, block the upward growth of substrate defects, and is beneficial to improving the crystal quality of the epitaxy.

[0047] The passivation layer 5 can fill the unsaturated dangling bonds generated on the sidewalls of the etched steps, isolate air, reduce the surface state density, thereby reducing the surface leakage current and improving the stability.

[0048] The lower electrode 6 disposed outside the N-type layer 221 and the upper electrode 3 disposed on the surface of the P-type cap layer 24. Both the upper electrode 3 and the lower electrode 6 are formed by electron beam evaporation of Ti / Pt / Au, and the thicknesses can be 50 nm / 50 nm / 300 nm respectively. The Ti layer can form a good ohmic contact with the metal contact electrode material, and Au can maintain good adhesion and firmness with the subsequent packaging wire bonding.

[0049] Further, the infrared detector of this embodiment further includes: a light passing hole, which is disposed on the P-type cap layer and penetrates the passivation layer on the P-type cap layer.

[0050] The light passing hole 4 is used to receive the external infrared signal input to the infrared detector, and the light passing hole 4 can be any one of a circular, elliptical, square, triangular or other polygonal structures.

[0051] According to an embodiment of the present disclosure, the substrate includes an N-type GaAs substrate in the (001) direction, which is double-sided polished, the surface is a crystal plane, and the doping concentration of the N-type GaAs substrate is not less than 10 17 cm -3 , and the lattice constant of the substrate 1 determines the lattice constants of other epitaxial materials.

[0052] Further, the doping element of the N-type layer includes Si, and the doping concentration of Si is not less than 10 18 cm -3; The doping element of the P-type layer includes Be, and the doping concentration of Be is not less than 10 18 cm -3 。

[0053] The P-type capping layer 24 is a metal electrode contact layer, and its thickness can be 20 nm to 50 nm. Be-doped InGaAs can be used, and the doping concentration is 2.0×10 18 cm -3 ~1.0×10 19 cm -3 。The P-type doped capping layer 24 can be used to prevent the visible infrared unit 22 in contact with it from directly contacting with air and undergoing an oxidation reaction and is beneficial to the transport of carriers.

[0054] The thickness of the P-type layer 225 can be 400 nm to 600 nm. Be can be used as the doping element, and the Be doping concentration ≥ 10 18 cm -3 。

[0055] The thickness of the short-wave absorption layer 224 can be 400 nm to 600 nm, which can improve the collection of carriers by the electrode. It is an unintentionally doped layer, and the carrier concentration without doping is 10 14 cm -3 ~10 16 cm -3 。

[0056] The thickness of the first buffer layer 223 can be 300 nm to 400 nm. It is an unintentionally doped layer, and the carrier concentration without doping is 10 14 cm -3 ~10 16 cm -3 。

[0057] The thickness of the visible light absorption layer 222 can be 400 nm to 600 nm, which can improve the collection of carriers by the electrode. It is an unintentionally doped layer, and the carrier concentration without doping is 10 14 cm -3 ~10 16 cm -3 。

[0058] The thickness of the N-type layer 221 can be 400 - 600 nm. Si can be used as the doping element, and the Si doping concentration ≥ 10 18 cm -3 。

[0059] The second aspect of the present disclosure provides a method for manufacturing an infrared detector, including: epitaxially growing a stacked N-type layer, a visible light absorption layer, a short-wave absorption layer, and a P-type layer in sequence; wherein, the visible light absorption layer is configured to absorb visible light photons to generate first carriers; the short-wave absorption layer is configured to absorb infrared photons to generate second carriers; under the action of an applied electric field, electrons in the first carriers and electrons in the second carriers move towards the P-type layer, and holes in the first carriers and holes in the second carriers move towards the N-type layer, and the movement of electrons and holes forms a current.

[0060] In an embodiment of the present disclosure, the method for manufacturing a wide-spectrum short-wave infrared detector using a molecular beam epitaxy device can accurately control the growth accuracy, so that the finally obtained epitaxial structure conforms to the design value and has good uniformity.

[0061] Figure 2 Schematically shows a schematic diagram of the method for manufacturing an infrared detector according to an embodiment of the present disclosure.

[0062] As Figure 2 shown, in some possible embodiments, the manufacturing method of this embodiment includes:

[0063] Step S101: Epitaxially grow a second buffer layer 21 on a substrate 1.

[0064] Specifically, during the heating process of the substrate 1, determine the reconstruction temperature according to the reconstruction situation of the substrate 1, including: observing the substrate 1 using a reflection high-energy electron diffraction device. At high temperature, the substrate 1 presents an X4 reconstruction, the reconstruction fringes are denser, and there are three reconstruction fringes between every two reconstruction points. At low temperature, the substrate 1 presents an X2 reconstruction, the reconstruction fringes are sparser, and there is one reconstruction fringe between every two reconstruction points. First, cool the substrate 1 to present an X2 reconstruction, and then gradually increase the temperature of the substrate 1, and observe the transition temperature when the substrate 1 changes from X2 reconstruction to X4 reconstruction, and call it the reconstruction temperature T C , determine the reconstruction temperature T C .

[0065] Determine the growth temperature of the second buffer layer 21 according to the reconstruction temperature, which can be T C +60 °C. The material of the second buffer layer 21 can be undoped GaAs, the As / Ga beam ratio can be 15, the thickness of the second buffer layer 21 can be, for example, 400 nm, and the growth rate can be Ga0.6 ML / s, where ML represents atomic layer.

[0066] Step S102: Epitaxially grow a visible infrared unit 22 on the second buffer layer 21.

[0067] Specifically, an N-type layer 221, a visible light absorption layer 222, a first buffer layer 223, a short-wave absorption layer 224, and a P-type layer 225 are sequentially epitaxially grown and stacked on the second buffer layer 21 to form a visible infrared unit 22.

[0068] Among them, the thickness of the N-type layer 221 can be 500 nm, the material can be GaAs doped with Si, and the doping concentration of Si can be 2.0×10 18 cm -3 , the temperature of the Si source furnace can be 1200 °C, the growth temperature of the N-type layer 221 can be T C +60 °C, the As / Ga beam current ratio can be 15, and the growth rate can be Ga 0.6 ML / s.

[0069] The thickness of the visible light absorption layer 222 can be 400 nm, the material can be undoped GaAs, and the growth temperature of the visible light absorption layer 222 can be T C +60 °C, the As / Ga beam current ratio can be 15, and the growth rate can be Ga 0.6 ML / s.

[0070] The thickness of the first buffer layer 223 can be 400 nm, the material can be undoped InAlAs, and the growth temperature of the graded buffer layer 223 can be T C -20 °C, the As / In beam current ratio can be 12, and the growth rate can be In 0.5 ML / s.

[0071] The thickness of the short-wave absorption layer 224 can be 400 nm, the material can be undoped InGaAs, and the growth temperature of the short-wave infrared absorption layer 224 can be T C +60 °C, the As / Ga beam current ratio can be 12, and the growth rate can be Ga 0.15 ML / s.

[0072] The thickness of the P-type layer 225 can be 500 nm, the material can be InGaAs doped with Be, and the doping concentration of Be can be 2.0×10 18 cm -3 , the temperature of the Be source furnace can be 106 °C, and the growth temperature of the N-type layer 221 can be T C +60 °C, the As / Ga beam current ratio can be 12, and the growth rate can be Ga 0.15 ML / s.

[0073] Step S103: Epitaxially grow a P-type capping layer 23 on the visible infrared unit 22. Among them, the second buffer layer 21, the N-type layer 221, the visible light absorption layer 222, the first buffer layer 223, the short-wave absorption layer 224, the P-type layer 225, and the P-type capping layer 23 constitute an epitaxial structure 2.

[0074] Specifically, the thickness of the P-type cap layer 23 can be 30 nm, the material can be Be-doped InGaAs, the Be doping concentration can be 5.0×10 18 cm -3 , the temperature of the Be source furnace can be 1100 °C, the growth temperature of the P-type doped cap layer 23 can be T C °C, the As / Ga beam current ratio can be 12, and the growth rate can be 0.15 ML / s of Ga.

[0075] Step S104: Etch the formed epitaxial structure 2 to form a stepped structure.

[0076] Specifically, inductively coupled plasma is used to etch the epitaxial structure 2 to form a stepped structure, so that the remaining epitaxial structure 2 is cylindrical. The gas used for etching can be CH4:Cl2:Ar, and the step depth reaches the N-type layer 221.

[0077] Step S105: Passivate the outside of the epitaxial structure 2.

[0078] Specifically, a passivation layer 5 is prepared by plasma enhanced chemical vapor deposition. The passivation layer 5 can be a SiO2 passivation layer, and the thickness can be 200 nm.

[0079] Step S106: Evaporate electrodes on the epitaxial structure 2 to form an upper electrode 3 and a lower electrode 6.

[0080] Specifically, the above upper electrode 3 and lower electrode 6 can be prepared by electron beam evaporation of Ti / Pt / Au. The thicknesses of Ti / Pt / Au can be 50 nm / 50 nm / 300 nm respectively, and the deposition conditions can be ≤100 °C. Among them, the upper electrode 3 is annular, with a light-transmitting hole 4 hollowed out in the middle, and the Ti layer of the upper electrode 3 is in contact with the P-type cap layer 23. The lower electrode 6 is annular, and the Ti layer is in contact with the N-type layer 221.

[0081] Furthermore, before step one, degassing and deoxidizing pretreatment of the substrate are also included.

[0082] Specifically, for the degassing treatment of the substrate: First, in the sample introduction chamber of the molecular beam epitaxy system, the substrate 1 is subjected to low-temperature degassing treatment. The conditions for low-temperature degassing can be, for example: the temperature is 200 °C, and the degassing time is 150 minutes. After the low-temperature degassing is completed, the substrate 1 is transferred to the buffer chamber of the molecular beam epitaxy system for high-temperature degassing. The conditions for high-temperature degassing can be, for example: the temperature is 420 °C, and the degassing time is 120 minutes.

[0083] After the high-temperature degassing is completed, the substrate 1 is transferred to the growth chamber of the molecular beam epitaxy system for deoxidation treatment. The conditions for the deoxidation treatment can be, for example: when the temperature of the substrate 1 reaches about 400 °C, the shutter of the As source furnace is opened to protect the substrate 1 under the atmosphere of the As2 beam. At the same time, a reflection high-energy electron diffraction device is used to observe the deoxidation situation in real time. When bright spots or stripes appear on the receiving screen of the reflection high-energy electron diffraction device, it indicates that the deoxidation begins. Generally, when the deoxidation stripes appear, the temperature is raised by 30 °C to 40 °C for the deoxidation treatment. The surface deoxidation temperature is generally 600 °C, and the deoxidation time is generally 30 to 90 minutes.

[0084] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0085] The above describes the embodiments of the present disclosure. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present disclosure. Although the embodiments are described separately above, this does not mean that the measures in the respective embodiments cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. An infrared detector, characterized in that, Comprising: An N-type layer, a visible light absorption layer, a short-wave absorption layer, and a P-type layer stacked in sequence; The visible light absorption layer is configured to absorb visible light photons to generate first carriers; The short-wave absorption layer is configured to absorb infrared photons to generate second carriers; Wherein, driven by the built-in electric field formed between the N-type layer and the P-type layer, the electrons in the first carriers and the electrons in the second carriers move towards the P-type layer, and the holes in the first carriers and the holes in the second carriers move towards the N-type layer, and the movement of the electrons and the holes forms an electric current.

2. The infrared detector according to claim 1, characterized in that, Further comprising: A first buffer layer, disposed between the visible light absorption layer and the short-wave absorption layer, and configured to smooth the bandgap between the visible light absorption layer and the short-wave absorption layer.

3. The infrared detector according to claim 2, wherein The materials of the N-type layer and the visible light absorption layer include GaAs; the material of the first buffer layer includes InAlAs; the materials of the short-wave absorption layer and the P-type layer include InGaAs.

4. The infrared detector according to claim 3, characterized in that, The bandgap width of the GaAs is 1.98 eV, and the cut-off wavelength is 0.6 μm; The bandgap width of the InAlAs is 2.05 eV - 2.09 eV, and the cut-off wavelength is 0.59 μm - 0.60 μm; The bandgap width of the InGaAs is 0.46 eV - 0.47 eV, and the cut-off wavelength is 2.64 μm - 2.70 μm.

5. The infrared detector according to claim 2, characterized in that, A stepped structure is formed on another part of the N-type layer by a part of the N-type layer region, the visible light absorption layer, the first buffer layer, the short-wave absorption layer, and the P-type layer.

6. The infrared detector according to claim 5, characterized in that, Further comprising: A second buffer layer, disposed on the surface of the N-type layer away from the visible light absorption layer; A substrate, disposed on the surface of the second buffer layer away from the N-type layer; A P-type capping layer, disposed on the P-type layer; An upper electrode, disposed annularly on the P-type capping layer; A lower electrode, disposed annularly on another part of the N-type layer region; A passivation layer, disposed on the outer regions of the N-type layer, the visible light absorption layer, the first buffer layer, the short-wave absorption layer, the P-type layer, and the P-type capping layer, and located in the region between the upper electrode and the lower electrode.

7. The infrared detector according to claim 1, characterized in that, Further comprising: A light-transmitting hole, disposed on the P-type capping layer and penetrating the passivation layer on the P-type capping layer.

8. The infrared detector according to claim 6, wherein The substrate comprises an N-type GaAs substrate in the (001) direction, wherein the doping concentration of the N-type GaAs substrate is not less than 10 17 cm -3 .

9. The infrared detector according to claim 1, characterized in that The doping element of the N-type layer includes Si, and the doping concentration of the Si is not less than 10 18 cm -3 ; The doping element of the P-type layer includes Be, and the doping concentration of Be is not less than 10 18 cm -3 .

10. A method for preparing an infrared detector, characterized in that, Comprising: An N-type layer, a visible light absorption layer, a short-wave absorption layer, and a P-type layer that are epitaxially grown and stacked in sequence; Wherein, the visible light absorption layer is configured to absorb visible light photons to generate first carriers; The short-wave absorption layer is configured to absorb infrared photons to generate second carriers; Wherein, under the action of an external electric field, the electrons in the first carriers and the electrons in the second carriers move towards the P-type layer, and the holes in the first carriers and the holes in the second carriers move towards the N-type layer, and the movement of the electrons and the holes forms an electric current.

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