Inter-band cascade photoelectric detector based on multi-interface strain compensation and preparation method thereof

Abstract

The invention discloses an inter-band cascade photoelectric detector based on multi-interface strain compensation and a preparation method thereof.The detector structure sequentially comprises a substrate, an N-type contact layer, an M-layer step cascade structure layer and a P-type contact layer from bottom to top, the substrate is made of a GaSb material, and the N-type contact layer is made of a GaSb material; the number M of the step cascade structure layers is a positive integer; the N-type contact layer is of a multi-interface strain compensation superlattice structure. And the N-type contact layer and the step cascade structure layer adopt a multi-layer interface to realize strain compensation. According to the invention, high-quality growth of the antimony-based high-performance inter-band cascade photoelectric detector is realized.

Description

Technical Field

[0001] The present invention relates to the field of inter-band cascade photoelectric detectors, and in particular to an inter-band cascade photoelectric detector based on multi-interface strain compensation and a preparation method thereof. Background Art

[0002] Interband cascade photodetectors (ICIPs) based on type II superlattices have attracted extensive research by researchers due to their high-temperature operation at medium and long wavelengths and high carrier collection efficiency. They have successively completed medium and long-wave ICIPs operating above room temperature, interband cascade focal plane arrays operating at 180K, the discovery and explanation of electrical gain phenomena, and the demonstration of high-frequency devices from 1.3GHz to 10GHz. These studies have made significant progress in understanding the advantages of ICI, and have produced encouraging results in the range from short-wave red to very long wavelengths, providing the possibility of realizing room-temperature infrared imaging systems and high-speed sensor networks, which will promote their continued research and development.

[0003] However, the complex epitaxial structure of ICIP makes it very challenging in the device epitaxy process. For ICIP devices, it has a very complex multiple cascade step structure. A single step contains InAs / GaSb superlattice (SL) absorption layer, AlSb / GaSb SL electron barrier layer and InAs / AlSb SL hole barrier layer. How to achieve ideal strain compensation in many superlattice structures is a major problem in inter-band cascade growth. Especially in the InAs / AlSb SL hole barrier layer, in order to block holes and ensure that electrons can tunnel effectively, the AlSb layer is generally only a few atomic layers (monolayer) thick, while the InAs layer thickness is often more than 20M. During the growth process, the lattice mismatch between the GaSb substrate and the GaSb substrate leads to strain accumulation to form lattice defects such as dislocations and stacking faults, which has a fatal impact on device performance. Therefore, achieving ideal strain compensation in the growth of ICIP devices is crucial to improving the overall performance of ICIP.

[0004] At present, in the growth scheme of such strained superlattice materials, some studies use the ternary alloy structure of InAs substrate to avoid lattice mismatch, but this also brings problems such as alloy composition control and expensive InAs substrate and inability to make large-scale. Another solution is to use InSb layer to compensate for the lattice constant difference between InAs layer and GaSb substrate in superlattice, and insert InSb layer on both sides of InAs layer to form double interface layer to achieve ideal strain compensation. However, for InAs / AlSb SL hole barrier layer region in ICIP device, in order to effectively balance the tensile stress caused by too thick InAs layer, the required InSb interface layer thickness also needs to be increased accordingly. The lattice constant of InSb is much larger than that of GaSb. When the thickness of InSb interface layer exceeds a certain threshold, the ability of double InSb interface to compensate strain gradually decreases, resulting in the inability to completely relax during material growth, and various new defects will be generated in the material, reducing the performance of ICIP device.

[0005] Currently, existing technologies are not sufficient to achieve high-quality ICIP device growth. Therefore, designing new antimony-based ICIP growth schemes is crucial to improving the overall performance of ICIP and promoting the realization of new ICIP designs and concepts.

[0006] The Chinese invention application with application number 201820557199.1 discloses "Long-wave superlattice infrared detector based on inter-band cascade structure". The structure disclosed in the patent uses three binary compounds of InAs / GaSb / AlSb to form superlattices and multi-quantum well materials with different period thicknesses to form a long-wave superlattice infrared detector based on an inter-band cascade structure. Its technical solution aims to reduce the dark current of the device and obtain a long-wave device with high sensitivity and high detection rate. Therefore, the patent is different from the technical problem to be solved by the present invention, and does not provide technical inspiration for solving the technical problem of the present invention. Summary of the invention

[0007] In order to solve the technical problem that when the thickness of the InSb interface layer exceeds a certain threshold, the ability of the double InSb interface to compensate for strain gradually decreases in the prior art cascade detector, resulting in the inability to completely relax the material during growth, causing various new defects in the material and reducing the performance of the ICIP device, the present invention provides an inter-band cascade photoelectric detector based on multi-interface strain compensation and a preparation method thereof. The technical solution adopted by the present invention is:

[0008] The first aspect of the present invention provides an inter-band cascade photodetector based on multi-interface strain compensation, wherein the detector structure comprises, from bottom to top, a substrate, an N-type contact layer, M-layers of step-cascade structure layers and a P-type contact layer, wherein the number of layers M of the step-cascade structure layers is a positive integer; the N-type contact layer is a superlattice structure with multi-interface strain compensation; and the P-type contact layer is made of GaSb material.

[0009] As a preferred solution, the number of layers M of the cascade structure layer is 4.

[0010] As a preferred solution, the N-type contact layer adopts 22 monolayers of InAs / 4 monolayers of AlSb superlattice material.

[0011] As a preferred solution, the terraced cascade structure layer comprises, from bottom to top, a hole barrier layer, an absorption layer and an electron barrier layer, wherein the hole barrier layer is a multi-interface strain-compensated superlattice structure.

[0012] As a preferred solution, the hole barrier layer adopts a multi-periodic 22 monolayer InAs / 4 monolayer AlSb superlattice material, and the hole barrier layer includes several InAs layers and several AlSb layers, wherein the InAs layer is inserted into several InSb interface layers.

[0013] As a preferred solution, the absorption layer adopts 8 monomolecular layers of InAs / 8 monomolecular layers of GaSb superlattice material.

[0014] As a preferred solution, the electron barrier layer is made of 4 monomolecular layers of AlSb / 13 monomolecular layers of GaSb superlattice material.

[0015] A second aspect of the present invention provides a method for preparing an inter-band cascade photodetector based on multi-interface strain compensation, the method comprising:

[0016] Obtaining the total thickness of the InSb interface layer required for strain compensation according to the thickness of the InAs layer and the thickness of the AlSb layer in the InAs / AlSb SL hole barrier layer in the inter-band cascade photodetector;

[0017] The number of required InSb interface layers is determined according to the total thickness of the required InSb interface layers, and the thickness of a single InSb interface layer does not exceed 0.8 monolayers and is not less than 0.4 monolayers; then the position of each InSb interface layer is determined.

[0018] As a preferred solution, before growth, the substrate is first subjected to a pre-degassing treatment, and then a deoxidation treatment is performed in a growth chamber. After that, the temperature is reduced to a preset value, a high-temperature GaSb buffer is grown for a preset time. The reconstruction transition temperature of the GaSb surface is tested by cooling and calibrated as Tc. Finally, at a temperature of Tc-15°C, a pre-designed hole barrier layer, an absorption layer, an electron barrier layer and a P-type contact layer are grown from bottom to top through the molecular beam epitaxy system; the molecular beam epitaxy system includes two In source furnaces, and the two In source furnaces are used to grow InAs and InSb interface layers in superlattice materials, respectively.

[0019] As a preferred solution, the total thickness of the InSb interface layer is calculated as follows:

[0020] InSb thickness = 0.1 × (InAs thickness - AlSb thickness);

[0021] The number of InSb interfaces is set to 3, the InAs growth rate range is 0.45ML / s to 0.55ML / s, the InSb growth rate range is 0.095ML / s to 0.105ML / s, the GaSb and AlSb growth rates range are 0.55ML / s to 0.65ML / s, the InSb interface layer is evenly distributed, and the InSb interface layer implementation method includes two preset shutter settings.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention effectively eliminates the tensile stress caused by the increase of the thickness of the InAs layer by inserting different numbers of InSb interface layers into the InAs layer, and reduces the compressive stress caused by the excessive thickness of the InSb interface layer, thereby reducing the formation of mound-like defects, thereby significantly improving the crystallization quality of the hole barrier layer, with higher internal crystallization quality, higher surface flatness, and significantly reducing the number of internal threading dislocations. This provides a better epitaxial foundation for subsequent InAs / GaSb and AlSb / GaSb SLs, and further epitaxy of ICIP detection devices of the best quality, which is crucial to improving the overall performance of ICIP. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 HRXRD characterization diagram of the hole barrier layer corresponding to the device using the traditional double interface strain compensation method provided in this embodiment;

[0025] Figure 2 is a HRXRD characterization diagram of the hole barrier layer corresponding to the device of the present invention provided in this embodiment;

[0026] Figure 3A structural diagram of an inter-band cascade photodetector based on multi-interface strain compensation provided in this embodiment;

[0027] Figure 4 Schematic diagram of the formation mechanism of hole-shaped defects on the surface of the InAs / AlSb SL hole barrier layer at the double InSb layer interface provided in this embodiment;

[0028] Figure 5 A schematic diagram of the hole barrier layer structure of the inter-band cascade photodetector based on multi-interface strain compensation provided in this embodiment;

[0029] Figure 6 A schematic diagram of a source furnace shutter setting mode 1 for the InAs / AlSb SL structure growth process of the band-to-band cascade photodetector preparation method based on multi-interface strain compensation provided in this embodiment;

[0030] Figure 7 A schematic diagram of a source furnace shutter setting mode 2 for the InAs / AlSb SL structure growth process of the inter-band cascade photodetector preparation method based on multi-interface strain compensation provided in this embodiment;

[0031] Figure 8 A schematic diagram of the start time of each source furnace during the growth of the InAs / AlSb SL hole barrier layer of the inter-band cascade photodetector based on multi-interface strain compensation provided in this embodiment;

[0032] Fig. 9 Element distribution diagram in a single period of the InAs / AlSb SL hole barrier layer of the inter-band cascade photodetector based on multi-interface strain compensation provided in this embodiment;

[0033] Fig.10 AFM image corresponding to the device of the present invention provided in this embodiment;

[0034] Fig.11 AFM image of ICIP grown using the conventional double interface strain compensation method provided in this embodiment;

[0035] Fig.12 The characterization result diagram corresponding to the device of the present invention provided in this embodiment;

[0036] Fig.13 The characterization result diagram corresponding to the conventional double-interface grown ICIP device provided in this embodiment;

[0037] Explanation of the reference numerals: 1, substrate; 2, N-type contact layer; 3, step-cascade structure layer; 3 / 31, hole barrier layer; 3 / 32, absorption layer; 3 / 33, electron barrier layer; 4, P-type contact layer. DETAILED DESCRIPTION

[0038] The accompanying drawings are only used for illustrative purposes and are not to be construed as limiting the present invention;

[0039] It should be clear that the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the embodiments of the present application.

[0040] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0041] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0042] In addition, in the description of this application, unless otherwise specified, "multiple" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0043] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0044] Example 1

[0045] Please refer to Figure 3This embodiment provides an inter-band cascade photodetector based on multi-interface strain compensation, and the detector structure includes, from bottom to top, a substrate 1, an N-type contact layer 2, M-layer terrace cascade structure layers 3 and a P-type contact layer 4, wherein the number of layers M of the terrace cascade structure layer 3 is a positive integer; the N-type contact layer 2 is a superlattice structure of multi-interface strain compensation; and the P-type contact layer 4 is made of GaSb material.

[0046] Specifically, please refer to Figure 1 and Figure 2 , Figure 1 and Figure 2 The HRXRD characterization of the InAs / AlSb SL hole barrier layer 3 / 31 in the ICIP device epitaxially grown by the traditional double-interface strain compensation method and the multi-interface strain compensation scheme adopted by the present invention is demonstrated. Through the scheme of the present invention, the crystallization quality of the InAs / AlSb SL hole barrier layer 3 / 31 is significantly improved, the internal crystallization quality is higher, the surface flatness is higher, and the number of internal threading dislocations is significantly reduced. This provides a better epitaxial foundation for subsequent InAs / GaSb and AlSb / GaSb SL, and then epitaxy of the best quality ICIP detection devices is crucial to improving the overall performance of ICIP. The multi-layer InSb interface stress balance growth method proposed by the present invention provides a new way to grow superlattice materials with a large InAs layer, and is generally applicable to the growth of very long-wavelength InAs / GaSb SL, InAs / InSb SL, and InAsSb digital alloys.

[0047] In a specific embodiment, the number M of layers of the cascade structure layer 3 is 4.

[0048] In a specific embodiment, the N-type contact layer 2 is made of a 22-monolayer InAs / 4-monolayer AlSb superlattice material.

[0049] In a specific embodiment, the terraced cascade structure layer 3 includes, from bottom to top, a hole barrier layer 3 / 31, an absorption layer 3 / 32, and an electron barrier layer 3 / 33, wherein the hole barrier layer 3 / 31 is a multi-interface strain-compensated superlattice structure;

[0050] Specifically, please refer to Figure 4 , Figure 4 The effect diagram of the InAs / AlSb SL hole barrier layer 3 / 31 structure of the double InSb layer interface and the formation mechanism of hole-shaped defects on the material surface under non-ideal strain compensation are shown. In the present invention, different numbers of InSb layers are inserted into the InAs layer, and the thickness and position of each InSb interface layer are designed to achieve an ideal strain compensation effect.

[0051] Specifically, please refer to Figure 5 , a schematic diagram of the structure of the InAs / AlSb SL hole barrier layer 3 / 31 of the ICIP device grown by the multi-interface strain compensation method in the ICIP device, showing the InSb interfaces at both ends and the middle of the InAs layer, the number, position and thickness of the InSb interface can be set accordingly according to the requirements. In the present invention: the thickness of the InAs layer is 22 monolayers, the thickness of the AlSb layer is 4 monolayers, the number of InSb interface layers is set to 3 layers, and the thickness of a single interface is controlled at 0.8 monolayers.

[0052] In a specific embodiment, the hole barrier layer 3 / 31 adopts a multi-periodic 22 monolayer InAs / 4 monolayer AlSb superlattice material, and the hole barrier layer 3 / 31 includes several InAs layers and several AlSb layers, wherein the InAs layer is inserted into several InSb interface layers.

[0053] In a specific embodiment, the absorption layer 3 / 32 is made of 8 monomolecular layers of InAs / 8 monomolecular layers of GaSb superlattice material.

[0054] In a specific embodiment, the electron barrier layer 3 / 33 is made of 4 monomolecular layers of AlSb / 13 monomolecular layers of GaSb superlattice material.

[0055] Example 2

[0056] This embodiment provides a method for preparing an inter-band cascade photodetector based on multi-interface strain compensation, the method comprising:

[0057] Obtaining the total thickness of the InSb interface layer required for strain compensation according to the thickness of the InAs layer and the thickness of the AlSb layer in the InAs / AlSb SL hole barrier layer in the inter-band cascade photodetector;

[0058] The number of required InSb interface layers is determined according to the total thickness of the required InSb interface layers, and the thickness of a single InSb interface layer does not exceed 0.8 monolayers and is not less than 0.4 monolayers; then the position of each InSb interface layer is determined.

[0059] In a specific embodiment, before growth, the substrate is first subjected to a pre-degassing treatment, and then subjected to a deoxidation treatment in a growth chamber, and then the temperature is reduced to a preset value, and a high-temperature GaSb buffer is grown for a preset time, and the reconstruction transition temperature of the GaSb surface is tested by cooling and calibrated as Tc, and finally, at a temperature of Tc-15°C, a pre-designed hole barrier layer, an absorption layer, an electron barrier layer, and a P-type contact layer are grown from bottom to top through the molecular beam epitaxy system; the molecular beam epitaxy system includes two In source furnaces, and the two In source furnaces are used to grow InAs and InSb interface layers in the superlattice material, respectively;

[0060] Specifically, before growth, the N+ substrate is first subjected to a pre-degassing treatment at 200°C and 420°C, and then subjected to a deoxidation treatment at 640°C in a growth chamber, after which the temperature is lowered to 600°C to grow a high-temperature GaSb buffer for 30 minutes, the reconstruction transition temperature of the GaSb surface is tested by cooling and calibrated as Tc, and finally, at a temperature of Tc-15°C, a pre-designed hole barrier layer, an absorption layer, an electron barrier layer and a P-type contact layer are grown from bottom to top through the molecular beam epitaxy system; the molecular beam epitaxy system includes two In source furnaces, which are respectively used to grow InAs and InSb interface layers in superlattice materials.

[0061] In a specific embodiment, the total thickness of the InSb interface layer is calculated as follows:

[0062] InSb thickness = 0.1 × (InAs thickness - AlSb thickness);

[0063] The number of InSb interfaces is set to 3, the InAs growth rate is 0.5ML / s, the InSb growth rate is 0.1ML / s, the GaSb and AlSb growth rate range is 0.6ML / s, the InSb interface layer is evenly distributed, and the InSb interface layer implementation method includes two preset shutter settings 1.

[0064] Specifically, please refer to Figure 6 , Figure 6 The source furnace shutter setting method 1 of the InAs / AlSb SL structure growth process with multi-boundary strain compensation is shown. The specific order is Sb / In / InAs / In / Sb / Sb / In / InAs / In / Sb / AlSb. Please refer to Figure 7 , Figure 7 The source furnace shutter setting mode 2 of the InAs / AlSb SL structure growth process with multi-interface InSb interface strain compensation is demonstrated, and the specific order is: InSb / no / InAs / no / InSb / no / InAs / no / InSb / no / AlSb. After determining the number, thickness and position of the required InSb interfaces and the thickness of the InAs layer, the appropriate growth rate and the opening time and opening and closing sequence of the equipment shutter are designed. The present invention is: the number of interfaces is set to 3, the InAs growth rate is 0.5 monolayer / s, the InSb growth rate is 0.1 monolayer / s, the GaSb and AlSb growth rates are 0.6 monolayer / s, the InSb interface positions are evenly distributed, and the shutter setting 1 is adopted.

[0065] Specifically, please refer to Figure 8 , Figure 8The opening time of each source furnace when growing the InAs / AlSb SL hole barrier layer of the ICIP device grown by the multi-interface strain compensation method is determined by the thickness of the InAs layer and the AlSb layer. The specific opening time in the present invention corresponds to 6s / 6s / 22s / 3s / 3s / 3s / 3s / 22s / 6s / 6s / 1.4s.

[0066] Specifically, please refer to Fig. 9 , Fig. 9 The element distribution in a single period of the InAs / AlSb SL hole barrier layer in the ICIP device is determined by observing the distribution of Sb atoms to confirm the distribution law of the InSb interface layer. In the present invention, it can be observed that the Sb atoms are mainly concentrated at both ends and in the middle of the InAs layer, which confirms the formation of three InSb interface layers.

[0067] Specifically, please refer to Fig.10 , Fig.10 This is an AFM image of ICIP grown using the multi-boundary strain compensation method in the present invention, showing the microscopic morphology of the sample surface, showing a 10×10μm 2 The atomic steps in the region make the surface very smooth, with a root mean square (RMS) roughness as low as Fig.11 The AFM image of ICIP grown by the traditional double interface strain compensation method is used as a reference in the present invention, showing a large number of dislocation defects and low sample flatness. The AFM results confirm that the new epitaxial scheme designed by the present invention can greatly improve the surface quality of the sample.

[0068] Specifically, please refer to Fig.12 , Fig.12 The HR-XRD characterization results of ICIP grown by the multi-boundary strain compensation method in the present invention show a high-intensity diffraction peak and a clear fifth-order satellite diffraction peak. The coincidence of the zero-order diffraction peak and the substrate peak further confirms the perfect match between the epitaxial material and the substrate lattice. The half-peak width of the first-order satellite peak is only 29 arcsec, which reflects the extremely high interface quality. Fig.13 The HR-XRD characterization results of ICIP grown by the traditional double interface strain compensation method are used as reference in the present invention. The satellite peaks of the HR-XRD test sample are almost invisible, indicating that the internal periodic arrangement of the material has been severely damaged. The HR-XRD characterization results confirm that the new epitaxial scheme designed by the present invention can greatly improve the internal crystal quality of the sample.

[0069] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An inter-band cascade photodetector based on multi-interface strain compensation, characterized in that: The detector structure comprises, from bottom to top, a substrate (1), an N-type contact layer (2), M-layer cascade structure layers (3) and a P-type contact layer (4), wherein the substrate (1) is made of GaSb material, the number of layers M of the cascade structure layers (3) is a positive integer; the N-type contact layer (2) is a multi-interface strain-compensated superlattice structure; and the P-type contact layer (4) is made of GaSb material.

2. The band-to-band cascade photodetector based on multi-interface strain compensation according to claim 1, characterized in that: The number M of layers of the cascade structure layer (3) is 4.

3. The inter-band cascade photodetector based on multi-interface strain compensation according to claim 1, characterized in that: The N-type contact layer (2) is made of a 22-monolayer InAs / 4-monolayer AlSb superlattice material.

4. The band-to-band cascade photodetector based on multi-interface strain compensation according to claim 1, characterized in that: The terraced cascade structure layer (2) comprises, from bottom to top, a hole barrier layer (3 / 31), an absorption layer (3 / 32) and an electron barrier layer (3 / 33), wherein the hole barrier layer is a multi-interface strain-compensated superlattice structure.

5. The inter-band cascade photodetector based on multi-interface strain compensation according to claim 4, characterized in that: The hole barrier layer (3 / 31) adopts a multi-periodic 22 monomolecular layer InAs / 4 monomolecular layer AlSb superlattice material, and the hole barrier layer (3 / 31) includes a plurality of InAs layers and a plurality of AlSb layers, wherein the InAs layer is inserted into a plurality of InSb interface layers.

6. The inter-band cascade photodetector based on multi-interface strain compensation according to claim 4, characterized in that: The absorption layer (3 / 32) is made of 8 monomolecular layers of InAs / 8 monomolecular layers of GaSb superlattice material.

7. The band-to-band cascade photodetector based on multi-interface strain compensation according to claim 4, characterized in that: The electron barrier layer (3 / 33) is made of 4 monomolecular layers of AlSb / 13 monomolecular layers of GaSb superlattice material.

8. A method for preparing an inter-band cascade photodetector based on multi-interface strain compensation, characterized in that: The method comprises: Obtaining the total thickness of the InSb interface layer required for strain compensation according to the thickness of the InAs layer and the thickness of the AlSb layer in the InAs / AlSb SL hole barrier layer in the inter-band cascade photodetector; The number of required InSb interface layers is determined according to the total thickness of the required InSb interface layers, wherein the thickness of a single InSb interface layer does not exceed 0.8 monolayers and is not less than 0.4 monolayers; and then the position of each InSb interface layer is determined.

9. The method for preparing an inter-band cascade photodetector based on multi-interface strain compensation according to claim 8, characterized in that: The preparation method further comprises: Before growth, the substrate is first subjected to a pre-degassing treatment, and then subjected to a deoxidation treatment in a growth chamber. After that, the temperature is reduced to a preset value, a high-temperature GaSb buffer is grown for a preset time. The reconstruction transition temperature of the GaSb surface is tested by cooling and calibrated as Tc. Finally, at a temperature of Tc-15°C, a pre-designed hole barrier layer, an absorption layer, an electron barrier layer and a P-type contact layer are grown from bottom to top through the molecular beam epitaxy system. The molecular beam epitaxy system includes two In source furnaces, and the two In source furnaces are used to grow InAs and InSb interface layers in the superlattice material, respectively.

10. The method for preparing an inter-band cascade photodetector based on multi-interface strain compensation according to claim 8, characterized in that: The total thickness of the InSb interface layer is calculated as: InSb thickness = 0.1 × (InAs thickness - AlSb thickness); The number of InSb interfaces is set to 3, the InAs growth rate range is 0.45ML / s to 0.55ML / s, the InSb growth rate range is 0.095ML / s to 0.105ML / s, the GaSb and AlSb growth rates range are 0.55ML / s to 0.65ML / s, the InSb interface layer is evenly distributed, and the InSb interface layer implementation method includes two preset shutter settings.

Images