Multi-period light absorption wide-spectrum indium gallium arsenic detector and preparation method thereof

Abstract

The invention provides a multi-period light absorption wide-spectrum indium gallium arsenic detector which comprises a substrate layer, a bottom electrode layer, a strain absorption layer and a top electrode layer. The substrate layer is located at the bottommost layer of the detector. The bottom electrode layer is over the substrate layer. The strain absorbing layer is over the bottom electrode layer. The top electrode layer is located above the strain absorption layer and located on the topmost layer of the detector. The strain absorption layer keeps complete strain with the bottom electrode layer and the top electrode layer, and the interior is of a multi-group periodic repetition structure. The invention also comprises a preparation method. According to the invention, multi-period double-layer different-component strain I nGaAs is used as an absorption layer for light absorption. The double-layer I nGaAs with the thickness lower than the critical thickness is kept in a strain state, so that high material quality is obtained, the I nP substrate can be conveniently removed, and the device is suitable for normal incidence and back incidence application and obtains wide spectral response. According to the preparation method, a conventional molecular beam epitaxy or metal organic chemical vapor deposition method is adopted for growth, and the structure and the preparation operation process are simple, easy to control and convenient to popularize.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronic materials and devices, and particularly to a multi-period light absorption wide-spectrum indium gallium arsenide detector and a preparation method thereof. Background Art

[0002] Indium gallium arsenide (InGaAs) material has good optical and electrical properties and is an excellent material for preparing short-wave infrared optoelectronic detectors. A focal plane detector based on InGaAs material is one of the ideal choices in the field of short-wave infrared detection. Based on In 0.53 Ga 0.47 As material prepared on a substrate lattice-matched with mature indium phosphide (InP), the cut-off wavelength of the detector is about 1.7 microns, covering the common optical fiber communication wavelengths. Driven by the application of optical fiber communication, it has developed rapidly. The detector structure mainly uses a relatively thick In 0.53 Ga 0.47 As as the absorption layer.

[0003] However, with the wider application scenarios, its application has gradually expanded from the field of optical fiber communication to fields such as medical imaging, cultural relic protection, and food safety. Multiple application scenarios require signal light with a wavelength greater than 1.7 microns. By increasing the In component in the InGaAs material, the bandgap width of InGaAs can be reduced, and the cut-off wavelength of the detector can be extended to the long wave. For example, if you want to extend the cut-off wavelength of the InGaAs detector to 1.8 microns, the In component needs to be increased to 0.57; when the cut-off wavelength is extended to 2.6 microns, the In component needs to be increased to 0.83. At this time, there is a lattice mismatch between the InGaAs epitaxial layer and the InP substrate. The existence of lattice mismatch will cause the degradation of material performance. As the epitaxial growth process proceeds, the stress generated by the lattice mismatch will be released in the form of wafer warping or dislocation defects. Eventually, the InGaAs absorption layer in the grown material is in a relaxed state. These wafer warping or dislocation defects will respectively lead to adverse effects such as increased lithography alignment difficulty, reduced flip-chip interconnection yield, increased device dark current, and increased blind pixel rate, restricting the development of InGaAs short-wave infrared focal plane detectors towards larger scale and higher performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-period light absorption wide-spectrum indium gallium arsenide detector and a preparation method thereof, mainly to solve the problems existing in the above-mentioned prior art, and it can overcome the problems of material quality degradation and device performance degradation of the existing extended wavelength wide-spectrum absorption InGaAs detector.

[0005] To achieve the above object, the technical solution adopted by the present invention is to provide a multi-period optical absorption wide-spectrum indium gallium arsenide detector, which is characterized in that it includes a base layer, a bottom electrode layer, a strain absorption layer, and a top electrode layer; the base layer is located at the bottom layer of the detector; the bottom electrode layer is located above the base layer; the strain absorption layer is located above the bottom electrode layer; the top electrode layer is located above the strain absorption layer and is at the top layer of the detector; the strain absorption layer is completely strained with the bottom electrode layer and the top electrode layer, and the inside is a multi-group periodic repeating structure.

[0006] Further, in the back-illuminated detector configuration, the base layer is removed; that is, the bottom layer of the detector is the bottom electrode layer, and above it are the strain absorption layer and the top electrode layer in sequence.

[0007] Further, the base layer includes a cutoff layer, a buffer layer, and a substrate layer; the substrate layer is located at the bottom of all detectors, and the material is InP; the buffer layer is located above the substrate layer, the material is InP, and the thickness is 500 nanometers to 2000 nanometers, with no doping limit; the cutoff layer is located above the buffer layer, and the material is In 0.53 Ga 0.47 As, the thickness is 300 nanometers to 1000 nanometers, with no doping limit; above the cutoff layer is the bottom electrode layer.

[0008] Further, the bottom electrode layer includes an N-type InP contact layer and an N electrode; in the bottom electrode layer, the N-type InP contact layer is located below, the thickness is 20 nanometers to 80 nanometers, and the electron concentration is 1×10 18 cm -3 to 5×10 18 cm -3 ; the N electrode is connected to the N-type InP contact layer from above.

[0009] Further, the top electrode layer includes a P-type InP contact layer and a P electrode; in the top electrode layer, the P-type InP contact layer is located below, the thickness is 100 nanometers to 500 nanometers, and the hole concentration is 1×10 18 cm -3 to 5×10 18 cm -3 ; the P electrode is connected to the P-type InP contact layer from above.

[0010] Further, the strain absorption layer includes a plurality of component strain layers; the plurality of component strain layers are stacked and arranged to form a periodically repeating structure; the component strain layer located at the bottom is fully strained with the bottom electrode layer and the top electrode layer; the component strain layer located at the top is fully strained with the top electrode layer; the component strain layer is undoped or N-type doped, and the electron concentration is 1×10 14 cm -3 to 3×10 16 cm -3 .

[0011] Further, the number of stacked component strain layers is m, where m is an integer and is greater than or equal to 5 and less than or equal to 30; the component strain layer includes a first strain layer and a second strain layer; the thickness of the first strain layer is d1, and the material is In x Ga 1-x As; where x is greater than 0.53 and less than or equal to 0.60, and d1 is greater than or equal to 100 nm and less than or equal to 300 nm; the thickness of the second strain layer is d2, and the material is In y Ga 1-y As, where y is greater than or equal to 0.50 and less than or equal to 0.53, and d2 is greater than or equal to 50 nm and less than or equal to 300 nm.

[0012] Further, between the parameter x of the first strain layer, the thickness d1 of the first strain layer, the parameter y of the second strain layer, the thickness d2 of the second strain layer, and the stacking number m, the following relational expressions are further satisfied:

[0013] x - 0.53 ≥ 0.53 - y;

[0014] (x - 0.53)×d1 ≥ (0.53 - y)×d2;

[0015] [(x - 0.53)×d1 - (0.53 - y)×d2]×m ≤ 100.

[0016] The present invention also discloses a preparation method for manufacturing the above multi-period optical absorption broadband indium gallium arsenide detector, which is characterized by including the steps of:

[0017] Step S1, generating the base layer by using molecular beam epitaxy or metal organic chemical vapor deposition method;

[0018] Step S2, generating the bottom electrode layer by using molecular beam epitaxy or metal organic chemical vapor deposition method;

[0019] Step S3, generating the strain absorption layer by using molecular beam epitaxy or metal organic chemical vapor deposition method;

[0020] Step S4: Use molecular beam epitaxy or metalorganic chemical vapor deposition to form the top electrode layer;

[0021] Step S5: Use photolithography to locate the photosensitive surface of the detector, and use wet or dry etching process to etch away the top electrode layer and the strain absorption layer in the area outside the photosensitive surface of the detector to form a detector structure;

[0022] Step S6: Generate an N electrode and a P electrode on the bottom electrode layer and the top electrode layer respectively; the N electrode is connected to the bottom electrode layer, and the P electrode is connected to the top electrode layer.

[0023] Further, in the back-illuminated detector configuration, after step S6, it further includes:

[0024] Step S7: Remove the substrate layer by wet etching.

[0025] In view of the above technical features, the multi-period light absorption broadband indium gallium arsenide detector and its preparation method of the present invention have the following advantages compared with the prior art:

[0026] 1. The multi-period light absorption broadband indium gallium arsenide detector of the present invention uses a bilayer of different components of strained InGaAs containing multiple periods as the absorption layer for light absorption. Among them, the bilayer InGaAs with a thickness below the critical thickness will remain in a strained state, and a higher material quality can be obtained.

[0027] 2. The multi-period light absorption broadband indium gallium arsenide detector of the present invention can conveniently remove the InP substrate, is suitable for front-illuminated and back-illuminated applications, and can obtain a wide spectral response.

[0028] 3. The preparation method of the multi-period light absorption broadband indium gallium arsenide detector of the present invention uses conventional molecular beam epitaxy or metalorganic chemical vapor deposition methods for growth. The structure and preparation process are simple and easy to control, and can be conveniently extended to the preparation of array-type focal plane detector chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of the multi-period light absorption broadband indium gallium arsenide detector of the present invention.

[0030] Figure 2 is a schematic structural diagram of the back-illuminated configuration of the multi-period light absorption broadband indium gallium arsenide detector of the present invention.

[0031] Figure 3 is a schematic structural diagram of a preferred embodiment of the multi-period light absorption broadband indium gallium arsenide detector of the present invention;

[0032] Figure 4It is a schematic structural diagram of another preferred embodiment of the multi-period light absorption wide-band InGaAs detector of the present invention;

[0033] Figure 5 It is a method flow chart of the method for preparing the multi-period light absorption wide-spectrum InGaAs detector of the present invention.

[0034] In the figure: 1-base layer, 2-bottom electrode layer, 3-strain absorption layer, 4-top electrode layer, 5-passivation film; 11-substrate layer, 12-buffer layer, 13-cutoff layer;

[0035] 21-N type I nP contact layer, 22-N electrode;

[0036] 31 - component strain layer, 32 - first strain layer, 33 - second strain layer.

[0037] 41-P type I nP contact layer, 42-P electrode. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0039] See also Figures 1 to 4 The present invention discloses a multi-period light absorption wide-band InGaAs detector. As shown in the figure, a preferred embodiment thereof comprises a substrate layer 1, a bottom electrode layer 2, a strain absorption layer 3 and a top electrode layer 4.

[0040] The base layer 1 is located at the bottom, and is further composed of a substrate layer 11, a buffer layer 12 and a cut-off layer 13. The substrate layer 11 is made of InP material and is located at the bottom of the detector. Above the substrate layer is a buffer layer 12 made of InP material with a thickness of 500 nanometers to 2000 nanometers and no doping limit. Above the buffer layer 12 is an InP material. 0.53 Ga 0.47 The cutoff layer 13 formed of As material has a thickness of 300 nanometers to 1000 nanometers, and is not limited to doping. The cutoff layer 13 is the top layer in the substrate layer 1, and above it is the bottom electrode layer 2. In the back-incident detector form, the substrate layer 1 is removed during the production process, and only the bottom electrode layer 2 is retained as the bottom layer, and the bottom electrode layer 2 is followed by the strain absorption layer 3 and the top electrode layer 4. In this way, the detector can capture external light from the direction of the bottom electrode layer 2.

[0041] In this embodiment, a buffer layer 12 with a thickness of 1000 nanometers is grown on the substrate layer 11, and the doping electron concentration is 3×1018 cm -3 A 500-nanometer-thick cutoff layer 13 is grown on the buffer layer 12, and the doping electron concentration is 3×10 18 cm -3 In another embodiment, a 1500 nanometer thick undoped buffer layer 12 is grown on the substrate layer 11 , and a 300 nanometer thick undoped stop layer 13 is grown on the buffer layer 12 .

[0042] The bottom electrode layer 2 includes an N-type I nP contact layer 21 and an N-electrode 22. The N-type I nP contact layer 21 covers the upper part of the base layer 1, and the N-electrode 22 is connected to the N-type I nP contact layer 21, and does not need to completely cover the N-type I nP contact layer 21. The thickness of the N-type I nP contact layer 21 is 20 nanometers to 80 nanometers, and the electron concentration is 1×10 18 cm -3 Up to 5×10 18 cm -3 The N electrode 22 is connected to the N-type InP contact layer 21 from above.

[0043] In this embodiment, the thickness of the N-type I nP contact layer 21 is 40 nanometers, and the doping electron concentration is 3×10 18 cm -3 In another embodiment, the growth thickness of the N-type I nP contact layer 21 is 30 nanometers, and the doping electron concentration is 2×10 18 cm -3 .

[0044] The strain absorption layer 3 is located above the bottom electrode layer 2. The strain absorption layer 3 includes a plurality of component strain layers 31. These component strain layers 31 are stacked and arranged to form a periodic repeating structure. The component strain layer 31 located at the bottom layer maintains complete strain with the N-type InP contact layer 21 in the bottom electrode layer 2. The component strain layer 31 is undoped or N-doped, with an electron concentration of 1×10 14 cm -3 Up to 3×10 16 cm -3 .

[0045] The component strain layer 31 includes a first strain layer 32 and a second strain layer 33. The material composition of the first strain layer 32 and the second strain layer 33, their thicknesses, and the number of stacked component strain layers 31 need to satisfy a certain relationship. Specifically, the number of stacked component strain layers 31 is m, where m is an integer and its value range is greater than or equal to 5 and less than or equal to 30. The material of the first strain layer 32 is In x Ga 1-xAs, wherein x is greater than 0.53 and less than or equal to 0.60. The thickness of the first strain layer 32 is d1, and d1 is greater than or equal to 100 nanometers and less than or equal to 300 nanometers. The material of the first strain layer 32 is In y Ga 1-y As, where y is greater than or equal to 0.50 and less than or equal to 0.53. The thickness of the second strain layer 33 is d2, which satisfies that d2 is greater than or equal to 50 nanometers and less than or equal to 300 nanometers. Then, x, y, d1, d2 and m further satisfy the following relationship:

[0046] x-0.53 ≥ 0.53-y;

[0047] (x-0.53)×d1≥(0.53-y)×d2;

[0048] [(x-0.53)×d1-(0.53-y)×d2]×m≤100.

[0049] See also Figure 3 In this embodiment, the strain absorption layer includes 10 periods of component strain layers 31, that is, m=10, and the total thickness is 3000 nanometers. The material of the first strain layer 32 is In 0.55 Ga 0.45 As, the thickness is 200 nanometers, that is, x=0.55, d1=200. The material of the second strain layer 33 is In 0.53 Ga 0.47 As, the thickness is 100 nanometers, that is, y = 0.53, d2 = 100. The component strain layer 31 is N-type doped, and the electron concentration is 3×10 15 cm -3 .

[0050] See also Figure 4 In another embodiment, the strain absorption layer may also include 15 periods of component strain layers 31, that is, m=15, with a total thickness of 4500 nanometers. The material of the first strain layer 32 is In 0.57 Ga 0.43 As, the thickness is 150 nanometers, that is, x=0.57, d1=150. The material of the second strain layer 33 is In 0.51 Ga 0.49 As, the thickness is 150 nanometers, that is, y = 0.51, d2 = 150. The component strain layer 31 is N-type doped, and the electron concentration is 1×10 16 cm -3 .

[0051] In other embodiments, the composition strained layer 31 may also be undoped.

[0052] The top electrode layer 4 is located above the strain absorption layer 4 and includes a P-type I nP contact layer 41 and a P electrode 42. The P-type I nP contact layer 41 covers the strain absorption layer 4, and the P electrode 42 passes through the passivation film 5 covering the P-type I nP contact layer 41 and is connected to the P-type I nP contact layer 41, and does not need to completely cover the P-type I nP contact layer 41. The component strain layer 31 located at the topmost layer maintains complete strain with the P-type I nP contact layer 41 in the top electrode layer 4. The thickness of the P-type I nP contact layer 41 is 100 nanometers to 500 nanometers, and the hole concentration is 1×10 18 cm -3 Up to 5×10 18 cm -3 The P electrode 42 is connected to the P-type InP contact layer 41 from above.

[0053] In this embodiment, the thickness of the P-type I nP contact layer is 300 nanometers, and the doping hole concentration is 2×10 18 cm -3 In another embodiment, the thickness of the P-type I nP contact layer is 500 nanometers, and the doping hole concentration is 1×10 18 cm -3 .

[0054] See also Figure 5 The present invention also discloses a method for manufacturing the above-mentioned multi-period light absorption wide-band InGaAs detector. A preferred embodiment thereof comprises the steps of:

[0055] Step S100, generating a base layer.

[0056] The base layer consists of a cut-off layer, a buffer layer and a substrate layer, wherein the substrate layer is made of InP material. The preparation of the detector starts from the substrate layer.

[0057] Step S101, heating the substrate layer to deoxidize it.

[0058] Step S102, growing a buffer layer.

[0059] A buffer layer is grown on top of the substrate layer using a molecular beam epitaxy method.

[0060] Step S103, growing a cut-off layer.

[0061] The stop layer is grown on the buffer layer using a molecular beam epitaxy method.

[0062] Step S200, generating a bottom electrode layer.

[0063] Specifically, in this step, the N-type InP contact layer in the bottom electrode layer is grown above the cutoff layer by using the molecular beam epitaxy method. The N-electrode located on the N-type InP contact layer is grown in a subsequent step.

[0064] Step S300: generating a strain absorbing layer.

[0065] A strain absorption layer is grown on the N-type InP contact layer by using a molecular beam epitaxy method. The strain absorption layer includes a plurality of periodically stacked component strain layers. Each component strain layer is composed of a first strain layer and a second strain layer.

[0066] Step S400, generating a top electrode layer.

[0067] Specifically, in this step, a P-type InP contact layer in the top electrode layer is grown on the strain absorption layer by using a molecular beam epitaxy method. A P electrode on the P-type InP contact layer is grown in a subsequent step.

[0068] At this point, the epitaxial growth stage ends.

[0069] Step S500: forming a detector structure.

[0070] The surface of the top electrode layer material is coated with photoresist and photolithography is performed, and the P-type InP contact layer and the strain absorption layer in the area outside the photosensitive surface of the detector are etched away by a wet or dry etching process, thereby forming multiple photosensitive units to constitute the detector structure.

[0071] Step S600, generating electrodes.

[0072] A P electrode and an N electrode are generated on the P-type InP contact layer and the N-type InP contact layer, respectively, so as to form a complete top electrode layer and a bottom electrode layer, wherein the N electrode is connected to the bottom electrode layer, and the P electrode is connected to the top electrode layer.

[0073] Step S601, forming a passivation film.

[0074] The SiN layer is formed on the surface of the material by inductively coupled plasma chemical vapor deposition. x Passivation film.

[0075] Step S602, photolithography of electrode region pattern.

[0076] On the P-type InP contact layer and the N-type InP contact layer, patterns of a P-electrode region and an N-electrode region are respectively formed by photolithography.

[0077] Step S603, removing the passivation film.

[0078] According to the photolithography pattern, the passivation films in the P-electrode region and the N-electrode region are removed by etching.

[0079] Step S603, growing electrodes.

[0080] Electron beam evaporation or magnetron sputtering is used to form P-type and N-type ohmic contact metals, which serve as P electrodes and N electrodes respectively. For the detector with normal incidence, all the processes are completed and a wide-spectrum detector with a complete structure has been obtained.

[0081] In its current form, the detector can also be used to detect back-incident signal light, but light with a wavelength less than 920 nanometers will be absorbed by the substrate layer and cannot be detected.

[0082] Step S700, removing the base layer.

[0083] For the back-incident detector form, in order to further enhance the detector's detection of light with a wavelength less than 920 nanometers, the substrate layer, buffer layer and cutoff layer are selectively removed by wet etching. At this time, the detector also has the ability to detect a wide spectrum under back-incident conditions.

[0084] Furthermore, in the above steps S100 to S400, a metal organic chemical vapor deposition method may be used instead of a molecular beam epitaxy method to complete the growth.

[0085] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A multi-period light absorption broadband InGaAs detector, characterized in that: It comprises a base layer, a bottom electrode layer, a strain absorption layer and a top electrode layer; the base layer is located at the bottom layer of the detector; the bottom electrode layer is located above the base layer; the strain absorption layer is located above the bottom electrode layer; the top electrode layer is located above the strain absorption layer and is at the top layer of the detector; the strain absorption layer maintains complete strain with the bottom electrode layer and the top electrode layer, and has multiple groups of periodic repeating structures inside.

2. The multi-period optical absorption broadband InGaAs detector according to claim 1, characterized in that: In the back-incident detector form, the base layer is removed; that is, the bottom layer of the detector is the bottom electrode layer, and the strain absorption layer and the top electrode layer are arranged above it.

3. The multi-period optical absorption broadband InGaAs detector according to claim 1 or 2, characterized in that: The base layer includes a cutoff layer, a buffer layer and a substrate layer; the substrate layer is located at the bottom of the detector and is made of InP; the buffer layer is located above the substrate layer and is made of InP with a thickness of 500 nanometers to 2000 nanometers and no doping limit; the cutoff layer is located above the buffer layer and is made of InP. 0.53 Ga 0.47 As, the thickness is 300 nanometers to 1000 nanometers, and the doping is not limited; the bottom electrode layer is located above the cutoff layer.

4. The multi-period optical absorption broadband InGaAs detector according to claim 1 or 2, characterized in that: The bottom electrode layer includes an N-type InP contact layer and an N electrode; in the bottom electrode layer, the N-type InP contact layer is located at the bottom, has a thickness of 20 nanometers to 80 nanometers, and an electron concentration of 1×10 18 cm -3 Up to 5×10 18 cm -3 ; The N electrode is connected to the N-type InP contact layer from above.

5. The multi-period optical absorption broadband InGaAs detector according to claim 1 or 2, characterized in that: The top electrode layer includes a P-type InP contact layer and a P electrode; in the top electrode layer, the P-type InP contact layer is located at the bottom, has a thickness of 100 nanometers to 500 nanometers, and a hole concentration of 1×10 18 cm -3 Up to 5×10 18 cm -3 ; The P electrode is connected to the P-type InP contact layer from above.

6. The multi-period optical absorption broadband InGaAs detector according to claim 1 or 2, characterized in that: The strain absorption layer comprises a plurality of component strain layers; the plurality of component strain layers are stacked and arranged to form a periodically repeated structure; the component strain layer at the bottom maintains complete strain with the bottom electrode layer and the top electrode layer; the component strain layer at the top maintains complete strain with the top electrode layer; the component strain layer is undoped or N-type doped, and the electron concentration is 1×10 14 cm -3 Up to 3×10 16 cm -3 .

7. The multi-period optical absorption broadband InGaAs detector according to claim 6, characterized in that: The number of stacked component strain layers is m, where m is an integer and is greater than or equal to 5 and less than or equal to 30; the component strain layer includes a first strain layer and a second strain layer; the thickness of the first strain layer is d1, and the material is In x Ga 1-x As; wherein x is greater than 0.53 and less than or equal to 0.60, d1 is greater than or equal to 100 nanometers and less than or equal to 300 nanometers; the thickness of the second strain layer is d2, and the material is In y Ga 1-y As, wherein y is greater than or equal to 0.50 and less than or equal to 0.53, and d2 is greater than or equal to 50 nanometers and less than or equal to 300 nanometers.

8. The multi-period optical absorption broadband InGaAs detector according to claim 7, characterized in that: The parameter x of the first strained layer, the thickness d1 of the first strained layer, the parameter y of the second strained layer, the thickness d2 of the second strained layer and the number m of stacking also satisfy the following relationship: x-0.53 ≥ 0.53-y; (x-0.53)×d1≥(0.53-y)×d2; [(x-0.53)×d1-(0.53-y)×d2]×m≤100.

9. A method for manufacturing the multi-period optical absorption broadband InGaAs detector as claimed in claim 1, characterized in that: Contains steps: Step S1, forming the base layer by molecular beam epitaxy or metal organic chemical vapor deposition method; Step S2, forming the bottom electrode layer by using molecular beam epitaxy or metal organic chemical vapor deposition method; Step S3, forming the strain absorption layer by using molecular beam epitaxy or metal organic chemical vapor deposition method; Step S4, forming the top electrode layer by molecular beam epitaxy or metal organic chemical vapor deposition; Step S5, positioning the photosensitive surface of the detector by photolithography, and etching away the top electrode layer and the strain absorption layer in the area outside the photosensitive surface of the detector by wet or dry etching process to form a detector structure; Step S6, generating an N electrode and a P electrode on the bottom electrode layer and the top electrode layer respectively; the N electrode is connected to the bottom electrode layer, and the P electrode is connected to the top electrode layer.

10. The method for preparing a multi-period optical absorption broadband InGaAs detector according to claim 9, characterized in that: In the back-incident detector form, after step S6, the method further comprises: Step S7, removing the base layer by wet etching.

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