Multicolor Ge-based S and P co-doped barrier impurity band detector and preparation method thereof

Abstract

The invention provides a multi-color Ge-based S, P co-doped barrier impurity band detector and a preparation method thereof, the multi-color Ge-based S, P co-doped barrier impurity band detector comprises a mesa array composed of a plurality of pixels, and the pixels comprise a high-conductivity Ge substrate layer, an absorption layer, a SiNx passivation layer, a high-purity Ge barrier layer and a positive electrode contact layer; a negative electrode is formed on the lower surface of the high-conductivity Ge substrate layer, the absorption layer is located on the upper surface of the high-conductivity Ge substrate layer, and the absorption layer is an S and P co-doped absorption layer; the high-purity Ge barrier layer is located on the upper surface of the absorption layer; the positive electrode contact layer is formed on the upper surface of the high-purity Ge barrier layer, and a positive electrode is formed in a local area on the positive electrode contact layer; pixel isolation grooves are formed in the side faces of the positive electrode contact layer and the barrier layer, and the SiNx passivation layer is located at the bottoms of the pixel isolation grooves. According to the invention, spectral response that a single detector covers 2-150 [mu] m can be realized, and the response bandwidth of the device is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor photoelectric detectors, and in particular to a multi-color Ge-based S, P co-doped blocking impurity band detector and a preparation method thereof. Background Art

[0002] The ultra-wideband multi-color high-sensitivity infrared-terahertz detection technology of 2-150μm has broad application prospects in the field of deep space detection. As the core of this technology, the detector has great research significance. The blocking impurity band (BIB) detector is based on the impurity band jump conduction mechanism. It has the advantages of wide response that can cover the infrared-terahertz band, low dark current and high sensitivity. It is the preferred detector type for deep space dark and weak target detection. It has been focused on by Europe, the United States, Japan and other countries, and has been applied in many major astronomical projects, such as the James Webb Telescope and the Spitzer Telescope. Taking the Spitzer Telescope as an example, it has achieved ultra-wideband detection of 2-150μm through the integration of Si-based, Ge-based BIB detectors and InSb detectors, and has the ability to explore the universe at ultra-long distances. However, the integration of multiple detectors requires the cooperation of multiple optical lenses to realize the splitting of light paths in different bands into different detectors, which results in large information loss. On the other hand, the power consumption and load of the entire astronomical telescope increase, resulting in high operating costs. Therefore, it is necessary to develop new detection technologies to enable a single detector to cover the entire 2-150μm band.

[0003] BIB detectors can be divided into Si-based, Ge-based and GaAs-based detectors according to their substrates, of which the first two are the most widely used. By doping different impurities in the substrate and introducing different impurity energy levels, different band coverage can be achieved. The cutoff wavelength of Si-based devices is 40μm, and the cutoff wavelength of Ge-based devices is 200μm. Therefore, Ge-based BIB detectors have the potential to develop in the direction of 2-150μm ultra-wideband multicolor.

[0004] However, the existing Ge-based BIB detectors have the following defects: ① Since the absorption layer is doped with a single element Ga, the short-wave direction band does not reach 2μm; ② A planar structure design based on surface selective ion implantation is mostly adopted. The ion implantation thickness is thin, and the absorption layer is only 2-3μm, and it is difficult to improve indicators such as response rate and quantum efficiency; in addition, the planar structure will also limit the preparation of large-array focal plane devices; ③ The table-type structure is difficult to prepare. In order to achieve high-sensitivity detection, it is necessary to realize the epitaxy of the absorption layer with a thickness of hundreds of μm to ensure the light absorption efficiency. At the same time, a clean and steep absorption layer / barrier layer interface is required to achieve the suppression of device dark current and noise. Traditional epitaxial means are difficult to achieve in an integrated manner, resulting in a large gap between the array scale, response coverage frequency band, quantum efficiency, dark current and other indicators of the Ge-based BIB detector and its application.

[0005] In the Chinese patent document with the publication number CN112713219A, a co-doped barrier impurity band detection system and method are disclosed, including: step S1: injecting As ions or P ions on the single-side surface of the high-resistance silicon substrate, and annealing in a furnace tube; step S2: continuing to epitaxially grow an absorption layer co-doped with As and P elements on the surface after ion implantation; step S3: continuing to epitaxially grow high-resistance silicon as a barrier layer on the absorption layer through a metal organic chemical vapor deposition process; step S4: forming a local positive electrode contact layer on the barrier layer; forming a mesa structure in the barrier layer, the positive electrode contact layer and the absorption layer of a certain depth. Step S5: depositing a silicon dioxide passivation layer on the surface, sidewall and bottom of the mesa; step S6: opening positive and negative electrode holes on the silicon dioxide passivation layer; step S7: forming a positive electrode and a negative electrode with good ohmic contact in the positive and negative electrode holes. Summary of the invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a multi-color Ge-based S, P co-doped blocking impurity band detector and a preparation method thereof.

[0007] A multicolor Ge-based S, P co-doped blocking impurity band detector provided by the present invention comprises: a table-type array composed of a plurality of picture elements, wherein the picture elements comprise: a high-conductivity Ge substrate layer, an absorption layer, a SiNx passivation layer, a high-purity Ge blocking layer, and a positive electrode contact layer;

[0008] A negative electrode is formed on the lower surface of the high-conductivity Ge substrate layer; the absorption layer is located on the upper surface of the high-conductivity Ge substrate layer, and the absorption layer is an S and P co-doped absorption layer; the high-purity Ge barrier layer is located on the upper surface of the absorption layer; the positive electrode contact layer is formed on the upper surface of the high-purity Ge barrier layer, and a positive electrode is formed in a local area on the positive electrode contact layer;

[0009] A pixel isolation groove is formed on the side of the positive electrode contact layer and the barrier layer, and the SiNx passivation layer is located at the bottom of the pixel isolation groove.

[0010] Preferably, the high-conductivity Ge substrate is doped with P element, has a resistivity of less than 0.005Ω·cm, and a thickness of 500μm.

[0011] Preferably, the absorption layer is Ge-based S and P co-doped, prepared by CVD process, and the doping concentrations of S and P in Ge are both 10 15 cm -3 The absorption layer has a thickness of 100 μm.

[0012] Preferably, the high-purity Ge barrier layer is prepared by low-temperature MBE technology, the growth temperature is controlled below 500° C., the resistivity is greater than 30Ω·cm, and the thickness of the barrier layer is 5-10 μm.

[0013] Preferably, the pixel isolation groove is etched by an inductively coupled plasma process, which is realized by a cycle of etching process and passivation process, and the final etching depth is 15 μm; the passivation layer is a SiNx film prepared by a plasma enhanced chemical vapor deposition process, and has a thickness of 200 nm.

[0014] Preferably, the positive electrode and the negative electrode are manufactured by first evaporating a layer of chromium with a thickness of 50 nm, and then evaporating a layer of gold with a thickness of 150 nm.

[0015] A method for preparing a multicolor Ge-based S, P co-doped blocking impurity band detector according to the present invention comprises:

[0016] Step S1: cleaning the high-conductivity Ge substrate to remove surface pollutants and oxides;

[0017] Step S2: A 100 μm thick Ge-based S and P co-doped absorption layer is grown on a high-conductivity Ge substrate by CVD process. The growth thickness is 100 μm, and the S and P doping concentrations are controlled at 10 15 cm -3 Magnitude;

[0018] Step S3: growing a 5-10 μm thick high-purity Ge barrier layer on the absorption layer by a low-temperature MBE process;

[0019] Step S4: spin-coating photoresist on the surface of the high-purity Ge barrier layer, exposing and developing to form an alignment mark window, and removing the photoresist bottom film remaining in the alignment mark window area;

[0020] Step S5: evaporating Ni and Au thin films on the surface of the high-purity Ge barrier layer as alignment marks, and cleaning the sample after the evaporation process to remove excess photoresist and metal outside the mark window;

[0021] Step S6: depositing a SiO2 film on the surface of the high-purity Ge barrier layer, and implanting P ions into the surface of the high-purity Ge barrier layer to form a positive electrode contact layer;

[0022] Step S7: performing thermal annealing on the sample and removing the SiO2 protective layer;

[0023] Step S8: sequentially evaporating Cr and Au thin films on the lower surface of the high-conductivity Ge substrate to form a negative electrode; spin-coating photoresist on the surface of the positive electrode contact layer, exposing and developing to form a positive electrode evaporation window, removing the photoresist bottom film in the positive electrode window area, and sequentially evaporating Cr and Au thin films to form a positive electrode;

[0024] Step S9: etching an isolation groove on the surface of the positive electrode contact layer, and depositing a SiNx passivation layer in the groove to complete pixel isolation.

[0025] Preferably, step S1 comprises: obtaining a high-conductivity Ge substrate, ultrasonically treating it in acetone, ethanol and deionized water for 10 minutes in sequence to remove organic pollutants; soaking it in an NH4OH:H2O solution with a volume ratio of 1:10 for 10 minutes, soaking it in an HCl:H2O solution with a volume ratio of 1:10 for 2 minutes, then rinsing it in deionized water for 5 minutes to remove surface particulate pollutants and oxides, and finally blowing it dry with nitrogen.

[0026] Preferably, the step S9 comprises: forming an isolation etching window on the surface of the positive electrode contact layer, and performing etching in the isolation etching window area, first using C4F8 gas etching, and then using SF6 and C4F8 gas etching, for multiple cycles, to remove the positive electrode contact layer and the high-purity Ge barrier layer in the isolation etching window until the absorption layer is exposed;

[0027] Plasma enhanced chemical vapor deposition is used to evaporate the SiNx passivation layer in the etched isolation groove, and the sample that has completed the evaporation process is cleaned to remove the photoresist.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The absorption layer of the present invention adopts Ge-based S and P co-doping, wherein the energy band width of Ge is 0.67eV, and the ionization energies of S and P are 0.018eV and 0.012eV respectively. Combining the intrinsic response of Ge and the impurity band response of S and P, based on the synergistic mechanism of energy band engineering and hopping conduction, a single detector can achieve a spectral response covering 2-150μm, which greatly improves the device response bandwidth.

[0030] 2. The present invention adopts a table-type structure design, and can realize the preparation of a 100μm absorption layer by CVD epitaxy. Compared with the absorption layer thickness of 2-3μm in the planar structure, the absorption efficiency of the device to the incident signal is effectively increased, and the response rate and quantum efficiency of the device are improved;

[0031] 3. The present invention adopts a combination of CVD epitaxy and low-temperature MEB epitaxy to prepare the absorption layer and the barrier layer. First, a 100 μm Ge-based S, P co-doped absorption layer is prepared using a CVD epitaxy technology with a faster growth rate, and then a 5-10 μm high-purity Ge barrier layer is prepared using a low-temperature MBE epitaxy technology with a slower rate. Thus, while ensuring the epitaxial growth of the 100 μm thick absorption layer, the diffusion of impurities in the absorption layer is suppressed by the low-temperature MBE technology. The use of a low-rate epitaxial barrier layer is conducive to obtaining a clean and steep absorption layer / barrier layer interface, which can effectively reduce the dark current of the device and improve the sensitivity of the device.

[0032] 4. The present invention adopts a table-type structural design, which is conducive to the preparation of large-array focal plane devices. Etching isolation is used between different pixels, and a SiNx passivation layer is deposited in the isolation groove, which can effectively reduce crosstalk between pixels and reduce surface leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0034] Figure 1 This is a schematic diagram of the unit structure of the mesa-type Ge-based S, P co-doped barrier impurity band detector proposed by the present invention;

[0035] Figure 2 A schematic diagram of a focal plane array of a mesa-type Ge-based S, P co-doped barrier impurity band detector proposed in the present invention;

[0036] Figure 3 This is a flow chart for preparing the mesa-type Ge-based S, P co-doped barrier impurity band detector proposed in the present invention. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0038] The present invention discloses a multicolor Ge-based S, P co-doped blocking impurity band detector, the detector is a table-type array composed of multiple pixels, one pixel includes a negative electrode, a high-conductivity Ge substrate layer, an absorption layer, a SiNx passivation layer, a high-purity Ge blocking layer, a positive electrode contact layer, and a positive electrode. The absorption layer is a Ge-based epitaxial layer co-doped with S and P, and has a spectral response coverage of 2-150μm.

[0039] Specifically, the high-conductivity Ge substrate is heavily n-type doped, and the crystal orientation of the substrate is <100> ,exist <100> The epitaxial layer grown crystal-wise has better crystal quality, can reduce defects and improve the performance of the epitaxial layer. The substrate is double-sided polished to make its surface flat and smooth, which is beneficial for subsequent epitaxial growth and other process steps.

[0040] On the upper surface of the high-conductivity Ge substrate, a Ge-based S and P co-doped absorption layer is grown by chemical vapor deposition (CVD) technology. On the surface of the absorption layer, a high-purity Ge barrier layer is grown by low-temperature MBE epitaxy technology. On the surface of the high-purity Ge barrier layer, a positive electrode contact layer is formed by ion implantation and rapid thermal annealing process. On the lower surface of the high-conductivity Ge substrate, a negative electrode is prepared by electron beam evaporation process; on the surface of the positive electrode contact layer, a positive electrode is prepared by photolithography and electron beam evaporation process; on the side of the positive electrode contact layer and the barrier layer, a pixel isolation groove is formed by photolithography and reactive ion etching; at the bottom of the pixel isolation groove, a SiNx passivation layer is formed by plasma enhanced chemical vapor deposition process.

[0041] The high-conductivity Ge substrate is doped with P, with a resistivity of less than 0.005Ω·cm and a thickness of 500μm. The absorption layer is Ge-based S and P co-doped, prepared by CVD process, and the doping concentrations of S and P in Ge are both 10 15 cm -3 This doping concentration can not only ensure sufficient impurity energy level density, but also avoid defects caused by over-doping. The thickness of the absorption layer is 100μm. The thick absorption layer can significantly improve the absorption efficiency of incident light, thereby improving the response rate and quantum efficiency of the device.

[0042] The main function of the high-purity Ge barrier layer is to form a high-impedance layer between the absorption layer and the electrode to reduce dark current and noise and improve the sensitivity and performance of the device. The high-purity Ge barrier layer is prepared by low-temperature MBE technology. MBE technology has the advantages of slow growth rate, good controllability and high purity. It is suitable for preparing high-purity Ge layers. The growth temperature is controlled below 500°C. The epitaxial purity is required to be as high as possible, and the resistivity is greater than 30Ω·cm. The thickness of the barrier layer is 5-10μm.

[0043] The implanted ions of the positive electrode contact layer are P ions, with an implantation energy of 40 keV and an implantation dose of 2×10 14 cm -2 ; The annealing conditions for forming the positive electrode contact layer are in a nitrogen atmosphere, an annealing temperature of 600°C, and an annealing time of 60s. The positive / negative electrodes are first evaporated with a layer of chromium (Cr) with a thickness of 50nm, and then evaporated with a layer of gold (Au) with a thickness of 150nm. The pixel isolation groove adopts an inductively coupled plasma etching process, which is achieved by a cycle of etching process and passivation process, and the final etching depth is 15μm. The passivation layer is a SiNx film prepared by a plasma enhanced chemical vapor deposition process, with a thickness of 200nm.

[0044] The present invention also discloses a method for preparing a multi-color Ge-based S and P co-doped blocking impurity band detector, wherein the detector has a single pixel structure as shown in FIG. Figure 1As shown, it includes a negative electrode, a high-conductivity Ge substrate layer, an absorption layer, a SiNx passivation layer, a high-purity Ge barrier layer, a positive electrode contact layer, and a positive electrode. Among them, the absorption layer is a Ge-based epitaxial layer co-doped with S and P, which can generate photogenerated carriers under the excitation of incident light in the 2-150μm band; the passivation layer is a SiNx material, located at the bottom of the pixel etching isolation groove, used to suppress surface leakage. The entire detector is a table-type array of n pixels, such as Figure 2 shown.

[0045] The preparation method of the multi-color Ge-based S, P co-doped blocking impurity band detector is as follows: Figure 3 As shown, the following steps are included:

[0046] Step S1: cleaning of high-conductivity Ge substrate: obtain an n-type high-conductivity Ge substrate with a resistivity of less than 0.005Ω·cm, a doping element of P, and double-sided polishing, and ultrasonicate it in acetone, ethanol, and deionized water for 10 minutes in turn to remove organic pollutants; then soak it in a NH4OH:H2O solution with a volume ratio of 1:10 for 10 minutes, soak it in a HCl:H2O solution with a volume ratio of 1:10 for 2 minutes, and then rinse it in deionized water for 5 minutes to remove surface particle pollutants and oxides, and finally blow it dry with nitrogen;

[0047] Step S2: CVD epitaxial absorption layer: The cleaned high-conductivity Ge substrate is placed into the CVD chamber, and a Ge-based S and P co-doped absorption layer is grown on the surface of the high-conductivity Ge substrate with a growth thickness of 100 μm, wherein the S and P doping concentrations are controlled at 10 15 cm -3 Magnitude;

[0048] Step S3: MBE epitaxial barrier layer: the sample after the absorption layer epitaxy is completed is sent into the MBE chamber, and a high-purity Ge barrier layer is epitaxially grown on the surface of the absorption layer, with a growth thickness of 5-10nm and a growth temperature controlled below 500°C. The epitaxial purity is required to be as high as possible, with a resistivity greater than 30Ω·cm, and the introduction of other impurity elements is avoided;

[0049] Step S4: Alignment mark photolithography: spin-coat the positive photoresist AZ5214 on the surface of the barrier layer with a thickness of 1.6 μm, and expose and develop to form an alignment mark window;

[0050] Step S5: plasma stripping: using a plasma stripping process to further remove the photoresist bottom film remaining in the alignment mark window area;

[0051] Step S6: Alignment mark deposition: using electron beam evaporation technology, deposition alignment marks on the surface of the barrier layer, and sequentially deposition of Ni and Au thin films, with thicknesses of 100 nm and 50 nm respectively;

[0052] Step S7: Stripping: Soak the sample after the evaporation process in an acetone solution at 80°C in a water bath for 30 minutes, ultrasonically clean it for 10 minutes, then ultrasonically clean it with isopropanol for 5 minutes, rinse it with deionized water, blow it dry with nitrogen, and complete the stripping of the photoresist and the metal outside the marking window;

[0053] Step S8: growing a SiO2 protective layer: using a plasma enhanced chemical vapor deposition process, a SiO2 film is deposited on the surface of the barrier layer with a deposition thickness of 20 nm;

[0054] Step S9: Ion implantation to form a positive electrode contact layer: Using an ion implantation process, P ions are implanted into the surface of the barrier layer with an implantation energy of 40 KeV and an implantation dose of 2×10 14 cm -2 ;

[0055] Step S10: ion implantation annealing: place the sample in a rapid annealing device, introduce nitrogen, maintain the temperature at 600°C, and anneal for 60 seconds;

[0056] Step S11: Removing the SiO2 protective layer: Soak the sample in a HF:H20 solution with a volume ratio of 1:10 for 20 seconds, rinse with deionized water, and blow dry with nitrogen to remove the surface SiO2 protective layer;

[0057] Step S12: negative electrode growth: using an electron beam evaporation process, Cr and Au thin films are sequentially deposited on the lower surface of the high-conductivity Ge substrate with thicknesses of 50 nm and 150 nm respectively to form a negative electrode;

[0058] Step S13: positive electrode photolithography: spin-coat the surface of the positive electrode contact layer with positive photoresist AZ5214 to a thickness of 1.6 μm, and perform exposure and development to form a positive electrode evaporation window;

[0059] Step S14: plasma stripping: using a plasma stripping process to further remove the photoresist bottom film remaining in the positive electrode evaporation window area;

[0060] Step S15: positive electrode growth: using electron beam evaporation technology to sequentially evaporate Cr and Au thin films in the positive electrode evaporation window with thicknesses of 50 nm and 150 nm respectively, to form a positive electrode;

[0061] Step S16: Stripping: Soak the sample after the evaporation process in an acetone solution at 80°C in a water bath for 30 minutes, ultrasonically clean it for 10 minutes, then ultrasonically clean it with isopropanol for 5 minutes, rinse it with deionized water, blow it dry with nitrogen, and complete the stripping of the photoresist and the metal outside the positive electrode evaporation window;

[0062] Step S17: annealing the electrode to form an ohmic contact: an annealing process is adopted in a nitrogen atmosphere at an annealing temperature of 400° C. for a holding time of 60 seconds to allow the electrode to form a good ohmic contact;

[0063] Step S18: Isolation photolithography: Spin-coat positive photoresist AZ4620 on the positive electrode contact layer and the electrode surface with a thickness of 6.5 μm, and perform exposure and development to form windows required for isolation etching;

[0064] Step S19: Isolation etching: using an inductively coupled plasma etching process, etching is performed in the isolation etching window area, first using C4F8 gas etching, then using SF6 and C4F8 gas etching, multiple cycles, to remove the positive electrode contact layer base and barrier layer in the isolation etching window until the absorption layer is exposed, and the etching depth is 15 μm;

[0065] Step S20: Growth of a passivation layer: Plasma enhanced chemical vapor deposition is used to evaporate a SiNx passivation layer in the etched isolation groove, with a deposition thickness of 200 nm;

[0066] Step S21: Removal of photoresist: soak the sample after the evaporation process in an acetone solution at 80°C in a water bath for 30 minutes, ultrasonically clean it for 10 minutes, then ultrasonically clean it with isopropanol for 5 minutes, rinse it with deionized water, and blow dry it with nitrogen to complete the removal of photoresist;

[0067] Step S22: Packaging test: Use a gold wire ball bonding machine to lead out the positive / negative electrodes of the device and connect them to an external test circuit to complete the detector preparation.

[0068] The present invention discloses a multi-color Ge-based S, P co-doped blocking impurity band detector and a preparation method thereof. The present invention introduces two impurities, S and P, into the absorption layer of the Ge-based BIB detector, with ionization energies of 0.018eV and 0.012eV respectively, and superimposes the intrinsic response of Ge at the same time. Based on the synergistic mechanism of energy band engineering and hopping conduction, a single detector can cover 2-150μm, providing a new means for the multi-colorization, miniaturization and integration of deep space exploration technology.

[0069] In order to solve the problem that traditional planar structure devices are difficult to improve indices such as response rate and quantum efficiency due to the thin thickness of the absorption layer, and the problem that it is difficult to prepare large-array focal plane devices with planar structures, the present invention increases the thickness of the absorption layer from 2-3μm to more than 100μm through a table-type device structure design, effectively increasing the device's absorption of incident signals, thereby improving the device's response rate and quantum efficiency; in addition, the table-type structure is also conducive to the preparation of large-array focal plane devices.

[0070] In order to solve the problem that traditional epitaxial means are difficult to achieve integrated epitaxy of an absorption layer with a thickness of 100 μm while ensuring a clean and steep absorption layer / barrier layer interface, the present invention combines CVD epitaxy with MBE epitaxy, and uses a faster CVD epitaxy technology to prepare a Ge-based S, P co-doped absorption layer with a thickness of 100 μm on a high-purity Ge substrate, and uses a slower low-temperature MBE epitaxy technology to epitaxially grow a barrier layer on the absorption layer, thereby ensuring the epitaxy of the absorption layer of 100 μm and obtaining a clean and steep absorption layer / barrier layer interface.

[0071] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0072] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A multi-color Ge-based S, P co-doped barrier impurity band detector, characterized in that: include: A table-type array composed of a plurality of pixels, wherein the pixels include: a high-conductivity Ge substrate layer, an absorption layer, a SiNx passivation layer, a high-purity Ge barrier layer, and a positive electrode contact layer; A negative electrode is formed on the lower surface of the high-conductivity Ge substrate layer; the absorption layer is located on the upper surface of the high-conductivity Ge substrate layer, and the absorption layer is an S and P co-doped absorption layer; the high-purity Ge barrier layer is located on the upper surface of the absorption layer; the positive electrode contact layer is formed on the upper surface of the high-purity Ge barrier layer, and a positive electrode is formed in a local area on the positive electrode contact layer; A pixel isolation groove is formed on the side of the positive electrode contact layer and the barrier layer, and the SiNx passivation layer is located at the bottom of the pixel isolation groove.

2. The multi-color Ge-based S, P co-doped barrier impurity band detector according to claim 1, characterized in that: The high-conductivity Ge substrate is doped with P element, has a resistivity of less than 0.005Ω·cm, and a thickness of 500μm.

3. The multi-color Ge-based S, P co-doped barrier impurity band detector according to claim 1, characterized in that: The absorption layer is Ge-based S and P co-doped and prepared by CVD process. The doping concentrations of S and P in Ge are both 10 15 cm -3 The absorption layer has a thickness of 100 μm.

4. The multi-color Ge-based S, P co-doped barrier impurity band detector according to claim 1, characterized in that: The high-purity Ge barrier layer is prepared by low-temperature MBE technology, the growth temperature is controlled below 500° C., the resistivity is greater than 30Ω·cm, and the thickness of the barrier layer is 5-10 μm.

5. The multi-color Ge-based S, P co-doped barrier impurity band detector according to claim 1, characterized in that: The pixel isolation groove is etched by an inductively coupled plasma process, which is realized by a cycle of etching and passivation, and the final etching depth is 15 μm. The passivation layer is a SiNx film prepared by a plasma enhanced chemical vapor deposition process, and has a thickness of 200 nm.

6. The multi-color Ge-based S, P co-doped barrier impurity band detector according to claim 1, characterized in that: The positive electrode and the negative electrode are manufactured by first evaporating a layer of chromium with a thickness of 50 nm, and then evaporating a layer of gold with a thickness of 150 nm.

7. A method for preparing a multi-color Ge-based S, P co-doped blocking impurity band detector, characterized in that: include: Step S1: cleaning the high-conductivity Ge substrate to remove surface pollutants and oxides; Step S2: A 100 μm thick Ge-based S and P co-doped absorption layer is grown on a high-conductivity Ge substrate by CVD process. The growth thickness is 100 μm, and the S and P doping concentrations are controlled at 10 15 cm -3 Magnitude; Step S3: growing a 5-10 μm thick high-purity Ge barrier layer on the absorption layer by a low-temperature MBE process; Step S4: spin-coating photoresist on the surface of the high-purity Ge barrier layer, exposing and developing to form an alignment mark window, and removing the photoresist bottom film remaining in the alignment mark window area; Step S5: evaporating Ni and Au thin films on the surface of the high-purity Ge barrier layer as alignment marks, and cleaning the sample after the evaporation process to remove excess photoresist and metal outside the mark window; Step S6: depositing a SiO2 film on the surface of the high-purity Ge barrier layer, and implanting P ions into the surface of the high-purity Ge barrier layer to form a positive electrode contact layer; Step S7: performing thermal annealing on the sample and removing the SiO2 protective layer; Step S8: sequentially evaporating Cr and Au thin films on the lower surface of the high-conductivity Ge substrate to form a negative electrode; spin-coating photoresist on the surface of the positive electrode contact layer, exposing and developing to form a positive electrode evaporation window, removing the photoresist bottom film in the positive electrode window area, and sequentially evaporating Cr and Au thin films to form a positive electrode; Step S9: etching an isolation groove on the surface of the positive electrode contact layer, and depositing a SiNx passivation layer in the groove to complete pixel isolation.

8. The method for preparing a multi-color Ge-based S, P co-doped blocking impurity band detector according to claim 7, characterized in that: The step S1 comprises: obtaining a high-conductivity Ge substrate, and sequentially ultrasonicating it in acetone, ethanol, and deionized water for 10 minutes to remove organic pollutants; sequentially soaking it in an NH4OH:H2O solution with a volume ratio of 1:10 for 10 minutes, and soaking it in an HCl:H2O solution with a volume ratio of 1:10 for 2 minutes, and then rinsing it in deionized water for 5 minutes to remove surface particle pollutants and oxides, and finally blowing it dry with nitrogen.

9. The method for preparing a multicolor Ge-based S, P co-doped blocking impurity band detector according to claim 7, characterized in that: The step S9 comprises: forming an isolation etching window on the surface of the positive electrode contact layer, and performing etching in the isolation etching window area, first using C4F8 gas etching, and then using SF6 and C4F8 gas etching, and performing multiple cycles to remove the positive electrode contact layer and the high-purity Ge barrier layer in the isolation etching window until the absorption layer is exposed; Plasma enhanced chemical vapor deposition is used to evaporate the SiNx passivation layer in the etched isolation groove, and the sample that has completed the evaporation process is cleaned to remove the photoresist.

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