A high-quantum-efficiency middle-very long wave dual-color infrared detector and a preparation method thereof

Abstract

The application discloses a high-quantum-efficiency middle-wave-very-long-wave dual-color infrared detector and a preparation method thereof, and relates to the technical field of semiconductors. The application stacks a substrate layer, a buffer layer, a middle-wave high-doping layer, a middle-wave absorbing layer, a very-long-wave absorbing layer, a very-long-wave barrier layer and a very-long-wave high-doping layer in sequence from bottom to top through a molecular beam epitaxy growth process; the above multi-layer structure is further locally etched to form a mesa structure and an exposed middle-wave high-doping layer, an upper electrode is arranged on one side of the very-long-wave high-doping layer close to the exposed middle-wave high-doping layer, and a lower electrode is arranged on the exposed middle-wave high-doping layer, so that a high-quantum-efficiency middle-wave-very-long-wave dual-color infrared detector is prepared. The dual-band quantum efficiency and the anti-interference capability of the infrared detector are obviously improved, the preparation process parameters are accurate and controllable, and the infrared detector is suitable for high-precision infrared detection scenes such as security and protection, remote sensing and medical treatment.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector and its fabrication method. Background Technology

[0002] Infrared detectors are used in security monitoring, aerospace remote sensing, medical diagnosis, industrial fault detection, and military target detection. In the field of infrared detection, mid-wave infrared and very long-wave infrared (VLWI) bands are two key application bands: mid-wave infrared corresponds to the main thermal radiation range of targets at normal temperatures (such as humans and industrial equipment), enabling accurate identification of close-range targets; VLWI has strong penetrating power, effectively capturing signals from distant targets in complex environments such as smoke and haze. Dual-color infrared detectors, combining these two bands, can simultaneously acquire dual infrared characteristic information of targets, significantly improving detection accuracy, anti-interference capabilities, and environmental adaptability. This represents a core research direction for the current development of infrared detection technology towards multi-band and high-performance applications.

[0003] Traditional dual-color infrared detectors use a back-to-back approach, such as NIPBPIN and PINBNIP structures. However, for mid-wave and very long-wave, the absorption region of the mid-wave will block the extraction of the very long-wave signal. Devices with this structure generally have very low quantum efficiency for very long waves. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector. This application utilizes molecular beam epitaxy to sequentially stack a substrate layer, a buffer layer, a mid-wave highly doped layer, a mid-wave absorption layer, a very-long-wave absorption layer, a very-long-wave barrier layer, and a very-long-wave highly doped layer from bottom to top. Further, the multilayer structure is locally etched to form a mesa structure and expose the mid-wave highly doped layer. An upper electrode is placed on the side of the very-long-wave highly doped layer near the exposed mid-wave highly doped layer, and a lower electrode is placed on the exposed mid-wave highly doped layer, thereby fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector. This infrared detector significantly improves dual-band quantum efficiency and anti-interference capability, and the fabrication process parameters are precise and controllable, making it suitable for high-precision infrared detection scenarios such as security, remote sensing, and medical applications.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, this application provides a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector, the infrared detector comprising, from bottom to top, a substrate layer, a buffer layer, a mid-wave highly doped layer, a mid-wave absorption layer, a very-long-wave absorption layer, a very-long-wave barrier layer, and a very-long-wave highly doped layer; wherein, a portion of the mid-wave highly doped layer, the mid-wave absorption layer, the very-long-wave absorption layer, the very-long-wave barrier layer, and the very-long-wave highly doped layer are etched away to form a mesa structure on the mid-wave highly doped layer and an exposed mid-wave highly doped layer; the thickness of the exposed mid-wave highly doped layer is less than the thickness of the mid-wave highly doped layer; a lower electrode is disposed on the exposed mid-wave highly doped layer; an upper electrode is disposed on the very-long-wave highly doped layer; the upper electrode is disposed on the side of the very-long-wave highly doped layer near the exposed mid-wave highly doped layer.

[0007] In the dual-color infrared detector structure constructed in this application, the mid-wave highly doped layer and the mid-wave absorption layer, from bottom to top, together constitute the mid-wave detection unit, while the very long-wave absorption layer, the very long-wave barrier layer, and the very long-wave highly doped layer together constitute the very long-wave detection unit. The mid-wave detection unit absorbs mid-wave infrared light to generate charge carriers, and the very long-wave detection unit absorbs very long-wave infrared light to generate charge carriers. Both are collected independently by electrodes, achieving dual-color signal differentiation. Moreover, the two different detection units are stacked vertically, eliminating the need for two independent detectors, simplifying the system size and thickness, and reducing costs.

[0008] Furthermore, in the dual-color infrared detector structure of this application, the presence of a very long-wavelength barrier layer prevents carriers from the mid-wavelength detection unit from diffusing to the very long-wavelength detection unit, while simultaneously limiting the reverse diffusion of carriers from the very long-wavelength detection unit, thus reducing carrier recombination losses. In addition, the mesa structure reduces leakage current channels on the device sides, lowers dark current, and improves signal-to-noise ratio and quantum efficiency. Thanks to this structural design, a single local etching process can simultaneously form the mesa structure as the detection core region, creating an exposed highly doped mid-wavelength layer as the lower electrode contact region. This eliminates the need for additional isolation layer fabrication or multiple etching steps, simplifying the semiconductor processing flow and reducing production difficulty and cost. Moreover, the area and thickness of the exposed highly doped mid-wavelength layer as the lower electrode contact region can be controlled according to the etching process, precisely matching the deposition range of the lower electrode and preventing the electrode from covering the detection region of the mesa structure, further reducing interference to the detection core region and ensuring the structural stability of the device during long-term operation. Furthermore, its contact resistance with the lower electrode is low, enabling more efficient transmission of the current signal corresponding to mid-wavelength detection.

[0009] Furthermore, in the dual-color infrared detector structure of this application, the upper electrode is positioned close to the lower electrode, which shortens the carrier transport path and reduces the recombination probability of carriers during transport. At the same time, it reduces the series resistance, enabling more carriers to successfully reach the electrode and be converted into output signals more efficiently, thereby improving the response speed, signal output efficiency, and quantum efficiency of the dual-color infrared detector.

[0010] In one feasible implementation, the substrate is a GaSb-Te substrate, wherein the Te doping concentration is 3 × 10⁻⁶. 17 ~7×10 17 cm -3 .

[0011] In this application, the lattice constants of the GaSb-Te substrate and the upper buffer layer GaSb are very similar, which can significantly reduce defects such as dislocations and stress at the interface between the substrate and the buffer layer; and the reduction of defects can suppress nonradiative recombination of charge carriers, thereby improving quantum efficiency.

[0012] In one feasible implementation, the buffer layer is GaSb with a thickness of 500~660nm.

[0013] In this application, the atomic arrangement on the surface of the GaSb-Te substrate layer becomes disordered due to repeated high-temperature deoxidation. The presence of the GaSb buffer layer can cover its surface defects, forming a smoother interface and reducing carrier recombination centers. Moreover, the presence of the GaSb buffer layer can effectively prevent the diffusion of Te doped in the substrate to other layers, avoiding runaway doping concentrations in other layers.

[0014] In one feasible implementation, the mid-wavelength highly doped layer comprises 8 mL InAs / 8 mL GaSb with a thickness of 400–600 nm; wherein the dopant used is Be, the doping type is p-type, and the doping concentration is 1 × 10⁻⁶. 18 ~3×10 18 cm -3 .

[0015] In this application, the bandgap of the 8MLInAs / 8MLGaSb superlattice is highly matched with the photon energy of mid-wave infrared light, which can efficiently absorb mid-wave infrared light and improve the collection efficiency of mid-wave signals.

[0016] In one feasible implementation, the mid-wave absorption layer comprises 8MLInAs / 8MLGaSb with a thickness of 400~600nm; wherein the dopant used is Be, the doping type is p-type, and the doping concentration is 1×10⁻⁶. 16 ~3×10 16 cm -3 .

[0017] The same 8MLInAs / 8MLGaSb superlattice structure as the mid-wave highly doped layer ensures that its bandgap matches mid-wave infrared light, which can maximize the absorption of mid-wave photons and generate charge carriers, significantly improving the quantum efficiency of mid-wave detection.

[0018] In one feasible implementation, the very long wavelength absorbing layer comprises 16MLInAs / 7MLGaSb with a thickness of 1500~2500nm; wherein the dopant used is Be, the doping type is p-type, and the doping concentration is 1×10⁻⁶. 16 ~3×10 16 cm -3 .

[0019] In this application, the bandgap of the 16MLInAs / 7MLGaSb superlattice periodic structure is highly matched with the photon energy of very long-wave infrared light, enabling efficient absorption of very long-wave infrared light and achieving efficient absorption of very long-wave signals. Moreover, the thicker absorption layer further ensures its absorption efficiency. In addition, the lower concentration of p-type doping can reduce carrier scattering, extend the lifetime of very long-wave photogenerated carriers, ensure that carriers can be effectively collected by the top electrode, and improve quantum efficiency.

[0020] In one feasible implementation, the very long-wavelength barrier layer comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 400~600nm; wherein the dopant used includes any one of Si and Te, the doping type is n-type, and the doping concentration is 3×10⁻⁶. 16 ~5×10 17 cm -3 .

[0021] In the dual-color infrared detector structure of this application, the bandgap of AlSb in the very long-wavelength barrier layer is much larger than that of InAs and GaSb. The 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb superlattice can serve as the valence band barrier of the device. At the same time, the carriers in this region have a large effective mass, which can effectively reduce the dark current of the device.

[0022] In one feasible implementation, the very long wavelength highly doped layer comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 400~600nm; wherein the dopant used includes any one of Si and Te, the doping type is n-type, and the doping concentration is 1×10⁻⁶. 18 ~3×10 18 cm -3 .

[0023] A pn junction is formed between the very long-wavelength highly doped layer and the very long-wavelength barrier layer. The junction generates a built-in electric field pointing from the n-region to the p-region, achieving effective carrier separation and outputting a very long-wavelength photocurrent signal through the upper electrode. At the same time, the superlattice structure that is completely identical to the very long-wavelength barrier layer can ensure the matching of lattice constants between the two, reduce interface defects, avoid carrier recombination caused by defects, and further improve quantum efficiency.

[0024] Secondly, this application provides a method for fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector, comprising the following steps:

[0025] A buffer layer, a medium-wavelength highly doped layer, a medium-wavelength absorbing layer, a very long-wavelength absorbing layer, a very long-wavelength barrier layer, and a very long-wavelength highly doped layer are sequentially grown on a substrate using molecular beam epitaxy.

[0026] The mid-wave highly doped layer, mid-wave absorption layer, very long wave absorption layer, very long wave barrier layer and very long wave highly doped layer are partially etched away to form a mesa structure and expose the mid-wave highly doped layer.

[0027] An upper electrode is deposited on the side of the very long-wave highly doped layer close to the exposed mid-wave highly doped layer, and a lower electrode is deposited on the exposed mid-wave highly doped layer, thus fabricating the high quantum efficiency mid-wave-very long-wave dual-color infrared detector.

[0028] In one feasible implementation, the specific parameters of the molecular beam epitaxy growth process include: growth temperature of 450~550℃, background vacuum of the growth chamber of 100~200 Torr; the specific parameters of the etching include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow rate ratio of (3~5):1, RF power of 100~150W, bias voltage of 20~50V, and etching pressure of 0.5~1Pa.

[0029] In one feasible implementation, the material used for the upper electrode includes either Au-Ti alloy or Au-Pt-Ti alloy; the material used for the lower electrode includes either Au-Zn alloy or Au-Be alloy.

[0030] Beneficial technical effects:

[0031] In the structure of the dual-color infrared detector of this application, a dual-color detection structure capable of simultaneously responding to mid-wave infrared and very long-wave infrared is constructed by vertically stacking mid-wave / very long-wave functional layers. This eliminates the need for additional splicing or integration of multiple monochromatic detectors, enabling synchronous detection of infrared signals in two bands. This simplifies the system size and thickness, reduces costs, and broadens the application scenarios of infrared detectors.

[0032] Furthermore, the structure of the dual-color infrared detector in this application also improves the carrier conversion and collection efficiency by matching the substrate layer and buffer layer lattices, matching the mid-wave absorption layer and mid-wave highly doped layer lattices to reduce interface defects, suppressing carrier recombination with a very long-wave barrier layer, forming an exposed mid-wave highly doped layer as the contact area of ​​the lower electrode, and optimizing the positions of the upper and lower electrodes and the mesa structure to shorten the carrier path, thereby achieving a high quantum efficiency.

[0033] In addition, the application of mature molecular beam epitaxy growth technology and parameter-controllable Cl2 / BCl3 etching technology facilitates the mass production of the dual-color infrared detector of this application, reducing costs and making it easier to promote production. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the high quantum efficiency mid-wave-very-long-wave dual-color infrared detector prepared in Example 1.

[0035] Figure 2 This is a schematic diagram of the fabrication process for a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector.

[0036] Figure 3 This is a schematic diagram of the structure of the mid-wave-very-long-wave dual-color infrared detector made in Comparative Example 1.

[0037] Figure 4 This is a schematic diagram of the structure of the mid-wave-very-long-wave dual-color infrared detector prepared in Comparative Example 2.

[0038] Figure 5 This is a schematic diagram of the structure of the mid-wave-very-long-wave dual-color infrared detector prepared in Comparative Example 3.

[0039] Explanation of reference numerals in the attached figures: 1. Substrate layer; 2. Buffer layer; 3. Medium-wavelength highly doped layer; 4. Medium-wavelength absorption layer; 5. Very long-wavelength absorption layer; 6. Very long-wavelength barrier layer; 7. Very long-wavelength highly doped layer; 8. Upper electrode; 9. Lower electrode; 31. Exposed medium-wavelength highly doped layer; X. Mesa structure. Detailed Implementation

[0040] To facilitate understanding of the content described in this application, the technical solutions described herein are further explained below with reference to specific embodiments; however, this application is not limited thereto. All equivalent transformations or simple substitutions made based on the substantive content of this application should fall within the protection scope of this application.

[0041] The singular forms “for,” “or,” “a,” “any,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0042] The following describes in detail, with reference to different embodiments, the fabrication method of the high quantum efficiency mid-wave-very-long-wave dual-color infrared detector provided in this application.

[0043] Example 1

[0044] like Figure 2 As shown, a method for fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0045] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 450℃, background vacuum degree of growth chamber 100Torr).

[0046] The Te doping concentration in substrate layer 1 is 3 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 500 nm;

[0047] The medium-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0048] Mid-wave absorption layer 4 comprises 8MLInAs / 8MLGaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 16 cm -3 ;

[0049] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 2000nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2×10⁻⁶. 16 cm -3 ;

[0050] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 500 nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 2 × 10⁻⁶. 17 cm -3 ;

[0051] The very long wavelength highly doped layer 7 consists of 18 mL InAs / 3 mL GaSb / 5 mL AlSb / 3 mL GaSb, with a thickness of 500 nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0052] S2. Partial etching is used to remove the medium-wave highly doped layer 3, the medium-wave absorbing layer 4, the very long-wave absorbing layer 5, the very long-wave barrier layer 6, and the very long-wave highly doped layer 7 to form the mesa structure X and the exposed medium-wave highly doped layer 31.

[0053] The exposed medium-wave high-doped layer 31 has a thickness that is 250 nm less than the thickness of the medium-wave high-doped layer 3.

[0054] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow rate ratio of 4:1, an RF power of 120W, a bias voltage of 30V, and an etching pressure of 0.8Pa.

[0055] S3. An upper electrode 8, made of Au-Ti alloy, is deposited on the side of the very long-wave highly doped layer 7 near the exposed mid-wave highly doped layer 31. A lower electrode 9, made of Au-Zn alloy, is deposited on the exposed mid-wave highly doped layer 31, thus fabricating the high quantum efficiency mid-wave-very long-wave dual-color infrared detector, with the structure as shown in the figure. Figure 1 As shown.

[0056] Example 2

[0057] like Figure 2 As shown, a method for fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0058] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 500℃, background vacuum degree of growth chamber is 120Torr).

[0059] The Te doping concentration in substrate layer 1 is 5 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 580nm;

[0060] The medium-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 400 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 1 × 10⁻⁶. 18 cm -3 ;

[0061] Mid-wave absorption layer 4 consists of 8MLInAs / 8MLGaSb with a thickness of 400nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 1×10⁻⁶. 16 cm -3 ;

[0062] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 1500nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 1×10⁻⁶. 16 cm -3 ;

[0063] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 400nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 3×10⁻⁶. 16 cm -3 ;

[0064] The very long wavelength highly doped layer 7 consists of 18 mL InAs / 3 mL GaSb / 5 mL AlSb / 3 mL GaSb, with a thickness of 400 nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 1 × 10⁻⁶. 18 cm -3 ;

[0065] S2. Partial etching is used to remove the medium-wave highly doped layer 3, the medium-wave absorbing layer 4, the very long-wave absorbing layer 5, the very long-wave barrier layer 6, and the very long-wave highly doped layer 7 to form the mesa structure X and the exposed medium-wave highly doped layer 31.

[0066] The exposed medium-wave high-doped layer 31 has a thickness that is 200 nm less than the thickness of the medium-wave high-doped layer 3.

[0067] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow rate ratio of 3:1, an RF power of 100W, a bias voltage of 20V, and an etching pressure of 0.5Pa.

[0068] S3. An upper electrode 8 made of Au-Pt-Ti alloy is deposited on the side of the very long wave highly doped layer 7 near the exposed medium wave highly doped layer 31, and a lower electrode 9 made of Au-Be alloy is deposited on the exposed medium wave highly doped layer 31, thus obtaining the high quantum efficiency medium wave-very long wave dual-color infrared detector.

[0069] Example 3

[0070] like Figure 2 As shown, a method for fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0071] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 550℃, background vacuum degree of growth chamber is 200Torr).

[0072] The Te doping concentration in substrate layer 1 is 7 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 660nm;

[0073] The medium-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 600 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 3 × 10⁻⁶. 18 cm -3 ;

[0074] Mid-wave absorption layer 4 comprises 8MLInAs / 8MLGaSb with a thickness of 600nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 3×10⁻⁶. 16 cm -3 ;

[0075] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 2500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 3 × 10⁻⁶. 16 cm -3 ;

[0076] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 600nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 5×10⁻⁶. 16 cm -3 ;

[0077] The very long wavelength highly doped layer 7 consists of 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 600nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 3×10⁻⁶. 18 cm -3 ;

[0078] S2. Partial etching is used to remove the medium-wave highly doped layer 3, the medium-wave absorbing layer 4, the very long-wave absorbing layer 5, the very long-wave barrier layer 6, and the very long-wave highly doped layer 7 to form the mesa structure X and the exposed medium-wave highly doped layer 31.

[0079] The thickness of the exposed medium-wave high-doped layer 31 is lower than that of the medium-wave high-doped layer 3, which is 400 nm.

[0080] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow ratio of 5:1, an RF power of 150W, a bias voltage of 50V, and an etching pressure of 1Pa.

[0081] S3. An upper electrode 8 made of Au-Ti alloy is deposited on the side of the very long wave highly doped layer 7 near the exposed medium wave highly doped layer 31, and a lower electrode 9 made of Au-Be alloy is deposited on the exposed medium wave highly doped layer 31, thus obtaining the high quantum efficiency medium wave-very long wave dual-color infrared detector.

[0082] Example 4

[0083] like Figure 2 As shown, a method for fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0084] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 520℃, background vacuum degree of growth chamber is 180Torr).

[0085] The Te doping concentration in substrate layer 1 is 6 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 640nm;

[0086] The medium-wavelength highly doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 450 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 1.5 × 10⁻⁶. 18 cm -3 ;

[0087] The mid-wave absorption layer 4 comprises 8 mL InAs / 8 mL GaSb with a thickness of 450 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 1.5 × 10⁻⁶. 16 cm -3 ;

[0088] The very long wavelength absorbing layer 5 consists of 16 mL InAs / 7 mL GaSb with a thickness of 1800 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 1.5 × 10⁻⁶. 16 cm -3 ;

[0089] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 450nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 8×10⁻⁶. 16 cm -3 ;

[0090] The very long wavelength highly doped layer 7 comprises 18 mL InAs / 3 mL GaSb / 5 mL AlSb / 3 mL GaSb with a thickness of 450 nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 1.5 × 10⁻⁶. 18 cm -3 ;

[0091] S2. Partial etching is used to remove the medium-wave highly doped layer 3, the medium-wave absorbing layer 4, the very long-wave absorbing layer 5, the very long-wave barrier layer 6, and the very long-wave highly doped layer 7 to form the mesa structure X and the exposed medium-wave highly doped layer 31.

[0092] The thickness of the exposed medium-wave high-doped layer 31 is lower than that of the medium-wave high-doped layer 3, which is 220 nm.

[0093] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow rate ratio of 3.5:1, an RF power of 110W, a bias voltage of 25V, and an etching pressure of 0.6Pa.

[0094] S3. An upper electrode 8 made of Au-Pt-Ti alloy is deposited on the side of the very long wave highly doped layer 7 near the exposed medium wave highly doped layer 31. A lower electrode 9 made of Au-Zn alloy is deposited on the exposed medium wave highly doped layer 31, thus obtaining the high quantum efficiency medium wave-very long wave dual-color infrared detector.

[0095] Example 5

[0096] like Figure 2 As shown, a method for fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0097] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 480℃, background vacuum degree of growth chamber is 110 Torr).

[0098] The Te doping concentration in substrate layer 1 is 4 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 520nm;

[0099] The mid-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 550 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2.5 × 10⁻⁶. 18 cm -3 ;

[0100] The mid-wave absorption layer 4 comprises 8 mL InAs / 8 mL GaSb with a thickness of 550 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2.5 × 10⁻⁶. 16 cm -3 ;

[0101] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 2200nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2.5×10⁻⁶. 16 cm -3 ;

[0102] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 550nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 1×10⁻⁶. 17 cm -3 ;

[0103] The very long wavelength highly doped layer 7 comprises 18 mL InAs / 3 mL GaSb / 5 mL AlSb / 3 mL GaSb with a thickness of 550 nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 2.5 × 10⁻⁶. 18 cm -3 ;

[0104] S2. Partial etching is used to remove the medium-wave highly doped layer 3, the medium-wave absorbing layer 4, the very long-wave absorbing layer 5, the very long-wave barrier layer 6, and the very long-wave highly doped layer 7 to form the mesa structure X and the exposed medium-wave highly doped layer 31.

[0105] The exposed medium-wave high-doped layer 31 has a thickness that is lower than that of the medium-wave high-doped layer 3, which is 350 nm.

[0106] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow rate ratio of 4.5:1, an RF power of 140W, a bias voltage of 40V, and an etching pressure of 0.9Pa.

[0107] S3. An upper electrode 8 made of Au-Ti alloy is deposited on the side of the very long wave highly doped layer 7 near the exposed medium wave highly doped layer 31, and a lower electrode 9 made of Au-Zn alloy is deposited on the exposed medium wave highly doped layer 31, thus obtaining the high quantum efficiency medium wave-very long wave dual-color infrared detector.

[0108] Example 6

[0109] like Figure 2 As shown, a method for fabricating a high quantum efficiency mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0110] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 510℃, background vacuum degree of growth chamber is 190Torr).

[0111] The Te doping concentration in substrate layer 1 is 6.5 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 560nm;

[0112] The medium-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0113] Mid-wave absorption layer 4 comprises 8MLInAs / 8MLGaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 16 cm -3 ;

[0114] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 2000nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2×10⁻⁶. 16 cm -3 ;

[0115] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 500 nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 5 × 10⁻⁶. 17 cm -3 ;

[0116] The very long wavelength highly doped layer 7 consists of 18 mL InAs / 3 mL GaSb / 5 mL AlSb / 3 mL GaSb, with a thickness of 500 nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0117] S2. Partial etching is used to remove the medium-wave highly doped layer 3, the medium-wave absorbing layer 4, the very long-wave absorbing layer 5, the very long-wave barrier layer 6, and the very long-wave highly doped layer 7 to form the mesa structure X and the exposed medium-wave highly doped layer 31.

[0118] The thickness of the exposed medium-wave high-doped layer 31 is lower than that of the medium-wave high-doped layer 3, which is 300 nm.

[0119] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow ratio of 4:1, an RF power of 130W, a bias voltage of 35V, and an etching pressure of 0.7Pa.

[0120] S3. An upper electrode 8 made of Au-Pt-Ti alloy is deposited on the side of the very long wave highly doped layer 7 near the exposed medium wave highly doped layer 31, and a lower electrode 9 made of Au-Be alloy is deposited on the exposed medium wave highly doped layer 31, thus obtaining the high quantum efficiency medium wave-very long wave dual-color infrared detector.

[0121] Comparative Example 1

[0122] A method for fabricating a mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0123] S1. GaSb buffer layer 2, medium-wavelength highly doped layer 3, medium-wavelength absorption layer 4, very long-wavelength absorption layer 5 and very long-wavelength highly doped layer 7 are sequentially grown on GaSb-Te substrate layer 1 by molecular beam epitaxy (growth temperature 450℃, background vacuum degree of growth chamber 100Torr).

[0124] The Te doping concentration in substrate layer 1 is 3 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 500 nm;

[0125] The medium-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0126] Mid-wave absorption layer 4 comprises 8MLInAs / 8MLGaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 16 cm -3 ;

[0127] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 2000nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2×10⁻⁶. 16 cm -3 ;

[0128] The very long wavelength highly doped layer 7 consists of 18 mL InAs / 3 mL GaSb / 5 mL AlSb / 3 mL GaSb, with a thickness of 500 nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0129] S2. The mid-wave high-doped layer 3, mid-wave absorption layer 4, very long-wave absorption layer 5 and very long-wave high-doped layer 7 are partially etched away to form the mesa structure X and the exposed mid-wave high-doped layer 31.

[0130] The exposed medium-wave high-doped layer 31 has a thickness that is 250 nm less than the thickness of the medium-wave high-doped layer 3.

[0131] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow rate ratio of 4:1, an RF power of 120W, a bias voltage of 30V, and an etching pressure of 0.8Pa.

[0132] S3. An upper electrode 8, made of Au-Ti alloy, is deposited on the side of the very long-wave highly doped layer 7 near the exposed mid-wave highly doped layer 31. A lower electrode 9, made of Au-Zn alloy, is deposited on the exposed mid-wave highly doped layer 31, thus fabricating the mid-wave-very long-wave dual-color infrared detector, the structure of which is as follows: Figure 3 As shown.

[0133] Comparative Example 2

[0134] A method for fabricating a mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0135] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 550℃, background vacuum degree of growth chamber is 200Torr).

[0136] The Te doping concentration in substrate layer 1 is 7 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 660nm;

[0137] The medium-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 600 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 3 × 10⁻⁶. 18 cm -3 ;

[0138] Mid-wave absorption layer 4 comprises 8MLInAs / 8MLGaSb with a thickness of 600nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 3×10⁻⁶. 16 cm -3 ;

[0139] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 2500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 3 × 10⁻⁶. 16 cm -3 ;

[0140] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 600nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 5×10⁻⁶. 16 cm -3 ;

[0141] The very long wavelength highly doped layer 7 consists of 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 600nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 3×10⁻⁶. 18 cm -3 ;

[0142] S2. The mid-wave highly doped layer 3, mid-wave absorption layer 4, very long wave absorption layer 5, very long wave barrier layer 6 and very long wave highly doped layer 7 are partially etched away to form a mesa structure X.

[0143] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow ratio of 5:1, an RF power of 150W, a bias voltage of 50V, and an etching pressure of 1Pa.

[0144] S3. An upper electrode 8, made of Au-Ti alloy, is deposited on the side of the very long-wave highly doped layer 7 near the exposed mid-wave highly doped layer 31. A lower electrode 9, made of Au-Be alloy, is deposited on the exposed mid-wave highly doped layer 31, thus fabricating the mid-wave-very long-wave dual-color infrared detector, the structure of which is as follows. Figure 4 As shown.

[0145] Comparative Example 3

[0146] A method for fabricating a mid-wave-very-long-wave dual-color infrared detector includes the following steps:

[0147] S1. A GaSb buffer layer 2, a medium-wavelength highly doped layer 3, a medium-wavelength absorbing layer 4, a very long-wavelength absorbing layer 5, a very long-wavelength barrier layer 6, and a very long-wavelength highly doped layer 7 are sequentially grown on a GaSb-Te substrate layer 1 by a molecular beam epitaxy process (growth temperature 510℃, background vacuum degree of growth chamber is 190Torr).

[0148] The Te doping concentration in substrate layer 1 is 6.5 × 10⁻⁶. 17 cm -3 The thickness of buffer layer 2 is 560nm;

[0149] The medium-wave high-doped layer 3 consists of 8 mL InAs / 8 mL GaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0150] Mid-wave absorption layer 4 comprises 8MLInAs / 8MLGaSb with a thickness of 500 nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2 × 10⁻⁶. 16 cm -3 ;

[0151] The very long wavelength absorbing layer 5 consists of 16MLInAs / 7MLGaSb with a thickness of 2000nm; the dopant used is Be, the doping type is p-type, and the doping concentration is 2×10⁻⁶. 16 cm -3 ;

[0152] The very long-wavelength barrier layer 6 comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 500 nm; the dopant used is Si, the doping type is n-type, and the doping concentration is 5 × 10⁻⁶. 17 cm -3 ;

[0153] The very long wavelength highly doped layer 7 consists of 18 mL InAs / 3 mL GaSb / 5 mL AlSb / 3 mL GaSb, with a thickness of 500 nm; the dopant used is Te, the doping type is n-type, and the doping concentration is 2 × 10⁻⁶. 18 cm -3 ;

[0154] S2. Partial etching is used to remove the medium-wave highly doped layer 3, the medium-wave absorbing layer 4, the very long-wave absorbing layer 5, the very long-wave barrier layer 6, and the very long-wave highly doped layer 7 to form the mesa structure X and the exposed medium-wave highly doped layer 31.

[0155] The thickness of the exposed medium-wave high-doped layer 31 is lower than that of the medium-wave high-doped layer 3, which is 300 nm.

[0156] The specific etching parameters include: using a Cl2 / BCl3 mixed gas as the etching gas, with a Cl2 to BCl3 gas flow ratio of 4:1, an RF power of 130W, a bias voltage of 35V, and an etching pressure of 0.7Pa.

[0157] S3. An upper electrode 8, made of Au-Pt-Ti alloy, is deposited on the side of the very long-wave highly doped layer 7 away from the exposed mid-wave highly doped layer 31. A lower electrode 9, made of Au-Be alloy, is deposited on the exposed mid-wave highly doped layer 31, thus fabricating the mid-wave-very long-wave dual-color infrared detector, the structure of which is as follows: Figure 5 As shown.

[0158] The mid-wave-very-long-wave dual-color infrared detector prepared in Comparative Example 1 lacks a very-long-wave barrier layer 6. Therefore, it is impossible to avoid the mutual diffusion of impurities between the upper very-long-wave highly doped layer 7 and the lower very-long-wave absorption layer 5. Consequently, it is difficult to ensure the low-doping characteristics of the very-long-wave absorption layer 5 and to suppress carrier recombination. As a result, the quantum efficiency of the mid-wave-very-long-wave dual-color infrared detector is relatively low.

[0159] In the structure of the mid-wave-very-long-wave dual-color infrared detector prepared in Comparative Example 2, there is no exposed mid-wave highly doped layer 31. Instead, the buffer layer 2 is in direct contact with the lower electrode 9. The contact resistance between the two is significantly higher than that between the exposed mid-wave highly doped layer 31 and the lower electrode 9. Therefore, it is difficult to efficiently transmit the current signal corresponding to mid-wave detection, and the quantum efficiency is significantly reduced.

[0160] In the structure of the mid-wave-very-long-wave dual-color infrared detector prepared in Comparative Example 3, the upper electrode 8 is located on the side of the very-long-wave highly doped layer 7 away from the exposed mid-wave highly doped layer 31. This extends the carrier transport path, thereby increasing the recombination probability of carriers during transport. At the same time, it increases the series resistance, making it possible for fewer carriers to successfully reach the electrode. Ultimately, this reduces the response speed, signal output efficiency, and quantum efficiency of the mid-wave-very-long-wave dual-color infrared detector.

[0161] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0162] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.

Claims

1. A high quantum efficiency mid-wave-very-long-wave dual-color infrared detector, characterized in that, The infrared detector comprises, from bottom to top, a substrate layer (1), a buffer layer (2), a mid-wave highly doped layer (3), a mid-wave absorption layer (4), a very long-wave absorption layer (5), a very long-wave barrier layer (6), and a very long-wave highly doped layer (7); wherein, parts of the mid-wave highly doped layer (3), the mid-wave absorption layer (4), the very long-wave absorption layer (5), the very long-wave barrier layer (6), and the very long-wave highly doped layer (7) are partially etched away to form a mesa structure (X) on the mid-wave highly doped layer (3) and an exposed mid-wave highly doped layer (31); the thickness of the exposed mid-wave highly doped layer (31) is less than the thickness of the mid-wave highly doped layer (3); a lower electrode (9) is disposed on the exposed mid-wave highly doped layer (31); an upper electrode (8) is disposed on the very long-wave highly doped layer (7); the upper electrode (8) is disposed on the side of the very long-wave highly doped layer (7) close to the exposed mid-wave highly doped layer (31); The doping type of the medium-wave high-doped layer (3), the medium-wave absorption layer (4) and the very long-wave absorption layer (5) is p-type; the doping type of the very long-wave barrier layer (6) and the very long-wave high-doped layer (7) is n-type. The method for preparing the infrared detector includes the following steps: A buffer layer (2), a medium-wave highly doped layer (3), a medium-wave absorption layer (4), a very long-wave absorption layer (5), a very long-wave barrier layer (6), and a very long-wave highly doped layer (7) are sequentially grown on a substrate layer (1) using molecular beam epitaxy. The mid-wave high-doped layer (3), mid-wave absorption layer (4), very long-wave absorption layer (5), very long-wave barrier layer (6) and very long-wave high-doped layer (7) are partially etched away to form a mesa structure (X) and the exposed mid-wave high-doped layer (31). An upper electrode (8) is deposited on the side of the very long wave highly doped layer (7) close to the exposed medium wave highly doped layer (31), and a lower electrode (9) is deposited on the exposed medium wave highly doped layer (31), thus obtaining the high quantum efficiency medium wave-very long wave dual-color infrared detector. The specific parameters of the molecular beam epitaxy growth process include: growth temperature of 450~550℃, background vacuum degree of growth chamber of 100~200 Torr; the specific parameters of the etching process include: using Cl2 / BCl3 mixed gas as etching gas, gas flow ratio of Cl2 to BCl3 of (3~5):1, RF power of 100~150W, bias voltage of 20~50V, and etching pressure of 0.5~1Pa. The substrate layer (1) is a GaSb-Te substrate, wherein the doping concentration of Te is 3 x 10 17 7 x 10 17 cm -3 .

2. The high quantum efficiency mid-very long wave dual-color infrared detector according to claim 1, characterized in that, The buffer layer (2) is GaSb with a thickness of 500~660nm.

3. The high quantum efficiency mid-wave-very-long-wave dual-color infrared detector according to claim 1, characterized in that, The medium-wave high-doped layer (3) comprises 8MLInAs / 8MLGaSb with a thickness of 400~600nm; the dopant used is Be with a doping concentration of 1×10⁻⁶. 18 ~3×10 18 cm -3 .

4. A high quantum efficiency mid-wave-very-long-wave dual-color infrared detector according to claim 1, characterized in that, The middle wave absorption layer (4) comprises 8MLInAs / 8MLGaSb, and the thickness is 400-600nm; wherein the dopant used is Be, and the doping concentration is 1×10 16 ~3×10 16 cm -3 .

5. A high quantum efficiency mid-wave-very-long-wave dual-color infrared detector according to claim 1, characterized in that, The very long wavelength absorption layer (5) comprises 16MLInAs / 7MLGaSb with a thickness of 1500~2500nm; the dopant used is Be with a doping concentration of 1×10⁻⁶. 16 ~3×10 16 cm -3 .

6. A high quantum efficiency mid-wave-very-long-wave dual-color infrared detector according to claim 1, characterized in that, The very long wave barrier layer (6) comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 400~600nm; the dopant used includes either Si or Te, with a doping concentration of 3×10⁻⁶. 16 ~5×10 17 cm -3 .

7. A high quantum efficiency mid-wave-very-long-wave dual-color infrared detector according to claim 1, characterized in that, The very long wavelength highly doped layer (7) comprises 18MLInAs / 3MLGaSb / 5MLAlSb / 3MLGaSb with a thickness of 400~600nm; the dopant used includes any one of Si and Te, with a doping concentration of 1×10⁻⁶. 18 ~3×10 18 cm -3 .

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