Etching method of double-color second-class superlattice infrared detector

Abstract

The invention provides an etching method of a double-color second-class superlattice infrared detector, and belongs to the technical field of chip manufacturing. The method comprises the following steps: providing a double-color second-class superlattice infrared detector, and forming a photoresist mask on the surface of the double-color second-class superlattice infrared detector; under the condition that the ratio of the longitudinal etching rate to the transverse etching rate is not less than 5: 1, performing dry etching on the surface of the double-color second-class superlattice infrared detector to obtain an initial mesa structure; the initial mesa structure is subjected to wet etching, a middle mesa structure is obtained, the wet etching time is smaller than or equal to 2 min, and the wet etching temperature is smaller than or equal to 10 DEG C; and post-processing the middle table-board structure to obtain the table-board structure. Through organic combination of a high-anisotropy forming effect of dry etching and a low-damage repairing effect of wet etching, the low surface damage characteristic is considered while high aspect ratio etching is realized, the dark current of the device is fundamentally reduced, and the intrinsic detection performance of the device is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chip manufacturing technology, and in particular to an etching method of a dual-color second-type superlattice infrared detector. BACKGROUND

[0002] Infrared detectors can effectively detect targets under complex environmental conditions. Dual-color infrared detectors have stronger anti-background interference capability, can significantly reduce false alarm rate and improve detection accuracy, and have important value in early warning, search and tracking application scenarios. Especially in long-wave and very long-wave bands, dual-color infrared detectors based on antimony-based second-type superlattice materials have advantages of low dark current, low defect density and high process stability, and have become a key research and application direction. In the manufacturing process of such detector devices, the etching process is a key link to determine the performance of the device. Since the dual-color infrared detector is usually composed of two monochromatic detectors stacked together, in order to achieve effective isolation between the detection units, the etching depth needs to be significantly increased, even several times of the monochromatic device, thereby putting forward more stringent requirements for the steepness, aspect ratio and damage control of the etching process.

[0003] Existing etching technologies mainly include wet etching and dry etching: although the wet etching has relatively low material damage due to the chemical reaction mechanism, the isotropic characteristics inevitably cause serious lateral etching, thereby destroying the mesa integrity and leading to insufficient repeatability and uniformity of etching, which is difficult to meet the process requirements of deep trench and small line width structure. Dry etching uses the anisotropic effect of plasma to obtain a deep trench structure with high aspect ratio, but at the same time, the strong energy plasma will cause significant damage to the material surface during etching, leading to increased surface leakage of the device, increased dark current and serious restriction on the performance of the device.

[0004] Therefore, in the prior art, wet etching or dry etching is used alone, which is difficult to balance the steepness and low damage of the deep trench mesa, and cannot meet the requirements of the dual-color second-type superlattice infrared detector for high-performance mesa structure. Therefore, there is an urgent need in the art for an etching process that can effectively reduce plasma damage and maintain the integrity of the sidewall while achieving high aspect ratio etching, so as to improve the overall detection performance of the device. SUMMARY

[0005] To solve the above problems, the present application provides an etching method of a dual-color second-type superlattice infrared detector, comprising the following steps: A dual-color second-type superlattice infrared detector is provided, and a photoresist mask is formed on the surface of the dual-color second-type superlattice infrared detector; etching the surface of the dual-color type-II superlattice infrared detector under the condition that the ratio of the longitudinal etching rate to the lateral etching rate is not less than 5:1 to obtain an initial mesa structure; wet etching the initial mesa structure to obtain an intermediate mesa structure, wherein the wet etching time is ≤2 min and the wet etching temperature is ≤10℃; post-processing the intermediate mesa structure to obtain a mesa structure.

[0006] Optionally, in the step of etching the surface of the dual-color type-II superlattice infrared detector under the condition that the ratio of the longitudinal etching rate to the lateral etching rate is not less than 5:1 to form the initial mesa structure, the parameters of the dry etching include: the etching gas component is any one of BCl3 / Ar, CH4 / H2 / Ar, CH4 / H2 / BCl3 / Cl2 / Ar, Cl2 / Ar and SiCl4 / Cl2.

[0007] Optionally, the radio frequency power is any value in the range of 50W-150W, the pressure is any value less than 20mTorr, and the etching time is any value in the range of 2min-5min.

[0008] Optionally, when the etching gas component is Cl2 / Ar, the ratio of Cl2 / Ar is any value in the range of (1-5):(10-15).

[0009] Optionally, the flow rate of Cl2 is any value in the range of 2sccm-4sccm, and the flow rate of Ar is any value in the range of 8sccm-10sccm.

[0010] Optionally, the etching depth of the dry etching is any value in the range of 1μm-5μm.

[0011] Optionally, the dry etching is plasma etching.

[0012] Optionally, in the step of wet etching the initial mesa structure to obtain the intermediate mesa structure, the parameters of the wet etching include: the etching solution is selected from at least one or a combination of multiple of hydrofluoric acid, hydrogen peroxide, hydrogen chloride, phosphoric acid or ammonia.

[0013] Optionally, the etching depth of the wet etching is any value in the range of 10nm-50nm.

[0014] Optionally, in the step of post-processing the intermediate mesa structure to obtain the mesa structure, the post-processing step includes: removing photoresist and cleaning the dual-color type-II superlattice infrared detector with the intermediate mesa structure.

[0015] According to the present invention, dry etching is performed under the condition that the ratio of longitudinal etching rate to lateral etching rate is not less than 5:1, making longitudinal etching the dominant force, thereby significantly suppressing the lateral propagation caused by lateral etching and obtaining an initial mesa with steep sidewalls, excellent aspect ratio, and uniform structure. Furthermore, a short-time low-temperature wet etching process effectively removes and passivates the surface damage layer and defect states formed during dry etching, further improving surface smoothness and structural integrity, and reducing defect density. This invention organically combines the high anisotropic shaping effect of dry etching with the low-damage repair effect of wet etching, achieving high aspect ratio etching while also considering low surface damage characteristics, fundamentally reducing the dark current of the device and improving its intrinsic detection performance. This invention effectively overcomes the shortcomings of existing technologies where dry etching or wet etching alone cannot simultaneously meet the requirements of mesa steepness and low damage, solving the technical problem of achieving both high aspect ratio and low defect state requirements in the deep etching process of dual-color class-two superlattice infrared detectors. Attached Figure Description

[0016] Figure 1 A schematic diagram of an etching method for a two-color class-two superlattice infrared detector according to an embodiment of the present invention is shown; Figure 2 The SEM image of the dual-color type-two superlattice infrared detector after dry etching in Embodiment 1 of the present invention is shown. Figure 3 The SEM image of the two-color type-two superlattice infrared detector after wet etching in Embodiment 1 of the present invention is shown. Detailed Implementation

[0017] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0018] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0019] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] Figure 1 A schematic diagram of an etching method for a two-color, type-two superlattice infrared detector according to an embodiment of the present invention is shown. Figure 1 As shown, the etching method includes the following steps: S1 provides a two-color type-two superlattice infrared detector and forms a photoresist mask on the surface of the two-color type-two superlattice infrared detector.

[0021] S2. Under the condition that the ratio of longitudinal etching rate to transverse etching rate is not less than 5:1, the surface of the two-color type-two superlattice infrared detector is dry etched to obtain the initial mesa structure.

[0022] S3. The initial mesa structure is subjected to wet etching to obtain the intermediate mesa structure, wherein the wet etching time is ≤2min and the wet etching temperature is ≤10℃.

[0023] S4, post-processing the intermediate table structure to obtain the table structure.

[0024] According to the present invention, dry etching is performed under the condition that the ratio of longitudinal etching rate to lateral etching rate is not less than 5:1, making longitudinal etching the dominant force, thereby significantly suppressing the lateral propagation caused by lateral etching and obtaining an initial mesa with steep sidewalls, excellent aspect ratio, and uniform structure. Furthermore, a short-time low-temperature wet etching process effectively removes and passivates the surface damage layer and defect states formed during dry etching, further improving surface smoothness and structural integrity, and reducing defect density. This invention organically combines the high anisotropic shaping effect of dry etching with the low-damage repair effect of wet etching, achieving high aspect ratio etching while also considering low surface damage characteristics, fundamentally reducing the dark current of the device and improving its intrinsic detection performance. This invention effectively overcomes the shortcomings of existing technologies where dry etching or wet etching alone cannot simultaneously meet the requirements of mesa steepness and low damage, solving the technical problem of achieving both high aspect ratio and low defect state requirements in the deep etching process of dual-color class-two superlattice infrared detectors.

[0025] In step S1, a mask is formed on the device surface using photoresist. The purpose of this is to selectively protect the target area during subsequent etching, preventing non-target areas from being etched and ensuring precise shaping and clear boundaries of the mesa structure. This process includes steps such as photoresist coating, exposure, and development.

[0026] In step S2, material in the non-mask region of the device surface is removed by dry etching to form an initial mesa structure with a high aspect ratio. The anisotropic effect of dry etching makes the longitudinal etching rate significantly higher than the lateral etching rate, thus ensuring the realization of the high aspect ratio structure. However, this process may cause an increase in surface defects and plasma damage, leading to problems such as increased device leakage current and dark current. In one embodiment, the ratio of the longitudinal etching rate to the lateral etching rate is not less than 5:1, for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. When the longitudinal rate is significantly greater than the lateral rate, the plasma bombardment directionality is enhanced, and the material is mainly removed along the vertical direction, thereby ensuring the controllability of the aspect ratio and structural integrity to achieve high-precision isolation of the deep trench mesa, thus ensuring the electrical and optical independence between different detection units of the dual-color class-II superlattice infrared detector. When the etching rate ratio is not less than 5:1, it can ensure that the etched structure has steep sidewalls, avoiding mesa collapse or sidewall tilting due to excessive lateral etching. If the etching rate ratio is less than 5:1, severe lateral drilling is likely to occur, leading to distortion or even failure of the platform structure.

[0027] In one embodiment, the parameters for dry etching include: the etching gas composition is any one of BCl3 / Ar, CH4 / H2 / Ar, CH4 / H2 / BCl3 / Cl2 / Ar, Cl2 / Ar, and SiCl4 / Cl2. This gas combination effectively ensures that the longitudinal etching rate is significantly higher than the lateral rate, thereby maintaining a rate ratio above 5:1, resulting in a steep and uniform mesa structure, while reducing surface damage and residue formation. The radio frequency (RF) power is any value between 50W and 150W, for example, 50W, 70W, 90W, 100W, 110W, 120W, or 150W. The RF power directly determines the energy and density of ions in the plasma. When the RF power is controlled within this range, the ions can provide sufficient kinetic energy to achieve anisotropic etching while avoiding excessive bombardment that introduces severe deep defects. The pressure can be any value less than 20 mTorr, such as 3 mTorr, 5 mTorr, 8 mTorr, 11 mTorr, 13 mTorr, 15 mTorr, or 19 mTorr. When the pressure is controlled within this range, the directionality of ion movement is maintained, the anisotropy of longitudinal etching is enhanced, and the steepness of the etching morphology is guaranteed. The etching time can be any value between 2 min and 5 min, such as 2 min, 3 min, 3.5 min, 4 min, or 5 min. When the etching time is within this range, the etching depth can be ensured, and unwanted surface defects can be reduced.

[0028] In one embodiment, the gas composition for dry etching is Cl2 / Ar, with a ratio of (1-5):(10-15), such as 1:10, 1:12.5, 1:15, 2.5:10, 2.5:12.5, 2.5:15, 5:10, or 5:15. Cl2 acts as the active etching gas, providing the chemical reaction, while Ar acts as the physical sputtering gas, enhancing the directional effect of ions. When the ratio is controlled within this range, sufficient chemical reaction rate can be ensured while suppressing excessive lateral etching, achieving high aspect ratio etching. In one embodiment, the Cl2 flow rate is any value between 2 sccm and 4 sccm, such as 2 sccm, 3 sccm, or 4 sccm, and the Ar flow rate is any value between 8 sccm and 10 sccm, such as 8 sccm, 9 sccm, or 10 sccm. When the gas flow rate is controlled within this range, longitudinal directionality can be effectively maintained while ensuring the etching rate, avoiding excessive damage to the mesa. If the Cl2 flow rate is too low, chemical etching will be insufficient; if it is too high, isotropy will be enhanced. Too low an Ar flow rate will lead to insufficient ion bombardment and a decrease in aspect ratio; too high an Ar flow rate will exacerbate physical damage. In one embodiment, the etching depth of the dry etching is any value between 1 μm and 5 μm, for example, 1 μm, 2 μm, 3 μm, 4 μm, or 5 μm. This depth range can meet the electrical isolation requirements between different functional layers in a dual-color detector, while avoiding over-etching and damage to the underlying sensitive layer. When the etching depth is below 1 μm, interlayer isolation is insufficient, and electrical crosstalk is severe; when the etching depth exceeds 5 μm, the cumulative effect of etching time and ion bombardment leads to increased surface damage and decreased device performance. In one embodiment, the dry etching is plasma etching. Plasma etching, as the most commonly used process in dry etching, utilizes a combination of chemical reaction and physical bombardment to achieve high aspect ratio etching. Its advantage is high efficiency, but it introduces a certain degree of plasma damage.

[0029] In step S3, the initial mesa structure is treated with wet etching to remove the surface damage layer caused by ion bombardment during dry etching and to achieve surface smoothing. Secondary assisted wet etching can effectively reduce the surface defect state density, thereby suppressing leakage current and dark current. However, improper wet etching control can easily lead to excessive lateral etching, compromising mesa integrity; therefore, strict setting of process parameters is necessary. In one embodiment, the wet etching parameters include: the etching solution is selected from at least one or more combinations of hydrofluoric acid, hydrogen peroxide, hydrogen chloride, phosphoric acid, or ammonia, for example, a combination of hydrofluoric acid and hydrogen peroxide, used to remove the oxide layer and achieve surface passivation. The concentration of hydrofluoric acid is in the range of 1%-5%, for example, 1%, 3%, or 5%. The concentration of hydrogen peroxide is in the range of 1%-10%, for example, 1%, 5%, or 10%. Through optimized combinations of different etching solutions and their concentrations, the integrity and stability of the mesa structure can be ensured while effectively removing the defect layer. The wet etching time is ≤2 min, for example, it can be 15 s, 30 s, 50 s, 60 s, 70 s, 90 s, 100 s, 110 s, or 120 s. When the etching time exceeds 2 min, significant lateral etching is likely to occur, leading to mesa deformation. Controlling the etching time within 2 min achieves a balance between effective repair and morphology preservation. The wet etching temperature is ≤10℃, for example, it can be 4℃, 5℃, 6℃, 7℃, 8℃, 9℃, or 10℃. Under low temperature conditions, the chemical reaction rate is effectively suppressed, avoiding over-etching and side reactions, and ensuring etching accuracy. When the temperature exceeds 10℃, the etching rate accelerates significantly, easily leading to uncontrollable lateral etching and structural damage. In one embodiment, the etching depth of the wet etching is any value between 10 nm and 50 nm, for example, it can be 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm. This depth range ensures that the surface damage layer formed by ion bombardment is completely removed, while avoiding over-etching that damages the device structure. When the etching depth is less than 10nm, the defect layer may not be completely removed; when the etching depth exceeds 50nm, it will cause deviations in the mesa dimensions or even damage.

[0030] In step S4, the intermediate mesa structure is cleaned and photoresist is removed through post-processing to eliminate residual organic matter, etching byproducts, and contaminants, ensuring the cleanliness and stability of the mesa structure. In one embodiment, the post-processing step includes: photoresist removal and cleaning of the dual-color type-two superlattice infrared detector containing the mesa structure obtained in step S3. Specifically, the photoresist is ultrasonically treated sequentially in acetone and ethanol solutions to ensure complete removal. Subsequently, the device is cleaned in deionized water to complete the etching process. This treatment method not only thoroughly removes surface residues, preventing them from introducing leakage paths or affecting device stability during subsequent device operation, but also restores the cleanliness of the mesa surface, further reducing dark current and improving the long-term reliability of the device.

[0031] Example 1 Embodiment 1 of the present invention provides an etching method for a two-color type-two superlattice infrared detector, comprising the following steps: (1) A photoresist with a thickness of 2 μm was spin-coated onto the surface of a two-color class-II superlattice infrared detector device. After pre-baking at 90 °C for 1 min, it was exposed to ultraviolet light at an exposure energy of 150 mJ / cm². 2 Then, it is developed for 60 seconds to form a clear photolithographic pattern.

[0032] (2) Then the device is fixed in the inductively coupled plasma dry etching chamber, the vacuum is evacuated to below 2 mTorr, and a Cl2 / Ar mixed gas with a ratio of 1:3 is introduced into the reaction chamber at flow rates of 3 sccm and 9 sccm, respectively. The working pressure is 10 mTorr, the RF power is set to 100 W, and the etching time is 3 min to obtain the initial mesa structure.

[0033] (3) The device containing the initial mesa structure was placed in a wet etching solution of HF / H2O2 to obtain an intermediate mesa structure. The concentration of HF was 3% and the concentration of H2O2 was 5%. The device was stirred and soaked at 8°C for 60 seconds, and the wet etching depth was 30 nm.

[0034] (4) The intermediate mesa structure was ultrasonicated in acetone and anhydrous ethanol solutions for 2 minutes each to remove photoresist residue, and then cleaned in deionized water to obtain the mesa structure.

[0035] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that steps (1) to (2) are not performed.

[0036] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that step (3) is not performed.

[0037] Comparative Example 3 Comparative Example 3 provides an etching method for a two-color type-two superlattice infrared detector, comprising the following steps: (1) A photoresist with a thickness of 2 μm was spin-coated onto the surface of a two-color class-II superlattice infrared detector device. After pre-baking at 90 °C for 1 min, it was exposed to ultraviolet light at an exposure energy of 150 mJ / cm². 2 Then, it is developed for 60 seconds to form a clear photolithographic pattern.

[0038] (2) Then the device is fixed in the inductively coupled plasma dry etching chamber, the vacuum is evacuated to below 2 mTorr, and a Cl2 / Ar mixed gas with a ratio of 1:1 is introduced into the reaction chamber at flow rates of 5 sccm and 5 sccm respectively. The working pressure is 25 mTorr, the RF power is set to 120 W, and the etching time is 4 min to obtain the initial mesa structure.

[0039] (3) The device containing the initial mesa structure was placed in a wet etching solution of HF / H2O2 to obtain an intermediate mesa structure. The concentration of HF was 5% and the concentration of H2O2 was 10%. The device was stirred and soaked at room temperature for 130 s, and the wet etching depth was 70 nm.

[0040] (4) The intermediate mesa structure was ultrasonicated in acetone and anhydrous ethanol solutions for 2 minutes each to remove photoresist residue, and then cleaned in deionized water to obtain the mesa structure.

[0041] Table 1 below shows the performance of the devices in Embodiment 1 and Comparative Examples 1-3 of the present invention.

[0042] Table 1 shows the observation of mesa sidewall steepness using scanning electron microscopy and sample roughness measured using atomic force microscopy. The dark current density of Example 1 and Comparative Examples 1-3 was measured using a current-voltage characteristic testing platform. As shown in Table 1, Comparative Example 1, using wet etching alone, suffered severe side etching due to its isotropic characteristics, resulting in mesa structural distortion and a significant increase in dark current. Comparative Example 2, using dry etching alone, achieved a high longitudinal-to-transverse etching rate ratio, but plasma bombardment caused significant surface damage, resulting in a still high dark current. In Comparative Example 3, the etching process parameters resulted in a longitudinal-to-transverse etching rate ratio of less than 5:1, and excessive wet etching led to side etching and mesa collapse, causing particularly severe performance degradation. In contrast, Example 1 of this invention, with a longitudinal-to-transverse etching rate ratio greater than 5:1, obtained a steep and complete initial mesa. Subsequent short-time low-temperature wet etching effectively removed ion bombardment damage and maintained sidewall integrity, resulting in a device dark current density of only 2.1 × 10⁻⁶. -5 A / cm 2Compared to comparative examples 1-3, the degradation rates were reduced by approximately 76%, 67%, and 78%, respectively. This result demonstrates that the present invention, through the synergistic combination of the high anisotropic shaping of dry etching and the low-damage repair effect of wet etching, not only achieves a high aspect ratio and steepness of the deep trench mesa structure, but also effectively suppresses plasma damage, significantly improves the electrical performance of the device, and ultimately solves the technical challenge of balancing etching morphology integrity and low damage in existing technologies.

[0043] Figure 2 The SEM image of the dual-color type-two superlattice infrared detector after dry etching in Embodiment 1 of the present invention is shown. Figure 3 The SEM image of the two-color type-two superlattice infrared detector after wet etching in Embodiment 1 of the present invention is shown. Figure 2 The image shows the mesa morphology obtained after single-step dry etching. Obvious plasma bombardment marks are observed on the mesa sidewalls, indicating high surface roughness and morphological defects at the trench edges. This suggests that while dry etching alone can achieve a high aspect ratio, it inevitably introduces significant surface damage and sidewall roughening. In contrast, Figure 3 The mesa morphology obtained by combining dry etching with short-time low-temperature wet etching clearly shows smooth and intact trench sidewalls, with almost no roughness or damage traces caused by dry etching. The trench boundaries are clear, and the structural steepness is significantly improved. This result fully demonstrates that the present invention, through the organic combination of dry etching and secondary auxiliary wet etching, effectively reduces plasma etching damage and surface roughness while maintaining high aspect ratio and steepness. This significantly improves the integrity and process uniformity of the mesa structure, providing a solid structural guarantee for reducing device dark current and improving detection performance.

[0044] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.

Claims

1. An etching method for a two-color class-two superlattice infrared detector, characterized in that, Includes the following steps: A dual-color type-two superlattice infrared detector is provided, and a photoresist mask is formed on the surface of the dual-color type-two superlattice infrared detector; Under the condition that the ratio of longitudinal etching rate to transverse etching rate is not less than 5:1, the surface of the dual-color type-two superlattice infrared detector is dry etched to obtain the initial mesa structure. The initial mesa structure is subjected to wet etching to obtain an intermediate mesa structure, wherein the wet etching time is ≤2 min and the wet etching temperature is ≤10℃. The intermediate platform structure is post-processed to obtain the platform structure.

2. The etching method according to claim 1, characterized in that, In the step of dry etching the surface of the dual-color type-two superlattice infrared detector to form an initial mesa structure under the condition that the ratio of longitudinal etching rate to transverse etching rate is not less than 5:1, the parameters of the dry etching include: the etching gas composition is any one of BCl3 / Ar, CH4 / H2 / Ar, CH4 / H2 / BCl3 / Cl2 / Ar, Cl2 / Ar and SiCl4 / Cl2; The RF power is any value between 50W and 150W, the pressure is any value less than 20mTorr, and the etching time is any value between 2min and 5min.

3. The etching method according to claim 2, characterized in that, When the etching gas composition is Cl2 / Ar, the Cl2 / Ar ratio is any value in (1-5):(10-15); The flow rate of Cl2 is any value between 2 sccm and 4 sccm, and the flow rate of Ar is any value between 8 sccm and 10 sccm.

4. The etching method according to claim 3, characterized in that, The etching depth of the dry etching method is any value between 1μm and 5μm.

5. The etching method according to claim 4, characterized in that, The dry etching method is plasma etching.

6. The etching method according to claim 1, characterized in that, In the step of performing wet etching on the initial mesa structure to obtain the intermediate mesa structure, the parameters of the wet etching include: the etching solution is selected from at least one or more combinations of hydrofluoric acid, hydrogen peroxide, hydrogen chloride, phosphoric acid, or ammonia.

7. The etching method according to claim 6, characterized in that, The corrosion depth of the wet etching process is any value between 10nm and 50nm.

8. The etching method according to any one of claims 1-7, characterized in that, In the step of post-processing the intermediate mesa structure to obtain the mesa structure, the post-processing step includes: removing and cleaning the photoresist from the two-color type-two superlattice infrared detector with the mesa structure.

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