Method for regulating and controlling residual stress of tellurium-cadmium-mercury epitaxial film

Abstract

The invention discloses a method for regulating and controlling the residual stress of a tellurium-cadmium-mercury epitaxial film, which is characterized in that the temperature difference in a film placement area is controlled by carrying out simulated temperature measurement and temperature field correction on a heat treatment system, the uniformity of a high-temperature field in a film surface in a heat treatment process is ensured, and the introduction of extra stress caused by non-uniform temperature field in the heat treatment process is inhibited. Through the design of the step heating process and the step cooling process, the real-time temperature field uniformity in the heating process and the cooling process is guaranteed, and introduction of additional stress is avoided; residual stress in the epitaxial growth process is effectively eliminated through the constant-temperature heat treatment step; through thin film edge scratching, an edge stress concentration area caused by faster heat dissipation of the thin film edge in the cooling process is removed. According to the method, the residual stress in the epitaxial film can be effectively removed, meanwhile, new stress is effectively prevented from being introduced in the heat treatment process for removing the stress, and development and production of high-quality tellurium-cadmium-mercury materials and high-performance infrared detectors are supported.

Description

Technical Field

[0001] This invention belongs to the field of infrared thin film materials technology, specifically relating to a method for controlling the residual stress of mercury cadmium telluride epitaxial thin films. Background Technology

[0002] Due to its advantages such as high quantum efficiency, low dark current, and the ability to flexibly adjust the absorption band by modifying its composition, mercury cadmium telluride (HCdT) has become the primary photosensitive material for the development of high-performance infrared detectors. It has been widely used in high-end equipment, undertaking the crucial task of target detection. With the development of military technology, threats are continuously evolving towards lower temperatures and faster speeds. To achieve high-sensitivity, high-time-efficiency detection and identification, infrared detectors are required to possess even better performance.

[0003] High-quality mercury cadmium telluride (HCdT) materials are typically prepared using liquid phase epitaxy, molecular beam epitaxy, and metal-organic vapor phase epitaxy (MOVE) on substrates such as cadmium zinc telluride (CdT), silicon, germanium, and gallium arsenide (GaAs). Mismatch between the substrate and the thin film, temperature and composition fluctuations during growth, and inconsistent in-plane cooling rates during post-growth cooling can all lead to residual stress within the film. This residual stress directly increases the dark current of infrared detectors, degrading their performance. It also causes significant warpage, affecting photolithography and indium pillar interconnect processes, resulting in dead pixels. Especially for large-area infrared detectors, ensuring minimal warpage of the thin film material is crucial for achieving a low dead pixel rate. In practical processes, the surface profile of the epitaxial substrate is usually strictly controlled, thereby indirectly controlling the surface profile of the epitaxial film, i.e., the warpage. However, due to numerous uncontrollable factors during epitaxial growth and subsequent cooling, including temperature field and cooling rate, residual stress inevitably forms in the epitaxial film, leading to a significant difference between the film's surface profile and the substrate's surface profile. This makes it impossible to truly control the film's surface profile effectively by controlling the substrate's surface profile. Therefore, there is an urgent need to conduct technical research to eliminate residual stress in thin films without introducing new stress, thereby effectively improving film quality. Summary of the Invention

[0004] To address the above problems, this invention provides a method for controlling the residual stress in mercury cadmium telluride epitaxial films. This method effectively removes residual stress in the epitaxial film while effectively avoiding the introduction of new stress during the stress-removal heat treatment process. Therefore, by adopting the method proposed in this invention, the surface profile of the epitaxial film can be precisely controlled through the control of the substrate surface profile, supporting the development of high-performance infrared detectors.

[0005] The present invention provides a method for controlling the residual stress of mercury cadmium telluride epitaxial thin films, characterized in that the method mainly includes the following steps: S1 (substrate surface profile testing), S2 (thin film preparation), S3 (surface treatment), S4 (vacuum encapsulation), S5 (simulated temperature measurement and temperature field adjustment of the heat treatment system), S6 (vacuum tube installation), S7 (step heating), S8 (constant temperature heat treatment), S9 (step cooling), S10 (vacuum tube opening), S11 (thin film edge scribing), S12 (thin film surface profile testing), and S13 (data analysis).

[0006] According to the above scheme, step S1 (substrate surface shape test) specifically involves testing and recording the surface shape and PV (peak to valley) value of the epitaxial substrate, with the PV value recorded as PV. 衬底 This step accurately records the surface profile of the substrate, providing a basis for judging the effect of subsequent residual stress relief in thin films; the substrate can be one of zinc cadmium telluride, germanium, silicon, gallium arsenide, etc.

[0007] According to the above scheme, step S2 (thin film preparation) specifically involves preparing mercury cadmium telluride thin films using methods such as liquid phase epitaxy, molecular beam epitaxy, and metal-organic vapor phase epitaxy. Residual stress is generated during the epitaxial growth process, leading to significant differences in the surface profile between the substrate and the thin film.

[0008] According to the above scheme, step S3 (surface treatment) specifically involves: surface etching and cleaning of the grown mercury cadmium telluride film. The surface treatment uses a bromine-containing organic solution for etching, followed by rinsing with deionized water for 10 to 30 minutes, preferably 15 minutes. The bromine content in the bromine-containing organic solution is 0.1% to 0.5% (volume fraction), preferably 0.2%. The organic solvent can be ethanol, methanol, etc., preferably methanol. The etching time is 30 to 60 seconds, preferably 35 seconds. This step ensures the film surface is clean and free of contamination, guaranteeing film quality.

[0009] According to the above scheme, step S4 (vacuum sealing) specifically involves: placing the mercury cadmium telluride film and liquid mercury into a sealed vacuum tube, with a vacuum level better than 5 × 10⁻⁶. -4 Torr, the distance between the mercury cadmium telluride film and the liquid mercury is 10 cm to 30 cm, preferably 20 cm. The vacuum tube is made of quartz and is sealed by burning after the vacuum is evacuated.

[0010] According to the above scheme, step S5 (simulated temperature measurement and temperature field adjustment of the heat treatment system) involves simulating temperature measurement and correcting the temperature field of the heat treatment system. This step uses an unsealed temperature measuring tube and a thermocouple to simulate the temperature of the heat treatment system; the structure and material of the temperature measuring tube are the same as the vacuum tube described in step S4. This step, through simulated temperature measurement and based on the temperature control unit of the heat treatment system, adjusts the temperature field to within 0.5℃ in the film placement area, effectively ensuring the uniformity of the temperature field within the film surface during the heat treatment process and suppressing the generation of thermal stress caused by uneven temperature field.

[0011] According to the above scheme, step S6 (vacuum tube installation) specifically involves: placing the vacuum tube containing the mercury cadmium telluride film into the heat treatment system, and assembling two thermocouples for measuring the film position and the liquid mercury position. These thermocouples are placed outside the vacuum tube, close to the outer wall of the vacuum tube, and aligned with the center of the mercury cadmium telluride film and the liquid mercury position, respectively, to achieve real-time monitoring of the temperature at the center of the mercury cadmium telluride film and the liquid mercury position.

[0012] According to the above scheme, step S7 (step heating) specifically involves: using a step heating method to raise the temperature of the film position from room temperature to 350℃~400℃, preferably 360℃, with ≥3 steps, and the holding time for each step being 30 minutes~90 minutes, preferably 60 minutes; step heating ensures the real-time temperature field uniformity during the heating process and avoids the introduction of additional stress; in addition, in this step, the temperature of the liquid mercury position is 10℃~20℃ lower than the temperature of the film position, preferably 15℃, to avoid excessive mercury loss or excessive mercury replenishment in the film.

[0013] According to the above scheme, step S8 (constant temperature heat treatment) involves performing constant temperature heat treatment at a temperature of 350℃~400℃, preferably 360℃, for a duration of 10 hours~30 hours, preferably 15 hours. This step effectively removes residual stress from the epitaxial growth process. Furthermore, in this step, the temperature at the liquid mercury position is 10℃~20℃ lower than the temperature at the thin film position, preferably 15℃, to avoid excessive mercury loss or excessive mercury replenishment in the thin film.

[0014] According to the above scheme, step S9 (step cooling) specifically involves: using step cooling to reduce the temperature of the film from the isothermal heat treatment temperature stage to room temperature, with ≥3 steps, and the isothermal time for each step being 30 to 90 minutes, preferably 60 minutes; step cooling ensures the real-time temperature field uniformity during the cooling process and further avoids the introduction of additional stress; in addition, in this step, the temperature of the liquid mercury position is 10°C to 20°C lower than the film position temperature, preferably 15°C, to avoid excessive mercury loss or excessive mercury replenishment in the film.

[0015] According to the above scheme, step S10 (vacuum tube opening) specifically involves opening the vacuum tube and removing the mercury cadmium telluride film. This step requires ensuring that the film is not subjected to additional damage or compression.

[0016] According to the above scheme, step S11 (film edge scrubbing) specifically involves scrubbing off the film edge, with a single scrubbing width h. n ≤0.5mm, and record the cumulative side width as h. 累计 =h1+ h2+…+h n , where n is the number of scribing operations (i.e., the number of cycles in this step); scribing is performed using a mechanical cutting method. In each cycle, the scribing width on each side remains consistent. Scibing effectively removes stress concentrations at the edges caused by faster heat dissipation at the film edges during the cooling process. The scribing width refers to the distance from the film edge to the infeed position, i.e., the width of the scribed film edge.

[0017] According to the above scheme, step S12 (thin film surface shape test) specifically involves: testing and recording the surface shape and PV value of the mercury cadmium telluride thin film, with the PV value denoted as PV. 薄膜 Meanwhile, the maximum acceptable PV value of the thin film is denoted as PV. 目标 This step allows for the testing and recording of the thin film surface profile, providing support for subsequent analysis.

[0018] According to the above scheme, step S13 (data analysis) specifically involves: comparing and analyzing the surface profile and PV value of the grown mercury cadmium telluride film and the cadmium zinc telluride substrate used, and simultaneously comparing the PV values. 薄膜 and PV 目标 Size.

[0019] Based on the analysis results, if the two have large differences in facial features (i.e., their facial features are significantly different or quite different) or PV 薄膜 >PV 目标 At the same time h 累计 If the diameter is ≤2mm, repeat steps S11 to S13; if the surface shape of the two is significantly different or the PV... 薄膜 >PV 目标 At the same time h 累计 If the value is greater than 2mm, then h will be... 累计 The value is reset to zero, and steps S3 to S13 are repeated; if the two face shapes are small (i.e., the face shapes are small or not obvious) and PV 薄膜 ≤PV 目标 Then the process ends.

[0020] The mechanism of this invention is as follows:

[0021] This invention utilizes high-temperature heat treatment under highly uniform temperature field conditions to effectively eliminate residual stress in epitaxial thin films. Simultaneously, through a stepped heating and cooling design, it effectively mitigates the problem of insufficient temperature field uniformity within the film surface caused by differences in heating and cooling rates during the heating and cooling processes, suppressing residual attraction introduced by temperature field inhomogeneity. Furthermore, this invention proposes to further remove stress concentrations at the edges caused by faster heat dissipation at the film edges during the cooling process after heat treatment by scrubbing the film edges. By combining these methods, this invention not only effectively eliminates residual stress after epitaxial growth but also effectively avoids the introduction of new stress during heat treatment. After implementing the methods proposed in this invention, the surface profile of the epitaxial thin film becomes predictable, allowing for precise control of the epitaxial thin film surface profile through substrate surface control. This effectively supports the development and production of high-performance infrared detectors, especially large-area array infrared detectors.

[0022] The beneficial effects of this invention are as follows:

[0023] (1) By simulating temperature measurement and temperature field correction of the heat treatment system, the temperature difference in the thin film placement area is controlled below 0.5℃, ensuring the uniformity of the high-temperature field within the thin film surface during the heat treatment process and suppressing the introduction of additional stress due to the non-uniform temperature field during the heat treatment process; by designing the step heating and step cooling processes, the real-time temperature field uniformity during the heating and cooling processes is ensured, further avoiding the introduction of additional stress; the residual stress in the epitaxial growth process is effectively eliminated through the isothermal heat treatment step; and the edge stress concentration area caused by the faster heat dissipation at the edge of the thin film during the cooling process is further removed through thin film edge scrubbing. Therefore, by adopting the method proposed in this invention, the residual stress in the epitaxial thin film can be effectively removed, while effectively avoiding the introduction of new stress during the stress removal heat treatment process, supporting the development and production of high-quality mercury cadmium telluride materials and high-performance infrared detectors;

[0024] (2) By adopting the method provided by the present invention, the residual stress in the thin film can be effectively controlled, making the surface shape of the epitaxial thin film predictable. This enables the thin film surface shape to be effectively controlled by controlling the substrate surface shape, and the warpage of the mercury cadmium telluride epitaxial thin film can be precisely controlled. This is beneficial to the implementation of back-end photolithography, indium pillar interconnect and other device processes, and supports the development and production of low blind element ratio large-area infrared detectors. Attached Figure Description

[0025] To further illustrate the specific technical content of the present invention, the following detailed description is provided in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 The specific implementation methods and steps are shown in the flowcharts provided in the embodiments.

[0027] Figure 2 The surface profile test results of the substrate used in the embodiments.

[0028] Figure 3 The surface profile test results of the epitaxially grown film in the examples.

[0029] Figure 4 The surface profile test results of the thin film after residual stress regulation in the embodiment are shown in the figure. Detailed Implementation

[0030] To make the objectives, contents, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The given embodiments and figures are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0031] This embodiment provides a method for controlling the residual stress of mercury cadmium telluride epitaxial thin films. The method mainly includes the following steps: S1 (substrate surface profile testing), S2 (thin film preparation), S3 (surface treatment), S4 (vacuum encapsulation), S5 (simulated temperature measurement and temperature field adjustment of the heat treatment system), S6 (vacuum tube installation), S7 (step heating), S8 (constant temperature heat treatment), S9 (step cooling), S10 (vacuum tube opening), S11 (thin film edge scrubbing), S12 (thin film surface profile testing), and S13 (data analysis). A detailed flowchart is shown below. Figure 1 As shown.

[0032] In a specific embodiment, step S1 (substrate surface shape test) specifically involves testing and recording the surface shape and PV (peak to valley) value of the epitaxial substrate, with the PV value denoted as PV. 衬底 The substrate used was a 40mm × 50mm cadmium zinc telluride wafer. This step accurately recorded the substrate's surface profile, providing a basis for judging the subsequent residual stress relief effect of the thin film. Specific test results are as follows: Figure 2 As shown, its surface has a shape that is convex at the top and bottom and concave in the middle. PV 衬底 =4.22μm.

[0033] In a specific embodiment, step S2 (thin film preparation) involves preparing a mercury cadmium telluride thin film via liquid-phase epitaxy. The surface profile test results of the thin film after this step are as follows: Figure 3 As shown, its surface has a diagonally convex shape and a concave center. PV 衬底 =5.20μm, same as Figure 2 The significant difference in substrate surface shape indicates the presence of substantial residual stress within the thin film.

[0034] In a specific embodiment, step S3 (surface treatment) involves surface etching and cleaning of the grown mercury cadmium telluride film. The surface treatment uses a bromine-containing organic solution for etching, followed by rinsing with deionized water for 15 minutes. The bromine content in the bromine-containing organic solution is 0.2% (volume fraction), the organic solvent is methanol, and the etching time is 35 seconds. This step ensures the film surface is clean and free of contamination, guaranteeing film quality.

[0035] In a specific embodiment, step S4 (vacuum sealing) involves: placing the mercury cadmium telluride film and liquid mercury into a sealed vacuum tube, with a vacuum level better than 5 × 10⁻⁶. -4 Torr, the distance between the mercury cadmium telluride film and the liquid mercury is 20 cm. The vacuum tube is made of quartz, and is sealed by burning after the vacuum is completed.

[0036] In a specific embodiment, step S5 (simulated temperature measurement and temperature field adjustment of the heat treatment system): simulated temperature measurement and temperature field correction are performed on the heat treatment system. This step uses an unsealed temperature measuring tube and a temperature measuring thermocouple to simulate the temperature of the heat treatment system; wherein, the structure and material of the temperature measuring tube are the same as those of the vacuum tube described in step S4; this step adjusts the temperature field based on the temperature control unit of the heat treatment system through simulated temperature measurement, adjusting the temperature difference in the film placement area to within 0.5℃, effectively ensuring the uniformity of the temperature field within the film surface during the heat treatment process, and suppressing the generation of thermal stress caused by uneven temperature field.

[0037] In a specific embodiment, step S6 (vacuum tube installation) involves placing the vacuum tube containing the mercury cadmium telluride film into the heat treatment system and assembling two thermocouples for measuring the film position and the liquid mercury position. These thermocouples are placed outside the vacuum tube, close to the outer wall of the vacuum tube, and aligned with the center of the mercury cadmium telluride film and the liquid mercury position, respectively, to achieve real-time monitoring of the temperature at the center of the mercury cadmium telluride film and the liquid mercury position.

[0038] In a specific embodiment, step S7 (step heating) is as follows: the temperature at the film location is raised from room temperature to 360°C using a step heating method, with 3 steps and a holding time of 60 minutes for each step; step heating ensures the real-time temperature field uniformity during the heating process and avoids the introduction of additional stress; in addition, in this step, the temperature at the liquid mercury location is 15°C lower than the temperature at the film location to avoid excessive mercury loss or excessive mercury replenishment in the film.

[0039] In a specific embodiment, step S8 (constant temperature heat treatment): constant temperature heat treatment is performed at a temperature of 360°C for 15 hours. This step effectively removes residual stress from the epitaxial growth process. In addition, in this step, the temperature of the liquid mercury position is 15°C lower than the temperature of the thin film position to avoid excessive mercury loss or excessive mercury replenishment in the thin film.

[0040] In a specific embodiment, step S9 (step cooling) is as follows: the temperature at the film location is cooled from the isothermal heat treatment temperature stage to room temperature using a step cooling method. There are 3 steps, and the isothermal time for each step is 60 minutes. Step cooling ensures the real-time temperature field uniformity during the cooling process and further avoids the introduction of additional stress. In addition, in this step, the temperature at the liquid mercury location is 15°C lower than the temperature at the film location to avoid excessive mercury loss or excessive mercury replenishment in the film.

[0041] In a specific embodiment, step S10 (vacuum tube opening) involves opening the vacuum tube and removing the mercury cadmium telluride film. This step requires ensuring that the film is not subjected to additional damage or compression.

[0042] In a specific embodiment, step S11 (film edge scrubbing) specifically involves scrubbing off the film edge, with a single scrubbing width h. n =0.5mm, and record the cumulative side width as h. 累计 =h1+ h2+…+h n , where n is the number of scribing operations (i.e., the number of cycles in this step); scribing is performed using a mechanical cutting method. In each cycle, the scribing width on each side remains consistent. Scibing effectively removes stress concentrations at the edges caused by faster heat dissipation at the film edges during the cooling process. The scribing width refers to the distance from the film edge to the infeed position, i.e., the width of the scribed film edge.

[0043] In a specific embodiment, step S12 (thin film surface shape test) specifically involves testing and recording the surface shape and PV value of the mercury cadmium telluride thin film, with the PV value denoted as PV. 薄膜 Meanwhile, the maximum acceptable PV value of the thin film is denoted as PV. 目标 =4.5μm. This step enables the testing and recording of the film surface profile, providing support for subsequent analysis. The surface profile obtained in a specific embodiment is shown below. Figure 4 As shown, its surface has a shape that is convex at the top and bottom and concave in the middle. PV 薄膜 =3.46μm.

[0044] According to the above scheme, step S13 (data analysis) specifically involves: comparing and analyzing the surface profile and PV value of the grown mercury cadmium telluride film and the cadmium zinc telluride substrate used, and simultaneously comparing the PV values. 薄膜 and PV 目标 Size.

[0045] Based on the analysis results, since the surface shapes of the two are relatively similar and PV 薄膜 (3.46μm)≤PV 目标 (4.5μm), process terminated.

[0046] The results show that after epitaxial growth, the surface profile of the thin film differs from that of the substrate. After heat treatment using the method provided by this invention, the surface profile of the thin film becomes similar to that of the substrate, and the PV value meets the control requirements.

Claims

1. A method for controlling the residual stress of mercury cadmium telluride epitaxial thin films, characterized in that, Includes the following steps: S1. Substrate Surface Shape Test: Test and record the surface shape and PV of the epitaxial substrate. 衬底 value; S2, Thin film preparation; S3, Surface treatment; S4, vacuum sealing; S5. The heat treatment system simulates temperature measurement and adjusts the temperature field to ensure the uniformity of the temperature field; S6. Vacuum tube installation: Place the vacuum tube containing the mercury cadmium telluride film into the heat treatment system and assemble the thermocouples for measuring the position of the film and the liquid mercury. S7. Step heating: The temperature at the film location is raised from room temperature to 350℃~400℃ using a step heating method. There are ≥3 steps, and the holding time for each step is 30 minutes~90 minutes. Step heating ensures the uniformity of the real-time temperature field during the heating process and avoids the introduction of additional stress. S8. Constant temperature heat treatment: Perform constant temperature heat treatment at a temperature of 350℃~400℃ for 10 hours~30 hours to remove residual stress from the epitaxial growth process. S9. Step cooling: Step cooling is used to cool the temperature of the film from the isothermal heat treatment temperature stage to room temperature. The number of steps is ≥3, and the isothermal time of each step is 30 minutes to 90 minutes. Step cooling ensures the real-time temperature field uniformity during the cooling process and avoids the introduction of additional stress. S10. Vacuum tube opening, remove mercury cadmium telluride film; S11. Film Edge Removal: Removing the edge of the film, with a single removal width h. n ≤0.5mm, and record the cumulative side width as h. 累计 =h1+ h2+…+h n where n is the number of times the edge is drawn; S12. Thin Film Surface Shape Test: Test and record the surface shape and PV of the mercury cadmium telluride thin film. 薄膜 The value is set as PV, and the maximum acceptable PV value of the thin film is denoted as PV. 目标 ; S13. Data Comparison: Compare the surface profile and PV value of the grown mercury cadmium telluride film and the cadmium zinc telluride substrate used; S14. Analysis and Judgment: If the two have large differences in appearance or PV 薄膜 >PV 目标 At the same time h 累计 If the difference in surface shape is large or the PV is ≤2mm, repeat steps S11 to S13; 薄膜 >PV 目标 At the same time h 累计 If the value is greater than 2mm, then h will be... 累计 The value is reset to zero, and steps S3 to S13 are repeated; if the difference in surface shape between the two is small and PV 薄膜 ≤PV 目标 Then the process ends.

2. The method for controlling the residual stress of mercury cadmium telluride epitaxial thin films according to claim 1, characterized in that, The substrate in step S1 is any one of zinc cadmium telluride, germanium, silicon, and gallium arsenide.

3. The method for controlling the residual stress of mercury cadmium telluride epitaxial thin films according to claim 1, characterized in that, The surface treatment in step S3 involves etching with a bromine-containing organic solution and rinsing with deionized water for 10 to 30 minutes. The bromine content in the bromine-containing organic solution is 0.1% to 0.5% by volume, and the organic solvent is either ethanol or methanol. The etching time is 30 to 60 seconds.

4. The method for controlling the residual stress of mercury cadmium telluride epitaxial thin films according to claim 1, characterized in that, The vacuum tube in step S4 is made of quartz, and after the vacuum is drawn, it is sealed by burning.

5. The method for controlling the residual stress of a mercury cadmium telluride epitaxial thin film according to claim 1, characterized in that, Step S5 uses an unsealed temperature measuring tube and a temperature measuring thermocouple to simulate the temperature of the heat treatment system; wherein the structure and material of the temperature measuring tube are the same as those of the vacuum tube described in step S4; this step, through simulated temperature measurement, adjusts the temperature field based on the temperature control unit of the heat treatment system, and adjusts the temperature difference in the film placement area to within 0.5℃, ensuring the uniformity of the temperature field within the film surface during the heat treatment process and suppressing the generation of thermal stress caused by uneven temperature field.

6. The method for controlling the residual stress of a mercury cadmium telluride epitaxial thin film according to claim 1, characterized in that, In steps S7, S8, and S9, the temperature at the liquid mercury location is 10°C to 20°C lower than the temperature at the thin film location.

7. The method for controlling the residual stress of mercury cadmium telluride epitaxial thin films according to claim 1, characterized in that, The edge scribing in step S11 is done by mechanical cutting. In a single cycle, the scribing width of each side remains consistent. The scribing effectively removes the stress concentration at the edges caused by faster heat dissipation at the edges of the film during the cooling process.

8. A method for controlling the residual stress of a mercury cadmium telluride epitaxial thin film according to any one of claims 1 to 7, characterized in that, In step S2, the thin film is prepared using any one of liquid phase epitaxy, molecular beam epitaxy, or metal-organic vapor phase epitaxy.

9. A method for controlling the residual stress of a mercury cadmium telluride epitaxial thin film according to any one of claims 1 to 7, characterized in that, The vacuum sealing in step S4 includes placing a mercury cadmium telluride film and liquid mercury into a sealed vacuum tube, with the distance between the mercury cadmium telluride film and liquid mercury being 10 cm to 30 cm.

10. A method for controlling the residual stress of a mercury cadmium telluride epitaxial thin film according to any one of claims 1 to 7, characterized in that, In step S6, two temperature-measuring thermocouples are placed outside the vacuum tube, close to the outer wall of the vacuum tube, and aligned with the center of the mercury cadmium telluride film and the liquid mercury, respectively.

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