In-orbit repair method for space radiation damage of space-borne photoelectric detector

Abstract

The application discloses a kind of on-orbit repair methods of space radiation damage of spaceborne photoelectric detector, comprising: disconnecting the power supply of TEC in photoelectric detector;Reverse voltage is applied to TEC;Chip temperature is maintained for a predetermined time;Disconnect the power supply of reverse application to TEC, end annealing repair;Normal on the power supply of TEC.The application utilizes the reverse heating of TEC of photoelectric detector, realizes the on-orbit real-time annealing repair of radiation damage, can dissipate interface charge to repair ionization damage, and can also repair lattice defects, the method only needs to set TEC reverse heating program, can extend the on-orbit working life and reliability of detector, and has broad application prospect.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor devices, and in particular relates to an on-orbit repair method for space radiation damage of a spaceborne photodetector. Background Technology

[0002] In applications such as space laser communication, laser detection, and remote sensing imaging, photodetectors play a crucial role as core components. However, high-energy particles in the space environment can cause radiation damage to photodetectors on satellites, leading to performance degradation or even failure. Currently, in practical engineering applications, radiation damage to photodetectors is mainly addressed through passive methods such as shielding, derating, and adjusting operating conditions. On-orbit radiation repair of damaged devices is not feasible. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide an on-orbit repair method for space radiation damage of spaceborne photoelectric detectors.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An on-orbit repair method for space radiation damage to a spaceborne photodetector includes the following steps: S100, Disconnect the power supply to the TEC in the photodetector; S200, Apply reverse voltage to TEC; S300, maintain chip temperature for the predetermined time; S400, disconnect the reverse power applied to the TEC to end the annealing repair; S500, normally connected to the TEC power supply.

[0005] Furthermore, the photodetector includes a housing, a photodetector chip disposed inside the housing, and a cooler connected to the photodetector chip, wherein the cooler is a TEC.

[0006] Furthermore, the spectral response of the photodetector is in the wavelength range of 300 nm to 3000 nm.

[0007] Furthermore, the smallest photosensitive element of the photodetector is a semiconductor photodiode.

[0008] Furthermore, inside the photodetector, the end face of the cooling end of the TEC is tightly attached to the photodetector chip, and the end face of the heat dissipation end is tightly integrated with the heat-conducting structure, forming a good heat conduction channel.

[0009] Furthermore, in step S100, after disconnecting the TEC power supply in the photodetector, the temperature of the photodetector chip is monitored until the temperature of the photodetector reaches a stable value, and then step S200 is executed.

[0010] Furthermore, in step S200, the temperature of the photodetector chip is controlled to reach a predetermined value or within a predetermined temperature range by controlling the voltage value between the two electrodes of the TEC or the current value of the TEC.

[0011] Furthermore, in step S200, the temperature of the photodetector chip is controlled to be maintained between 40°C and 100°C, based on the actual high-temperature resistance of the photodetector.

[0012] Furthermore, in step S300, the chip temperature is maintained for less than 2000 hours.

[0013] Furthermore, after performing step S500, the repair effect of the photoelectric detection chip after annealing is detected. If the requirements are not met, steps S100 to S500 are repeated.

[0014] This invention proposes an on-orbit autonomous radiation damage repair method for spaceborne photodetectors. The core of this method utilizes the existing thermoelectric cooler (TEC) within the detector's package. By applying a reverse voltage, it switches the TEC from cooling mode to heating mode, thereby performing controlled high-temperature annealing on the detector chip. This method effectively dissipates the charge accumulated at the device interface due to ionizing radiation and partially repairs lattice defects caused by displacement damage, significantly restoring key performance indicators such as dark current, noise, and responsivity. The key advantages of this solution are its extremely high integration and extremely low implementation cost. For high-performance photodetectors that already widely employ TEC for shallow cooling packaging, no changes to the mechanical structure or optical design are required. Only an upgrade to the existing temperature control circuitry and software, along with setting the TEC reverse heating program, is needed to add autonomous repair functionality to the existing hardware. This not only avoids the increased weight, power consumption, and layout complexity associated with installing a separate heater but also achieves a significant leap in detector lifespan with near-zero hardware marginal cost, providing an efficient and economical on-orbit maintenance solution for long-life, high-reliability space missions. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of an embodiment of the on-orbit repair method for space radiation damage of a spaceborne photodetector according to the present invention.

[0016] Figure 2 This is a schematic diagram of the photodetector.

[0017] The diagrams in the instruction manual are labeled as follows: 1. Outer shell; 2. Photoelectric detection chip; 3. Cooler; 4. Optical window. Detailed Implementation

[0018] The following specific examples illustrate the implementation of the present invention. The illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0019] High-energy particle radiation in the space environment can damage photodetectors on satellites, causing performance degradation or even complete failure. Once a satellite is launched into orbit, if the photodetectors suffer performance degradation due to radiation damage, replacement is not an option. Currently, the main approach is to extend the lifespan of components through passive methods such as throttling usage and adjusting operating conditions. There are currently no effective means to repair radiation-induced damage.

[0020] Studies have shown that high-temperature annealing of irradiated semiconductor devices can dissipate interface charges generated by ionizing radiation and, to some extent, repair lattice defects caused by displacement damage. Therefore, it is possible to investigate the use of a thermoelectric cooler (TEC) to reverse-heat photodetector chips for on-orbit, real-time repair of radiation-damaged photodetectors. This would allow for the repair of radiation damage at extremely low cost for photodetectors already packaged with TEC shallow cooling, without altering the original device structure.

[0021] In many short-wave infrared units or focal plane detectors, a TEC cooler is often integrated to cool and control the chip, thereby reducing dark current and improving the signal-to-noise ratio. It's worth noting that reversing the voltage across the TEC cooler can heat the chip. By controlling the chip temperature within a suitable range through closed-loop control, not only is the chip's performance and reliability not affected, but it can also achieve an annealing repair effect.

[0022] Please see Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the on-orbit repair method for space radiation damage to a spaceborne photodetector according to the present invention. The on-orbit repair method for space radiation damage to a spaceborne photodetector in this embodiment includes the following steps: S100, Disconnect the power supply to the TEC in the photodetector. The photodetector can be a single-element detector, a multi-quadrant detector, or a focal plane array detector.

[0023] Please see Figure 2This is a schematic diagram of a photodetector. The photodetector includes a housing 1, a photodetector chip 2 disposed inside the housing 1, and a cooler 3 connected to the photodetector chip 2. The photodetector chip 2 is generally mounted on the substrate surface of the cooler 3. An optical window 4 is provided on the housing 1 directly above the photodetector chip 2. The leads of the cooler 3 are led out and connected to a control power supply (not shown in the figure). The substrate material of the photodetector chip 2 can be Si, GaAs, or InP, etc. The spectral response range of the photodetector is generally in the wavelength range of 300nm to 3000nm. The smallest photosensitive element (unit) of the photodetector is a semiconductor photodiode. The cooler 3 is generally a TEC. Therefore, for photodetectors using TEC, this embodiment does not need to change the structure of the photodetector and can be directly implemented on existing photodetectors. Inside the photodetector, the end face of the cooling end of the TEC is tightly attached to the photodetector chip 2, and the end face of the heat dissipation end is tightly combined with the heat-conducting structure, forming a good heat conduction channel.

[0024] In aerospace and other fields, photodetectors commonly employ hermetically sealed metal or ceramic enclosures to ensure performance and lifespan in harsh environments. Specifically, the housing 1 is typically made of metal or ceramic materials. Metal housings are widely used in high-performance, high-reliability photodetectors and components. Metal housings effectively shield electromagnetic interference, protect internal sensitive circuits, and facilitate hermetically sealed metal-glass or metal-ceramic enclosures, preventing moisture and contaminant intrusion and ensuring long-term reliability. Furthermore, metal housings provide robust protection, facilitate installation, and promote heat dissipation. Since metal is a good thermal conductor, it helps to conduct heat generated by the detector away or efficiently cooperate with the TEC cooler 3. Kovar alloy is a commonly used material for metal housings.

[0025] Ceramic housings are commonly used in multi-pin, high-density packaged photodetectors such as focal plane arrays. The core advantage of ceramic housings lies in their ideal thermal expansion matching performance. They also possess excellent high-frequency characteristics, making them suitable for high-speed detectors. Furthermore, ceramic housings can achieve hermetically sealed packaging. Additionally, ceramics are perfect electrical insulators, allowing them to be used directly as a packaging substrate for fabricating complex thin-film circuits, leading out hundreds or even thousands of electrodes from the detector array while ensuring electrical isolation between channels, without the need for additional insulating layers. Moreover, ceramics have high mechanical strength and shape stability under drastic temperature changes, providing a robust and flat mounting platform for the TEC and photodetector chip 2. If a ceramic housing is used, a metal heat sink is generally still required at the bottom of the housing 1 for heat dissipation. This heat sink is located at the bottom of the housing 1 and is tightly bonded to the TEC heat dissipation surface using a welding process, typically employing high thermal conductivity tungsten-copper or molybdenum-copper alloys.

[0026] The cooler 3 of the photodetector is generally equipped with a heat-conducting structure to dissipate the heat generated by the photodetector chip 2 and the heat generated by the TEC hot end in a timely manner. Since both metal and ceramic shells have good thermal conductivity, when using a metal or ceramic shell for packaging, the shell 1 can be used directly as the heat-conducting structure, and there is no need to set up an additional heat-conducting structure.

[0027] For example, ceramic materials such as alumina and aluminum nitride are excellent thermal conductors (especially aluminum nitride, whose thermal conductivity is comparable to that of metallic aluminum). This allows the heat generated by the photodetector chip 2, as well as the enormous heat generated by the TEC hot end, to be quickly and evenly conducted away through the ceramic substrate, making it a crucial part of the heat dissipation system. When the TEC is operating, the entire component cycles through a wide temperature range, and the ideal thermal expansion matching of the ceramic shell allows it to expand and contract synchronously with the chip, greatly reducing thermal stress caused by thermal cycling, preventing the photodetector chip 2 from cracking or solder joint failure, and ensuring long-term reliability.

[0028] After disconnecting the TEC power supply in the photodetector, the temperature of the photodetector chip 2 is typically monitored until it reaches a stable value before executing step S200. Once the TEC power supply is actively cut off, the TEC immediately stops operating and ceases to provide cooling power. Since the temperature of the photodetector chip 2 itself does not change instantaneously, a process is required for it to slowly recover from its low-temperature operating state to a stable state balanced with the ambient temperature. By reading data from the temperature sensor integrated on the photodetector chip 2 in real time, its temperature change curve can be tracked. Waiting for the photodetector temperature to reach a stable value protects the photodetector chip 2 from thermal stress damage. The photodetector chip 2, its connecting solder joints, and the underlying base are made of different materials. If the temperature gradient is too large or changes too rapidly, the different degrees of thermal expansion and contraction of these materials can generate significant internal stress, potentially leading to chip cracking, solder joint failure, or damage to the packaging structure.

[0029] S200. Apply a reverse voltage to the TEC. The principle behind this step is the reversibility of the Peltier effect in the TEC. When a direct current flows through the TEC in a specific direction (defined as forward), according to the Peltier effect, the first end (cooling end) of the TEC absorbs heat, and the second end (heat dissipation end) releases heat, thus achieving cooling. At this time, the photodetector chip 2 is attached to the cooling end to cool it down, and the heat dissipation end dissipates heat through the heat sink. When the polarity of the applied direct current is reversed (i.e., reverse voltage), the direction of the current flowing through the TEC is also reversed. According to the reversibility of the Peltier effect, the direction of heat transfer is also completely reversed. The cooling end, which originally absorbed heat, becomes the heat dissipation end, and the heat dissipation end becomes the heat absorption end. Therefore, the essence of applying a reverse voltage is to instantly switch the TEC from a refrigerator to a heater, actively heating the object that was originally being cooled (i.e., the photodetector chip 2), thereby annealing and repairing the photodetector chip 2.

[0030] In this step, the temperature of the photodetector chip 2 can be controlled to reach a predetermined value or within a predetermined temperature range by controlling the voltage value between the two electrodes of the TEC or the current value of the TEC, combined with the temperature information fed back by the temperature sensor. Since the photodetector's high-temperature resistance has an upper limit, the annealing temperature should be set considering the actual high-temperature resistance of the photodetector to avoid damage. Generally, the temperature of the photodetector chip 2 is maintained between 40℃ and 100℃, preferably between 60℃ and 80℃. This temperature has been optimized through ground experiments, achieving the best balance between repair effectiveness and thermal stress risk.

[0031] S300. Maintain the chip temperature for a predetermined time. The time for maintaining the chip temperature (i.e., controlling the temperature of the photodetector chip 2 between 40°C and 100°C) is preferably less than 2000 hours, and generally not less than 1 hour. For example, the time for maintaining the chip temperature can be 24 hours to 240 hours. The predetermined time length is crucial; it must be long enough to allow sufficient time for defects in the photodetector chip 2 to migrate and self-repair. During this period, the temperature of the photodetector chip 2 is generally continuously monitored to ensure its stability. Simultaneously, system power consumption and status can also be monitored to prevent overheating.

[0032] The principle of the annealing repair mechanism is as follows: the photodetector chip 2 is heated to a certain annealing temperature (higher than the normal operating temperature, but much lower than the material's melting point) and maintained for a sufficient time. During this process, the heat provides additional kinetic energy to the lattice atoms. Some point defects generated by radiation (such as vacancies and interstitial atoms) can migrate after gaining sufficient energy. When vacancies and interstitial atoms meet, they may recombine and return to their original positions, restoring the lattice to a regular arrangement. Although annealing may not be able to repair all damage (especially complex cluster defects), it can effectively reduce the point defect density, thereby significantly reducing dark current and noise, and restoring the performance of the photodetector chip 2 to a certain extent.

[0033] S400: Disconnect the reverse power supply to the TEC to end the annealing repair. Removing the reverse voltage applied to the TEC means that the active heating process stops immediately, and the photodetector chip 2 no longer has an external heat source (the TEC has stopped supplying heat to the chip). Since heating has stopped and the temperature of the photodetector chip 2 is higher than the ambient temperature, its temperature will begin to drop naturally.

[0034] S500, normally connected to the TEC power supply. After annealing, the system generally does not immediately start cooling, but continues to monitor the temperature of the photodetector chip 2 in real time until the temperature of the photodetector chip 2 naturally drops to a preset safe starting cooling temperature (e.g., near ambient temperature). The above-mentioned natural cooling process aims to release the internal thermal stress accumulated in the photodetector chip 2 at high temperatures and to make the temperature distribution of the photodetector chip 2 more uniform, providing a stable temperature environment for the subsequent cooling process.

[0035] Once the temperature conditions of the photodetector chip 2 are met, the controller will normally connect the power supply to the TEC, applying a controlled, gradually increasing positive voltage. The temperature control system typically has a set safe maximum cooling rate. Based on real-time temperature feedback, the controller dynamically adjusts the positive voltage / current to ensure that the temperature of the photodetector chip 2 decreases along a preset, gradual curve, rather than experiencing a sudden, sudden drop. Under precise temperature control, the temperature of the photodetector chip 2 will be steadily reduced to the preset low-temperature operating point. Once the target temperature is reached, the TEC enters a constant-temperature maintenance mode, precisely offsetting heat leakage by dynamically adjusting a small current to maintain long-term temperature stability. At this point, the photodetector has fully recovered to normal operating status, completing a safe transition from repair mode to operating mode.

[0036] Of course, steps S100 to S500 described above represent only one repair cycle. Multiple repair cycles are possible within the operational lifespan of the photodetector product. During the repair process, the photodetector can be in a powered-on or unpowered state. After executing step S500, the repair effect of the photodetector chip after annealing is generally checked. If the requirements are not met, steps S100 to S500 are repeated until the predetermined conditions are met.

[0037] The assessment of the repair effect after annealing of photodetector chip 2 is a standardized, on-orbit diagnostic and calibration procedure. Once photodetector chip 2 has completed annealing and repair and stabilized at its standard operating temperature, the photodetector enters diagnostic mode. At this time, the photodetector automatically or according to ground commands executes a series of preset measurement sequences to obtain measurements of relevant parameters (e.g., dark current, noise, responsivity, and quantum efficiency) to assess whether the photodetector's performance parameters have been restored. All data obtained in this process can be compared and analyzed with data before repair, initial on-orbit data, and ground test data to determine the repair effect. If the photodetector's performance has recovered well, it can be immediately put into normal scientific observation missions. If the repair effect is mediocre, adjustments to the subsequent annealing strategy (e.g., temperature, duration) may be necessary.

[0038] This embodiment has the following beneficial effects: 1. Reverse heating is achieved by using the existing semiconductor thermoelectric cooler 3 (TEC) of the photodetector, without the need to add a special heating component or change the packaging structure for the annealing function, thus realizing a high degree of integration of device functions and perfect reuse of hardware resources.

[0039] 2. It has achieved real-time autonomous radiation damage repair capability in orbit. The detector can perform annealing autonomously, periodically, or on demand during satellite operation, promptly restoring performance, significantly reducing the need for ground intervention, and significantly improving the satellite's long-term autonomous survivability and performance maintenance capability in orbit.

[0040] 3. High-temperature annealing can effectively dissipate interface charges generated by ionizing radiation and repair ionizing damage; it can also repair lattice defects caused by displacement damage to a certain extent, thus enabling the repair of the two major types of damage caused by space radiation.

[0041] 4. The TEC reverse heating principle used in this embodiment has been verified in orbit, the technical path is reliable, and the engineering implementation risk is low.

[0042] 5. For photodetectors already packaged with TEC for shallow cooling, this solution requires no additional major hardware costs. Repair functionality can be achieved simply by upgrading the software or circuitry and setting the TEC reverse heating program, offering extremely high cost-effectiveness and versatility.

[0043] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for on-orbit repair of space radiation damage to a spaceborne photodetector, characterized in that, Includes the following steps: S100, Disconnect the power supply to the TEC in the photodetector; S200, Apply reverse voltage to TEC; S300, maintain chip temperature for the predetermined time; S400, disconnect the reverse power applied to the TEC to end the annealing repair; S500, normally connected to the TEC power supply.

2. The on-orbit repair method for space radiation damage of a spaceborne photoelectric detector as described in claim 1, characterized in that: The photodetector includes a housing, a photodetector chip disposed inside the housing, and a cooler connected to the photodetector chip, wherein the cooler is a TEC.

3. The on-orbit repair method for space radiation damage of a spaceborne photoelectric detector as described in claim 2, characterized in that: The spectral response of the photodetector is in the wavelength range of 300 nm to 3000 nm.

4. The on-orbit repair method for space radiation damage of a spaceborne photoelectric detector as described in claim 1, characterized in that: The smallest photosensitive element of the photodetector is a semiconductor photodiode.

5. The on-orbit repair method for space radiation damage of a spaceborne photoelectric detector as described in claim 1, characterized in that: Inside the photodetector, the end face of the cooling end of the TEC is tightly attached to the photodetector chip, and the end face of the heat dissipation end is tightly integrated with the heat-conducting structure, forming a good heat conduction channel.

6. The method for on-orbit repair of space radiation damage to a spaceborne photodetector as described in any one of claims 1 to 5, characterized in that: In step S100, after disconnecting the TEC power supply in the photodetector, the temperature of the photodetector chip is monitored until the temperature of the photodetector reaches a stable value, and then step S200 is executed.

7. The method for on-orbit repair of space radiation damage to a spaceborne photoelectric detector as described in any one of claims 1 to 5, characterized in that: In step S200, the temperature of the photodetector chip is controlled to reach a predetermined value or within a predetermined temperature range by controlling the voltage value between the two electrodes of the TEC or the current value of the TEC.

8. The method for on-orbit repair of space radiation damage to a spaceborne photoelectric detector as described in any one of claims 1 to 5, characterized in that: In step S200, the temperature of the photodetector chip is controlled to be maintained between 40°C and 100°C, based on the actual high-temperature resistance of the photodetector.

9. The method for on-orbit repair of space radiation damage to a spaceborne photodetector as described in any one of claims 1 to 5, characterized in that: In step S300, the chip temperature is maintained for less than 2000 hours.

10. The method for on-orbit repair of space radiation damage to a spaceborne photoelectric detector as described in any one of claims 1 to 5, characterized in that: After performing step S500, the repair effect of the photoelectric detection chip after annealing is detected. If the requirements are not met, steps S100 to S500 are repeated.

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