A Germanium Single Crystal Dislocation Level Control Device

Abstract

This invention provides a germanium single crystal dislocation level control device, belonging to the field of germanium single crystal dislocation control technology. It includes a furnace body, a lifting rod, a support tray, and a reaction chamber. The furnace body has a receiving cavity and heaters arranged in a ring on the inner wall of the receiving cavity. The lifting rod is located inside the receiving cavity, and its lower end is fixedly connected to the bottom of the furnace body. The support tray is arranged horizontally, and its lower end is fixedly installed on the upper end of the lifting rod. The reaction chamber is mounted on the support tray. Multiple annular support members are arranged vertically and horizontally within the reaction chamber. Multiple germanium single crystals are placed on the multiple annular support members, and an installation gap is provided between the outer surface of the germanium single crystal and the inner wall of the reaction chamber. The germanium single crystal dislocation level control device provided by this invention can simultaneously form germanium single crystals with multiple different dislocation densities, improving the preparation efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of germanium single crystal dislocation control technology, and more specifically, it relates to a germanium single crystal dislocation level control device. Background Technology

[0002] Germanium single crystals, with their diamond structure, hold an irreplaceable position in infrared optics, detection, and solar cell applications. Dislocations are a typical defect in semiconductor materials, directly affecting their electrical and processing properties, thus influencing their final use. Excessive dislocation levels reduce crystal processing performance, making it prone to breakage, and also degrade its electrical properties. Dislocation-free germanium single crystals contain numerous point defects and vacancies, affecting their electronic properties, molecular doping effects, and electron transport characteristics. The presence of dislocations facilitates the absorption of vacancies. In detector applications, the presence of dislocations severely impacts carrier collection efficiency. Therefore, detector-grade high-purity germanium materials have very strict requirements for dislocation density; both excessively high and low dislocation densities degrade the detector's energy resolution. Dislocations can form intermediate energy levels in the band gap, leading to the capture of photogenerated carriers, resulting in decreased charge collection efficiency, increased leakage current, and reduced energy resolution. A dislocation density exceeding 5 × 10⁻⁶ is considered optimal. 3 cm -2 At this point, the detector's energy resolution deteriorates significantly. Furthermore, dislocation-free high-purity germanium crystals grown in a hydrogen atmosphere cannot be used in detector fabrication because hydrogen vacancies exist within the crystal, acting as strong charge trapping centers. Dislocations can isolate hydrogen vacancies and eliminate charge trapping; when the dislocation density of the crystal exceeds 100 cm⁻¹... -2 At this concentration, the low concentration has almost no impact on the detector's performance. Therefore, the dislocation density of detector-grade high-purity germanium crystals should be around 1 × 10⁻⁶. 2 ~5×10 3 cm -2 Therefore, obtaining high-purity germanium single crystals with dislocations present and being able to control and adjust the dislocation level is crucial for detector-grade high-purity germanium single crystals.

[0003] The conventional method for controlling the dislocation level of germanium single crystals involves designing a suitable temperature gradient for growth within the Czochralski furnace's thermal field, including heaters, insulation tanks, flow guides, and the upper insulation structure. Dislocations are then eliminated using a seed crystal necking technique. Following shoulder formation, shoulder rotation, equal diameter setting, and tailing processes, a suitable germanium single crystal is obtained. However, while dislocation-free germanium single crystals are readily obtained using this method, germanium single crystals with low dislocation densities are difficult to achieve. After eliminating native dislocations in the seed crystal through seed crystal necking, setting a suitable thermal field so that the stress level in the crystal during growth is less than the edge strength required to generate dislocations results in dislocation-free germanium single crystals. However, if the stress level in the crystal exceeds the edge strength required to generate dislocations, dislocations will be generated and multiply rapidly through climb or slip, leading to defective crystals. This method results in low germanium single crystal production efficiency and makes it impossible to produce germanium single crystals with varying dislocation densities. Utility Model Content

[0004] The purpose of this invention is to provide a dislocation level control device for germanium single crystals, so as to solve the technical problems of low efficiency and inability to produce germanium single crystals with different dislocation densities in the traditional germanium single crystal preparation method.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: to provide a germanium single crystal dislocation level control device, comprising:

[0006] The furnace body has an internal cavity and heaters arranged in a ring on the inner wall of the cavity.

[0007] The lifting rod is located inside the receiving cavity, and its lower end is fixedly connected to the bottom of the furnace body;

[0008] The support tray is arranged horizontally, and its lower end is fixedly installed on the upper end of the lifting rod;

[0009] A reaction chamber is mounted on the support tray; the reaction chamber is provided with a plurality of annular support members arranged at intervals; a plurality of germanium single crystals are respectively placed on the plurality of annular support members, and an installation gap is provided between the outer surface of the germanium single crystal and the inner wall of the reaction chamber.

[0010] In one possible implementation, the annular support includes a plurality of support blocks located at the same horizontal height, and the support blocks are evenly spaced along the circumference of the reaction chamber; one end of each support block is connected to the side wall of the reaction chamber.

[0011] In one possible implementation, the upper end of the support block is provided with a groove on the side near the center of the reaction chamber, and the plurality of grooves form a limiting groove for accommodating germanium single crystals, and the limiting groove is used to limit the germanium single crystals to be located at the center of the reaction chamber.

[0012] In one possible implementation, the inner wall of the reaction chamber is provided with a connection hole, and the support block is provided with a mounting shaft that mates with the connection hole.

[0013] In one possible implementation, the sum of the inner diameter and width of the annular support is greater than the outer diameter of the germanium single crystal.

[0014] In one possible implementation, the reaction chamber is located at the center of the heater.

[0015] In one possible implementation, the reaction chamber is a cylindrical structure with a wall thickness ≥ 5 mm.

[0016] In one possible implementation, the upper end of the support tray is provided with a central groove for mounting the reaction chamber.

[0017] In one possible implementation, the reaction chamber includes sleeves arranged sequentially from top to bottom, with each sleeve corresponding to one of the annular supports, and each sleeve containing one of the annular supports; a limiting connector for connecting two adjacent sleeves is fixed on the outer wall of the sleeve, the upper end of the limiting connector has a rotating hole, and the lower end has a connecting shaft for engaging with the rotating hole on the adjacent limiting connector.

[0018] The beneficial effects of the germanium single crystal dislocation level control device provided by this utility model are as follows: Compared with the prior art, the germanium single crystal dislocation level control device of this utility model first assembles the device, arranges a heater in the furnace cavity, and then installs a lifting rod and a support tray in sequence. Next, a reaction chamber is prepared, and multiple annular supports are installed in the reaction chamber. Multiple prepared dislocation-free germanium single crystals are placed on different annular supports, ensuring a certain installation distance between the germanium single crystals and the inner wall of the reaction chamber. Then, the reaction chamber is placed on the support tray inside the furnace. The lifting rod is activated to drive the reaction chamber to rise and fall to the center position of the heater. The heater is then activated to cause the furnace to undergo heating, holding, and cooling states according to a set temperature change pattern, generating the required density of dislocations within the germanium single crystal. The difficulty of obtaining germanium single crystal products with different dislocation densities by using different temperature change curves for the heat treatment of dislocation-free germanium single crystals is greatly reduced. In this way, multiple germanium single crystals with different dislocation densities can be formed simultaneously, improving the preparation efficiency. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the germanium single crystal dislocation level control device provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram showing the connection between the reaction chamber and the germanium single crystal provided in an embodiment of the present invention;

[0022] Figure 3 This is a top view of the reaction chamber provided in an embodiment of the present invention.

[0023] The following are the labeling elements in the figure:

[0024] 10. Furnace body; 11. Receiving cavity; 12. Heater; 20. Lifting rod; 21. Support tray; 30. Reaction chamber; 31. Installation spacing; 32. Sleeve; 40. Annular support; 41. Support block; 42. Groove; 50. Limiting connector; 51. Rotating hole; 52. Connecting shaft; 53. Square hole; 54. Square shaft; 60. Germanium single crystal. Detailed Implementation

[0025] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0026] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0027] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] Please see Figures 1 to 3 The present invention provides a germanium single crystal dislocation level control device. A germanium single crystal dislocation level control device includes a furnace body 10, a lifting rod 20, a support tray 21, and a reaction chamber 30. The furnace body 10 has a receiving cavity 11 and a heater 12 arranged in a ring on the inner wall of the receiving cavity 11. The lifting rod 20 is located inside the receiving cavity 11, and its lower end is fixedly connected to the bottom of the furnace body 10. The support tray 21 is arranged horizontally, and its lower end is fixedly installed on the upper end of the lifting rod 20. The reaction chamber 30 is installed on the support tray 21. The reaction chamber 30 has multiple annular support members 40 arranged vertically at intervals. Multiple germanium single crystals 60 are respectively placed on the multiple annular support members 40, and an installation gap 31 is provided between the outer surface of the germanium single crystal 60 and the inner wall of the reaction chamber 30.

[0030] The germanium single crystal dislocation level control device provided by this utility model, compared with the prior art, firstly assembles the device by arranging a heater 12 in the receiving cavity 11 of the furnace body 10, and then sequentially installing a lifting rod 20 and a support tray 21 inside the furnace body 10; next, a reaction chamber 30 is prepared, and multiple annular supports 40 are installed in the reaction chamber 30. Multiple prepared dislocation-free germanium single crystals 60 are placed on different annular supports 40, with a certain installation distance 31 between the germanium single crystals 60 and the inner wall of the reaction chamber 30; then, the reaction chamber 30 is placed on the support tray 21 inside the furnace body 10. The lifting rod 20 is activated to drive the reaction chamber 30 to rise and fall to the center position of the heater 12. The heater 12 is activated to cause the furnace body 10 to undergo heating, holding, and cooling states according to the set temperature change pattern, so that the germanium single crystals 60 generate the required density of dislocations. By employing different heat treatment methods and temperature profiles for dislocation-free germanium single crystal 60, the difficulty of obtaining germanium single crystal 60 products with varying dislocation densities is significantly reduced. This approach allows for the simultaneous formation of multiple germanium single crystal 60 crystals with different dislocation densities, thereby improving preparation efficiency.

[0031] Specifically, the temperature change inside the furnace body 10 caused by the heater 12 is set as follows:

[0032] 1) The temperature inside the furnace body 10 is raised from room temperature to 400-450℃ at a rate of 1-8℃ / min;

[0033] 2) Increase the temperature inside the furnace body 10 to 650-700℃ at a rate of 0.5-3℃ / min;

[0034] 3) Maintain the temperature inside the furnace body 10 at 650-700℃ and keep it at this temperature for 0.5-3 hours;

[0035] 4) Reduce the temperature inside the furnace body 10 to 350-450℃ at a rate of 0.5-1.5℃ / h;

[0036] 5) Reduce the temperature inside the furnace body 10 to 150-250℃ at a rate of 0.5-3℃ / h;

[0037] 6) Reduce the temperature inside the furnace body 10 to room temperature at a rate of 1.5-4℃ / h;

[0038] Finally, multiple germanium single crystals 60 were removed, and test pieces were cut from the beginning and end of each germanium single crystal 60, with a thickness of 5 mm.

[0039] Taking two germanium single crystals 60 placed in the reaction chamber 30 as an example, before placing them into the reaction chamber 30, the two prepared germanium single crystals 60 are cleaned and labeled A and B respectively; germanium single crystal 60 A is placed on the upper layer and germanium single crystal 60 B is placed on the lower layer, and the reaction chamber 30 is locked. Dislocation testing is performed on the test piece using the etching method. The test result shows that the dislocation level of product A is 800 cm. -1 ~1200cm -1 The dislocation level of product B is 1100cm. -1 ~1600cm -1 .

[0040] The reaction chamber 30 is made of molybdenum or other materials with good thermal conductivity, high temperature resistance and chemical stability. The function of the reaction chamber 30 is twofold: first, to prevent the dislocation-free germanium single crystal 60 from being directly exposed to the heater 12, which would cause an excessive temperature difference between the surface temperature and the internal temperature of the single crystal, resulting in uneven stress distribution inside the single crystal and causing a large number of dislocations to multiply; second, to place the single crystal in different temperature zones, which can adjust the dislocation range of each layer of germanium single crystal 60.

[0041] The furnace body 10 is a pit-type annealing furnace, the lifting rod 20 is a lifting crucible rod, and the support tray 21 is a cured carbon felt tray.

[0042] Germanium single crystal 60, processed using a germanium single crystal dislocation level control device, achieved a dislocation density precisely falling to 1×10⁻⁶ after heat treatment. 2 ~5×10 3 cm -2 Within the range.

[0043] Please see Figures 1 to 3As a specific embodiment of the germanium single crystal dislocation level control device provided by this utility model, the annular support 40 includes multiple support blocks 41 located at the same horizontal height, and the support blocks 41 are evenly spaced along the circumference of the reaction chamber 30; one end of each support block 41 is connected to the side wall of the reaction chamber 30; the annular support 40 is composed of multiple support blocks 41 evenly spaced along the circumference of the reaction chamber 30, and one end of each support block 41 is connected to the side wall of the reaction chamber. This method ensures that the germanium single crystal 60 is subjected to uniform force during placement, avoiding additional stress during crystal growth caused by uneven support, which could affect dislocation control; simultaneously, the evenly distributed support blocks 41 facilitate the rational planning of the germanium single crystal 60 placement position within the reaction chamber 30, fully utilizing space to achieve simultaneous growth of multiple crystals, further improving production efficiency, and optimizing the performance of the germanium single crystal dislocation level control device.

[0044] Please see Figure 3 As a specific embodiment of the germanium single crystal dislocation level control device provided by this utility model, the upper end of the support block 41 is provided with grooves 42 on the side near the center of the reaction chamber 30. Multiple grooves 42 form a limiting groove for accommodating the germanium single crystal 60, and the limiting groove is used to limit the germanium single crystal 60 to be located at the center of the reaction chamber 30. The grooves 42 on the upper end of the support block 41 near the center of the reaction chamber 30, forming a limiting groove, can limit the germanium single crystal 60 to the center of the reaction chamber 30. The limiting groove precisely positions the crystal, ensuring it is in the central region of the thermal field, making the temperature gradient uniform in all directions of the crystal, and avoiding abnormal dislocation proliferation caused by local stress concentration due to positional displacement. At the same time, the limiting structure can prevent displacement collisions during crystal growth, reduce mechanical stress interference, further ensure the accuracy of dislocation density control, and is beneficial for maintaining consistent conditions during parallel growth of multiple crystals, improving product yield and performance stability.

[0045] Multiple annular support members 40 can be arranged sequentially from top to bottom, and the radial dimensions of the limiting grooves formed on the multiple annular support members 40 gradually change; in this way, it can be used to process germanium single crystals 60 of different sizes.

[0046] In one specific embodiment of the germanium single crystal dislocation level control device provided by this utility model, the inner wall of the reaction chamber 30 is provided with a connecting hole, and the support block 41 is provided with a mounting shaft that mates with the connecting hole; the connecting hole is set to a square hole 53, and the mounting shaft is set to a square shaft 54. The support block 41 is installed from the reaction chamber 30, and the square shaft 54 ​​mates with the square hole 53, thereby ensuring that the mounting block is stably and accurately installed in the reaction chamber 30. Alternatively, the connecting hole can be set to a threaded hole, and the mounting shaft can be provided with an external thread section that mates with the threaded hole.

[0047] Please see Figures 1 to 3 As a specific embodiment of the germanium single crystal dislocation level control device provided by this utility model, by setting the sum of the inner diameter and width of the annular support 40 to be greater than the outer diameter of the germanium single crystal 60, it is ensured that the germanium single crystal 60 is stably placed on the annular support 40, avoiding the crystal from tipping over due to insufficient support surface; at the same time, the reserved edge space reduces the obstruction of the support to the growth area on the side of the crystal, so that the installation distance 31 between the inner wall of the reaction chamber 30 and the outer side of the crystal can be effectively utilized, ensuring the uniformity of the thermal field distribution, avoiding local temperature anomalies caused by the support structure hindering heat conduction, thereby more accurately controlling the stress state during the crystal growth process and helping to achieve precise control of dislocation density.

[0048] Please see Figure 1 and Figure 2 As a specific embodiment of the germanium single crystal dislocation level control device provided by this utility model, the reaction chamber 30 is positioned at the center of the heater 12, allowing the heat generated by the annular heating of the heater 12 to radiate evenly to the periphery of the reaction chamber 30. This ensures a symmetrical temperature field distribution in the growth region of the germanium single crystal 60 within the chamber, avoiding abnormal local temperature gradients caused by deviation from the center. This reduces dislocation multiplication or uneven distribution problems caused by uneven thermal stress in the crystal. Simultaneously, the thermal field stability at the center is higher, facilitating precise control of temperature gradient changes at each growth stage when the height of the reaction chamber 30 is finely adjusted via the lifting rod 20, making the dislocation density control process more stable and controllable.

[0049] Please see Figures 1 to 3 In this embodiment, the reaction chamber 30 adopts a cylindrical structure with a wall thickness of ≥5mm. The thicker wall enhances the structural strength of the reaction chamber 30, enabling it to withstand thermal stress under high-temperature conditions during crystal growth and preventing deformation that could disrupt the thermal field and affect dislocation control. Furthermore, the thick wall design helps maintain the stability of the thermal field within the chamber, reducing the interference of external temperature fluctuations on the crystal growth region, resulting in a more uniform temperature gradient distribution. This allows for precise control of the internal stress level of the crystal and inhibits abnormal dislocation proliferation. In addition, the cylindrical structure facilitates the arrangement of annular supports 40 at intervals within the chamber, enabling layered polycrystalline growth. Combined with a stable thermal environment, this further improves the consistency of dislocation density and production efficiency during polycrystalline growth.

[0050] Please see Figure 1As a specific embodiment of the germanium single crystal dislocation level control device provided by this utility model, a central slot for mounting the reaction chamber 30 is provided at the upper end of the support tray 21. The central slot can accurately position the reaction chamber 30, ensuring that its axis coincides with the central axis of the furnace body 10 heater 12, avoiding uneven heat field distribution due to installation misalignment, thereby ensuring the symmetry of the temperature field in the growth region of the germanium single crystal 60 and reducing dislocation anomalies caused by uneven thermal stress. At the same time, the limiting effect of the central slot can enhance the stability of the reaction chamber 30 installation, especially during the height adjustment process of the lifting rod 20, preventing the chamber from shaking or shifting, maintaining the accuracy of thermal field adjustment, helping to more stably control the stress state in crystal growth, and achieving precise control of dislocation density.

[0051] Please see Figures 1 to 3 As a specific embodiment of the germanium single crystal dislocation level control device provided by this utility model, the reaction chamber 30 adopts a modular sleeve 32 structure, consisting of multiple sleeves 32 connected sequentially from top to bottom, with each sleeve 32 corresponding to a ring support 40. The ring support 40 is installed inside the sleeve 32 to support the germanium single crystal 60 in layers. The limiting connector 50 on the outer wall of the sleeve 32 achieves detachable connection between adjacent sleeves 32 through the cooperation of the upper rotating hole 51 and the lower connecting shaft 52. This method gives the reaction chamber 30 a flexible layer expansion capability, allowing the number of sleeves 32 to be increased or decreased according to production needs, adapting to the growth of germanium single crystals 60 of different sizes or batches, significantly improving the versatility of the device and the flexibility of production planning. The detachable structure facilitates independent maintenance, cleaning, or replacement of the supports and crystals in each layer of sleeves 32, reducing operational complexity and improving maintenance efficiency. Meanwhile, after the sleeves 32 are stably connected via the limiting connector 50, they form a continuous and closed cylindrical structure, ensuring the integrity and uniformity of the thermal field within the reaction chamber 30 and preventing heat leakage or sudden temperature gradient changes caused by layering gaps. Optionally, the rotating hole 51 includes a circular hole and a square hole 53 arranged sequentially, and the connecting shaft 52 includes a circular shaft and a square shaft 54. The circular shaft is rotatably connected to the circular hole, and the square hole 53 is fitted with the square shaft 54. Through this structure, the square shaft 54 ​​on the rotating shaft is disengaged from the square hole 53. The two adjacent sleeves 32 can be rotated relative to each other by means of the circular hole and the circular shaft, thus opening the two sleeves 32 and facilitating the opening or closing of the sleeves 32. When the square shaft 54 ​​on the upper sleeve 32 is inserted into the square hole 53, the two sleeves 32 are fixed.

[0052] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A germanium single crystal dislocation level control device, characterized in that, include: The furnace body has an internal cavity and heaters arranged in a ring on the inner wall of the cavity. The lifting rod is located inside the receiving cavity, and its lower end is fixedly connected to the bottom of the furnace body; The support tray is arranged horizontally, and its lower end is fixedly installed on the upper end of the lifting rod; A reaction chamber is mounted on the support tray; the reaction chamber is provided with a plurality of annular support members arranged at intervals; a plurality of germanium single crystals are respectively placed on the plurality of annular support members, and an installation gap is provided between the outer surface of the germanium single crystal and the inner wall of the reaction chamber.

2. The apparatus for controlling the level of dislocations in a germanium single crystal according to claim 1, wherein The annular support includes multiple support blocks located at the same horizontal height, and the support blocks are evenly spaced along the circumference of the reaction chamber; one end of each support block is connected to the side wall of the reaction chamber.

3. The germanium single crystal dislocation level control device as described in claim 2, characterized in that, The upper end of the support block is provided with grooves on the side near the center of the reaction chamber. Multiple grooves form a limiting groove for accommodating germanium single crystals, and the limiting groove is used to limit the germanium single crystals to be located at the center of the reaction chamber.

4. The germanium single crystal dislocation level control device as described in claim 2, characterized in that, The inner wall of the reaction chamber is provided with a connection hole, and the support block is provided with a mounting shaft that mates with the connection hole.

5. The germanium single crystal dislocation level control device as described in claim 1, characterized in that, The sum of the inner diameter and width of the ring support is greater than the outer diameter of the germanium single crystal.

6. The germanium single crystal dislocation level control device as described in claim 1, characterized in that, The reaction chamber is located at the center of the heater.

7. The germanium single crystal dislocation level control device as described in claim 1, characterized in that, The reaction chamber has a cylindrical structure, and the wall thickness of the cylindrical structure is ≥5mm.

8. The germanium single crystal dislocation level control device as described in claim 1, characterized in that, The upper end of the support tray is provided with a central groove for mounting the reaction chamber.

9. The germanium single crystal dislocation level control device as described in claim 1, characterized in that, The reaction chamber includes sleeves arranged sequentially from top to bottom, with each sleeve corresponding to a plurality of annular supports. Each sleeve contains an annular support. A limiting connector for connecting two adjacent sleeves is fixed on the outer wall of the sleeve. The upper end of the limiting connector has a rotating hole, and the lower end has a connecting shaft for engaging with the rotating hole on the adjacent limiting connector.

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