Equipment for smelting and purifying germanium in seed crystal induction zone

Abstract

The utility model provides equipment for smelting and purifying germanium in a seed crystal induction zone. The equipment comprises a smelting furnace assembly and a heating assembly, through the seed crystal groove and the transition groove in the first end of the material loading boat body, in the zone melting process, seed crystals can effectively induce germanium to grow in a single crystal form, dislocation in the crystal growth process and generation of polycrystalline crystals are reduced through rotation of the seed crystals, the stability of the germanium single crystal growth process is improved, a certain stirring effect on a melting zone is achieved, and the growth efficiency of the germanium single crystal is improved. The impurity diffusion rate is improved, the thickness of the diffusion layer is reduced, and the influence of the change of the cross section of the germanium crystal on the crystal growth form and the temperature gradient is avoided through the buffer effect of the transition section; through the combination of the main heater and the auxiliary heater, a stable temperature gradient distribution and heat preservation interval can be formed, the influence of external environment change on the zone melting purification process is reduced, the stability of a melting zone is maintained, the stable growth of crystals is also facilitated, the quality of high-purity germanium single crystals is ensured, and the stability of the process is maintained.

Description

Technical Field

[0001] The utility model relates to the technical field of special crystal growth technology, in particular to a device for purifying germanium through seed crystal induction zone melting. Background Art

[0002] Germanium is a typical rare earth metallic element, located in the fourth period, main group IV. It has relatively high melting and boiling points, at 938.25°C and 2833°C, respectively. Germanium is an excellent semiconductor element with high carrier mobility, making it a core material for many cutting-edge products, such as semiconductor devices, aerospace measurement and control equipment, and nuclear physics detectors. However, these high-end products require extremely high germanium purity, at least 9N or higher, and in the field of nuclear physics detection, even 13N purity is required. Due to germanium's relatively high boiling point, the current mainstream germanium purification method is zone melting. This method utilizes the difference in the distribution coefficients of impurities between the solid and liquid phases during metal solidification. By locally heating the metal to form a molten zone, the impurities are redistributed between the solid and liquid phases of the main metal, achieving the goal of targeted impurity enrichment and purification of the main metal.

[0003] The raw material for zone melting and purification is primarily reduced germanium ingots obtained through chemical purification, with a purity generally around 5N. Through repeated zone melting, impurity elements are continuously enriched at the head and tail ends of the germanium ingot. In previous zone melting processes for germanium purification, the germanium grew in a polycrystalline form, reducing the efficiency of impurity removal, resulting in long zone melting cycles, high energy consumption, and low growth efficiency. The horizontal single crystal zone melting method is significantly affected by the environment and can easily lead to unstable single crystal growth. Therefore, there is an urgent need to develop germanium purification equipment with a short purification cycle, low energy consumption, and high purification efficiency. Utility Model Content

[0004] The purpose of the utility model is to provide a germanium purification device with a short purification cycle, low energy consumption and high purification efficiency in response to the shortcomings of the above-mentioned background technology.

[0005] In order to achieve the above-mentioned object, the utility model provides a device for seed crystal induction zone melting and purification of germanium, comprising a melting furnace component and a heating component;

[0006] The smelting furnace assembly includes a quartz tube, a sealing kit provided at both ends of the quartz tube, and a support assembly for supporting the quartz tube. The two ends of the quartz tube are sealed from the outside by the sealing kit. The first end of the quartz tube is provided with an air inlet, and the second end is provided with an air outlet. The air inlet and the air outlet are both provided with valves. The air inlet is connected to the air circuit system. The second end of the quartz tube is also provided with a vacuum port, and the vacuum port is connected to the vacuum system.

[0007] A material loading boat is provided in the quartz tube, and the material loading boat includes a material trough, a transition trough, and a seed crystal trough which are arranged in sequence. The material trough is used to place the material to be purified. The two ends of the transition trough are respectively connected to the material trough and the seed crystal trough. The cross section of the transition trough is circular, and the cross-sectional area gradually decreases from the material trough to the seed crystal trough. The seed crystal trough is used to place the induced seed crystal. The cross sections of the induced seed crystal and the seed crystal trough are both circular. The induced seed crystal is a high-purity germanium single crystal. The seed crystal trough is connected to a rotating mechanism and is driven to rotate by the rotating mechanism.

[0008] The heating assembly includes a transmission box, an insulation layer and a heater. The transmission box is mounted on a quartz tube and is used to heat the loading boat inside the quartz tube. The transmission box is connected to a moving mechanism. The insulation layer is arranged inside the transmission box. The heater is arranged inside the insulation layer. The heat generated heats the quartz tube.

[0009] Furthermore, the support assembly includes a support rod and a support platform, the two ends of the support rod are respectively connected to the sealing kit and the support platform, the bottom of the support platform is connected to a lifting mechanism, and the lifting mechanism is used to adjust the height position and tilt angle of the support platform.

[0010] Furthermore, the material of the loading boat itself is high-purity graphite or high-purity quartz or carbon-coated quartz or silicon-coated graphite boat.

[0011] Furthermore, the transition trough and the seed crystal trough are also provided with a cover plate, and the cover plate is used to open for layout and sampling.

[0012] Furthermore, the rotating mechanism includes a motor, a transmission shaft and a sealing sleeve. The motor is arranged outside the quartz tube, the first end of the transmission shaft is connected to the motor, the second end of the transmission shaft passes through the sealing kit into the quartz tube and is connected to the seed crystal groove, the sealing sleeve is wrapped around the outside of the transmission shaft, and the sealing sleeve is fixedly connected to the sealing kit.

[0013] Furthermore, the transmission box is configured as a cylindrical ring and is sleeved on the quartz tube.

[0014] Furthermore, the heaters are arranged in three groups, the heater located in the center is a main heater for maintaining the temperature of the melting zone, and the heaters located on both sides are auxiliary heaters for adjusting the temperature gradient.

[0015] Furthermore, the distance between the auxiliary heater and the main heater can be adjusted.

[0016] The above solution of the utility model has the following beneficial effects:

[0017] The device for purifying germanium by seed crystal induction zone melting provided by the utility model has a seed crystal groove and a transition groove at the first end of a loading boat body. During the zone melting process, the seed crystal can effectively induce the growth of germanium in the form of a single crystal. Then, through the rotation of the seed crystal, dislocations in the crystal growth process and the formation of polycrystalline crystals are reduced, thereby improving the stability of the germanium single crystal growth process. The device also has a certain stirring effect on the melting zone, thereby increasing the diffusion rate of impurities and reducing the thickness of the diffusion layer. Through the buffering effect of the transition section, the influence of changes in the cross section of the germanium crystal on the crystal growth form and temperature gradient is avoided.

[0018] The utility model can form a stable temperature gradient distribution and heat preservation zone through the combination of the main heater and the auxiliary heater, thereby reducing the influence of the external environment change on the regional melting and purification process, maintaining the stability of the melting zone, and at the same time, the stable melting zone is conducive to the stable diffusion of impurities at the solid-liquid interface in the diffusion layer, avoiding impurity residues and unstable migration caused by external factors, and is also conducive to the stable growth of crystals, ensuring the quality of high-purity germanium single crystals and maintaining the stability of the process;

[0019] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0021] Figure 2 for Figure 1 Enlarged view of point A.

[0022] [Description of Reference Numerals]

[0023] 1-quartz tube; 2-sealing kit; 3-support rod; 4-support platform; 5-lifting mechanism; 6-air inlet; 7-air outlet; 8-vacuum port; 9-loading boat; 10-material trough; 11-transition trough; 12-seed crystal trough; 13-induced seed crystal; 14-melting zone; 15-cover plate; 16-motor; 17-drive shaft; 18-sealing sleeve; 19-transmission box; 20-insulation layer; 21-main heater; 22-auxiliary heater; 23-moving mechanism. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to a locking connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0027] like Figure 1 、 Figure 2 As shown, an embodiment of the present invention provides an apparatus for seed crystal induced zone melting and purification of tantalum, comprising a smelting furnace assembly and a heating assembly. The smelting furnace assembly comprises a quartz tube 1, a sealing kit 2 disposed at both ends of the quartz tube 1, support rods 3, and a support platform 4. The ends of the quartz tube 1 are sealed from the outside world by the sealing kit 2. The ends of the support rods 3 are respectively connected to the sealing kit 2 and the support platform 4 to support and secure the quartz tube 1 and the entire smelting furnace assembly. Furthermore, a lifting mechanism 5 can be connected to the bottom of the support platform 4, which adjusts the height and tilt angle of the support platform 4, i.e., the quartz tube 1.

[0028] The quartz tube 1 is provided with an air inlet 6 at the first end and an air outlet 7 at the second end. Both the air inlet 6 and the air outlet 7 are equipped with valves to control the opening and closing of the air inlet 6 and the air outlet 7, thereby adjusting the type and pressure of the gas within the quartz tube 1. Furthermore, the second end of the quartz tube 1 is provided with a vacuum port 8, which is connected to a vacuum system to evacuate the interior of the quartz tube 1.

[0029] The gas system connected to gas inlet 6 includes high-purity hydrogen and inert gas lines. Both high-purity hydrogen and inert gas have a purity of 5N or higher and flow through a deoxidation tube. The gas system also includes a mass flow controller, a barometer, and an exhaust gas processor. The system is also connected to a vacuum system, which includes vacuum piping, a vacuum pump, a barometer, and seals.

[0030] In this embodiment, a loading boat 9 is disposed within the quartz tube 1. The loading boat 9 is placed parallel to the quartz tube 1 and includes a material trough 10, a transition trough 11, and a seed crystal trough 12, which are arranged in sequence. The material trough 10 is used to hold the material to be purified. The transition trough 11 is connected to the material trough 10 and the seed crystal trough 12 at both ends. The transition trough 11 has a circular cross-section, and the cross-sectional area gradually decreases from the material trough 10 to the seed crystal trough 12. The seed crystal trough 12 is used to hold an induction seed crystal 13. Both the induction seed crystal 13 and the seed crystal trough 12 have circular cross-sections. The induction seed crystal 13 is a high-purity germanium single crystal. The seed crystal trough 12 is also connected to a rotating mechanism and rotates when driven by the rotating mechanism, driving the seed crystal to grow in rotation. This can effectively reduce the formation of dislocations and avoid the formation of polycrystalline crystals. It also has a certain stirring effect on the melt zone 14, reducing the thickness of the diffusion layer. In addition, a detachable cover plate 15 is provided above the transition trough 11 and the seed crystal trough 12 for opening for setting out and sampling.

[0031] It should be noted that the material of the loading boat 9 itself is a high-purity graphite boat, a high-purity quartz boat, a carbon-coated quartz boat, a silicon-coated graphite boat, etc., and the purity of the material is 5N or above.

[0032] In this embodiment, the rotating mechanism includes a motor 16, a transmission shaft 17, and a sealing sleeve 18. The motor 16 is mounted outside the quartz tube 1. The first end of the transmission shaft 17 is connected to the motor 16, and the second end passes through the sealing sleeve 2 into the interior of the quartz tube 1 and connects to the seed crystal tank 12. The sealing sleeve 18 wraps around the exterior of the transmission shaft 17 and can be fixed to the sealing sleeve 2 to seal the connection between the transmission shaft 17 and the quartz tube 1. Furthermore, a bearing or other device can be provided at the connection to provide rotational support for the transmission shaft 17, ensuring more stable and reliable transmission.

[0033] In this embodiment, the heating assembly includes a transmission box 19, an insulation layer 20, and a heater. The transmission box 19 is configured as a cylindrical ring and is sleeved onto the quartz tube 1 to heat the internal loading boat 9. The transmission box 19 is connected to a moving mechanism 23 (specifically, a crawler drive in this embodiment; guide rails or the like may also be provided to guide the transmission box 19). The moving mechanism 23 drives the transmission box 19 to move along the quartz tube 1 to adjust the heating position. The heater is disposed within the insulation layer 20, which is disposed in contact with the inner wall of the transmission box 19. The insulation layer 20 is relatively thin (or not present) on the inner wall of the transmission box 19 where it contacts the quartz tube 1, so that the heat generated by the heater can sufficiently heat the quartz tube 1.

[0034] As a preferred embodiment, three groups of heaters are provided in this embodiment. The central heater is the main heater 21, which is used to maintain the temperature of the melt zone 14. The heaters on both sides are auxiliary heaters 22, which are used to adjust the temperature gradient. The spacing between the auxiliary heaters 22 and the main heaters 21 can be adjusted to a certain extent and can be fixed.

[0035] When the equipment provided in this embodiment is used to prepare high-purity germanium, the following steps are included:

[0036] S1, pretreatment, soaking the loading boat 9 in aqua regia + hydrofluoric acid solution for 10-30 minutes; taking out the loading boat 9 and soaking it in dilute nitric acid for 24 hours; after the soaking, soaking it in deionized water for 1 hour, repeating three times, rinsing it with deionized water three times, and finally drying it in a vacuum drying oven or blowing it with dry nitrogen, and placing it in a clean environment for use.

[0037] S2, loading. Under a protective atmosphere, cast a certain mass of crude germanium in the same mold as the loading boat 9. After cooling, load the material according to the shape of the loading boat 9 and cover it with a cover plate 15. Place the loading boat 9 containing the germanium material to be purified into a suitable position in the quartz tube 1, align the first end of the seed crystal groove 12 with the main heater 21, and install the sealing kit 2 of the quartz tube 1. Connect the transmission shaft 17 in place and check the air tightness of the equipment.

[0038] S3. After ensuring that the equipment is airtight, close the air inlet valve 6 and the air outlet valve 7, start the vacuum system to extract the air in the quartz tube 1; wait until the pressure on the pressure gauge drops to a lower level, and turn off the vacuum; open the gas system and the air inlet valve 6, fill the quartz tube 1 with high-purity inert gas until the pressure gauge shows a slightly positive pressure, and close the air inlet valve 6; repeat the above operation 3 times to ensure that all the air in the quartz tube 1 is discharged; then open the gas system and the air inlet valve 6, fill the quartz tube 1 with high-purity hydrogen until the pressure gauge shows a slightly positive pressure, open the air outlet valve 7, and adjust the hydrogen flow rate.

[0039] S4, start the temperature rising program, set the temperature rising rate of the main heater 21 and the auxiliary heater 22, and the final temperature of the main heater 21 and the auxiliary heater 22, until the heaters reach the specified temperature, and enter the seeding growth stage.

[0040] S5, during the seeding growth stage, the motor 16 is turned on to make the transmission shaft 17 rotate steadily at a certain speed, driving the induced seed crystal 13 to rotate. At this time, the transmission box 19 is driven to move toward the second end of the quartz tube 1 at a certain speed. During this process, the molten zone 14 formed by the heater continuously moves toward the second end of the quartz tube 1, and the germanium crystal continuously grows on the induced seed crystal 13 until the molten zone 14 is about to cross the transition groove 11. The motor is turned off to stop the rotation of the induced seed crystal 13.

[0041] S6, purification stage, adjust the program, under a certain width of the melting zone 14, make the transmission box 19 move toward the second end of the quartz tube 1 at a certain moving speed until it reaches the end of the melting zone 14, and slowly cool the melting zone 14 to room temperature.

[0042] S7, repeating S4-S6 until the germanium ingot is purified to a certain purity. During the seed crystal induction growth stage, the melt zone movement rate is maintained at a low level, allowing the germanium to grow stably in the form of a single crystal under the guidance of the induction seed crystal 13, and the cross-sectional area of the germanium crystal is gradually expanded during the transition stage.

[0043] S8: The hydrogen gas is turned off and high-purity nitrogen is introduced into the quartz tube 1. After all the remaining hydrogen in the tube is exhausted, the high-purity nitrogen gas is turned off, the purified germanium ingot is removed, and the end is cut off at a predetermined position using a wire cutting method, such as a wire cutting method, leaving the middle section of the high-purity germanium ingot. After the impurity-rich section of the induction seed crystal 13 is cut off, it can be reused multiple times.

[0044] In summary, the equipment for seed crystal induced zone melting and purification of germanium provided in this embodiment realizes the single crystal zone melting and purification process, effectively improves the impurity removal efficiency, and avoids the problems of low zone melting purification efficiency, unstable process, unstable product quality, etc. caused by factors such as impurity grain boundary inclusions and external environmental interference in the traditional zone melting process. It effectively improves the efficiency of germanium zone melting and purification, reduces the zone melting cycle, and improves the operation quality.

[0045] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A device for purifying germanium by seed crystal induced zone melting, characterized in that: Includes a melting furnace assembly and a heating assembly; The smelting furnace assembly includes a quartz tube, a sealing kit provided at both ends of the quartz tube, and a support assembly for supporting the quartz tube. The two ends of the quartz tube are sealed from the outside by the sealing kit. The first end of the quartz tube is provided with an air inlet, and the second end is provided with an air outlet. The air inlet and the air outlet are both provided with valves. The air inlet is connected to the air circuit system. The second end of the quartz tube is also provided with a vacuum port, and the vacuum port is connected to the vacuum system. A material loading boat is provided in the quartz tube, and the material loading boat includes a material trough, a transition trough, and a seed crystal trough which are arranged in sequence. The material trough is used to place the material to be purified. The two ends of the transition trough are respectively connected to the material trough and the seed crystal trough. The cross section of the transition trough is circular, and the cross-sectional area gradually decreases from the material trough to the seed crystal trough. The seed crystal trough is used to place the induced seed crystal. The cross sections of the induced seed crystal and the seed crystal trough are both circular. The induced seed crystal is a high-purity germanium single crystal. The seed crystal trough is connected to a rotating mechanism and is driven to rotate by the rotating mechanism. The heating assembly includes a transmission box, an insulation layer and a heater. The transmission box is mounted on a quartz tube and is used to heat the loading boat inside the quartz tube. The transmission box is connected to a moving mechanism. The insulation layer is arranged inside the transmission box. The heater is arranged inside the insulation layer. The heat generated heats the quartz tube.

2. The device for purifying germanium by seed crystal induced zone melting according to claim 1, characterized in that: The support assembly includes a support rod and a support platform. The two ends of the support rod are respectively connected to the sealing kit and the support platform. The bottom of the support platform is connected to a lifting mechanism, and the lifting mechanism is used to adjust the height position and tilt angle of the support platform.

3. The device for purifying germanium by seed crystal induced zone melting according to claim 1, characterized in that: The material of the loading boat itself is high-purity graphite or high-purity quartz or carbon-coated quartz or silicon-coated graphite boat.

4. The device for purifying germanium by seed crystal induced zone melting according to claim 1, characterized in that: The transition trough and the seed crystal trough are further provided with a cover plate, and the cover plate is used for opening for setting out and sampling.

5. The device for purifying germanium by seed crystal induced zone melting according to claim 1, characterized in that: The rotating mechanism includes a motor, a transmission shaft and a sealing sleeve. The motor is arranged outside the quartz tube. The first end of the transmission shaft is connected to the motor. The second end of the transmission shaft passes through the sealing kit into the quartz tube and is connected to the seed crystal groove. The sealing sleeve is wrapped around the outside of the transmission shaft and is fixedly connected to the sealing kit.

6. The device for purifying germanium by seed crystal induced zone melting according to claim 1, characterized in that: The transmission box is configured as a cylindrical ring and is sleeved on the quartz tube.

7. The device for purifying germanium by seed crystal induced zone melting according to claim 1, characterized in that: The heaters are arranged in three groups. The heater located in the center is a main heater for maintaining the temperature of the melting zone, and the heaters located on both sides are auxiliary heaters for adjusting the temperature gradient.

8. The device for purifying germanium by seed crystal induced zone melting according to claim 7, characterized in that: The distance between the auxiliary heater and the main heater is adjustable.

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