Temperature gradient regulation and control device for growth of large-size germanium single crystals

Abstract

The utility model discloses a temperature gradient regulation and control device for large-size germanium single crystal growth, and belongs to the technical field of germanium crystal growth. The device comprises a furnace body, a guide cylinder, a heat preservation cylinder, a ventilation ring and a graphite crucible, the furnace body comprises a main chamber and an auxiliary chamber, and the auxiliary chamber is arranged at the top of the main chamber; the ventilation ring is a tubular metal circular ring, the circular ring is hollow, the inner diameter of the circular ring is larger than the equal diameter of growing germanium single crystals, a plurality of air outlets are evenly formed in the inner wall and the outer wall of the circular ring, an air inlet is formed in the top face of the circular ring, and the ventilation ring is installed on the upper portion of the inner side of the guide cylinder and tightly attached to the guide cylinder or installed on the upper portion of the outer side of the guide cylinder and tightly attached to the guide cylinder. Low-temperature protective gas is blown to the flow guide cylinder through the ventilation ring, so that the temperature of the flow guide cylinder is reduced, the low-temperature flow guide cylinder serves as a cold end, crystallization latent heat, especially crystallization latent heat in the shouldering stage, transmission of crystallization latent heat radiation during shouldering is accelerated, the shouldering probability of growing large-size germanium single crystals is increased, and the purpose that the large-size germanium single crystals enter the equal-diameter stage through shouldering is smoothly achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of germanium crystal growth, and in particular relates to a temperature gradient control device for growing large-size germanium single crystals. Background Art

[0002] Germanium single crystals, with their high refractive index and ability to capture weak energy, serve as a key lens element in infrared optical systems for low- and medium-orbit satellites. They can improve dispersion issues in lightweight infrared systems and enhance clearer space imaging. With the advancement of space-based Earth monitoring satellite technology, the requirements for imaging accuracy and range are increasing. Consequently, the radial dimensions of the required germanium single crystal lenses are increasing, reaching a maximum diameter of approximately 500 mm, posing greater challenges to germanium single crystal growth technology.

[0003] Growing large germanium single crystals often results in shouldering or high crystal stress due to the poor heat transfer capacity of germanium metal. Conventional cooling methods, while enabling faster and more accurate design of thermal field systems to grow appropriate germanium single crystals, are unable to dissipate the latent heat of crystallization in a timely manner during the shouldering phase of growth. However, as the radial size of germanium crystals increases to approximately 500 mm, conventional cooling methods are unable to dissipate the latent heat of crystallization in a timely manner. Utility Model Content

[0004] The utility model provides a temperature gradient control device for growing large-sized germanium single crystals, the purpose of which is to enable the large-sized germanium single crystals to take away the crystallization latent heat in time.

[0005] A temperature gradient control device for growing large-size germanium single crystals, characterized in that it includes a furnace body, a guide tube, an insulation tube, a ventilation ring and a graphite crucible, the furnace body includes a main chamber and a sub-chamber, the main chamber is cylindrical and is provided with a furnace cover that gradually shrinks upward, the sub-chamber is arranged on the top of the furnace cover, and an opening and closing door is provided on the side of the sub-chamber, and the suspended seed crystal clamp passes through the sub-chamber from top to bottom into the main chamber; a lifting platform is provided at the bottom of the main chamber, and a graphite crucible is installed on the lifting platform, a heater is provided on the outside of the graphite crucible and is electrically connected to a power supply, an insulation tube is provided on the outside of the control console and the heater, and a guide tube is provided in the center of the top of the insulation tube; the ventilation ring is a tubular metal ring, the inside of the ring is hollow, the inner diameter of the ring is larger than the diameter of the equal diameter of the growing germanium single crystal, a number of air outlet holes are evenly provided on the inner and outer walls of the ring, and an air inlet is provided on the top surface of the ring, and the ventilation ring is installed on the upper inner side of the guide tube, close to the guide tube, or installed on the upper outer side of the guide tube, close to the guide tube.

[0006] Furthermore, the ventilation ring is made of a stainless steel tube with an inner diameter of 10 mm, which is bent into a circular ring, and the inner diameter of the circular ring is 650 mm.

[0007] Furthermore, the ventilation ring has 16 air outlet holes, each of which has a diameter of 1 mm.

[0008] The beneficial effects of the present invention are as follows: low-temperature protective gas is blown into the guide tube through the ventilation ring, so that the temperature of the guide tube is reduced. The low-temperature guide tube serves as a cold end, which quickly takes away the latent heat of crystallization, especially the latent heat of crystallization in the shoulder release stage, so that the transmission of the latent heat of crystallization radiation during shoulder release is accelerated, the probability of shoulder release in growing large-size germanium single crystals is increased, and the shoulder is smoothly transformed into the equal-diameter stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of the structure of a temperature gradient control device for growing large-size germanium single crystals in Example 1.

[0010] Figure 2 This is a schematic diagram of the structure of a temperature gradient control device for growing large-size germanium single crystals in Example 2.

[0011] Figure 3 Schematic diagram of the ventilation ring structure.

[0012] Among them: 1- auxiliary chamber; 2- main chamber; 3- germanium single crystal, 30- seed crystal, 31- shoulder release, 32- shoulder rotation, 33- equal diameter; 4- guide tube; 5- insulation tube; 6- graphite crucible; 7- heater; 8- ventilation ring, 80- air inlet, 81- air outlet. DETAILED DESCRIPTION

[0013] Example 1: A temperature gradient control device for growing large-sized germanium single crystals, comprising a furnace body, a guide tube 4, a heat-insulating tube 5, a vent ring 8, and a graphite crucible 6. The furnace body comprises a main chamber 2 and a sub-chamber 1. The main chamber 2 is cylindrical and is provided with a furnace cover that gradually shrinks upward. The sub-chamber 1 is arranged on the top of the furnace cover. An opening and closing door is provided on the side of the sub-chamber 1. The suspended seed crystal clamp passes through the sub-chamber from top to bottom and enters the main chamber. A lifting platform is provided at the bottom of the main chamber 2. The graphite crucible 6 is installed on the lifting platform. The outside of the graphite crucible 6 is provided with a lifting platform. A heater 7 is provided and electrically connected to a power source, an insulation tube 5 is sheathed on the outside of the heater 7, and a guide tube 4 is provided at the center of the top of the insulation tube 5; a ventilation ring 8 is a tubular metal ring, the inside of the ring is hollow, the inner diameter of the ring is larger than the diameter of the growing germanium single crystal 33, 16 air outlet holes 81 are evenly provided on the inner and outer walls of the ring, each air outlet hole has a diameter of 1 mm, an air inlet 80 is provided on the top surface of the ring, and the ventilation ring 8 is installed on the guide tube 4 and is installed on the upper outer side of the guide tube 4, close to the guide tube 4.

[0014] During operation, the auxiliary chamber 1 and main chamber 2 are opened, a seed crystal is secured to the seed crystal holder, and a zone-melting germanium ingot is placed in the graphite crucible. The furnace is then sealed, evacuated, and a protective gas is introduced. A power source is connected to generate heat in the heater 7, which radiates heat to the graphite crucible 6 and then to the zone-melting germanium ingot, melting it into a molten metal. Nitrogen is introduced through the inlet 80 of the vent ring 8, and nitrogen is purged into the flow tube 4 through the outlet 81, lowering the temperature of the flow tube 4. The low-temperature flow tube 4 acts as a cold end, rapidly dissipating the latent heat of crystallization, particularly during the shoulder release phase, thereby accelerating the transfer of this latent heat of crystallization radiation. The vent ring 8 continuously regulates the furnace temperature during the single crystal growth stages (seeding 30, shoulder release 31, shoulder rotation 32, and equal diameter 33), maintaining a stable temperature within the furnace. After crystal growth is complete, the crystal is lifted into the auxiliary chamber 1, the top cover of the main chamber 2 is closed, and the door of the auxiliary chamber 1 is opened to remove the crystal.

[0015] Example 2: A temperature gradient control device for growing large-sized germanium single crystals, comprising a furnace body, a guide tube 4, a heat-insulating tube 5, a vent ring 8, and a graphite crucible 6. The furnace body comprises a main chamber 2 and a sub-chamber 1. The main chamber 2 is cylindrical and is provided with a furnace cover that gradually shrinks upward. The sub-chamber 1 is provided on the top of the furnace cover. An opening and closing door is provided on the side of the sub-chamber 1. The suspended seed crystal clamp passes through the sub-chamber from top to bottom and enters the main chamber. A lifting platform is provided at the bottom of the main chamber 2. The graphite crucible 6 is installed on the lifting platform. The outside of the graphite crucible 6 is provided with a lifting platform. A heater 7 is provided and electrically connected to a power source, an insulation tube 5 is sheathed on the outside of the heater 7, and a guide tube 4 is provided at the center of the top of the insulation tube 5; a ventilation ring 8 is a tubular metal ring, the inside of the ring is hollow, the inner diameter of the ring is larger than the diameter of the equal diameter 33 of the growing germanium single crystal, 16 air outlet holes 81 are evenly provided on the inner and outer walls of the ring, each air outlet hole has a diameter of 1 mm, an air inlet 80 is provided on the top surface of the ring, and the ventilation ring 8 is installed on the guide tube 4 and is installed on the upper inner side of the guide tube 4, close to the guide tube 4.

[0016] During operation, the auxiliary chamber 1 and main chamber 2 are opened, a seed crystal is secured to the seed crystal holder, and a zone-melting germanium ingot is placed in the graphite crucible. The furnace is then sealed, evacuated, and a protective gas is introduced. A power source is connected to generate heat in the heater 7, which radiates heat to the graphite crucible 6 and then to the zone-melting germanium ingot, melting it into a molten metal. Argon is introduced through the inlet 80 of the vent ring 8, and nitrogen is purged into the flow tube 4 through the outlet 81, lowering the temperature of the flow tube 4. The low temperature of the flow tube 4 acts as a cold end, rapidly dissipating the latent heat of crystallization, particularly during the shoulder release phase, thereby accelerating the transfer of this latent heat of crystallization radiation. The vent ring 8 continuously regulates the furnace temperature during the single crystal growth stages (seeding 30, shoulder release 31, shoulder rotation 32, and equal diameter 33) to maintain a stable temperature within the furnace. After crystal growth is complete, the crystal is lifted into the auxiliary chamber 1, the top cover of the main chamber 2 is closed, and the door of the auxiliary chamber 1 is opened to remove the crystal.

Claims

1. A temperature gradient control device for growing large-size germanium single crystals, characterized by: It includes a furnace body, a guide tube, an insulation tube, a ventilation ring and a graphite crucible. The furnace body includes a main chamber and a sub-chamber. The main chamber is cylindrical and is provided with a furnace cover that gradually shrinks upward. The sub-chamber is arranged on the top of the furnace cover. An opening and closing door is provided on the side of the sub-chamber. The suspended seed crystal clamp passes through the sub-chamber from top to bottom into the main chamber; a lifting platform is provided at the bottom of the main chamber, and a graphite crucible is installed on the lifting platform. A heater is provided on the outside of the graphite crucible and is electrically connected to a power supply. An insulation tube is provided on the outside of the control console and the heater, and a guide tube is provided in the center of the top of the insulation tube; the ventilation ring is a tubular metal ring with a hollow interior. The inner diameter of the ring is larger than the diameter of the equal diameter of the grown germanium single crystal. A number of air outlets are evenly provided on the inner and outer walls of the ring, and an air inlet is provided on the top surface of the ring. The ventilation ring is installed on the upper inner side of the guide tube, close to the guide tube, or installed on the upper outer side of the guide tube, close to the guide tube.

2. A temperature gradient control device for growing large-size germanium single crystals according to claim 1, characterized in that The ventilation ring is made of a stainless steel tube with an inner diameter of 10 mm and bent into a circular ring. The inner diameter of the circular ring is 650 mm.

3. A temperature gradient control device for growing large-size germanium single crystals according to claim 1, characterized in that The ventilation ring is provided with 16 air outlet holes, each of which has a diameter of 1 mm.

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