Kyropoulos method for quickly growing large-size sapphire single crystal

A growth method, sapphire technology, applied in the direction of single crystal growth, single crystal growth, crystal growth, etc., can solve the problems of long growth cycle, low crystal yield, limited popularization and application, etc., and achieve short growth cycle and large growth crystal size , the effect of broad application prospects

Active Publication Date: 2011-08-03

HARBIN AURORA OPTOELECTRONICS TECH

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AI-Extracted Technical Summary

Problems solved by technology

[0005] The Kyropoulos method has been proven by many foreign companies to be the most suitable method for growing large-sized sapphire single crystals for industrial production. However, due to the long growth period of the traditional Kyropoul...

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Method used

(4) additional temperature field adjustment: start the auxiliary temperature regulation system, adjust the temperature field in the furnace, so that the position of the cold center in the melt coincides with the geometric c...

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Abstract

The invention provides a Kyropoulos method for quickly growing a large-size sapphire single crystal. Processes of charging, vacuumizing, heating for melting, auxiliary temperature field adjustment, crystal leading, shoulder extending, shoulder contracting, equal-diameter growth, pull-off, cooling annealing and discharging are finished in a growth furnace of the large-size sapphire single crystal. The Kyropoulos method for quickly growing the large-size sapphire single crystal is greatly improved on the basis of the conventional Kyropoulos method, and has the advantages of shorter growth period, larger size and higher quality of the grown crystal, higher yield of the crystal, lower unit production cost and the like.

Application Domain

Polycrystalline material growthBy pulling from melt +1

Technology Topic

SapphireSingle crystal +4

Examples

Experimental program(2)

Example Embodiment

[0027] Embodiment 1: The specific process of this embodiment is as follows:

[0028] (1) Furnace loading: 31 kg of high-purity alumina raw material (purity> 99.997%) Loaded into the crucible of the single crystal furnace, the 12mm diameter A-direction (or C-direction, M-direction, R-direction) seed crystals that have been accurately oriented are first mounted on the seed crystal holder, and the seed crystal orientation accuracy is ±0.1o , Then install the seed crystal clamp on the seed rod, close the single crystal furnace cover, start the cooling water circulation system, adjust the cooling water flow, and control the outlet water temperature within the range of 27±1℃;

[0029] (2) Vacuum: start the vacuum system to make the pressure in the furnace reach 10 -3 Pa.

[0030] (3) Heating material: start the heating system, adjust the heating voltage, and heat at a heating rate of 400°C/h. When the temperature reaches 2150°C, stop heating. At this time, the raw materials are all melted; after holding for 3 hours, adjust the heating voltage. Cool down to 2060°C at a cooling rate of 30°C/h and observe the state of the melt surface. At this time, the state of the liquid surface is stable, and the relative deviation between the cold center position in the melt and the geometric center of the crucible is 15 mm;

[0031] (4) Additional temperature field adjustment: start the auxiliary temperature adjustment system, adjust the temperature field in the furnace, so that the cold center position in the melt coincides with the geometric center position of the crucible; adjust the heating voltage, and cool down to 2050°C at a cooling rate of 5°C/h , Observe the state of the liquid surface of the melt, at this time the state of the liquid surface is stable;

[0032] (5) Seeding: Slowly adjust the height of the seed rod so that the lower end of the seed crystal is 8 mm above the liquid level. After 10 minutes of stability, start seeding. First, reduce the diameter of the seed crystal to 10 mm, and then seed the seed 5 times. The crystal diameter is gradually reduced to 4mm;

[0033] (6) Shoulder off: Pull up the seed crystal rod at a speed of 0.05mm/h, while adjusting the heating voltage, cooling down at a rate of 1℃/h, part of the melt begins to crystallize around the seed crystal; after 5 hours, the crystal diameter When it reaches 40 mm, pull the seed rod upwards at a speed of 1mm/h while adjusting the heating voltage to cool down at a rate of 2°C/h; after 5 hours, the crystal mass reaches 0.4 kg, and it is raised at a speed of 0.15mm/h Pull the seed rod and adjust the heating voltage at the same time to cool down at a rate of 3℃/h;

[0034] (7) Retract the shoulders: 15 hours later, when the crystal mass reaches 2 kg, pull the seed rod upwards at a speed of 0.25mm/h, while adjusting the heating voltage to cool down at a rate of 2°C/h. At this time, the single crystal diameter begins to shrink;

[0035] (8) Isodiameter growth: After 5 hours, when the crystal mass reaches 3 kg, the seed rod is pulled up at a speed of 0.15mm/h, while the heating voltage is adjusted to cool down at a rate of 2.5°C/h. At this time, the single crystal begins to grow with equal diameter, and the mass increases uniformly, and the mass increase rate is 380-500 g/h.

[0036] (9) Pull-off: After 70 hours, the quality of the crystal no longer increases, indicating that the crystal has been grown. At this time, the seed rod is quickly pulled up at a speed of 8mm/h to completely separate the crystal from the crucible wall;

[0037] (10) Cooling annealing: adjust the heating voltage, cooling down to 1400°C at a rate of 300°C/h, then annealing at a cooling rate of 40°C/h; when the temperature drops to 1000°C, at a rate of 50-200°C/h Cool down until the heating voltage drops to zero; close the vacuum system and pass in high-purity argon for rapid cooling. When the furnace pressure is close to 10 5 When Pa, stop passing argon;

[0038] (11) Out of the furnace: After holding for 5 hours, open the air inlet valve to make the pressure in the single crystal furnace the same as the outside, close the cooling water circulation system, open the single crystal furnace cover, take out the sapphire single crystal, and complete the entire process.

Example Embodiment

[0039] Embodiment 2: The specific process of this embodiment is as follows:

[0040] (1) Furnace loading: 85 kg of high-purity alumina raw material (purity> 99.997%) Loaded into the crucible of the single crystal furnace, the accurately oriented 18mm diameter A-direction (or C-direction, M-direction, R-direction) seed crystals are first mounted on the seed crystal holder, and the seed crystal orientation accuracy is ±0.1o , Then install the seed crystal clamp on the seed rod, close the single crystal furnace cover, start the cooling water circulation system, adjust the cooling water flow, and control the outlet water temperature within the range of 27±1℃;

[0041] (2) Vacuum: start the vacuum system to make the pressure in the furnace reach 10 -3 Pa.

[0042] (3) Heating the material: start the heating system, adjust the heating voltage, and heat at a heating rate of 200°C/h. When the temperature reaches 2150°C, stop heating. At this time, all the raw materials are melted; after holding for 5 hours, adjust the heating voltage, Cool down to 2060°C at a cooling rate of 20°C/h, and observe the state of the melt surface. At this time, the state of the liquid surface is stable, and the relative deviation between the cold center position in the melt and the geometric center of the crucible is 30 mm;

[0043] (4) Additional temperature field adjustment: start the auxiliary temperature adjustment system, adjust the temperature field in the furnace, so that the cold center position in the melt coincides with the geometric center position of the crucible; adjust the heating voltage to cool down to 2050°C at a cooling rate of 3°C/h , Observe the state of the liquid surface of the melt, at this time the liquid surface is stable;

[0044] (5) Seeding: Slowly adjust the height of the seed rod so that the lower end of the seed crystal is 4 mm above the liquid level. After 25 minutes of stability, start seeding. First, shrink the diameter of the seed crystal to 12 mm, and then seed the seed 8 times. The crystal diameter is gradually reduced to 6mm;

[0045] (6) Shoulder off: pull the seed crystal rod upwards at a speed of 0.1mm/h, while adjusting the heating voltage, cooling down at a rate of 0.5°C/h, part of the melt begins to crystallize around the seed crystal, this is a time for shouldering Stage: After 10 hours, when the crystal diameter reaches 80 mm, pull the seed rod upwards at a speed of 2mm/h, while adjusting the heating voltage, and reduce the temperature at a rate of 1℃/h. This is the rapid pulling stage; 10 After hours, the crystalline mass reaches 0.8 kg. Pull the seed rod upwards at a speed of 0.2mm/h, while adjusting the heating voltage to cool down at a rate of 2°C/h. This is the secondary shouldering stage;

[0046] (7) Retracting the shoulders: After 25 hours, the crystalline mass reaches 3.5 kg. Pull the seed rod upwards at a speed of 0.5/h, while adjusting the heating voltage to cool down at a rate of 1°C/h. At this time, the single crystal diameter begins to shrink;

[0047] (8) Iso-diameter growth: After 15 hours, the crystal mass reaches 4.5 kg, and the seed rod is pulled up at a speed of 0.2mm/h, while the heating voltage is adjusted, and the temperature is lowered at a rate of 2°C/h. At this time, the single crystal starts to grow with equal diameter, and the mass increases uniformly, and the mass increase rate is 700-800 g/h.

[0048] (9) Pull off: After 110 hours, when the crystal quality no longer increases, it indicates that the crystal has grown. At this time, the seed rod is quickly pulled up at a speed of 3mm/h to completely separate the crystal from the crucible wall;

[0049] (10) Cooling annealing: adjust the heating voltage, cooling down to 1500°C at a rate of 150°C/h, and annealing at a cooling rate of 20°C/h; when the temperature drops to 800°C, at a rate of 30-100°C/h Cool down until the heating voltage drops to zero; close the vacuum system and pass in high-purity argon for rapid cooling. When the furnace pressure is close to 10 5 When Pa, stop passing argon;

[0050] (11) Out of the furnace: After holding for 12 hours, open the inlet valve to make the pressure in the single crystal furnace the same as the outside, close the cooling water circulation system, open the single crystal furnace cover, take out the sapphire single crystal, and complete the entire process.

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Classification and recommendation of technical efficacy words

Quality improvement
Shorten the growth cycle

Kyropoulos method for quickly growing large-size sapphire single crystal

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

Examples

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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