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Growth apparatus for large-areaed crystal by temperature gradient technique and crystal growth method thereof

A growth device and large-area technology, applied in crystal growth, single crystal growth, chemical instruments and methods, etc., can solve the problems of inability to grow crystals, crystal cracking, and high cost

Inactive Publication Date: 2004-03-31
SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this device still has disadvantages: during the growth process, a large amount of flowing helium gas is required to establish a temperature gradient, and the device is complex and costly.
The disadvantage is that when growing crystals with a particularly high melting point size greater than 120mm (such as Al 2 o 3 When the melting point is 2050°C), the temperature difference between the upper and lower sides of the furnace reaches about 200-350°C, and the maximum temperature reaches about 2350°C, while the softening temperature of the molybdenum material used in the crucible and insulation screen is about 2200°C in a carbon (C)-containing atmosphere, which will make The crucible and insulation screen are destroyed, and the crystal cannot be grown
In addition, since the temperature gradient of this method is basically fixed during the growth process, the temperature gradient cannot be dynamically adjusted, and it is easy to crack when growing larger-area crystals, especially when growing calcium fluoride crystals (CaF 2 ) and yttrium aluminate crystals (YAlO 3 ), the crystal is severely cracked, or there are a large number of mosaic structures in the crystal

Method used

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  • Growth apparatus for large-areaed crystal by temperature gradient technique and crystal growth method thereof
  • Growth apparatus for large-areaed crystal by temperature gradient technique and crystal growth method thereof
  • Growth apparatus for large-areaed crystal by temperature gradient technique and crystal growth method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Carry out calcium fluoride crystal (CaF 2 ) growth

[0036] Graphite (C) crucible 1 has a size of Ф220×250 mm, and is a conical crucible with a seed crystal groove in the center of the bottom. The graphite heating element 2 is barrel-shaped, and the inner layer of the insulation screen is lined with a molybdenum cylinder of tungsten sheets. [111] Oriented seeds. 10kg CaF 2 Powder and 1kg PbF 2 After the powder was mixed in the mixer for 24 hours, 1% of PbF 2 The powder is used as a deoxidation scavenger, with 2t / cm 2 The isostatic pressing block, or CaF 2 The crystal block material is directly loaded into the crucible 1, sealed with a graphite crucible cover, placed in a temperature gradient furnace, and heated up to 800°C (thermocouple 5) while vacuuming, and filled with a high-purity argon protective atmosphere to 1 atmosphere. By adjusting the main heating element and the auxiliary heating element, the temperature is independently controlled respectively, and ...

Embodiment 2

[0037] Embodiment 2: carry out sapphire crystal (Al 2 o 3 ) growth

[0038] The crucible 1 made of molybdenum (Mo) has a size of Ф160×180 mm, and is a conical crucible with a seed crystal groove in the center of the bottom. The graphite heating element 2 is barrel-shaped, and the inner layer of the insulation screen is lined with a molybdenum cylinder of tungsten sheets. [0001] Orientation Seed. Sapphire (Al 2 o 3 ) powder with 2t / cm 2 The isostatic pressure forging block, or sapphire (Al 2 o 3 ) crystal block material, directly put into the crucible 1, place in the temperature gradient furnace, heat up to 1000°C (thermocouple 5) while vacuuming, fill the high-purity argon protective atmosphere to 1 atmosphere, adjust the main heating element and The temperature of the auxiliary heating element is independently controlled. After forming a stable and suitable thermal field, two sets of intelligent temperature controllers will automatically complete the whole process of ...

Embodiment 3

[0039] Embodiment 3: Carry out garnet crystal (Y 3 al 5 o 12 ) growth

[0040] The crucible 1 made of molybdenum (Mo) has a size of Ф160×180 mm, and is a conical crucible with a seed crystal groove in the center of the bottom. The graphite heating element 2 is barrel-shaped, and the inner layer of the insulation screen is lined with a molybdenum cylinder of tungsten sheets. [111] Oriented seeds. The 5:3 stoichiometric ratio of Al 2 o 3 and Y 2 o 3 After the powder is mixed in the mixer for 24 hours, use 2t / cm 2 isostatic pressure forging into blocks, put it directly into the crucible 1, place it in a temperature gradient furnace, raise the temperature to 1000°C (thermocouple 5) while vacuuming, fill the high-purity argon protective atmosphere to 1 atmosphere, and adjust the main The temperature of the heating element and the auxiliary heating element are independently controlled. After forming a stable and suitable thermal field, two sets of intelligent temperature co...

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PUM

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Abstract

A temperature-gradient device for growing crystals with large area and a method of growing crystals. The device comprises a bell-like vacuum resistance oven, cone crucible and a heater in the oven, the crucible at the center of the oven, the heater comprising main cylinder heater of graphite and auxiliary cone heater with an irregular shape, vacuum system, UPS regulated power supply, two sets of controllable silicon trigger circuits, two sets of temperature controllers. The device could adjust automatically temperature gradient in growing crystals.The invention could grow complete nonsplitingcrystals with the size of more than 5 inch.

Description

technical field [0001] The present invention relates to vertical temperature gradient condensation crystallization method (VGF) crystal growth method and its device, especially a kind of temperature gradient method growth device of large-area crystal and its method for crystal growth, for easily cracked crystals, such as calcium fluoride crystal (CaF 2 ), yttrium aluminate crystals (YAlO 3 ), garnet crystals (Y 3 Al 5 o 12 ) and sapphire crystal (Al 2 0 3 ), etc. can grow complete uncracked crystals larger than 5 inches in diameter. Background technique [0002] In 1970, scientists F.Schmid and D.J.Viechnicki of Crystal Systems Inc. (CSI) in the American Ceramic Society, Volume 53, Issue 9 (J.Am.Ceramic Society53(9)528(1970)) Published the article "Growth of Sapphire Disks from the Melt by a Gradient Furnace Technique" (Growth of Sapphire Disks from the Melt by a Gradient Furnace Technique), and proposed for the first time to use the Heat Exchanger Method (HEM) to grow...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B11/00
Inventor 周国清徐军司继良赵广军邓佩珍
Owner SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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