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Annealing method for lithium aluminate crystal

A lithium aluminate and crystal technology is applied in the field of annealing of lithium aluminate crystals, which can solve the problems of wafer warpage deformation, crystal quality influence, crystal warpage and the like, and achieves the effects of easy operation, improved yield and low cost

Inactive Publication Date: 2009-04-22
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, lithium aluminate crystals generally exist more or less Li during the growth process. 2 The volatilization of O causes the crystal to deviate from the stoichiometric ratio relatively seriously, which affects the quality of the crystal; in addition, the thermal stress generated during the crystal growth and cooling process will cause the crystal to warp or even crack during the slicing process.
The commonly used method to solve the above problems is to adopt vapor transport equilibrium (VTE) technology, which can restore the stoichiometric ratio of lithium aluminate crystals and effectively release the stress to a large extent, but the heat treatment of the wafer can easily lead to the damage of the wafer. warping

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] γ-LiAlO with a purity greater than 99.9% 2 Powder with Li with a purity greater than 99.9% 2 CO 3 The powder is evenly mixed and ground at a molar ratio of 1:x (x=0.2), then put into an alumina crucible, slowly heated up to 700°C, kept for 1 hour, and then slowly raised to 900°C, kept for 1 hour to obtain rich Lithium aluminate powder.

[0020] Put an appropriate amount of the lithium-rich lithium aluminate powder at the bottom of the alumina crucible, and then gently put the γ-LiAlO that needs to be annealed 2 Crystal, and then evenly disperse the above-mentioned lithium-rich lithium aluminate powder around the crystal, the lithium-rich lithium aluminate powder completely covers the γ-LiAlO that needs to be annealed 2 Crystal, the general requirements are: γ-LiAlO 2 The thickness of the lithium-rich lithium aluminate powder between the crystal and the bottom of the alumina crucible is not less than 1 cm, γ-LiAlO 2 The thickness of the lithium-rich lithium aluminat...

Embodiment 2

[0027] The lithium-rich lithium aluminate powder used in Example 1 and Li with a purity greater than 99.9% 2 CO 3 The powder is evenly mixed and ground at a molar ratio of 5:1, then put into an alumina crucible, slowly heated up to 700°C, and kept for 1 hour, then slowly raised to 900°C, kept for 1 hour, so as to obtain lithium-rich lithium aluminate Powder.

[0028] Put an appropriate amount of the above-mentioned lithium-rich lithium aluminate powder at the bottom of the alumina crucible, and then gently put the γ-LiAlO that needs to be annealed 2 Crystal, and then evenly disperse the above-mentioned lithium-rich lithium aluminate powder around the crystal, the lithium-rich lithium aluminate powder completely covers the γ-LiAlO that needs to be annealed 2 Crystal, the general requirements are: γ-LiAlO 2 The thickness of the lithium-rich lithium aluminate powder between the crystal and the bottom of the alumina crucible is not less than 1 cm, γ-LiAlO 2 The thickness of th...

Embodiment 3

[0031] This embodiment is γ-LiAlO with a purity greater than 99.9% and an average particle size of less than 300 microns 2 The powder is used as the lithium-rich lithium aluminate powder described in the present invention.

[0032] Put an appropriate amount of the above-mentioned lithium-rich lithium aluminate powder at the bottom of the alumina crucible, and then gently put the γ-LiAlO that needs to be annealed 2 Crystal, and then evenly disperse the above-mentioned lithium-rich lithium aluminate powder around the crystal, the lithium-rich lithium aluminate powder completely covers the γ-LiAlO that needs to be annealed 2 Crystal, the general requirement is: γ-LiAlO 2 The thickness of the lithium-rich lithium aluminate powder between the crystal and the bottom of the alumina crucible is not less than 1 cm, γ-LiAlO 2 The thickness of the lithium-rich lithium aluminate powder between the crystal and the inner wall of the alumina crucible is not less than 2 cm, γ-LiAlO 2 The t...

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Abstract

The invention relates to a method for annealing a lithium aluminate crystal, which is characterized by comprising the following steps: embedding a gamma-LiAlO2 crystal to be annealed into lithium aluminate powder rich in lithium in an alumina crucible; covering an aluminum cover of the alumina crucible, and then heating up the alumina crucible slowly to certain temperature of between 1 000 and 1,500 DEG C in a muffle furnace and keeping the temperature for 5 to 72 hours; and reducing the temperature to the room temperature slowly, and taking out the gamma-LiAlO2 crystal. Experiments show that the method can effectively release the residual stress in the lithium aluminate crystal and simultaneously avoid the nonstoichiometric ratio volatilization of the components of the lithium aluminate crystal at high temperature annealing, significantly improves the quality of the lithium aluminate crystal, makes the lithium aluminate crystal easy to be cut and processed into thinner wafers, significantly improves the yield of the lithium aluminate crystal wafers, and has the advantages of low cost, easy operation and the like.

Description

technical field [0001] The invention relates to lithium aluminate crystals, in particular to an annealing method for lithium aluminate crystals. technical background [0002] In 1997, the blue laser diode developed by Nichia Company using gallium nitride (GaN) has a continuous working life of more than 10,000 hours. At present, the mainstream technology uses substrates such as sapphire (Sapphire) and silicon carbide (SiC), and these substrates There is a large lattice mismatch and thermal mismatch with the GaN epitaxial film, which leads to the complexity of the preparation process and the high defect density caused by huge stress. The fundamental way to solve this problem is to use homogeneous substrate epitaxy, but there are great technical difficulties in the growth of GaN crystals because of its high vapor pressure, especially bulky bulk single crystals. Therefore, people are trying to explore other heterogeneous substrates that can replace GaN bulk single crystals and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B33/02C30B29/22
Inventor 周圣明林辉王军腾浩
Owner SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI