CN111485283A - A kind of crystal growth device and growth method - Google Patents

Abstract

The invention discloses a crystal growth device, comprising an outer crucible and an inner crucible which are independent of each other, wherein the diameter of the inner crucible is smaller than the diameter of the outer crucible; The top of the inner crucible is provided with a crucible cover, the crucible cover is provided with an inner crucible fixing rod, the bottom of the inner crucible fixing rod is fixed on the crucible cover, and the top of the inner crucible fixing rod is connected to the furnace The body is connected; the bottom of the outer crucible is provided with a crucible support rod that controls the lifting and lowering of the outer crucible. At the same time, the invention also discloses a method for growing crystals by using the device. The crystal prepared by the growth device and the growth method of the present invention has no defects such as cracking, bubbles, inclusions, and scattering.

Description

A kind of crystal growth device and growth method

technical field

The invention relates to the field of crystal preparation, in particular to a crystal growth device and a growth method.

Background technique

The pulling method is a method of growing crystals from melts. It has the advantages of fast growth rate, easy observation and high crystal quality. It is widely used in the growth of silicon, germanium, sapphire, laser crystals and scintillation crystals.

After the raw material is melted in the crucible, the impurities in the raw material and the thermal field will float on the surface of the crucible and gather in the middle of the melt, which will affect the seeding and crystal growth. Cracking or decreased utilization. In addition, in the traditional pulling device and crystal growth method, with the progress of crystal growth, the melt in the crucible gradually decreases, the exposed surface of the crucible gradually increases, and the thermal radiation effect of the crucible on the crystal gradually increases, resulting in a near-crystal growth surface. The temperature gradient decreases gradually, which is easy to cause defects such as supercooling of components, interface inversion, wrapping, and cloud formation.

Therefore, it is necessary to design a new crystal growth device and growth method to solve the above-mentioned technical problems.

SUMMARY OF THE INVENTION

Based on this, the purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a crystal growth device and growth method.

In order to achieve the above object, the technical scheme adopted in the present invention is: a crystal growth device, comprising an outer crucible and an inner crucible independent of each other, the diameter of the inner crucible is smaller than the diameter of the outer crucible; the bottom of the inner crucible is A small hole is provided for the melt to flow in or out, a crucible cover is provided on the top of the inner crucible, an inner crucible fixing rod is arranged on the crucible cover, and the bottom of the inner crucible fixing rod is fixed on the crucible cover, The top of the inner crucible fixing rod is connected with the furnace body; the bottom of the outer crucible is provided with a crucible support rod that controls the lifting and lowering of the outer crucible.

Preferably, the diameter of the small hole is 2-5mm. The hole with a diameter of 2-5mm can effectively prevent impurities in the melt from entering the inner crucible, and also allow the melt to pass through.

Preferably, the bottom of the outer crucible is provided with a heat preservation device, the bottom of the heat preservation device is provided with a crucible holder, and the crucible support rod is provided at the bottom of the crucible holder.

At the same time, the present invention also provides a method for growing a crystal, using the above-mentioned growth device to grow a crystal.

Preferably, the crystal growth method includes the following steps:

S1, material chemical stage: the outer crucible is placed outside the inner crucible; the outer crucible is lowered so that the bottom of the inner crucible is higher than the top of the outer crucible; then the raw materials are placed in the outer crucible, and the temperature rises to melt the raw materials until the melt is stable;

S2. Crystal growth stage: slowly raise the outer crucible so that the melt in the outer crucible enters the inner crucible through the small hole at the bottom of the inner crucible; after the melt is stabilized, crystal growth is completed in the inner crucible.

More preferably, in step S2, after the crystal growth is completed, the outer crucible is slowly lowered, so that the melt flows into the outer crucible through the small hole at the bottom of the inner crucible, and the bottom of the inner crucible is higher than the top of the outer crucible, and then the melt is cooled. .

When the bottom of the inner crucible of the present application contacts the melt, the floating impurities in the melt center of the outer crucible will gather on the melt between the inner and outer crucibles, and finally adhere to the outer wall of the inner crucible. After the melt is stable, the crystal growth is completed in the inner crucible. After the crystal growth is completed, the outer crucible is slowly lowered so that the melt flows into the outer crucible through the small hole at the bottom of the inner crucible, and the bottom of the inner crucible is higher than the top of the outer crucible. After the melt is cooled, the uncrystallized tailings are kept in the outer crucible for easy cleaning.

Preferably, in step S2, after the crystal growth is completed, the descending rate of the outer crucible is 0.5-2 mm/h. During the descending process of the outer crucible, the crystal gradually moves away from the high-temperature melt and the outer crucible, the temperature field where the crystal is located changes, and the crystal gradually cools. Keeping the falling rate of the outer crucible at 0.5-2mm/h can reduce the thermal stress caused by the change of the crystal temperature field and prevent the crystal from cracking.

Preferably, in step S2, as the crystal growth proceeds, the outer crucible gradually rises, so that the melt in the outer crucible enters the inner crucible, and the liquid level in the inner crucible and the outer crucible is always maintained at the same height. The height of the liquid level remains unchanged, which can keep the temperature gradient in which the crystal grows consistent, and reduce the crystal growth defects caused by the change of the temperature gradient.

In addition, the present invention also provides a crystal prepared by the crystal growth method. The crystal prepared by the growth device and the growth method of the present application has no defects such as cracking, bubbles, inclusions, and scattering.

Preferably, the crystal is one of doped garnet crystal, doped yttrium vanadate crystal, doped yttrium lutetium silicate crystal, doped lithium niobate crystal, doped lithium tantalate crystal .

Compared with the prior art, the beneficial effects of the present invention are:

The crystal prepared by the growth device and the growth method of the present invention has no defects such as cracking, bubbles, inclusions, and scattering.

Description of drawings

1 is a schematic structural diagram of a crystal growth device according to the present invention;

FIG. 2 is a comparison diagram of the crystal scattering situation (left) without using the growth device and production method of the present invention and the scattering situation (right) of the crystal grown by using the growth device and production method of the present invention;

3 is a comparison diagram of the crystal dislocation situation (left) without using the growth device and production method of the present invention and the crystal dislocation situation (right) grown by using the growth device and production method of the present invention.

Among them, 1, outer crucible; 2, inner crucible; 3, crucible cover; 4, inner crucible fixing rod; 5, crucible bottom insulation; 6, crucible holder; 7, crucible support rod; 8, melt; 9, liquid level ; 10, seed rod; 11, crystal.

Detailed ways

In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

The schematic structural diagram of the crystal growth device according to the present invention is shown in FIG. 1 : it includes an outer crucible 1 and an inner crucible 2 that are independent of each other, and the diameter of the inner crucible 2 is smaller than that of the outer crucible 1; Small holes for inflow or outflow, the diameter of the small holes is 2-5mm; the top of the inner crucible 2 is provided with a crucible cover 3, the crucible cover 3 is provided with an inner crucible fixing rod 4, and the bottom of the inner crucible fixing rod 4 is fixed on the crucible cover 3 The top of the inner crucible fixing rod 4 is connected with the furnace body; the bottom of the outer crucible 1 is provided with a crucible support rod 7 that controls the lifting of the outer crucible 1, the bottom of the outer crucible 1 is provided with a heat preservation device 5, and the bottom of the heat preservation device 5 is provided with a crucible The holder 6 and the crucible support rod 7 are arranged at the bottom of the crucible holder 6 .

The crystal growth method of the present invention adopts the above-mentioned crystal growth device, and the specific steps are as follows:

S1, chemical material stage: lower the outer crucible 1, make the bottom of the inner crucible 2 higher than the top of the outer crucible 1, place the raw material in the outer crucible 1; heat up and melt the raw material, until the melt 8 is stable;

S2. Crystal growth stage: slowly rise the outer crucible 1, so that the melt in the outer crucible 1 enters the inner crucible 2 through the small hole at the bottom of the inner crucible 2; after the melt is stabilized, keep the height of the liquid level 9 unchanged, and lower the seed rod 10. Complete the growth of the crystal 11 in the inner crucible 2; after the growth of the crystal 11 is completed, slowly lower the outer crucible 1, and the lowering rate of the outer crucible is 0.5-2mm/h, so that the melt flows into the outer crucible 1 through the small hole at the bottom of the inner crucible 2 , and make the bottom of the inner crucible 2 higher than the top of the outer crucible 1 .

Example 1

An embodiment of the crystal growth method of the present invention, the crystal growth method described in this embodiment is carried out by using the above crystal growth device, and the specific steps are as follows:

Put 15kg of cerium-doped yttrium lutetium silicate polycrystalline raw material into the outer crucible, fix the inner crucible on the inner crucible fixing rod; adjust the height of the inner and outer crucibles so that the bottom of the inner crucible is higher than the top of the outer crucible. Turn on the power to enter the chemical stage, and start to heat up the chemical. After the material is finished, observe that the raw material is completely melted, and irregular particle impurities appear in the center of the outer crucible. The outer crucible is slowly raised through the crucible support rod, so that the inner crucible contacts the melt in the outer crucible, and the melt enters the inner crucible through a hole with a diameter of 2 mm at the bottom of the inner crucible. After the melt is stabilized, the seed rod is lowered to start crystal growth. During the crystal growth process, the outer crucible is slowly raised through the crucible support rod, and the melt level is kept at the same height. After the crystal growth is completed, slowly lower the outer crucible through the crucible support rod, and the lowering rate of the outer crucible is 0.5mm/h, so that the melt in the inner crucible enters the outer crucible through the hole at the bottom, and the bottom of the inner crucible is higher than the outer crucible. The top is lower than the bottom of the inner crucible.

The crystal prepared by the above-mentioned growth method is colorless, the crystal diameter is 80 mm, the length is 200 mm, and the crystal has no defects such as cracking, bubbles, inclusions, and scattering.

Example 2

An embodiment of the crystal growth method of the present invention, the crystal growth method described in this embodiment is carried out by using the above crystal growth device, and the specific steps are as follows:

9kg of cerium-doped gadolinium gallium aluminum garnet raw material was put into the outer crucible, and the inner crucible was fixed on the inner crucible fixing rod. Adjust the height of the inner and outer crucibles so that the bottom of the inner crucible is higher than the top of the outer crucible. Turn on the power to enter the chemical stage, and start to heat up the chemical. After the material is finished, observe that the raw material is completely melted, and irregular particle impurities appear in the center of the outer crucible. The outer crucible is slowly raised through the crucible support rod, so that the inner crucible contacts the melt in the outer crucible, and the melt enters the inner crucible through a hole with a diameter of 3 mm at the bottom of the inner crucible. After the melt is stabilized, the seed rod is lowered to start crystal growth. During the crystal growth process, the outer crucible is slowly raised through the crucible support rod, and the melt level is kept at the same height. After the crystal growth is over, slowly lower the outer crucible through the crucible support rod, and the lowering rate of the outer crucible is 1mm/h, so that the melt in the inner crucible enters the outer crucible through the bottom hole, and the bottom of the inner crucible is higher than the outer crucible. The top is lower than the bottom of the inner crucible.

The crystal prepared by the above-mentioned growth method is yellow, the crystal diameter is 60 mm, the length is 200 mm, and the crystal has no defects such as cracking, bubbles, inclusions, and scattering.

Example 3

An embodiment of the crystal growth method of the present invention, the crystal growth method described in this embodiment is carried out by using the above crystal growth device, and the specific steps are as follows:

27kg of neodymium-doped yttrium aluminum garnet raw material was put into the induction crucible, and the inner crucible was fixed on the inner crucible fixing rod. Adjust the height of the inner and outer crucibles so that the bottom of the inner crucible is higher than the top of the outer crucible. Turn on the power to enter the chemical stage, and start to heat up the chemical. After the material is finished, observe that the raw material is completely melted, and irregular particle impurities appear in the center of the outer crucible. The outer crucible is slowly raised through the crucible support rod, so that the inner crucible contacts the melt in the outer crucible, and the melt enters the inner crucible through a hole with a diameter of 5 mm at the bottom of the inner crucible. After the melt is stabilized, the seed rod is lowered to start crystal growth. During the crystal growth process, the outer crucible is slowly raised through the crucible support rod, and the melt level is kept at the same height. After the crystal growth is completed, the outer crucible is slowly lowered through the crucible support rod, and the lowering rate of the outer crucible is 2 mm/h, so that the melt in the inner crucible enters the outer crucible through the bottom hole, and the bottom of the inner crucible is higher than the outer crucible. The top is lower than the bottom of the inner crucible.

The crystal prepared by the above growth method is purple, the crystal diameter is 100 mm, the length is 200 mm, and the crystal has no defects such as cracking, bubbles, inclusions, and scattering.

Fig. 2 is a comparison diagram of the scattering situation of the crystal without using the growth device and production method of the present invention (left) and the scattering situation of the crystal grown by the growth device and production method of the present invention (right); Fig. 3 is the crystal without the growth device of the present invention. The comparison diagram of the crystal dislocation situation (left) of the production method and the crystal dislocation situation (right) grown by the growth device and the production method; it can be seen that the crystal prepared by the crystal growth device and the growth method has no Defects such as cracking, bubbles, inclusions, scattering, etc., the dislocation density is significantly reduced.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that, The technical solutions of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims (10)

1. A crystal growing apparatus, comprising an outer crucible and an inner crucible which are independent from each other, wherein the diameter of the inner crucible is smaller than that of the outer crucible; the bottom of the inner crucible is provided with a small hole for enabling melt to flow in or out, the top of the inner crucible is provided with a crucible cover, an inner crucible fixing rod is arranged on the crucible cover, the bottom of the inner crucible fixing rod is fixed on the crucible cover, and the top of the inner crucible fixing rod is connected with a furnace body; and a crucible supporting rod for controlling the outer crucible to lift is arranged at the bottom of the outer crucible.

2. The crystal growing apparatus of claim 1, wherein the diameter of said aperture is 2-5 mm.

3. The crystal growing apparatus according to claim 1, wherein a heat retaining device is provided at the bottom of the outer crucible, a susceptor is provided at the bottom of the heat retaining device, and the crucible support rod is provided at the bottom of the susceptor.

4. A method for growing a crystal, characterized in that the crystal is grown by using the growing apparatus of claim 1 to 3.

5. The method of growing a crystal according to claim 4, comprising the steps of:

s1, material melting stage: sleeving the outer crucible outside the inner crucible; lowering the outer crucible so that the bottom of the inner crucible is higher than the top of the outer crucible; then placing the raw materials in an outer crucible, and heating to melt the raw materials until the melt is stable;

s2, crystal growth stage: slowly raising the outer crucible to ensure that the melt in the outer crucible enters the inner crucible through a small hole at the bottom of the inner crucible; after the melt is stabilized, crystal growth is completed in the inner crucible.

6. The method of claim 5, wherein after the crystal growth is completed, the outer crucible is slowly lowered to allow the melt to flow into the outer crucible through the bottom aperture of the inner crucible and to allow the bottom of the inner crucible to be higher than the top of the outer crucible, and then the melt is cooled in step S2.

7. The method for growing a crystal according to claim 6, wherein in step S2, the lowering rate of the outer crucible after the crystal growth is completed is 0.5 to 2 mm/h.

8. A method for growing a crystal as defined in claim 5, wherein in step S2, the outer crucible is gradually raised as the crystal growth progresses, so that the melt in the outer crucible enters the inner crucible, and the liquid levels in the inner crucible and the outer crucible are always maintained at the same level.

9. A crystal produced by the crystal growth method according to any one of claims 4 to 8.

10. The crystal of claim 9, wherein the crystal is one of a doped garnet crystal, a doped yttrium vanadate crystal, a doped lutetium yttrium silicate crystal, a doped lithium niobate crystal, and a doped lithium tantalate crystal.

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