Device and method for adding seed crystals during crystal growth

Abstract

The invention belongs to the technical field of crystal growth, and particularly relates to a seed crystal adding device and method during crystal growth. The invention relates to a seed crystal adding device during crystal growth. The seed crystal adding device mainly comprises a growth container and a seed crystal storage device, the seed crystal storage device is arranged in the growth container; a gap exists between the inner diameter of the growth container and the outer diameter of the seed crystal storage device; the bottom of the seed crystal storage device is attached to the bottom of the growth container; and the top of the seed crystal storage device is an opening. In addition, the invention also provides an adding method of the seed crystal during crystal growth, and the seed crystal is added by using the adding method. According to the seed crystal adding device and the seed crystal adding method during crystal growth, the seed crystal after single crystal growth can be reused, meanwhile, growth crucible breakage caused by the fact that the size of the seed crystal is not matched with the size of a growth crucible is avoided, and polycrystal generation is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of crystal growth, and in particular relates to a device and method for adding seed crystals during crystal growth. Background Art

[0002] The mobile heater method is a method for growing cadmium zinc telluride or cadmium telluride single crystals. In the process of material loading, seed crystals are added, and alloy materials and feed materials are also added to the growth crucible. The growth crucible is then sealed and welded under high vacuum, placed in a heating furnace, and heated to a high temperature so that the alloy material dissolves a portion of the seed crystals, and cadmium zinc telluride or cadmium telluride single crystals grow.

[0003] During the heating process, the size of the seed crystal will affect the quality of single crystal growth. When the seed crystal size is inappropriate, for example, when the seed crystal size is too large, the seed crystal and the inner wall of the growth crucible fit tightly. When the heating furnace body is heated, the seed crystal expands, causing the growth crucible to break, resulting in material waste; and when the seed crystal size is too small, the gap between the seed crystal and the inner wall of the growth crucible is too large, which will cause the pure tellurium in the alloy material to melt and flow into the gap, corroding the outer wall of the seed crystal, resulting in polycrystalline growth, which is not conducive to the growth of single crystals. At the same time, the tellurium in the gap will also flow into the bottom area of ​​the seed crystal, corroding the bottom of the seed crystal, causing the tellurium inclusion particles to move upward as the single crystal gradually grows, deteriorating the quality of the seed crystal, and the seed crystal cannot be reused. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a device and method for adding seed crystals during crystal growth, which can enable the seed crystals to be reused after growing a single crystal, while avoiding the breakage of the growth crucible caused by the mismatch between the seed crystal and the growth crucible size, and avoiding the production of polycrystals.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a device for adding seed crystals during crystal growth, comprising a growth container and a seed crystal storage device; the seed crystal storage device is arranged inside the growth container; there is a gap between the inner diameter of the growth container and the outer diameter of the seed crystal storage device; the bottom of the seed crystal storage device is in contact with the bottom of the growth container; and the top of the seed crystal storage device is an opening.

[0006] A device for adding seed crystals during crystal growth includes a growth container and a seed crystal storage device. By using the adding device, after the seed crystals are used to grow a single crystal, the seed crystals after growth can be reused, while avoiding the generation of polycrystals. The seed crystal storage device is used to store the seed crystals, and the top is open, so that after the seed crystals are placed, the tellurium material on the top of the seed crystals will dissolve the seed crystals, and a single crystal will grow. The seed crystal storage device is placed inside the growth container, and the growth container provides a growth space for the growth of the single crystal.

[0007] Furthermore, the growth container includes a growth crucible and a closure; the growth crucible is a vertical tank body with an opening at the top, and the closure is arranged at the opening at the top of the growth crucible. After the material is loaded, the growth crucible and the closure are integrally connected to form a closed space.

[0008] The growth container includes a growth crucible and a closure. The top of the growth crucible has an opening. The closure is arranged at the opening at the top of the growth crucible. After the material is loaded, a vacuum is drawn to form a vacuum-enclosed space for the growth of single crystals.

[0009] Furthermore, a heating furnace body is provided outside the growth container, and a gap exists between the inner wall of the heating furnace body and the outer wall of the growth container; a heater is provided in the heating furnace body; a cavity exists inside the heating furnace body, and the growth container is provided in the cavity.

[0010] A heater is arranged in the heating furnace body, and a growth container is arranged in a cavity inside the heating furnace body to meet the temperature during the growth of the single crystal and enable the single crystal to grow.

[0011] Further, the bottom of the growth container is connected to the lifting device.

[0012] The lifting device can drive the growth container to move inside the cavity of the heating furnace to meet the different temperature requirements of the single crystal during and after the growth.

[0013] The present invention also provides a method for adding seed crystals during crystal growth, using the above-mentioned device for adding seed crystals during crystal growth to add seed crystals, and the method comprises the following steps: Step S1, processing the seed crystal, the outer diameter of the seed crystal is D1, the height is H1, the processed seed crystal is cleaned and dried, and loaded into a seed crystal storage device, the inner diameter of the seed crystal storage device is D2, the outer diameter is D21, and the height is H2, and the seed crystal is closely matched with the seed crystal storage device; Step S2, placing a seed crystal storage device containing seed crystals at the bottom of a growth crucible, the inner diameter of the growth crucible is D3, adding alloy material and feed into the growth crucible, adding a sealing piece to the top of the growth crucible, evacuating and sealing, and placing the sealed growth crucible in a heating furnace body so that the center area of ​​the tellurium material in the alloy material is located at the highest temperature position; Step S3, the heating furnace body starts to heat up to a specified temperature and maintains a constant temperature for 3 days, the lifting device is started, and the single crystal grows. After the growth is completed, the temperature of the heating furnace body is lowered to room temperature; Step S4, open the growth container, take out the single crystal, cut it radially after a specified length from the bottom of the seed crystal upward, and keep the cut seed crystal for next use.

[0014] Further, the single crystal is selected from one of a cadmium zinc telluride single crystal or a cadmium telluride single crystal; the molecular formula of the single crystal is Cd 1-x Zn x Te 1-y Se y (x=0~0.3, y=0~0.2).

[0015] Further, in step S1, the height H2 of the seed crystal storage device is (0.4-0.8)×H1; and the difference between the outer diameter D1 of the seed crystal and the inner diameter D2 of the seed crystal storage device is within 0.5 mm.

[0016] Furthermore, in step S2, the difference between the outer diameter D21 of the seed crystal storage device and the inner diameter D3 of the growth crucible is within 0.3 mm; the diameter of the alloy material is 95% to 99.5% of the inner diameter of the growth crucible, and the height is 15% to 100% of the inner diameter of the growth crucible.

[0017] Furthermore, in step S3, the heating furnace body starts to heat up to a specified temperature, which is 700°C to 1000°C.

[0018] Furthermore, in step S4, after a designated length is set upward from the bottom of the seed crystal, it is cut radially, and the designated length is 30-40 mm.

[0019] Beneficial Effects 1. The device and method for adding seed crystals during crystal growth of the present invention can avoid the risk of the growth crucible breaking during the heating process of the heating furnace body due to the mismatch between the seed crystal and the growth crucible size, thereby avoiding the waste of materials; 2. The device and method for adding seed crystals during crystal growth of the present invention can prevent tellurium material in the alloy material from flowing into the outside of the seed crystal and causing the formation of sidewall polycrystals, thereby facilitating the growth of single crystals; 3. The device and method for adding seed crystals during crystal growth of the present invention can prevent tellurium material in the alloy material from flowing into the bottom area of ​​the seed crystal, corroding the bottom of the seed crystal, and causing the tellurium material to migrate in the seed crystal; 4. The device and method for adding seed crystals during crystal growth of the present invention can ensure that the seed crystals after the single crystal is grown are of good quality and can be reused, thus saving resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a device for adding seed crystals during crystal growth; Figure 2 is a picture of the top of the cadmium zinc telluride seed crystal obtained by the addition method of Example 2; Figure 3 This is a picture of the bottom of the cadmium zinc telluride seed crystal obtained by the addition method of Example 2.

[0021] In the accompanying drawings: 1. growth container; 2. seed crystal storage device; 11. growth crucible; 12. closure member. DETAILED DESCRIPTION

[0022] The present invention is further illustrated by specific examples below. These examples are exemplary and are intended to illustrate the problem and explain the present invention, but are not intended to be limiting.

[0023] Example 1 like Figure 1 The device for adding seed crystals during crystal growth shown in the figure comprises a growth container 1 and a seed crystal storage device 2; the seed crystal storage device 2 is a pyrolytic boron nitride ceramic crucible, which is arranged inside the growth container 1; there is a gap between the inner diameter of the growth container 1 and the outer diameter of the seed crystal storage device 2; the bottom of the seed crystal storage device 2 is fitted with the bottom of the growth container 1; and the top of the seed crystal storage device 2 is an opening.

[0024] A device for adding seed crystals during crystal growth includes a growth container 1 and a seed crystal storage device 2. By using the adding device, after the seed crystals are used to grow a single crystal, the seed crystals can be reused after the growth is completed, while avoiding the generation of polycrystals. The seed crystal storage device 2 is a pyrolytic boron nitride ceramic crucible, which is resistant to high temperatures, has high mechanical strength, a smooth surface without pores, higher purity, and is easy to clean. The seed crystal storage device 2 is used for storing seed crystals, and the top is open, so that after the seed crystals are placed, the tellurium material on the top of the seed crystals will dissolve the seed crystals, and a single crystal will grow. The seed crystal storage device 2 is placed inside the growth container 1, and the growth container 1 provides a growth space for the growth of single crystals.

[0025] The growth container 1 includes a growth crucible 11 and a closure 12; the growth crucible 11 is a quartz crucible, which is a vertical tank with an opening at the top; the closure 12 is a quartz plug, which is arranged at the opening at the top of the growth crucible 11. After the material is loaded, the growth crucible 11 and the closure 12 are integrally connected to form a closed space.

[0026] The growth container 1 includes a growth crucible 11 and a closure 12. The growth crucible 11 is a quartz crucible with large size, high precision, strong temperature resistance, good heat preservation and stable quality. The growth crucible 11 has an opening at the top, and the closure 12 is arranged at the opening at the top of the growth crucible 11. After the material is loaded, a vacuum is drawn to form a vacuum-tight space for the growth of single crystals.

[0027] A heating furnace body is provided outside the growth container 1, and a gap exists between the inner wall of the heating furnace body and the outer wall of the growth container 1; a heater is provided in the heating furnace body; a cavity exists inside the heating furnace body, and the growth container 1 is provided in the cavity.

[0028] A heater is arranged in the heating furnace body, and the growth container 1 is arranged in the cavity inside the heating furnace body to meet the temperature during the growth of the single crystal, so that the single crystal can grow.

[0029] The bottom of the growth container 1 is connected to the lifting device.

[0030] The lifting device can drive the growth container 1 to move inside the cavity of the heating furnace to meet the different temperature requirements of the single crystal during and after the growth.

[0031] Example 2 A method for adding seed crystals during the growth of cadmium zinc telluride single crystals comprises the following steps: Step S1, processing the seed crystal required for growing the cadmium zinc telluride single crystal, the seed crystal is a directional seed crystal, the outer diameter D1 of the seed crystal is 74 mm, and the height H1 is 30 mm; Step S2, ultrasonically clean the processed seed crystal with deionized water and dry it, and then load the dried seed crystal into a pyrolytic boron nitride ceramic crucible, wherein the height H2 of the pyrolytic boron nitride ceramic crucible is 40 mm, the inner diameter D2 is 74.1 mm, and the outer diameter D21 is 75 mm. The difference between the outer diameter D1 of the seed crystal and the inner diameter D2 of the pyrolytic boron nitride ceramic crucible is controlled within 0.1 mm, so that the seed crystal is closely matched with the inner wall of the pyrolytic boron nitride ceramic crucible; Step S3, placing a pyrolytic boron nitride ceramic crucible containing seed crystals at the bottom of a quartz crucible, the inner diameter D3 of the quartz crucible is 75.2 mm, so that the difference between the outer diameter D21 of the pyrolytic boron nitride ceramic crucible and the inner diameter D3 of the quartz crucible is controlled within 0.3 mm, and then adding a tellurium and cadmium zinc telluride alloy material into the quartz crucible, the alloy material is a column material, the diameter is 98% of the diameter of the quartz crucible, and the height is 90% of the inner diameter of the quartz crucible, and then adding cadmium zinc telluride feed; Step S4, adding a quartz plug on the top of the cadmium zinc telluride feedstock to evacuate the chamber, placing the quartz crucible under high vacuum <10E-5 Torr, and sealing the quartz plug with the quartz crucible to form a high vacuum closed space; Step S5, placing the sealed quartz crucible in a heating furnace body so that the center of the tellurium material in the alloy material is located at the highest temperature point; Step S6, heating the furnace body to 980°C at a heating rate of 30°C / h, maintaining the constant temperature for 3 days, starting the quartz crucible lifting device to lower the quartz crucible, and growing the CdZnTe single crystal at a rate of 10 mm / day; Step S7, after the CdZnTe single crystal grows to a specified length, the temperature of the heating furnace is slowly lowered to room temperature at a rate of 30°C / d; Step S8, open the quartz crucible, take out the cadmium zinc telluride single crystal, cut it radially from 40 mm above the bottom of the seed crystal, and keep the cut seed crystal for next use.

[0032] Morphological Analysis of CdZnTe Seed Crystals Figure 2 is a picture of the top of the cadmium zinc telluride seed crystal obtained by the addition method of Example 2; Figure 3 This is a picture of the bottom of the cadmium zinc telluride seed crystal obtained by the addition method of Example 2.

[0033] No tellurium inclusions were found on the top of the CdZnTe seed crystal obtained by the adding method of Example 2, and the bottom of the CdZnTe seed crystal was not corroded, thereby improving the quality of the CdZnTe seed crystal after the CdZnTe single crystal was grown, and allowing the CdZnTe seed crystal to be reused.

Claims

1. A device for adding seed crystals during crystal growth, characterized in that: It comprises a growth container (1) and a seed crystal storage device (2); the seed crystal storage device (2) is arranged inside the growth container (1); there is a gap between the inner diameter of the growth container (1) and the outer diameter of the seed crystal storage device (2); the bottom of the seed crystal storage device (2) fits with the bottom of the growth container (1); and the top of the seed crystal storage device (2) is open.

2. The device for adding seed crystals during crystal growth according to claim 1, characterized in that: The growth container (1) comprises a growth crucible (11) and a closure member (12); the growth crucible (11) is a vertical tank body having an opening at the top; the closure member (12) is arranged at the opening at the top of the growth crucible (11); after the material is loaded, the growth crucible (11) and the closure member (12) are integrally connected to form a closed space.

3. The device for adding seed crystals during crystal growth according to claim 2, characterized in that: A heating furnace body is provided outside the growth container (1), and a gap exists between the inner wall of the heating furnace body and the outer wall of the growth container (1); a heater is provided in the heating furnace body; a cavity exists inside the heating furnace body, and the growth container (1) is provided in the cavity.

4. The device for adding seed crystals during crystal growth according to claim 3, characterized in that: The bottom of the growth container (1) is connected to a lifting device.

5. A method for adding seed crystals during crystal growth, characterized in that: The seed crystal is added by using the device for adding seed crystal during crystal growth as claimed in claim 4, and the method comprises the following steps: Step S1, processing the seed crystal, the outer diameter of the seed crystal is D1, the height is H1, the processed seed crystal is cleaned and dried, and loaded into a seed crystal storage device, the inner diameter of the seed crystal storage device is D2, the outer diameter is D21, and the height is H2, and the seed crystal is closely matched with the seed crystal storage device; Step S2, placing a seed crystal storage device containing seed crystals at the bottom of a growth crucible, the inner diameter of the growth crucible is D3, adding alloy material and feed into the growth crucible, adding a sealing piece to the top of the growth crucible, evacuating and sealing, and placing the sealed growth crucible in a heating furnace body so that the center area of ​​the tellurium material in the alloy material is located at the highest temperature position; Step S3, the heating furnace body starts to heat up to a specified temperature and maintains a constant temperature for 3 days, the lifting device is started, and the single crystal grows. After the growth is completed, the temperature of the heating furnace body is lowered to room temperature; Step S4, open the growth container, take out the single crystal, cut it radially after a specified length from the bottom of the seed crystal upward, and keep the cut seed crystal for next use.

6. The method for adding seed crystals during crystal growth according to claim 5, characterized in that: The single crystal is selected from a cadmium zinc telluride single crystal or a cadmium telluride single crystal; the molecular formula of the single crystal is Cd 1-x Zn x Te 1-y Se y (x=0~0.3, y=0~0.2).

7. The method for adding seed crystals during crystal growth according to claim 5, characterized in that: In step S1, the height H2 of the seed crystal storage device is (0.4-0.8)×H1; the difference between the outer diameter D1 of the seed crystal and the inner diameter D2 of the seed crystal storage device is within 0.5 mm.

8. The method for adding seed crystals during crystal growth according to claim 5, characterized in that: In step S2, the difference between the outer diameter D21 of the seed crystal storage device and the inner diameter D3 of the growth crucible is within 0.3 mm; the diameter of the alloy material is 95% to 99.5% of the inner diameter of the growth crucible, and the height is 15% to 100% of the inner diameter of the growth crucible.

9. The method for adding seed crystals during crystal growth according to claim 5, characterized in that: In step S3, the heating furnace body starts to heat up to a specified temperature, which is 700°C to 1000°C.

10. The method for adding seed crystals during crystal growth according to claim 5, characterized in that: In step S4, the seed crystal is cut radially after being provided with a designated length upward from the bottom of the seed crystal, wherein the designated length is 30 to 40 mm.

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