Single crystal growth device and single crystal growth method

Abstract

The invention provides a single crystal growth device and a single crystal growth method.The single crystal growth device comprises a furnace body, a feeding mechanism and a crystal growth mechanism located in the furnace body, the crystal growth mechanism comprises a crucible assembly and a supporting mechanism, and the crucible assembly comprises an auxiliary crucible, a crystal growth crucible and a flow guide pipe. The raw materials are continuously and uniformly added into the crystal growth crucible through the auxiliary crucible, so that component segregation and single crystal raw material volatilization caused by long-time melting of the raw materials are effectively inhibited. According to the single crystal growth device and the single crystal growth method, the single crystal with uniform chemical components and piezoelectric properties can be grown.

Description

Technical Field

[0001] The present application relates to the technical field of crystal growth, and in particular to a single crystal growth device and a single crystal growth method. Background Art

[0002] Perovskite structure relaxor ferroelectric single crystal is the latest high-performance piezoelectric material developed internationally. The representative single crystal product with practical value is lead magnesium niobate-lead titanate (molecular formula is (1-x) [Pb (Mg 1 / 3 Nb 2 / 3 )O3]-x[PbTiO3], referred to as PMN-PT, abbreviated as PMNT) and lead indium niobate-lead magnesium niobate-lead titanate (molecular formula x[Pb(In 1 / 2 Nb 1 / 2 )O3]-y[Pb(Mg 1 / 3 Nb 2 / 3 )O3]-z[PbTiO3], where x+y+z=1, referred to as PIN-PMN-PT, abbreviated as PIMNT). This type of single crystal material has high piezoelectricity, high strain, high electromechanical coupling coefficient and high energy storage density. In particular, the piezoelectric performance is about 10 times higher than that of ordinary piezoelectric materials. It has great application value in many fields such as medical ultrasound imaging, underwater acoustic systems, and high strain actuators.

[0003] At present, the most commonly used method for growing relaxor ferroelectric single crystals is the crucible descent method. However, relaxor ferroelectric single crystal raw materials contain many components, mainly PbO, MgO, TiO2, Nb2O5, and In2O3. The segregation coefficients of each component in the melt are different, and PbO is volatile. Therefore, in the general crucible descent method of single crystal growth (putting the raw materials into the crystal growth crucible at one time), the crystal composition changes continuously from bottom to top, which causes the crystal performance to change continuously from bottom to top. High-end piezoelectric devices, such as underwater acoustic transducers and B-ultrasound probes, are combined and used by many relaxor ferroelectric single crystals. High-quality imaging requires not only a large piezoelectric constant of the crystal, but also good consistency of the piezoelectric constants between each crystal. The conventional crucible descent method for growing relaxor ferroelectric single crystals can no longer meet the requirements of good consistency of piezoelectric constants. Summary of the invention

[0004] The purpose of this application is to provide a single crystal growth device and a single crystal growth method to improve the uniformity of crystal composition and piezoelectric performance. The specific technical solution is as follows:

[0005] The first aspect of the present application provides a single crystal growth device, which includes: a furnace body, a feeding mechanism and a crystal growth mechanism located inside the furnace body, the furnace body includes a heat preservation layer and multiple heating components; the crystal growth mechanism includes a crucible assembly and a supporting mechanism; the crucible assembly includes an auxiliary crucible, a crystal growth crucible and a guide tube, the auxiliary crucible is formed by connecting an inner crucible and an outer crucible, a gap is provided between the side wall and the bottom of the inner crucible and the inner surface of the outer crucible, a plurality of holes are provided around the lower part of the side wall of the inner crucible, the crystal growth crucible includes a body and a crucible cover, the bottom of the outer crucible is connected to the crystal growth crucible cover through a guide tube; the feeding mechanism is arranged above the furnace body, and is connected to the inner crucible through the feeding tube; the furnace body and the crystal growth mechanism can move relative to each other in the vertical direction.

[0006] The single crystal growth device of the present application can realize continuous feeding during the crystal growth process, ensure that the concentration of each component in the melt remains unchanged during the entire crystal growth process, avoid uneven crystal composition due to different segregation coefficients of each component in the melt, and can reduce the volatilization of crystal raw materials and improve the uniformity of crystal performance.

[0007] In some embodiments of the present application, the outer diameter of the inner crucible is 0.5 to 0.9 times the inner diameter of the outer crucible; and the distance between the hole on the side wall of the inner crucible and the bottom of the inner crucible is 0.5 cm to 1.5 cm.

[0008] In some embodiments of the present application, the upper portion of the crystal growth crucible is cylindrical, and the lower portion is a seed crystal well. The seed crystal well and the upper portion of the crystal growth crucible have a conical transition portion, and the taper angle of the conical transition portion is 20°C to 60°C; the seed crystal well is a small cylinder with a sealed bottom, and the seed crystal is contained in the seed crystal well.

[0009] In some embodiments of the present application, the support mechanism includes a bracket and a support rod, the upper end of the bracket is used to fix the auxiliary crucible, and the lower end of the bracket is connected to the support rod; the top end of the support rod is used to support the crystal growth crucible.

[0010] In some embodiments of the present application, the single crystal growth device also includes a crucible lifting device and / or a furnace body lifting device, the upper end of the crucible lifting device is connected to the bottom end of the support rod, the upper end of the furnace body lifting mechanism is connected to the furnace body, and the lower ends of the crucible lifting device and the furnace body lifting device are connected to the base.

[0011] In some embodiments of the present application, the plurality of heating components are used to control the temperature at different locations within the furnace.

[0012] The second aspect of the present application provides a use of the single crystal growth device provided in the first aspect of the present application for growing a relaxor ferroelectric single crystal.

[0013] In some embodiments of the present application, the relaxor ferroelectric single crystal is selected from lead magnesium niobate-lead titanate or lead indium niobate-lead magnesium niobate-lead titanate.

[0014] The third aspect of the present application provides a single crystal growth method using the single crystal growth device provided in the first aspect of the present application, wherein the method is a continuous feeding crucible descent method.

[0015] In some embodiments of the present application, the single crystal growth method comprises the following steps:

[0016] Put seed crystals and raw materials with a height of 5 mm to 20 mm in the crystal growth crucible, fill the part below the inner crucible circumferential hole of the auxiliary crucible with raw materials, and put raw materials in the feeding mechanism;

[0017] Controlling the temperature of the auxiliary crucible to be at the melting temperature of the raw material to melt the raw material;

[0018] Crystal growth is carried out by lowering the crucible or raising the furnace body, so that the seed crystal position in the upper middle part of the seed crystal is used as the starting point of crystal growth, and the temperature here is controlled at the crystal growth temperature; the longitudinal temperature gradient of the crystal growth area in the furnace body and the crucible lowering speed or the furnace body rising speed are controlled, and the feeding speed is controlled so that the raw materials in the feeding mechanism enter the auxiliary crucible through the feeding pipe, and enter the crystal growth crucible through the guide pipe after the auxiliary crucible is melted.

[0019] In some embodiments of the present application, the feed rate is: ρπ(A / 2) 2 V g / day, where ρ is the crystal density, A is the diameter of the crystal growth crucible, and V is the crucible descent speed or the furnace ascent speed.

[0020] In some embodiments of the present application, the single crystal is a relaxor ferroelectric single crystal, the relaxor ferroelectric single crystal is selected from lead magnesium niobate-lead titanate or lead indium niobate-lead magnesium niobate-lead titanate, the melting temperature is 1320°C to 1400°C, the crystal growth temperature is 1280°C to 1290°C, the longitudinal temperature gradient is 0°C / cm to 40°C / cm, and the crucible descent speed or the furnace rise speed is 0.5 cm / day to 2 cm / day.

[0021] Beneficial effects of this application:

[0022] The present application provides a single crystal growth device and a single crystal growth method. By continuously adding materials during the crystal growth process, the component segregation and volatilization of the single crystal raw materials can be effectively suppressed, so that the crystal components are more uniform, and the performance parameters such as the crystal piezoelectric coefficient vary less, thereby improving the overall uniformity of the crystal composition and improving the overall stability of the crystal performance. The improvement of the overall uniformity of the crystal composition can make greater use of the entire crystal rod, reduce the proportion of waste materials, improve the processing utilization rate of materials, and reduce the production cost of single crystal materials. The single crystal growth device and the single crystal growth method provide the possibility of preparing relaxor ferroelectric single crystals with higher performance and larger size, further broadening the technical application space of relaxor ferroelectric single crystals.

[0023] Of course, implementing any product or method of the present application does not necessarily require achieving all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0025] Figure 1 A diagram of a crystal growth apparatus according to an embodiment of the present application.

[0026] In the figure, 1. feeding mechanism, 2. feeding pipe, 3. auxiliary crucible, 4. bracket, 5. guide tube, 6. heating component, 7. insulation layer, 8. crystal growth crucible, 9. seed crystal well, 10. support rod, 11. crucible lifting mechanism, 12. furnace body lifting mechanism, 13. base, 14. furnace body. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the present application belong to the scope of protection of the present application.

[0028] The traditional crucible descent method for growing single crystals is to add all the raw materials into the crucible at once before the crystal growth begins. Since the raw materials cannot be replenished during the growth process, the concentration of each component in the melt may change with the growth of the crystal, causing the crystal composition to change continuously from bottom to top, thereby causing the crystal performance to change continuously from bottom to top. The grown crystals are only suitable for fields with low requirements for crystal quality and cannot meet the application fields that require high-quality and high-uniformity crystals. Based on this, the present application provides a single crystal growth device and a single crystal growth method to improve the uniformity of the crystal and expand the application field of the crystal.

[0029] like Figure 1 As shown, the first aspect of the present application provides a single crystal growth device, which includes: a furnace body 14, a feeding mechanism 1 and a crystal growth mechanism located inside the furnace body, the furnace body 14 includes a heat preservation layer 7 and a plurality of heating components 6; the crystal growth mechanism includes a crucible assembly and a support mechanism; the crucible assembly includes an auxiliary crucible 3, a crystal growth crucible 8 and a guide tube 5, the auxiliary crucible 3 is formed by connecting an inner crucible and an outer crucible, a gap is provided between the side wall and the bottom of the inner crucible and the inner surface of the outer crucible, a plurality of holes are provided around the lower part of the side wall of the inner crucible, the crystal growth crucible 8 includes a body and a crucible cover, and the bottom of the outer crucible is connected to the crystal growth crucible cover through the guide tube 5; the feeding mechanism 1 is arranged above the furnace body and is connected to the inner crucible through the feeding tube 2; the furnace body 14 and the crystal growth mechanism can move relative to each other in the vertical direction. In some embodiments of the present application, the plurality of heating components 6 are used to control the temperature at different positions in the furnace body.

[0030] like Figure 1 As shown, the feeding mechanism 1 can evenly add the pre-prepared single crystal raw material into the inner crucible through the feeding tube 2. Through the heating and temperature control of the heating component 6, the raw material melts at the bottom of the inner crucible, flows into the outer crucible along the holes on the side wall of the inner crucible, and then flows into the crystal growth crucible 8 through the guide tube 5, thereby realizing continuous feeding during the crystal growth process, reducing the component changes caused by the volatilization of the raw material in the molten state in the crystal growth crucible for a long time, making the crystal composition and performance more uniform, and improving the overall performance of the crystal.

[0031] In some embodiments of the present application, Figure 1 As shown, the outer diameter of the inner crucible is 0.5 to 0.9 times the inner diameter of the outer crucible; the distance between the hole on the side wall of the inner crucible and the bottom of the inner crucible is 0.5 cm to 1.5 cm. The above structural design allows the single crystal raw material to be fully melted at the bottom of the inner crucible before flowing into the crystal growth crucible 8, which is conducive to obtaining highly uniform crystals.

[0032] In some embodiments of the present application, Figure 1As shown, the upper part of the crystal growth crucible 8 is cylindrical, and the lower part is a seed crystal well 9. The seed crystal well 9 and the upper part of the crystal growth crucible 8 have a tapered transition portion, and the taper angle of the tapered transition portion is 20°C to 60°C; the seed crystal well 9 is a small cylinder with a sealed bottom, and the seed crystal well 9 is filled with seed crystals.

[0033] In some embodiments of the present application, Figure 1 As shown, the support mechanism includes a bracket 4 and a support rod 10. The upper end of the bracket 4 is used to fix the auxiliary crucible 3, and the lower end of the bracket 4 is connected to the support rod 10; the top of the support rod 10 is used to support the crystal growth crucible 8. Through the above structural design, the entire crucible assembly can be stably maintained in the furnace body 14, so that the crystal growth process can be carried out continuously and stably.

[0034] In some embodiments of the present application, Figure 1 As shown, the single crystal growth device further includes a crucible lifting device 11 and / or a furnace lifting device 12, the upper end of the crucible lifting device 11 is connected to the bottom end of the support rod 10, the upper end of the furnace lifting mechanism 12 is connected to the furnace body 14, and the lower ends of the crucible lifting device 11 and the furnace lifting device 12 are connected to the base 13. Through the above-mentioned crucible lifting device 11 and / or furnace lifting device 12, the rise or fall of the crucible assembly and / or the furnace body 14 can be controlled.

[0035] In this application, if Figure 1 As shown, the feeding tube 2, the auxiliary crucible 3, the guide tube 5 and the crystal growth crucible 8 are all made of platinum with a thickness of 0.2 mm to 1.0 mm. The thicknesses of the feeding tube 2, the auxiliary crucible 3, the guide tube 5 and the crystal growth crucible 8 can be the same or different, as long as they are within the scope of this application and can achieve the purpose of this application.

[0036] In this application, if Figure 1 As shown, there is no particular limitation on the preparation method of the feeding tube 2, the auxiliary crucible 3, the flow guide tube 5 and the crystal growth crucible 8, as long as the purpose of the present application can be achieved. For example, they can be made by welding or by spinning.

[0037] In this application, if Figure 1 As shown, there is no particular limitation on the connection method of the inner crucible and the outer crucible, as long as the purpose of the present application can be achieved. For example, the connection can be made by welding.

[0038] In this application, if Figure 1 As shown, there is no particular limitation on the materials of the bracket 4 and the support rod 10, as long as the purpose of the present application can be achieved. For example, high temperature resistant ceramics can be selected.

[0039] In this application, if Figure 1As shown, there is no particular limitation on the material of the thermal insulation layer 7 as long as the purpose of the present application can be achieved. For example, microporous foam ceramic material can be used, which has the advantages of high temperature resistance (1800°C), high strength, no slag, heat vibration resistance, and no volatile pollution.

[0040] The second aspect of the present application provides a use of the single crystal growth device provided in the first aspect of the present application for growing a relaxor ferroelectric single crystal.

[0041] In some embodiments of the present application, the relaxor ferroelectric single crystal is selected from lead magnesium niobate-lead titanate or lead indium niobate-lead magnesium niobate-lead titanate. The above relaxor ferroelectric single crystal has the advantages of high voltage, high strain, high electromechanical coupling coefficient and high energy storage density.

[0042] The third aspect of the present application provides a single crystal growth method, using the single crystal growth device provided in the first aspect of the present application, such as Figure 1 As shown, the method is a continuous feeding crucible descending method, the single crystal is a relaxor ferroelectric single crystal, and the relaxor ferroelectric single crystal is selected from lead magnesium niobate-lead titanate or lead indium niobate-lead magnesium niobate-lead titanate. It includes the following steps:

[0043] Put seed crystals and raw materials with a height of 5 mm to 20 mm in the crystal growth crucible 8, fill the part below the inner crucible circumferential hole of the auxiliary crucible 3 with raw materials, and put raw materials in the feeding mechanism 1;

[0044] Control the temperature of the auxiliary crucible 3 to be at the melting temperature of the raw material, the melting temperature is 1320° C. to 1400° C., so that the raw material is melted;

[0045] Crystal growth is carried out by lowering the crucible or raising the furnace body, and the seed crystal position in the middle and upper part of the seed crystal is used as the starting point of crystal growth. The temperature here is controlled at the crystal growth temperature, and the crystal growth temperature is 1280°C~1290°C; the longitudinal temperature gradient of the crystal growth area in the furnace body is controlled to be 0°C / cm~40°C / cm, the crucible descending speed or the furnace rising speed is controlled to be 0.5 cm / day~2 cm / day, and the feeding speed is controlled so that the raw material in the feeding mechanism 1 enters the auxiliary crucible 3 through the feeding pipe 2, and enters the crystal growth crucible 8 through the guide pipe 5 after the auxiliary crucible 3 is melted.

[0046] The crystal growth method of the present application can effectively reduce the volatilization of crystals during the growth process, prepare crystals with uniform crystal composition and significantly reduced defects such as cracks, improve the overall performance of the crystals, thereby increasing the processing utilization rate of single crystal materials and the uniformity of chip performance, reducing the production cost of single crystal materials, and expanding the technical application space of materials.

[0047] In some embodiments of the present application, the feed rate is: ρπ(A / 2) 2V g / day, where ρ is the crystal density, A is the diameter of the crystal growth crucible, and V is the crucible descent speed or the furnace body ascending speed. By controlling the above-mentioned feeding speed, the crystal raw material can be continuously fed into the crystal growth crucible 8, ensuring the continuity and stability of the crystal growth process, obtaining crystals with stable quality, and reducing the waste of raw materials.

[0048] In the present application, seed crystals with few defects and a certain direction are selected, which can control the growth direction of the crystal, reduce defects in the crystal, improve the repeatability and consistency of crystal growth, and improve the overall quality of the crystal.

[0049] In the present application, the single crystal raw material is pre-synthesized PMNT or PIMNT ceramic particles, and the diameter of the ceramic particles is 0.1 mm to 1 mm. The present application has no particular restrictions on the method of pre-synthesizing PMNT or PIMNT ceramic particles, as long as the purpose of the present application can be achieved. For example, magnesium niobate, indium niobate, lead oxide, and titanium oxide powders are mixed in a stoichiometric ratio, sintered, crushed, and granulated to form PMNT or PIMNT ceramic particles.

[0050] Example

[0051] The following examples and comparative examples are given to more specifically describe the embodiments of the present application. Various tests and evaluations were performed according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0052] Test methods and equipment:

[0053] Crystal rod material rate test:

[0054] The fully grown crystal rod is peeled off from the crystal growth crucible, the seed crystal is cut off, and the weight is W1; the impurities, cracked parts and parts with inconsistent crystal orientations at the top of the crystal rod are cut off, and the weight is W2. The ratio of W2 to W1 is the material rate of the crystal rod.

[0055] Wafer piezoelectric constant test:

[0056] After the crystal rods obtained in each embodiment and comparative example were precisely oriented perpendicular to the crystal growth direction, wafers with a thickness of 1 mm were cut out, the wafers were coated and polarized, and 5 wafers were selected from top to bottom for piezoelectric constant d33 measurement. The positions of the wafers selected from top to bottom on each crystal rod were basically the same. The piezoelectric constant of the wafers was tested using a static piezoelectric coefficient d33 measuring instrument, model ZJ-3.

[0057] Numerical discreteness calculation:

[0058] Numerical dispersion = (the largest piezoelectric constant among the five wafers - the smallest piezoelectric constant among the five wafers) / the average value of the piezoelectric constants of the five wafers × 100%

[0059] Example 1

[0060] <Preparation of PMNT Crystal

[0061] Mix magnesium niobate, lead oxide, and titanium oxide powders according to a molar ratio of 0.68:3:0.96. After mixing, sintering, crushing, and granulating, pre-synthesize PMNT ceramic particles with a diameter of 0.5 mm. Before crystal growth, place a seed crystal with a diameter of 12 mm, a length of 50 mm, and a (001) orientation, as well as 10 mm high of PMNT ceramic particle raw materials in the crystal growth crucible 8 in advance. Fill the lower part of the hole in the inner crucible of the auxiliary crucible 3 with ceramic particle raw materials, and also place ceramic particle raw materials in the feeding mechanism 1 for standby. Control the temperature of the auxiliary crucible 3 at 1370 °C to melt the raw materials; use the midpoint position of the seed crystal in the length direction of the seed crystal as the starting point of crystal growth, set the crystal growth temperature here at 1285 °C, set the temperature gradient at the crystal growth location at 20 °C / cm, and set the crucible descent speed (or furnace body ascent speed) at 1 cm / day. The diameter of the crystal growth crucible is 6 cm, and the crystal density is 8.1 g / cm³. According to calculations, the feeding speed is 228.9 g / day. After crystal growth, obtain a PMNT crystal rod.

[0062] The crystal rod has no cracks, and the material utilization rate of the crystal rod reaches 92%. For the wafers after coating and poling, select 5 wafers from top to bottom on the crystal rod to measure the piezoelectric constant d33. The values are 1805, 1876, 1902, 1821, and 1911 (unit: pC / N) in sequence, and the numerical discreteness is 5.69%.

[0063] Example 2

[0064] <Preparation of PIMNT Crystal

[0065] Mix magnesium niobate, indium niobate, lead oxide, and titanium oxide powders according to a molar ratio of 0.9:0.69:6:1.92, and pre-synthesize PIMNT ceramic particles with a diameter of 0.8 mm through mixing, sintering, crushing, and granulation. Before crystal growth, place a seed crystal with a diameter of 12 mm, a length of 50 mm, and a (001) orientation, as well as 15 mm high of PMNT ceramic particle raw materials, in the crystal growth crucible 8 in advance. Fill the lower part of the hole in the inner crucible of the auxiliary crucible 3 with ceramic particle raw materials, and also place ceramic particle raw materials in the feeding mechanism 1 for later use. Control the auxiliary crucible 3 at 1350 °C to melt the raw materials; set the position of the seed crystal 15 mm below the top of the seed crystal as the starting point of crystal growth, set the crystal growth temperature here to 1283 °C, set the temperature gradient at the crystal growth site to 30 °C / cm, and set the crucible descent speed (or furnace body ascent speed) to 1.2 cm / day. The diameter of the crystal growth crucible is 6 cm, and the crystal density is 8.1 g / cm³. According to calculations, the feeding speed is 274.7 g / day. After crystal growth, a PIMNT crystal rod is obtained.

[0066] The crystal rod has no cracks, and the material extraction rate of the crystal rod reaches 90%. For the wafers after coating and poling, select 5 wafers from top to bottom to measure the piezoelectric constant d33. The values are 1531, 1487, 1506, 1418, and 1551 (unit: pC / N) in sequence, and the numerical discreteness is 8.87%.

[0067] Comparative Example 1

[0068] <PMNT Crystal Preparation>

[0069] Except for using the traditional method to put the raw materials into the crystal growth crucible at one time, the rest is the same as in Example 1.

[0070] There are cracks on the crystal rod, and the material extraction rate of the crystal rod is 80%. For the wafers after coating and poling, select 5 wafers from top to bottom to measure the piezoelectric constant d33. The values are 1752, 1638, 1602, 1233, and 1345 (unit: pC / N) in sequence, and the numerical discreteness is 34.28%.

[0071] Comparative Example 2

[0072] <PIMNT Crystal Preparation>

[0073] Except for using the traditional method to put the raw materials into the crystal growth crucible at one time, the rest is the same as in Example 2.

[0074] There are cracks on the crystal rod, and the material extraction rate of the crystal rod is 75%. For the wafers after coating and poling, select 5 wafers from top to bottom to measure the piezoelectric constant d33. The values are 1533, 1638, 1442, 1325, and 1287 (unit: pC / N) in sequence, and the numerical discreteness is 24.29%.

[0075] It can be seen from Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2 that the PMNT and PIMNT crystals prepared using the single crystal growth device and single crystal growth method provided by the present application have no obvious cracks, the crystal rod material rate is greater than 90%, and the piezoelectric performance uniformity of the chips cut from the same crystal rod from top to bottom is good. Five chips were selected from the top to bottom on the crystal rod, and the piezoelectric constant d33 was measured. The numerical discreteness between each chip was no more than 10%. However, the crystals prepared using the traditional method have obvious defects such as cracks, the crystal rod material rate is low, and five chips were selected from the top to bottom on the crystal rod to measure the piezoelectric constant d33. The numerical discreteness between each chip is as high as 34.28%, and the crystal rod uniformity is poor.

[0076] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application. Other crucible descent crystal growth methods with multiple components or containing volatile components are also applicable to the device and method.

Claims

1. A single crystal growth device, comprising: A furnace body, a charging mechanism and a crystal growth mechanism located inside the furnace body, The furnace body includes a heat-insulating layer and a plurality of heating components; The crystal growth mechanism includes a crucible assembly and a support mechanism; The crucible assembly comprises an auxiliary crucible, a crystal growth crucible and a flow guide tube, wherein the auxiliary crucible is formed by connecting an inner crucible and an outer crucible, a gap is provided between the side wall and the bottom of the inner crucible and the inner surface of the outer crucible, a plurality of holes are provided around the lower part of the side wall of the inner crucible, the crystal growth crucible comprises a body and a crucible cover, and the bottom of the outer crucible is connected to the crystal growth crucible cover through the flow guide tube; The feeding mechanism is arranged above the furnace body and is connected with the inner crucible through a feeding pipe; The furnace body and the crystal growth mechanism can move relative to each other in a vertical direction.

2. The single crystal growth device according to claim 1, wherein: The outer diameter of the inner crucible is 0.5 to 0.9 times the inner diameter of the outer crucible; the distance between the hole on the side wall of the inner crucible and the bottom of the inner crucible is 0.5 cm to 1.5 cm.

3. The single crystal growth apparatus according to claim 1, wherein: The upper part of the crystal growth crucible is cylindrical, and the lower part is a seed crystal well. The seed crystal well and the upper part of the crystal growth crucible have a conical transition part, and the taper angle of the conical transition part is 20°C to 60°C; the seed crystal well is a small cylinder with a sealed bottom, and the seed crystal is loaded with a seed crystal.

4. The single crystal growth apparatus according to claim 1, wherein: The support mechanism comprises a support and a support rod. The upper end of the support is used to fix the auxiliary crucible, and the lower end of the support is connected to the support rod. The top end of the support rod is used to support the crystal growth crucible.

5. The single crystal growth apparatus according to claim 1, wherein: The single crystal growth device also includes a crucible lifting device and / or a furnace lifting device, the upper end of the crucible lifting device is connected to the bottom end of the support rod, the upper end of the furnace lifting mechanism is connected to the furnace body, and the lower ends of the crucible lifting device and the furnace lifting device are connected to the base.

6. The single crystal growth apparatus according to claim 1, wherein: The plurality of heating assemblies are used to control the temperature at different positions in the furnace body.

7. Use of the single crystal growth apparatus according to claim 1 for growing relaxor ferroelectric single crystals.

8. The use according to claim 7, wherein The relaxor ferroelectric single crystal is selected from lead magnesium niobate-lead titanate or lead indium niobate-lead magnesium niobate-lead titanate.

9. A single crystal growth method, using the single crystal growth device according to any one of claims 1 to 6, wherein: The method is a continuous feeding crucible descent method.

10. The single crystal growth method according to claim 9, comprising the following steps: Put seed crystals and raw materials with a height of 5 mm to 20 mm in the crystal growth crucible, fill the part below the inner crucible circumferential hole of the auxiliary crucible with raw materials, and put raw materials in the feeding mechanism; Controlling the temperature of the auxiliary crucible to be at the melting temperature of the raw material to melt the raw material; Crystal growth is carried out by lowering the crucible or raising the furnace body, so that the seed crystal position in the upper middle part of the seed crystal is used as the starting point of crystal growth, and the temperature here is controlled at the crystal growth temperature; the longitudinal temperature gradient of the crystal growth area in the furnace body and the crucible lowering speed or the furnace body rising speed are controlled, and the feeding speed is controlled so that the raw materials in the feeding mechanism enter the auxiliary crucible through the feeding pipe, and enter the crystal growth crucible through the guide pipe after the auxiliary crucible is melted.

11. The single crystal growth method according to claim 10, wherein: The feeding speed is: ρπ(A / 2) 2 V g / day, where ρ is the crystal density, A is the diameter of the crystal growth crucible, and V is the crucible descent speed or the furnace ascent speed.

12. The single crystal growth method according to claim 10, wherein: The single crystal is a relaxor ferroelectric single crystal, which is selected from lead magnesium niobate-lead titanate or lead indium niobate-lead magnesium niobate-lead titanate, the melting temperature is 1320°C to 1400°C, the crystal growth temperature is 1280°C to 1290°C, the longitudinal temperature gradient is 0°C / cm to 40°C / cm, and the crucible descent speed or the furnace body ascending speed is 0.5 cm / day to 2 cm / day.

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