CN113913937A - Lithium niobate crystal and preparation method thereof - Google Patents

Lithium niobate crystal and preparation method thereof Download PDF

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CN113913937A
CN113913937A CN202111022496.9A CN202111022496A CN113913937A CN 113913937 A CN113913937 A CN 113913937A CN 202111022496 A CN202111022496 A CN 202111022496A CN 113913937 A CN113913937 A CN 113913937A
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lithium niobate
growth
crystal
niobate crystal
calculating
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CN113913937B (en
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薛冬峰
陈昆峰
王晓明
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Shenzhen Institute of Advanced Technology of CAS
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Shenzhen Institute of Advanced Technology of CAS
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/22—Complex oxides
    • C30B29/30—Niobates; Vanadates; Tantalates
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B28/00—Production of homogeneous polycrystalline material with defined structure
    • C30B28/02—Production of homogeneous polycrystalline material with defined structure directly from the solid state

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Abstract

The application belongs to the technical field of photoelectric materials, and particularly relates to a lithium niobate crystal and a preparation method thereof. The preparation method of the lithium niobate crystal comprises the following steps: calculating the temperature field structure of the growth of the lithium niobate crystal; calculating the growth parameters of the lithium niobate crystal; mixing and drying a lithium source and a niobium source to obtain a mixed raw material; sintering the mixed raw materials in an air atmosphere to obtain a lithium niobate polycrystalline material block; in the calculated temperature field structure, after melting the lithium niobate polycrystalline material block, under the guidance of seed crystal, according to the calculated growth parameters, crystal growth is carried out by adopting a Czochralski method, and then the lithium niobate crystal is obtained. According to the preparation method of the lithium niobate crystal, the temperature field structure and the growth parameters of the lithium niobate crystal are respectively calculated through simulation, deduction and calculation methods, and then crystal growth is carried out in the calculated temperature field structure according to the calculated crystal growth parameters by adopting a pulling method, so that the growth efficiency of the lithium niobate crystal is remarkably improved.

Description

Lithium niobate crystal and preparation method thereof
Technical Field
The application belongs to the technical field of photoelectric materials, and particularly relates to a lithium niobate crystal and a preparation method thereof.
Background
5G is advancing widely, with a completely new network architecture,a new era of wide interconnection of everything and man-machine deep interaction is started. The radio frequency front end is the core of mobile communication, and the filter can filter out-of-band interference and noise so as to meet the requirements of radio frequency systems and communication protocols on signal to noise ratio, and the function of the filter is very important. Since the filter is susceptible to Temperature variation, a Temperature compensation film is added to the surface layer in order to improve the Temperature characteristics of the SAW, and such a Temperature compensated SAW filter is called a TC-SAW filter (Temperature compensated SAW). The high-performance surface acoustic wave filter requires a large bandwidth, a high frequency, a low insertion loss, a small temperature coefficient of the center frequency, and the like. Lithium Niobate (LN) crystal material among a plurality of substrate materials has the advantages of large electromechanical coupling coefficient, large piezoelectric constant, high sound velocity and the like, is the preferred piezoelectric material for selecting electric signals of various frequency bands, and is an indispensable key material for forming the TC-SAW filter. Meanwhile, the acoustic surface filter device is developed towards miniaturization, batch and low cost, and the lithium niobate crystal material is required to be developed towards large size. Lithium niobate (LiNbO)3) The crystal has excellent physical properties such as photoelectric, birefringence, nonlinear optics, acoustooptic, photoelastic, photorefractive, piezoelectric, pyroelectric, ferroelectric and photovoltaic effects; the material has stable mechanical performance, high temperature resistance, corrosion resistance, easy processing and low cost, and can present various special properties after doping. Therefore, the lithium niobate crystal is known as "optical silicon".
The prior lithium niobate/lithium tantalate products in China are mainly four inches and are supplemented by six inches. At present, lithium niobate crystals are mainly obtained by directly growing in air by using a Cz technology (Czochralski, Czochralski method), wherein most of the growth steps are based on a platinum crucible high-frequency heating technology, and the technical problems of difficulty in regulating and controlling a growth interface temperature field, increase of crystal thermal stress and the like are faced, so that the crystals are easy to crack, and the yield is reduced. In addition, the growth speed is low, so that the crystal growth period is increased, the energy consumption is increased, the productivity is insufficient, the cost is high, and the domestic market demand is difficult to meet.
Disclosure of Invention
The application aims to provide a lithium niobate crystal and a preparation method thereof, and aims to solve the problems of low efficiency, high energy consumption and low yield of the existing large-size lithium niobate crystal preparation process to a certain extent.
In order to achieve the purpose of the application, the technical scheme adopted by the application is as follows:
in a first aspect, the present application provides a method for preparing a lithium niobate crystal, comprising the steps of:
calculating the temperature field structure of the growth of the lithium niobate crystal;
calculating the growth parameters of the lithium niobate crystal;
mixing and drying a lithium source and a niobium source to obtain a mixed raw material;
sintering the mixed raw materials in an air atmosphere to obtain a lithium niobate polycrystalline material block;
in the calculated temperature field structure, after the lithium niobate polycrystalline material block is melted, crystal growth is carried out by adopting a Czochralski method under the guidance of seed crystals according to the calculated growth parameters, and then the lithium niobate crystal is obtained.
Further, the step of calculating the temperature field structure of the lithium niobate crystal growth includes:
calculating the temperature gradient value in the crystal growth space in the growth process of the lithium niobate crystal;
and calculating the temperature field structure of the growth of the lithium niobate crystal according to the temperature gradient value, the thermal conductivity of the thermal insulation material and the appearance structure of the thermal insulation material.
Further, the step of calculating the temperature gradient value in the crystal growth space during the growth process of the lithium niobate crystal comprises:
assuming that the lithium niobate single crystal growth temperature field is a steady-state temperature field and has cylindrical symmetry, according to a heat transfer equation, the temperature expression is as shown in formula (III):
Figure BDA0003242048250000021
wherein r,
Figure BDA0003242048250000022
And z is the spatial variation of the crystal, T is the temperature;
establishing boundary conditions to obtain axial temperature gradient in the growth space of the lithium niobate crystal
Figure BDA0003242048250000023
As shown in formula (IV); and radial temperature gradient in the growth space of lithium niobate crystal
Figure BDA0003242048250000024
As shown in formula (V);
Figure BDA0003242048250000031
Figure BDA0003242048250000032
wherein r isaIs the radius, θ, of the lithium niobate crystalmAs a function of the equilibrium temperature, h ═ epsilon/K,. epsilon.is the heat exchange coefficient, and ═ epsilon0+εR，ε0For convective heat transfer coefficient,. epsilonRIs the radiative heat transfer coefficient.
Further, the step of calculating the temperature field structure of the lithium niobate crystal growth includes:
calculating the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material according to the geometric shape of the target lithium niobate crystal, the physical properties of the lithium niobate crystal and the heat conductivity of the heat-insulating material;
according to the temperature gradient value, the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material, the melt temperatures of the melt center of the lithium niobate crystal and a plurality of different positions away from the melt center are counted, and the radial temperature gradient is measured and calculated; and counting the ambient temperatures of the melt center of the lithium niobate crystal and a plurality of different positions vertically away from the melt center, and measuring and calculating the axial temperature gradient.
Further, the heat insulation material is at least one selected from a siliceous heat insulation material, a silicate heat insulation material, a corundum heat insulation material, a magnesium-calcium heat insulation material, an aluminum-magnesium heat insulation material, a magnesium-silicon heat insulation material and a zirconium heat insulation material.
Further, the step of calculating the growth parameters of the lithium niobate crystal comprises:
according to the chemical bonding theory of crystal growth, the anisotropic relative growth rate of lithium niobate crystals is calculated with reference to formula (I):
Figure BDA0003242048250000033
wherein R isuvwIs a lithium niobate crystal rim [ uvw ]]The relative growth rate in the direction, K is the rate constant,
Figure BDA0003242048250000034
is along [ uvw ]]Chemical bonding energy of directional growth, AuvwFor growth of elementary edges [ uvw ]]Projected area of direction, duvwIs a lithium niobate crystal rim [ uvw ]]The step height of the direction;
determining the maximum thermodynamic growth rates in different pulling growth directions according to the anisotropic relative growth rates and the lattice energy data of the lithium niobate crystal;
determining the pulling growth direction of the lithium niobate crystal to obtain the thermodynamic growth rate of the corresponding growth direction;
and calculating the pulling growth rate of the lithium niobate crystal according to the diameter and the length of the lithium niobate crystal needing to grow.
Further, the step of calculating the pull growth rate of the lithium niobate crystal includes:
calculating a pull-up growth rate of the lithium niobate crystal with reference to formula (II) according to the diameter and length of the lithium niobate crystal to be grown:
Figure BDA0003242048250000041
wherein v is the pulling speed of the lithium niobate crystal, KsCoefficient of thermal conductivity of crystal, dT/dxsIs lithium niobate crystalTemperature gradient of the body, KLdT/dx, which is the coefficient of thermal conductivity of the meltLTemperature gradient of the melt, psIs the density of lithium niobate crystals, and L is the latent heat of solidification.
Further, the conditions for sintering the mixed raw materials include: sintering treatment is carried out in an air atmosphere at the temperature of 700-1100 ℃.
Further, the crystal growth by the Czochralski method comprises the steps of: and after the lithium niobate polycrystalline material block is melted to generate a characteristic liquid flow line, carrying out seeding operation by using the seed crystal with a specific growth direction according to the calculated growth parameters, and then sequentially carrying out necking, quick shouldering, equal-diameter growth, pull-off and cooling to obtain the lithium niobate crystal.
Further, the temperature of the seeding operation is 1240-1270 ℃.
Further, in the seeding operation process, the crystal pulling speed is 2-4 mm/h.
Further, the length of the necking is 1-3 cm; the lifting speed in the quick shouldering process is 10-20 mm/h; the pulling speed in the constant diameter growth process is 2-4 mm/h.
Further, the lithium source comprises at least one of lithium carbonate and lithium oxide; the niobium source comprises niobium oxide.
In a second aspect, the present application provides a lithium niobate crystal produced by the above-described method.
According to the preparation method of the lithium niobate crystal provided by the first aspect of the application, the temperature field structure and the growth parameters of the lithium niobate crystal are respectively calculated through simulation, deduction and calculation methods, so that the optimal temperature field structure for crystal growth and the growth parameters such as the thermodynamically allowed fastest growth rate and pulling growth rate are respectively obtained. And then, in the calculated temperature field structure, crystal growth is carried out by adopting a Czochralski method according to the calculated crystal growth parameters, so that the growth efficiency of the lithium niobate crystal is obviously improved, the preparation energy consumption is low, the growth process time is short, and the crystal yield is high. And the prepared lithium niobate crystal has large size, and the problems that the growth technology of the large-size lithium niobate crystal has long design period, the growth parameters need to be repeatedly optimized, the yield is low, the large-size crystal is difficult to prepare and the like are effectively solved.
The lithium niobate crystal provided by the second aspect of the application is prepared by the method, the preparation efficiency is high, and the size of the prepared lithium niobate crystal is large and can be larger than 6 inches, so that the application requirement of a rapidly developed filter market is met.
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In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic view of a temperature field structure for crystal growth in an embodiment of the present application;
FIG. 2 is a schematic diagram showing the physical structure of a lithium niobate crystal provided in example 1 of the present application;
FIG. 3 is a schematic view of an incubation structure for crystal growth provided in example 1 of the present application;
FIG. 4 shows the quasi-static d adopted by the present application for the lithium niobate crystal provided in example 133Tester for detecting lithium niobate crystal d33Location point of piezoelectric constant.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In this application, the term "and/or" describes an association relationship of associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
In the present application, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (one) of a, b, or c," or "at least one (one) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c may be single or plural, respectively.
It should be understood that, in various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.
The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The weight of the related components mentioned in the description of the embodiments of the present application may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the content of the related components is scaled up or down within the scope disclosed in the description of the embodiments of the present application as long as it is scaled up or down according to the description of the embodiments of the present application. Specifically, the mass in the description of the embodiments of the present application may be in units of mass known in the chemical industry, such as μ g, mg, g, and kg.
The terms "first" and "second" are used for descriptive purposes only and are used for distinguishing purposes such as substances from one another, and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
A first aspect of embodiments of the present application provides a method for preparing a lithium niobate crystal, including the steps of:
s10, calculating a temperature field structure for the growth of the lithium niobate crystal;
s20, calculating the growth parameters of the lithium niobate crystal;
s30, mixing and drying a lithium source and a niobium source to obtain a mixed raw material;
s40, sintering the mixed raw materials in an air atmosphere to obtain a lithium niobate polycrystalline material block;
and S50, in the calculated temperature field structure, melting the lithium niobate polycrystalline material block, and carrying out crystal growth by adopting a Czochralski method under the guidance of seed crystals according to the calculated growth parameters to obtain the lithium niobate crystal.
In the preparation method of the lithium niobate crystal provided in the first aspect of the embodiment of the present application, the temperature field structure and the growth parameters of the lithium niobate crystal are respectively calculated by simulation, deduction and calculation methods, so as to respectively obtain the optimal temperature field structure for crystal growth and the growth parameters such as the thermodynamically-allowed fastest growth rate and the thermodynamically-allowed pulling growth rate. And then, in the calculated temperature field structure, according to the calculated crystal growth parameters, crystal growth is carried out by adopting a Czochralski method, the growth efficiency of the lithium niobate crystal is obviously improved, the preparation energy consumption is low, the growth process time is short, and the crystal yield is high. And the prepared lithium niobate crystal has large size, and the problems that the growth technology of the large-size lithium niobate crystal has long design period, the growth parameters need to be repeatedly optimized, the yield is low, the large-size crystal is difficult to prepare and the like are effectively solved.
In some embodiments, in the step S10, the step of calculating the temperature field structure of the lithium niobate crystal growth includes:
s11, calculating a temperature gradient value in a crystal growth space in the growth process of the lithium niobate crystal;
and S12, calculating the temperature field structure of the growth of the lithium niobate crystal according to the temperature gradient value, the heat conductivity of the heat insulation material and the appearance structure of the heat insulation material.
In some embodiments, in step S11, the step of calculating the temperature gradient value in the crystal growth space during the growth of the lithium niobate crystal includes:
s111, assuming that the lithium niobate single crystal growth temperature field is a steady-state temperature field (namely, the origin is fixed on the 0 point of the solid/liquid interface in the moving coordinate system), and the lithium niobate single crystal growth temperature field has cylindrical symmetry, and according to a heat transfer equation, the temperature expression is as shown in formula (III):
Figure BDA0003242048250000071
wherein r,
Figure BDA0003242048250000081
And z is the spatial variation of the crystal and T is the temperature.
The concept of the heat transfer equation is not particularly limited in the embodiments of the present application, and may be a heat transfer equation known to those skilled in the art, in which the radius of the lithium niobate single crystal is raThe length is l, the density is d, the specific heat is c, and the heat conduction coefficient K is constant.
In some embodiments, the heat transport equation is based on
Figure BDA0003242048250000082
The heat conduction equation of the crystal in the steady-state temperature field can be obtained as
Figure BDA00032420482500000810
Then, the cylindrical coordinates are used to obtain the above formula (III).
Then introducing a temperature function theta (r, z) instead of T (r, z), so that theta (r, z) is T (r, z) -T0To obtain the relation:
Figure BDA0003242048250000083
s112, establishing boundary conditions to obtain the axial temperature gradient in the lithium niobate crystal growth space
Figure BDA0003242048250000084
As shown in formula (IV); and radial temperature gradient in the growth space of lithium niobate crystal
Figure BDA0003242048250000085
As shown in formula (V);
Figure BDA0003242048250000086
Figure BDA0003242048250000087
wherein r isaIs the radius, θ, of the lithium niobate crystalmAs a function of the equilibrium temperature, h ═ epsilon/K,. epsilon.is the heat exchange coefficient, and ═ epsilon0+εR，ε0For convective heat transfer coefficient,. epsilonRIs the radiative heat transfer coefficient.
In some embodiments, boundary conditions are established:
when z is 0, θ is Tm-T0；
When z is equal to 1, the reaction is carried out,
Figure BDA0003242048250000088
when z is equal to raWhen the temperature of the water is higher than the set temperature,
Figure BDA0003242048250000089
wherein r isaIs the radius of the lithium niobate crystal, K is the thermal conductivity coefficient, TmTo equilibrate the temperature,. epsilon0For convective heat transfer coefficient,. epsilonRIs the radiative heat transfer coefficient.
When ε/K is small, an approximate solution of the differential equation to satisfy the boundary condition is obtained as shown in formula (III):
Figure BDA0003242048250000091
where θ m is the equilibrium temperature function, h ═ ε/K, ε is the heat exchange coefficient, ε ═ ε 0+ ε R, ε 0 is the convection heat exchange coefficient, and ε R is the radiant heat exchange coefficient.
Then, the components of the temperature gradient vector in the lithium niobate crystal in the axial direction and the radial direction, that is, the above axial temperature gradient formula (IV) and the above radial temperature gradient formula (V), can be derived.
In some embodiments, in the step S12, the step of calculating the temperature field structure of the lithium niobate crystal growth includes:
s121, calculating the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material according to the geometric shape of the target lithium niobate crystal, the lithium property of the lithium niobate crystal and the heat conductivity of the heat-insulating material;
s122, according to the temperature gradient value, the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material, counting the melt temperatures of the melt center of the lithium niobate crystal and a plurality of different positions away from the melt center, and measuring and calculating the radial temperature gradient; and counting the ambient temperatures of the melt center of the lithium niobate crystal and a plurality of different positions vertically away from the melt center, and measuring and calculating the axial temperature gradient.
Calculating the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material according to the temperature gradient value obtained in the step, the lithium property of the lithium niobate crystal and the heat conductivity of the heat-insulating material; and then calculating the axial temperature gradient and the radial temperature gradient according to the temperature gradient value, the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material to obtain the temperature field structure of the growing lithium niobate crystal. Specifically, according to the calculated temperature gradient in the three-dimensional space, the three-dimensional space assembly of different heat insulation materials is designed by utilizing the heat conductivity of different heat insulation materials and combining the geometric structures of the heat insulation materials, and the calculated temperature field structure can be met to complete the design and output.
In some embodiments, the insulation material is selected from at least one of a siliceous insulation material, a silicate insulation material, a corundum insulation material, a magnesium-calcium insulation material, an aluminum-magnesium insulation material, a magnesium-silicon insulation material, and a zirconium insulation material. The kind and selection of the thermal insulation material in the embodiments of the present application are not particularly limited, and those skilled in the art may select and adjust the type and selection of the common thermal insulation material, which are well known to those skilled in the art, according to the actual production situation, raw material situation and product requirement. The heat insulation material in the embodiment of the application is preferably a combination of a plurality of heat insulation materials, and more preferably a combination of a plurality of siliceous heat insulation materials, aluminum silicate heat insulation materials, corundum heat insulation materials, magnesium-calcium heat insulation materials, aluminum-magnesium heat insulation materials, magnesium-silicon heat insulation materials and zirconium refractory heat insulation materials. As shown in the attached figure 1, a building block type three-dimensional space heat insulation structure composed of different heat insulation materials can be designed by using various heat insulation materials such as alumina felt, corundum sand, mullite and the like and by combining the heat conductivity of different heat insulation materials with the geometric structures of the different heat insulation materials, so that the design of a temperature field structure is realized.
In some embodiments, in step S20, the step of calculating the growth parameters of the lithium niobate crystal includes:
s21, calculating the anisotropic relative growth rate of the lithium niobate crystal according to the chemical bonding theory of crystal growth and by referring to the formula (I):
Figure BDA0003242048250000101
wherein R isuvwIs a lithium niobate crystal rim [ uvw ]]The relative growth rate in the direction, K is the rate constant,
Figure BDA0003242048250000102
is along [ uvw ]]Chemical bonding energy of directional growth, AuvwFor growth of elementary edges [ uvw ]]Projected area of direction, duvwIs a lithium niobate crystal rim [ uvw ]]The step height of the direction;
s22, determining the maximum thermodynamic growth rates in different pulling growth directions according to the anisotropic relative growth rates and the lattice energy data of the lithium niobate crystal;
s23, determining the pulling growth direction of the lithium niobate crystal to obtain the thermodynamic growth rate of the corresponding growth direction;
s24, calculating the pulling growth rate of the lithium niobate crystal according to the diameter and the length of the lithium niobate crystal needing to grow.
The method comprises the following steps of calculating growth parameters of a lithium niobate crystal, determining a chemical bonding structure at a growth interface along the axial direction and the radial direction, and finding out a corresponding relative growth rate according to the formula (I); then combining the corresponding relative growth rates found out in the steps with the lattice energy of the lithium niobate crystal to obtain the growth rates of the lithium niobate crystal in different pulling growth directions; and finally, calculating the pulling growth rate of the lithium niobate crystal according to the equal diameter size and the growth rate of the lithium niobate crystal.
In some embodiments, in the step S21, the definition and selection of each parameter in the formula (I) are not particularly limited in the embodiments of the present application, and may be defined by conventional definitions well known to those skilled in the art, and are consistent with the basic common knowledge of those skilled in the art.
In some embodiments, in step S22, according to the calculated anisotropic relative growth rate, introducing into morphology simulation software to obtain a simulated thermodynamic growth morphology of the lithium niobate crystal; the relative growth rate R in different growth directions is obtained by calculation according to the formula (I) by combining the crystal structure of the lithium niobate and parameters such as bond length, bond angle and the likeuvw。
The concept of the growth rate of the lithium niobate crystal in the embodiments of the present application is not particularly limited, and may be defined by conventional definitions well known to those skilled in the art, and preferably refers to an increase in crystal mass per unit time, and specifically, the crystal growth rate of the lithium niobate crystal more preferably refers to the fastest growth rate thermodynamically allowed during the growth of the lithium niobate crystal.
The concept of the pull-up growth rate of lithium niobate crystals is not particularly limited by the examples herein, and may be defined by conventional definitions well known to those skilled in the art, and preferably, the pull-up growth rate herein refers to the linear rate of crystal growth per unit time in the pull method with a specific size, and growth with a large crystal size and a large pull rate results in a high crystal growth rate. The lattice energy of the examples of the present application refers to the energy consumed to destroy 1mol of crystal and to turn it into completely separated free ions in the gaseous state.
In some embodiments, in step S23, the anisotropic relative growth obtained from the above stepsRate RuvwAnd lattice energy data, determining the maximum thermodynamic growth rates in different pulling growth directions; according to the actual growth requirement, the thermodynamic growth rate of the corresponding growth direction can be determined by selecting the growth direction of the seed crystal. In some embodiments, the seed growth may be a thermodynamically optimal pull growth direction.
The pulling growth direction of the lithium niobate crystal in the embodiments of the present application is not particularly limited, and may be calculated by a person skilled in the art according to the above formula, and the person skilled in the art may select and adjust the pulling growth direction according to the actual application, the raw material condition, and the product requirement, and the pulling growth direction of the lithium niobate crystal in the embodiments of the present application is preferably the [010] or [001] direction.
In some embodiments, in the step S24, the step of calculating the pull growth rate of the lithium niobate crystal includes:
the pull-up growth rate of the lithium niobate crystal is calculated with reference to formula (II) according to the diameter and length of the lithium niobate crystal to be grown:
Figure BDA0003242048250000111
wherein v is the pulling speed of the lithium niobate crystal, KsCoefficient of thermal conductivity of crystal, dT/dxsIs the temperature gradient, K, of the lithium niobate crystalLdT/dx, which is the coefficient of thermal conductivity of the meltLTemperature gradient of the melt, psIs the density of lithium niobate crystals, and L is the latent heat of solidification.
The specific types of the lithium source and the niobium source are not particularly limited in the examples of the present application as long as they react to form the corresponding lithium niobate crystal phase. In some embodiments, in step S30, the lithium source includes at least one of lithium carbonate and lithium oxide; the niobium source comprises niobium oxide.
The mixing conditions of the lithium source and the niobium source are not particularly limited in the embodiments of the present application, and a person skilled in the art can adjust the mixing conditions according to actual production conditions and raw material conditions, the present application preferably performs uniform mixing, and the mixing time is preferably 20 to 48 hours, more preferably 20 to 30 hours, and more preferably 20 to 24 hours. The mixing method is not particularly limited, and a mixer is preferably used for mixing. In some embodiments, the lithium source and the niobium source are weighed according to a stoichiometric ratio and mixed in a dry environment for 20 to 24 hours by using a mixer to obtain a mixed raw material. Further, in order to reduce the volume of the mixed raw material, the mixed raw material was pressed into a cake shape by a press machine to obtain a cake-like mixed raw material.
In some embodiments, in step S40, the mixed raw materials are sintered in an air atmosphere to obtain the lithium niobate polycrystalline ingot. In some embodiments, the conditions for performing the sintering process on the mixed raw materials include: sintering treatment is carried out in an air atmosphere at the temperature of 700-1100 ℃. Since gas is generated during sintering and crystal growth is affected, heat treatment is performed in an air atmosphere in order to ensure removal of moisture and formation of oxides. In addition, in order to ensure that the required lithium niobate phase is formed, the sintering temperature is 700-1100 ℃, the lithium niobate crystal phase cannot be formed at a low temperature, and the lithium niobate crystal phase may be melted or decomposed at a high temperature. In some embodiments, the sintering temperature may be 700-800 ℃, 800-900 ℃, 900-1000 ℃, 1000-1100 ℃, and the like.
In some embodiments, in the step S50, after the lithium niobate polycrystalline ingot is melted in the calculated temperature field structure, the crystal is grown by the czochralski method under the guidance of the seed crystal according to the calculated growth parameters, so as to obtain the lithium niobate crystal. In some embodiments, the step of growing the crystal by the czochralski method comprises: and after melting the lithium niobate polycrystalline material block to generate a characteristic liquid flow line, carrying out seeding operation by using seed crystals with a specific growth direction according to the calculated growth parameters, and then sequentially carrying out necking, quick shouldering, equal-diameter growth, pull-off and cooling to obtain the lithium niobate crystal.
In some embodiments, lithium niobate crystals are loaded into a noble metal crucible, the crucible is loaded into a crystal growth furnace, and a thermal insulation material is designed and arranged according to the calculated temperature field structure; in the air atmosphere, heating up and starting up a heating device to heat up a polycrystalline material block to be higher than the melting point of lithium niobate, wherein the polycrystalline material is molten when a characteristic liquid flow line appears, then putting down a seed crystal with a specific growth direction for seeding operation, and obtaining the lithium niobate crystal through processes of necking down, quick shouldering, isodiametric growth, pull-off, cooling and the like, wherein the grown crystal is a cylinder, a flat shoulder and a flat tail. Wherein, the growth direction of the used lithium niobate seed crystal is selected according to the calculation result or the actual requirement, and the growth speed is different due to different growth directions.
In some embodiments, the temperature of the seeding operation is 1240-1270 ℃ which is determined when a liquid flow line occurs in the melt in the crucible or by an infrared thermometer for the purpose of melting the lithium niobate crystal. In some embodiments, the seeding operation may be performed at 1240-1250 deg.C, 1250-1260 deg.C, 1260-1270 deg.C, etc.
In some embodiments, in the seeding operation process, the crystal pulling speed is 2-4 mm/h, so that the growth efficiency of the lithium niobate crystal is effectively improved, the process time is shortened, and the cost is reduced. In some embodiments, the crystal pull rate may be 2mm/h, 3mm/h, 4mm/h, etc. during the seeding operation.
In some embodiments, the seeding process is performed remotely by observing the contact and growth/melting of the seed crystal and the melt surface through an observation window, and performing a "seeding" operation remotely. When the seed crystal just contacts the melt surface, the seed crystal slightly grows, and the growth temperature is proved to be proper; if melting, the growth temperature is proved to be too high, and the growth temperature is adjusted to be low. After seeding, the operation of necking is carried out, and the length of the necking is 1-3 cm. Then, the crystal enters a rapid shouldering stage, and the pulling speed is 10-20 mm/h; and then starting equal-diameter growth, wherein the pulling speed is 2-4 mm/h, and the whole growth process of the lithium niobate crystal is monitored in situ by utilizing a remote observation function.
A second aspect of the embodiments of the present application provides a lithium niobate crystal, which is produced by the above-described method.
The lithium niobate crystal provided by the second aspect of the embodiment of the application is prepared by the method, the preparation efficiency is high, and the size of the prepared lithium niobate crystal is large and can be larger than 6 inches, so that the application requirement of a rapidly developing filter market is met.
The lithium niobate crystal prepared in the embodiment of the application belongs to a trigonal system, has a melting point of 1250 ℃, and is lower than the melting points of rare earth orthosilicate scintillation crystals, rare earth silicate scintillation crystals, yttrium aluminum garnet scintillation crystals and other crystals. Different compositions, crystal structures and melting points make the growth methods of the lithium niobate crystal such as heating mode, growth rate, growth direction selection and the like completely different.
In order to make the details of the above-described implementation and operation of the present application clearly understandable to those skilled in the art and to make the progress of the lithium niobate crystal and the method for preparing the same apparent from the examples of the present application, the above-described technical solution is illustrated by the following examples.
Example 1
A lithium niobate crystal is prepared by the steps of:
(1) calculation of the growth rate of the lithium niobate crystal in the [001] direction:
a) according to formula (I)
Figure BDA0003242048250000141
And lithium niobate crystal data, calculation [001]]The relative growth rate of the direction was 1.2;
b) the growth rate obtained by the lattice energy data of the lithium niobate crystal is 20 mm/h;
c) the diameter of the lithium niobate crystal is 105mm, the length is 100mm, and the crystal density is 4.6g/cm3Melt density 3.8g/cm3Thermal conductivity 38W/(m.K) @25 ℃, latent heat of solidification 25.94kJ/mol, axial temperature gradient 40K/cm, and is represented by formula (II)
Figure BDA0003242048250000142
Obtaining the pulling growth rate of 8 mm/h;
d) selecting the initial growth rate of the experiment to be 8 mm/h;
(2) calculating the heat preservation layer:
a) the heat insulation material is light mullite with the heat conductivity coefficient of 0.35W/(m.K);
b) according to formula (IV)
Figure BDA0003242048250000143
And (V)
Figure BDA0003242048250000144
Calculating that the axial temperature gradient is 40K/cm, the radial temperature gradient is 5K/cm, and the heat-insulating layer is designed into a cylindrical light mullite heat-insulating structure with the thickness of 50 mm; wherein, the schematic diagram of the heat preservation structure is shown in figure 3;
(3) preparing a polycrystalline raw material:
a) weighing: accurately weighing raw materials of lithium carbonate and niobium oxide with a molar ratio of 48.6: 51.4;
b) mixing materials: mixing the weighed raw materials in a mixing machine for 24 hours, and keeping the external environment dry, wherein the humidity is less than 20%;
c) pressing materials: pressing the mixed raw materials into a cake shape through a press machine and a grinding tool;
d) firing materials: pre-burning the cake-shaped raw material for 10 hours at 850 ℃ under the air condition to obtain a polycrystalline raw material;
(4) and (3) crystal growth by a Czochralski method:
a) putting the polycrystalline raw material into a platinum crucible with the diameter of 150mm in a temperature field, building a heat-insulating layer, and selecting lithium niobate seed crystals in the [001] direction;
b) seeding: when the seed crystal just contacts the melt surface, the seed crystal slightly grows, the seeding temperature is proper, the seeding is started, and the pulling speed is adjusted to 8 mm/h;
c) necking and shouldering: the pulling speed is adjusted to 6mm/h, after the necking length is 1-3cm, the crystal enters a shouldering stage, and the pulling speed is 2 mm/h;
d) shoulder shrinkage and equal-diameter growth: the pulling speed is 3.0 mm/h;
e) pulling off and cooling: pulling out the crystal after the crystal grows to a set length, and then cooling for 12h to obtain the multi-domain lithium niobate crystal. Wherein, the outline schematic diagram of the grown lithium niobate crystal is shown in figure 2, the crystal has no ending and is horizontally placed on the shoulder.
Further, in order to verify the advancement of example 1 of the present application, the diameter of the lithium niobate crystal in the [001] direction as grown was measured to be 102. + -. 0.5mm in accordance with YS/T554-; the embodiment of the application realizes the preparation of the large-size lithium niobate crystal.
Performing visual inspection under laser beam irradiation and lamplight to detect no macroscopic quality defects such as cracks, bubbles, cloud layers and the like; the lithium niobate crystal prepared by the embodiment of the application has few defects and high quality.
In addition, quasi-static d is adopted33The tester detects 9 points in the lithium niobate crystal, wherein the lithium niobate crystal d33The detection position points of the piezoelectric constants are shown in FIG. 4, and d is detected33The values of the piezoelectric constants are shown in table 1 below. By means of lithium niobate crystals d33The detection of the piezoelectric constant shows that the lithium niobate crystal sample prepared by the embodiment of the application has uniform quality and high quality.
TABLE 1
Position of d33Value (pC/N)
1 12.0
2 19.1
3 11.2
4 15.1
5 11.6
6 17.5
7 16.3
8 14.4
9 18.2
According to the test results, in the preparation method of the lithium niobate crystal in the embodiment of the application, after the temperature field structure and the growth parameters of the lithium niobate crystal are respectively calculated through simulation, deduction and calculation methods, crystal growth is carried out by adopting a pulling method according to the calculated crystal growth parameters in the calculated temperature field structure, so that the growth efficiency of the lithium niobate crystal is remarkably improved, the preparation energy consumption is low, and the growth process time is short; and the preparation of large-size lithium niobate crystals is realized, the yield of the crystals is high, the defects of the crystals are few, and the quality is high. Can meet the application requirements of the rapidly developing filter market.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. A preparation method of lithium niobate crystal is characterized by comprising the following steps:
calculating the temperature field structure of the growth of the lithium niobate crystal;
calculating the growth parameters of the lithium niobate crystal;
mixing and drying a lithium source and a niobium source to obtain a mixed raw material;
sintering the mixed raw materials in an air atmosphere to obtain a lithium niobate polycrystalline material block;
in the calculated temperature field structure, after the lithium niobate polycrystalline material block is melted, crystal growth is carried out by adopting a Czochralski method under the guidance of seed crystals according to the calculated growth parameters, and then the lithium niobate crystal is obtained.
2. The method of producing a lithium niobate crystal according to claim 1, wherein the step of calculating the temperature field structure of the growth of the lithium niobate crystal comprises:
calculating the temperature gradient value in the crystal growth space in the growth process of the lithium niobate crystal;
and calculating the temperature field structure of the growth of the lithium niobate crystal according to the temperature gradient value, the thermal conductivity of the thermal insulation material and the appearance structure of the thermal insulation material.
3. The method of producing a lithium niobate crystal according to claim 2, wherein the step of calculating a temperature gradient value in a crystal growth space during the growth of the lithium niobate crystal comprises:
assuming that the lithium niobate single crystal growth temperature field is a steady-state temperature field and has cylindrical symmetry, according to a heat transfer equation, the temperature expression is as shown in formula (III):
Figure FDA0003242048240000011
wherein r,
Figure FDA0003242048240000015
And z is the spatial variation of the crystal, T is the temperature;
establishing boundary conditions to obtain axial temperature gradient in the growth space of the lithium niobate crystal
Figure FDA0003242048240000013
As shown in formula (IV); and radial temperature gradient in the growth space of lithium niobate crystal
Figure FDA0003242048240000014
As shown in formula (V);
Figure FDA0003242048240000012
Figure FDA0003242048240000021
wherein r isaIs the radius, θ, of the lithium niobate crystalmAs a function of the equilibrium temperature, h ═ epsilon/K,. epsilon.is the heat exchange coefficient, and ═ epsilon0+εR，ε0For convective heat transfer coefficient,. epsilonRIs the radiative heat transfer coefficient.
4. The method of producing a lithium niobate crystal according to claim 3, wherein the step of calculating the temperature field structure of the growth of the lithium niobate crystal comprises:
calculating the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material according to the geometric shape of the target lithium niobate crystal, the physical properties of the lithium niobate crystal and the heat conductivity of the heat-insulating material;
according to the temperature gradient value, the thickness of the heat-insulating layer and the appearance structure of the heat-insulating material, the melt temperatures of the melt center of the lithium niobate crystal and a plurality of different positions away from the melt center are counted, and the radial temperature gradient is measured and calculated; and counting the ambient temperatures of the melt center of the lithium niobate crystal and a plurality of different positions vertically away from the melt center, and measuring and calculating the axial temperature gradient.
5. The method of producing a lithium niobate crystal according to claim 4, wherein the heat insulating material is at least one selected from the group consisting of a siliceous heat insulating material, a silicate heat insulating material, a corundum heat insulating material, a magnesium-calcium heat insulating material, an aluminum-magnesium heat insulating material, a magnesium-silicon heat insulating material, and a zirconium heat insulating material.
6. The method of producing a lithium niobate crystal according to any one of claims 1 to 5, wherein the step of calculating the growth parameter of the lithium niobate crystal comprises:
according to the chemical bonding theory of crystal growth, the anisotropic relative growth rate of lithium niobate crystals is calculated with reference to formula (I):
Figure FDA0003242048240000022
wherein R isuvwIs a lithium niobate crystal rim [ uvw ]]The relative growth rate in the direction, K is the rate constant,
Figure FDA0003242048240000023
is along [ uvw ]]Chemical bonding energy of directional growth, AuvwFor growth of elementary edges [ uvw ]]Projected area of direction, duvwIs a lithium niobate crystal rim [ uvw ]]The step height of the direction;
determining the maximum thermodynamic growth rates in different pulling growth directions according to the anisotropic relative growth rates and the lattice energy data of the lithium niobate crystal;
determining the pulling growth direction of the lithium niobate crystal to obtain the thermodynamic growth rate of the corresponding growth direction;
and calculating the pulling growth rate of the lithium niobate crystal according to the diameter and the length of the lithium niobate crystal needing to grow.
7. The method of producing a lithium niobate crystal according to claim 6, wherein the step of calculating the pull growth rate of the lithium niobate crystal comprises:
calculating a pull-up growth rate of the lithium niobate crystal with reference to formula (II) according to the diameter and length of the lithium niobate crystal to be grown:
Figure FDA0003242048240000031
wherein v is the pulling speed of the lithium niobate crystal, KsCoefficient of thermal conductivity of crystal, dT/dxsIs the temperature gradient, K, of the lithium niobate crystalLdT/dx, which is the coefficient of thermal conductivity of the meltLTemperature gradient of the melt, psIs the density of lithium niobate crystals, and L is the latent heat of solidification.
8. The method of producing a lithium niobate crystal according to claim 1 or 7, wherein the conditions for subjecting the mixed raw material to the sintering treatment include: sintering at 700-1100 ℃ in air atmosphere;
and/or the step of performing crystal growth by the Czochralski method comprises: and after the lithium niobate polycrystalline material block is melted to generate a characteristic liquid flow line, carrying out seeding operation by using the seed crystal with a specific growth direction according to the calculated growth parameters, and then sequentially carrying out necking, quick shouldering, equal-diameter growth, pull-off and cooling to obtain the lithium niobate crystal.
9. The method for producing a lithium niobate crystal according to claim 8, wherein the temperature of the seeding operation is 1240 to 1270 ℃;
and/or in the seeding operation process, the crystal pulling speed is 2-4 mm/h;
and/or the length of the necking is 1-3 cm; the lifting speed in the quick shouldering process is 10-20 mm/h; the pulling speed in the constant diameter growth process is 2-4 mm/h;
and/or the lithium source comprises at least one of lithium carbonate and lithium oxide; the niobium source comprises niobium oxide.
10. A lithium niobate crystal produced by the method according to any one of claims 1 to 9.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003002782A (en) * 2001-06-15 2003-01-08 Toshiba Ceramics Co Ltd Method and device for pulling silicon single crystal
CN106757354A (en) * 2017-01-24 2017-05-31 中国科学院长春应用化学研究所 The growth of low-cost rare earth scintillation crystal
CN107488874A (en) * 2017-09-04 2017-12-19 中国科学院长春应用化学研究所 A kind of design method of temperature field structure for rare earth crystal growth technique and the growth technique of low-cost rare earth crystal
CN111206282A (en) * 2019-10-30 2020-05-29 德清晶辉光电科技股份有限公司 Production method of 8-inch lithium niobate crystal

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105019024B (en) * 2015-07-09 2018-02-06 山东大学 A kind of method that lithium niobate crysal near stoichiometric ratio is grown using the adjustable thermal field device of thermograde
CN107740188A (en) * 2017-09-04 2018-02-27 中国科学院长春应用化学研究所 The computational methods and computing system of pulling growth speed in the growth technique of low-cost rare earth crystal
JP7310339B2 (en) * 2019-03-12 2023-07-19 住友金属鉱山株式会社 Method for growing lithium niobate single crystal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003002782A (en) * 2001-06-15 2003-01-08 Toshiba Ceramics Co Ltd Method and device for pulling silicon single crystal
CN106757354A (en) * 2017-01-24 2017-05-31 中国科学院长春应用化学研究所 The growth of low-cost rare earth scintillation crystal
CN107488874A (en) * 2017-09-04 2017-12-19 中国科学院长春应用化学研究所 A kind of design method of temperature field structure for rare earth crystal growth technique and the growth technique of low-cost rare earth crystal
CN111206282A (en) * 2019-10-30 2020-05-29 德清晶辉光电科技股份有限公司 Production method of 8-inch lithium niobate crystal

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
孙丛婷等: "无机功能晶体材料的结晶过程研究", 《中国科学》 *

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