Method and device for calculating concave-convex degree of solid-liquid interface in real time in crystal growth process

Abstract

The invention discloses a device for calculating the concave-convex degree of a solid-liquid interface in real time in the crystal growth process, the device comprises a weighing system, a lifting furnace and a high-temperature thermal imaging system, the weighing system is arranged in the lifting furnace and used for recording the weight of a crystal in real time, and the high-temperature thermal imaging system is arranged on one side of the lifting furnace and used for recording the weight of the crystal in real time. The method is used for observing the diameter of the crystal in real time and relates to the technical field of real-time calculation of the concave-convex degree of the solid-liquid interface in the crystal growth process. According to the device for calculating the concave-convex degree of the solid-liquid interface in real time in the crystal growth process, data used for calculation all come from real-time growth data of the crystal, the real-time condition of the solid-liquid interface can be accurately described, growth process parameters are adjusted, and the change of the form of the solid-liquid interface can be responded in time according to the real-time monitoring data, so that the growth condition is optimized, and the growth efficiency is improved. The stability and the consistency of the crystal growth process are ensured, and the method is suitable for various crystal growth processes and equipment and has relatively high universality and adaptability.

Description

Technical Field

[0001] The invention relates to the technical field of real-time calculation of solid-liquid interface concavity and convexity during crystal growth, and in particular to a method and a device for real-time calculation of solid-liquid interface concavity and convexity during crystal growth. Background Art

[0002] Large-size single crystals are key basic materials in the fields of semiconductors, lasers, high-energy physics, radiation detection, etc. Crystal quality directly affects device performance, and the morphology of the solid-liquid interface during crystal growth has a key influence on crystal quality. The concavity and convexity of the solid-liquid interface not only affects the purity and structural integrity of the crystal, but also causes defects inside the crystal. Therefore, how to monitor and control the morphology of the solid-liquid interface in real time during crystal growth has become a key technical issue in improving crystal quality.

[0003] The existing method (CN110685008A) measures the weight of the growing crystal in real time, and makes a difference between the measured weight of the crystal and its theoretical weight; based on the difference between the two, a PID control algorithm is used to control the heating power required for crystal growth. A CCD rotating device is used to rotate the CCD optical magnifying device, and the CCD optical magnifying device measures the distance between the position corresponding to the gray value of the crystal reference line and the center line of the measurement reference line in real time. Based on the difference between the distance and its initial distance, a PID control algorithm is used to control the rotation speed of the crystal. The crystal rotation control system controls the rotation speed of the crystal to adjust the angle of the growth interface, so that the growth interface angle is always maintained in a very small range of fluctuations. Summary of the invention

[0004] To achieve the above objectives, the present invention provides a method and device for calculating the convexity and concavity of the solid-liquid interface in real time during the crystal growth process, which is implemented through the following technical scheme: A device for calculating the convexity and concavity of the solid-liquid interface in real time during the crystal growth process, comprising a weighing system, a pulling furnace and a high-temperature thermal imaging system, wherein the weighing system is arranged inside the pulling furnace for recording the weight of the crystal in real time, and the high-temperature thermal imaging system is arranged on one side of the pulling furnace for observing the diameter of the crystal in real time.

[0005] A method for calculating the concavity and convexity of a solid-liquid interface in real time during crystal growth comprises the following steps:

[0006] Step 1: First, calculate the rising speed v1 of the crystal according to the pulling speed v0;

[0007] Step 2: Calculate the instantaneous growth rate γ of the crystal when it grows at a flat interface based on the crystal's rising speed v1 and the crystal diameter d0 observed in real time by the high-temperature thermal imaging system. 平 ;

[0008] Step 3, calculating the actual growth rate γ of the crystal according to the crystal weight m recorded in real time by the weighing system;

[0009] Step 4: Use the surface of the spherical cap to represent the solid-liquid interface. According to the geometric relationship, it can be deduced that Surface area of ​​the spherical cap

[0010] Step 5: Based on the growth rate relationship, γ = S × v1 × ρ 晶体 , solve for h;

[0011] Step 6: According to the crystal diameter observed in real time by the high-temperature thermal imaging system, the volume of the flat interface crystal is calculated by numerical integration, thereby obtaining the mass m0 of the crystal;

[0012] Step 7: According to the calculated solid-liquid interface shape, the solid-liquid shape is changed in a targeted manner by adjusting the growth process parameters, including pulling speed, rotation speed, and power.

[0013] Preferably, in step 3, the comparison of γ 平 With the size of γ, if γ ≈ γ 平 , then it is a flat solid-liquid interface; if γ>γ 平 , then it is a concave interface or a convex interface.

[0014] Preferably, in step six, when m>m0, it is a convex interface with a height of h, and m≤m0 is a concave interface.

[0015] The present invention provides a method and device for real-time calculation of the concavity and convexity of the solid-liquid interface during crystal growth. It has the following beneficial effects:

[0016] 1. Real-time and high precision. All the data used for calculation are derived from the real-time growth data of the crystal, which can accurately describe the real-time status of the solid-liquid interface.

[0017] 2. Dynamic adjustment capability: Adjusting the growth process parameters can promptly respond to changes in the solid-liquid interface morphology based on real-time monitoring data, thereby optimizing growth conditions and ensuring the stability and consistency of the crystal growth process.

[0018] 3. Applicability: It is suitable for a variety of crystal growth processes and equipment, has strong versatility and adaptability, and can be used in different production environments.

[0019] 4. Improve crystal quality by real-time monitoring and high-precision control of the solid-liquid interface morphology, thereby reducing defects in the crystal growth process, improving the purity and structural integrity of the crystal, and ensuring the high quality of the final product.

[0020] 5. Guidance significance: Adjusting the growth process parameters can directly obtain data on the impact on the solid-liquid interface, which is of great significance for revealing the impact of growth process parameters on the solid-liquid interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The schematic diagram of the structure of the device for real-time calculation of the concavity and convexity of the solid-liquid interface during the crystal growth process of the present invention;

[0022] Figure 2 It is a geometric relationship diagram of the spherical crown surface of the present invention.

[0023] In the figure: 1. Weighing system; 2. Pulling furnace; 3. Crystal; 4. High-temperature thermal imaging system. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1-Figure 2 The present invention provides a technical solution: a method for calculating the concavity and convexity of the solid-liquid interface in real time during the crystal growth process, comprising the following steps:

[0026] Step 1: First, calculate the rising speed v1 of the crystal according to the pulling speed v0. In the formula, ρ 熔体 and ρ 晶体 are the densities of melt and crystal respectively, d' is the diameter of crucible, d0 is the crystal diameter observed in real time by high temperature thermal imaging system;

[0027] Step 2: Calculate the instantaneous growth rate γ of the crystal when it grows at a flat interface based on the crystal's rising speed v1 and the crystal diameter d0 observed in real time by the high-temperature thermal imaging system. 平 ,

[0028] Step 3: Calculate the actual growth rate γ of the crystal according to the crystal weight m recorded in real time by the weighing system. That is, the rate of change of crystal mass over time, compared with γ 平 With the size of γ, if γ ≈ γ 平 , then it is a flat solid-liquid interface; if γ>γ 平 , then it is a concave interface or a convex interface;

[0029] Step 4: Use the surface of the spherical cap to represent the solid-liquid interface. Figure 2The geometric relationship can be deduced Surface area of ​​the spherical cap

[0030] Step 5: Based on the growth rate relationship, γ = S × v1 × ρ 晶体 , solve for h;

[0031] Step 6: According to the crystal diameter observed in real time by the high-temperature thermal imaging system, the volume of the flat interface crystal is calculated by numerical integration, thereby obtaining the mass m0 of the crystal. If m>m0, it is a convex interface with a height of h, otherwise it is a concave interface.

[0032] Step 7: According to the calculated solid-liquid interface shape, by adjusting the growth process parameters, including pulling speed, rotation speed, and power, the solid-liquid shape is changed in a targeted manner to achieve the growth of high-quality crystals.

[0033] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field unless otherwise specified and limited.

Claims

1. A device for calculating the concavity and convexity of the solid-liquid interface in real time during crystal growth. Features: It includes a weighing system, a pulling furnace and a high-temperature thermal imaging system. The weighing system is arranged inside the pulling furnace and is used to record the weight of the crystal in real time. The high-temperature thermal imaging system is arranged on one side of the pulling furnace and is used to observe the diameter of the crystal in real time.

2. A method for calculating the concavity and convexity of the solid-liquid interface in real time during crystal growth. It is characterized in that The following steps are involved: Step 1: First, calculate the rising speed v1 of the crystal according to the pulling speed v0; Step 2: Calculate the instantaneous growth rate γ of the crystal when it grows at a flat interface based on the crystal's rising speed v1 and the crystal diameter d0 observed in real time by the high-temperature thermal imaging system. 平 ; Step 3, calculating the actual growth rate γ of the crystal according to the crystal weight m recorded in real time by the weighing system; Step 4: Use the surface of the spherical cap to represent the solid-liquid interface. According to the geometric relationship, it can be deduced that Surface area of ​​the spherical cap Step 5: Based on the growth rate relationship γ = S × v 1 ×ρ 晶体 , solve for h; Step 6: According to the crystal diameter observed in real time by the high-temperature thermal imaging system, the volume of the flat interface crystal is calculated by numerical integration, thereby obtaining the mass m0 of the crystal; Step 7: According to the calculated solid-liquid interface shape, the solid-liquid shape is changed in a targeted manner by adjusting the growth process parameters, including pulling speed, rotation speed, and power.

3. A method for calculating the concavity and convexity of the solid-liquid interface in real time during crystal growth according to claim 2, Features: In step 3, the comparison of γ 平 With the size of γ, if γ ≈ γ 平 , then it is a flat solid-liquid interface; if γ>γ 平 , then it is a concave interface or a convex interface.

4. A method for calculating the concavity and convexity of the solid-liquid interface in real time during crystal growth according to claim 1, Features: In the step six, when m>m0, it is a convex interface with a height of h, and m≤m0 is a concave interface.

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