Visual modeling and digital production method for indium phosphide single crystal growth process
By establishing a visual model for indium phosphide single crystal growth and optimizing the temperature distribution using a three-dimensional physical model and numerical simulation, the problems of low yield and high cost of indium phosphide single crystals were solved, achieving efficient and low-cost single crystal production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2023-07-12
- Publication Date
- 2026-06-05
AI Technical Summary
Indium phosphide single crystals have low yield, small wafer size, and high process cost. The lack of effective technical means to monitor the growth state of single crystals leads to high production costs and unstable quality.
A visualization model for indium phosphide single crystal growth was established. A thermal field simulation was constructed through a three-dimensional physical model and numerical simulation. The temperature distribution was optimized by using simulation and experimental correction methods, so as to realize the visualization monitoring and digital production of the single crystal growth process.
It improves the yield and production efficiency of indium phosphide single crystals, reduces production costs, enables real-time monitoring and optimization of the single crystal growth process, and reduces the probability of defects.
Smart Images
Figure CN116895348B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor materials, specifically to a visualization modeling and digital production method for the growth process of indium phosphide single crystals. Background Technology
[0002] Indium phosphide (InP) is an important III-V compound semiconductor material with excellent properties such as high electron mobility, high photoelectric conversion efficiency, high electron drift velocity, strong radiation resistance, and good thermal conductivity. It is widely used in integrated circuits, solar cells, sensors, and optical modules, especially in fiber optic communication, millimeter-wave, and wireless applications. Compared to gallium arsenide (GaAs), another fundamental material in microelectronics and optoelectronics, InP, as a second-generation semiconductor material, exhibits superior performance in communication and electrical applications, and is significantly better than GaAs in device fabrication and energy conversion efficiency. Therefore, although InP research started later, it has developed rapidly. However, the low yield and small wafer size of InP single crystals result in higher processing costs and higher device prices, significantly hindering the widespread application of InP. Therefore, optimizing the control of the InP single crystal growth process to improve the quality of InP single crystal products and process efficiency is of great significance.
[0003] Currently, the VB method and VGF method are widely used in the industrial production of indium phosphide single crystals. The crystals grown using the VB and VGF methods have similar properties, exhibiting relatively uniform crystals and low dislocation density. The VB method requires mechanical transmission control for crucible movement; therefore, the VBF method is more efficient in industrial production and can stably produce indium phosphide single crystals at a lower cost.
[0004] In VGF (Vacuum-Glass Fiber) single crystal furnaces, the internal thermal field and the temperature distribution of the melt are crucial initial conditions for single crystal growth. A reasonable temperature distribution, especially the axial and radial distribution of the melt, is essential for optimizing single crystal growth and improving the single crystal yield. The thermal field during indium phosphide single crystal growth differs from that before growth. Before growth, the thermal field is static and relatively constant. However, single crystal growth occurs under high temperature and pressure, and is a dynamic thermal field whose state is constantly changing due to factors such as heat dissipation during crystal growth and changes in melt volume. In actual processes, the actual temperature of the melt sealed inside the ampoule cannot be detected; only the temperature point outside the ampoule can be measured to characterize the internal melt temperature. The long growth cycle of indium phosphide single crystals and the lack of advanced technologies for monitoring the growth state result in high production costs and low yields of high-quality indium phosphide products, which has become a significant factor restricting the development and application of indium phosphide. Summary of the Invention
[0005] The purpose of this invention is to propose a novel solution to the problems of complex thermal field changes and unmonitorable single crystal growth states in the indium phosphide single crystal growth process by establishing a visualization model. Based on the actual indium phosphide single crystal growth process, this invention establishes a visualization model for indium phosphide single crystal growth. By monitoring changes in the thermal field and crystal growth states during the single crystal growth process, and detecting global parameter changes at each stage during virtual production under different process conditions, the characteristics of thermal field changes can be analyzed to optimize the indium phosphide single crystal production process.
[0006] The technical solution of this invention is: a visualization modeling and digital production method for the indium phosphide single crystal growth process, comprising the following steps:
[0007] S1: Use SolidWorks to create a three-dimensional physical model, which includes the high-pressure furnace body, crucible and feed pipe assembly, heating device, cooling device, heat preservation device, and support device.
[0008] S2: Based on the three-dimensional physical model, a numerical simulation model is established using ANSYS; the numerical simulation model includes the simulation of thermal field physical properties and crystal growth characteristics;
[0009] S3: Based on the established simulation model, simulate the thermal field of indium phosphide single crystal growth, construct a visualization model of indium phosphide single crystal growth, and adjust the distribution of different temperature gradients to grow single crystals using simulation and experimental correction methods.
[0010] S4: Use the established visualization model to guide production, and adopt digital production methods to monitor, predict and optimize the thermal field state of the indium phosphide single crystal growth process in order to control the crystal growth state;
[0011] In step S3, the establishment of a visual model for the growth of indium phosphide single crystals through thermal field simulation is completed through simulation and experimental correction. Specifically, it includes four processes: empty furnace simulation correction process, charging growth simulation process, secondary empty furnace simulation process, and production verification correction process.
[0012] The empty furnace simulation correction process refers to using a simulation model to simulate the thermal field results when no ampoules are inserted, denoted as simulated distribution 1, and recording the actual empty furnace temperature measurement results of the single crystal furnace as measured distribution 1. The simulation results are compared and corrected with the actual empty furnace temperature measurement results of the single crystal furnace so that the simulated empty furnace state is the same as the actual measured state, that is, the simulated distribution 1 is the same as the measured distribution 1.
[0013] The charging growth simulation process refers to the process of loading ampoules into the model after completing the empty furnace simulation correction process, and obtaining the temperature distribution in the melt during the simulated single crystal growth process through simulation calculation, which is denoted as simulation distribution 2; if the temperature distribution in the melt does not reach the expected distribution, the target temperature of the heater is adjusted accordingly until the temperature distribution in the melt reaches the expected effect, which is denoted as simulation distribution 2-1.
[0014] The secondary empty furnace simulation process refers to the process of removing the ampoule from the model after reaching the desired temperature distribution (simulation distribution 2-1) and keeping the heater temperature constant, and then performing the empty furnace simulation again to obtain the temperature distribution of the empty furnace simulation; denoted as simulation distribution 3.
[0015] The production verification correction process refers to conducting an actual empty furnace experiment based on the heater temperature in the simulated distribution 3 after completing the secondary empty furnace simulation process, so that the actual empty furnace thermal field temperature distribution is recorded as the measured distribution 2; if the measured distribution 2 is different from the simulated distribution 3, the thermal insulation system of the thermal field needs to be fine-tuned until it is consistent with the result of the simulated distribution 3; recorded as actual distribution 2-1.
[0016] In step S4, the model visualization model guides the production process by gradually increasing the temperature of the heater during actual material loading and growth until the heater's thermal field state is consistent with the actual distribution 2-1 obtained in step S3. After maintaining the constant temperature for a certain period of time, the temperature is lowered to grow the crystal, and a single crystal is obtained after the growth is completed.
[0017] As a preferred embodiment, the simulation model in step S2 is created by importing the three-dimensional physical model into ANSYS and setting the fixed parameters and adjustable parameters related to the thermal field. The fixed parameters are the inherent property parameters of the components during different simulation processes, including the geometric parameters, density, heat capacity, thermal conductivity of the medium, thermal convection thermal conductivity, and thermal emissivity of the high-pressure furnace body, crucible and material pipe device, heating device, cooling device, and heat preservation device. The adjustable parameters are the parameters that can be adjusted according to different simulation requirements during the simulation process, including the heating temperature parameter, heating time, and cooling water flow rate of the heating device.
[0018] As a preferred embodiment, the indium phosphide single crystal growth process employs the vertical gradient solidification (VGF) method.
[0019] As a preferred embodiment, the heating device is divided into four independently controlled parts along the axial direction of the single crystal furnace, thus dividing the temperature field inside the single crystal furnace into four temperature zones along the axial direction.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] The visualization model established in this invention mainly uses the construction of a visualized temperature field state inside a single crystal furnace to analyze the thermal field of the single crystal growth process, and is used to analyze the temperature environment that melts polycrystalline materials and ensures the normal growth of indium phosphide single crystals.
[0022] The visualization model established in this invention can be used for virtual production before process adjustment and industrial optimization. By simulating the changes in thermal field state during single crystal growth through digital production methods, the crystal growth state can be predicted, thereby verifying and optimizing the production process.
[0023] The process of establishing a visualization model in this method to optimize the production process can be used to optimize the production process at various stages before, during, and after the growth of indium phosphide single crystals, depending on different application requirements.
[0024] By employing digital production methods, this invention enables virtual production during the early stages of indium phosphide single crystal growth, allowing for cost-effective quality inspection of process products. The inspection cycle is short, the error tolerance is high, and process parameters are comprehensive. Furthermore, this invention is applicable to virtual production prior to industrial optimization and process upgrades, guiding the improvement of process control strategies.
[0025] This invention establishes a visualization model for indium phosphide single crystal growth, enabling monitoring of the crystal growth state and the thermal field within the crystal growth apparatus, and allowing for rapid development of emergency strategies in case of unforeseen circumstances. After the indium phosphide single crystal growth is completed, a visualization model for defective product manufacturing processes is established to analyze the defect generation process and thermal field changes during single crystal growth, identify the causes of defects, and optimize the production process. Attached Figure Description
[0026] Figure 1 This is the overall structure diagram of the indium phosphide single crystal growth model.
[0027] Figure 2 This is a partial structural diagram of the heating and cooling devices.
[0028] Figure 3 This is a structural diagram of the crucible and feed pipe assembly.
[0029] In the diagram: 1. High-pressure furnace body; 2. Crucible and feed pipe assembly; 3. Heating device; 4. Cooling device; 5. Insulation device; 6. Support device; 7. Feed pipe; 8. Seed crystal; 9. Indium phosphide polycrystalline; 10. Boron oxide; 11. Dopant; 12. Red phosphorus. Detailed Implementation
[0030] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be provided below to further explain the invention. The purpose of this explanation is to provide a more detailed understanding of the invention, not to limit it. Other embodiments obtained by those skilled in the art without inventive effort are all within the scope of protection of this invention.
[0031] The overall structure of the three-dimensional physical model of the single crystal growth furnace established in the embodiment of the visualization modeling and digital production method for the indium phosphide single crystal growth process described in this invention is shown in the attached figure. Figure 1 As shown in the attached figure, the partial structure of the heating and cooling devices of the single crystal furnace growth model is as follows. Figure 2 As shown in the attached figure, the main thermal field regions of the simulated melt melting and single crystal growth process, including the crucible and feed tube structure, are as follows. Figure 3 As shown. Example
[0032] This invention provides an embodiment of a visualization modeling and digital production method for the growth process of indium phosphide single crystals. This method is used to monitor the crystal growth state during the growth of indium phosphide single crystals. The purpose of this embodiment is to establish a visualization model with the same parameters as actual production to monitor the crystal growth process. The specific process is as follows:
[0033] S1: A three-dimensional physical model of the VGF method single crystal furnace was established using SolidWorks, and six main structural components were constructed: the high-pressure furnace body, the crucible and feed pipe assembly, the heating device, the cooling device, the heat preservation device, and the support device. The heating device was divided into four independently controlled sections along the axial direction of the single crystal furnace, thus dividing the temperature field inside the furnace into four temperature zones along the axial direction.
[0034] S2: Import the 3D physical model into ANSYS, set the thermal field attribute parameters for each structure, and mesh the thermal field analysis regions of the model. Add raw material attributes to the crucible and feed tube device. The raw material is a mixture of multiple raw materials, including seed crystals, polycrystalline indium phosphide, boron oxide, dopants, and red phosphorus, combined in a set proportion and arrangement.
[0035] Fixed parameters are the inherent property parameters of components during different simulation processes, including the geometric parameters, density, heat capacity, thermal conductivity of the medium, thermal convection thermal conductivity, and thermal emissivity of the crucible and other components; adjustable parameters include the heating device's heating temperature parameters, heating time, cooling water flow rate, and temperature parameters.
[0036] S3: Based on the established simulation model, simulate the thermal field of indium phosphide single crystal growth, construct a visualization model of indium phosphide single crystal growth, and adjust the distribution of different temperature gradients to grow single crystals using simulation and experimental correction methods.
[0037] The simulated distribution 1 of the thermal field state during empty furnace simulation and the measured distribution 1 of the thermal field state of single crystal furnace obtained by empty furnace simulation correction process are obtained by empty furnace actual measurement. The simulation distribution 1 is adjusted to be the same as the measured distribution 1.
[0038] After the ampoule was loaded into the model, the simulated thermal field distribution in the melt did not reach the expected state. The target temperature of the heater was adjusted according to the simulated distribution until the thermal field distribution in the melt reached the expected result, simulated distribution 2-1.
[0039] Next, the ampoule was removed from the model, and the heater temperature was kept constant to perform a second empty furnace simulation process to obtain the simulated thermal field distribution 3 of the empty furnace. Based on the heater temperature under this simulated thermal field state, the actual single crystal furnace was debugged, and the heat preservation device was fine-tuned until the measured thermal field state of the actual single crystal furnace, distribution 2-1, was the same as the simulated distribution 3.
[0040] S4: Utilize the established visualization model to guide actual material loading and production, and employ digital production methods to monitor, predict, and optimize the thermal field state during the indium phosphide single crystal growth process to control the crystal growth state:
[0041] During actual charge growth, the temperature of the heater is increased in stages during the polycrystalline indium phosphide heating and melting process until the thermal field state of the heater is consistent with the actual distribution 2-1 obtained in step S3. After maintaining the constant temperature for a certain period of time, the cooling growth process begins, and indium phosphide single crystal is obtained after the growth is completed.
[0042] The heating and melting process steps are as follows: Temperature zones I-IV are raised to 100℃ at a rate of 10℃ / min; the temperature zones I-IV are raised to 350℃ at a rate of 8-9℃ / min and held for 540 min; the temperature zones I-II are raised to 970℃ at a rate of 3-4℃ / min, and the temperature zones III-IV are raised to 1074℃ at a rate of 3-5℃ / min; the temperature zones I-II are slowly raised to 1016℃ at a rate of 0.01℃ / min and held for 90 h, while temperature zones III-IV are continuously held; the temperature zones I-II are slowly raised to 1029℃ at a rate of 0.01℃ / min and held for 24 h; and the temperature is held constant for 240 min.
[0043] The cooling growth process steps are as follows: the temperature of zone I is reduced to 910 ℃ at a rate of 0.09-0.3 ℃ / min, the temperature of zone II is reduced to 970 ℃ at a rate of 0.04-0.2 ℃ / min, and the temperature of zones III-IV is slowly reduced to 1068 ℃ at a rate of 1.5 ℃ / h; the temperature of zones I-IV is slowly reduced until the cooling is complete to obtain indium phosphide single crystals, with the cooling rate of zone I being 4-6 ℃ / h and the cooling rate of zone II being 3-4 ℃ / h.
[0044] Record crystal quality and thermal field state data during crystal growth, then complete the simulation process and optimize the model to simulate the single crystal production process.
[0045] Because the model simulation cycle is short, it can predict product defects that may be caused by process factors, making it easier to adjust process strategies in a timely manner.
[0046] This method can also be used to analyze the defect characteristics of indium phosphide single crystal products with known defects and reconstruct a single crystal growth visualization model of the product based on the process data in the production records. The single crystal growth model is used to simulate the thermal field state and crystal growth state of the indium phosphide single crystal growth process. Based on the simulation model, fault information such as the thermal field state during the defect generation process is diagnosed, and then the cause of the defect and process optimization strategies are analyzed. Example
[0047] This method can also analyze the quality data of indium phosphide single crystal products under this process based on the changes in single crystal growth status and thermal field parameters during the simulation, so as to optimize the process strategy.
[0048] The simulation model was set with inlet water temperature ranging from 22 ℃ to 34 ℃ in 2 ℃ intervals, for a total of 7 groups; and inlet water flow rate ranging from 60 L / h to 300 L / h in 40 L / h intervals, for a total of 6 groups; a total of 42 conditions were set.
[0049] Each condition is modeled using a visual modeling and digital production method for the indium phosphide single crystal growth process. The optimal model scheme is then identified and applied to production. The specific steps include:
[0050] S1: Use SolidWorks to create a three-dimensional physical model, which includes the high-pressure furnace body, crucible and feed pipe assembly, heating device, cooling device, heat preservation device, and support device.
[0051] S2: Based on the three-dimensional physical model, a numerical simulation model is established using ANSYS; the numerical simulation model includes the simulation of thermal field physical properties and crystal growth characteristics; the simulation model is created by importing the three-dimensional physical model into ANSYS and setting the fixed and adjustable parameters related to the thermal field.
[0052] S3: Based on the established simulation model, simulate the thermal field of indium phosphide single crystal growth, construct a visualization model of indium phosphide single crystal growth, and use simulation to adjust different temperature gradient distributions to grow single crystals.
[0053] The crystal growth process includes heating the melt, isothermal control, seed crystal welding, crystal growth, and crystal annealing. During crystal growth, the cooling rate of the heater is controlled at 1-3 ℃ / h, and the nitrogen pressure in the furnace is controlled at 2.7-3 MPa.
[0054] Repeat steps S2 and S3 until all 42 simulation models under different conditions are built; then, compare and analyze the single crystal growth results under the 42 different conditions to find the optimal combination of cooling water flow rate and temperature for single crystal product quality. This is used to optimize the process strategy and form the optimal visualization model scheme.
[0055] S4: Use the established optimal visualization model to guide production, and adopt digital production methods to monitor, predict and optimize the thermal field state of the indium phosphide single crystal growth process in order to control the crystal growth state.
[0056] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some examples of its application, and are not intended to limit the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention.
Claims
1. A visualization modeling and digital production method for the indium phosphide single crystal growth process, comprising the following steps: S1: Use SolidWorks to create a three-dimensional physical model, which includes the high-pressure furnace body, crucible and feed pipe assembly, heating device, cooling device, heat preservation device, and support device. S2: Based on the three-dimensional physical model, a numerical simulation model is established using ANSYS; the numerical simulation model includes the simulation of thermal field physical properties and crystal growth characteristics; S3: Based on the established simulation model, simulate the thermal field of indium phosphide single crystal growth, construct a visualization model of indium phosphide single crystal growth, and adjust the distribution of different temperature gradients to grow single crystals using simulation and experimental correction methods. S4: Use the established visualization model to guide production, and adopt digital production methods to monitor, predict and optimize the thermal field state of the indium phosphide single crystal growth process in order to control the crystal growth state; In step S3, the establishment of a visual model for the growth of indium phosphide single crystals through thermal field simulation is completed through simulation and experimental correction. Specifically, it includes four processes: empty furnace simulation correction process, charging growth simulation process, secondary empty furnace simulation process, and production verification correction process. The empty furnace simulation correction process refers to using a simulation model to simulate the thermal field results when no ampoules are inserted, denoted as simulated distribution 1, and recording the actual empty furnace temperature measurement results of the single crystal furnace as measured distribution 1. The simulation results are compared and corrected with the actual empty furnace temperature measurement results of the single crystal furnace so that the simulated empty furnace state is the same as the actual measured state, that is, the simulated distribution 1 is the same as the measured distribution 1. The charging growth simulation process refers to the process of loading ampoules into the model after completing the empty furnace simulation correction process, and obtaining the temperature distribution in the melt during the simulated single crystal growth process through simulation calculation, which is denoted as simulation distribution 2; if the temperature distribution in the melt does not reach the expected distribution, the target temperature of the heater is adjusted accordingly until the temperature distribution in the melt reaches the expected effect, which is denoted as simulation distribution 2-1. The secondary empty furnace simulation process refers to the process of removing the ampoule from the model after reaching the desired temperature distribution (simulation distribution 2-1) and keeping the heater temperature constant, and then performing the empty furnace simulation again to obtain the temperature distribution of the empty furnace simulation; denoted as simulation distribution 3. The production verification correction process refers to conducting an actual empty furnace experiment based on the heater temperature in the simulated distribution 3 after completing the secondary empty furnace simulation process, so that the actual empty furnace thermal field temperature distribution is recorded as the measured distribution 2; if the measured distribution 2 is different from the simulated distribution 3, the thermal insulation system of the thermal field needs to be fine-tuned until it is consistent with the result of the simulated distribution 3; recorded as actual distribution 2-1. In step S4, the model visualization model guides the production process by gradually increasing the temperature of the heater during actual material loading and growth until the heater's thermal field state is consistent with the actual distribution 2-1 obtained in step S3. After maintaining the constant temperature for a certain period of time, the temperature is lowered to grow the crystal, and a single crystal is obtained after the growth is completed.
2. The visualization modeling and digital production method for the indium phosphide single crystal growth process according to claim 1, characterized in that: In step S2, the simulation model is created by importing the three-dimensional physical model into ANSYS and setting the fixed and adjustable parameters related to the thermal field. The fixed parameters are the inherent property parameters of the components during different simulation processes, including the geometric parameters, density, heat capacity, thermal conductivity of the medium, thermal convection thermal conductivity, and thermal emissivity of the high-pressure furnace body, crucible and material pipe device, heating device, cooling device, and heat preservation device. The adjustable parameters are the parameters that can be adjusted according to different simulation requirements during the simulation process, including the heating temperature parameter, heating time, and cooling water flow rate of the heating device.
3. The visualization modeling and digital production method for the indium phosphide single crystal growth process according to claim 1, characterized in that: The indium phosphide single crystal growth process employs the vertical gradient solidification method (VGF).
4. The visualization modeling and digital production method for the indium phosphide single crystal growth process according to claim 3, characterized in that: The heating device is divided into four independently controlled parts along the axial direction of the single crystal furnace, which divides the temperature field inside the single crystal furnace into four temperature zones along the axial direction.