Crystal growth detection method and system for crystal growth equipment

Abstract

The invention relates to the technical field of crystal growth, in particular to a crystal growth detection method and system for crystal growth equipment. The method comprises the following steps of: determining a melt flow vector at each detection moment, determining an abnormal deposition direction in a crystal growth process according to a crystal contour in a contour image, acquiring an abnormal deposition vector, and further determining an abnormal deposition direction according to the crystal contour in the contour image at the adjacent previous detection moment and a crystal diffraction peak in an XRD (X-Ray Diffraction) spectrum. And regulating the magnetic field in the crystal growth furnace. By analyzing the melt concentration distribution in the crystal growth furnace and the form deviation condition of the crystal section contour, crystal growth detection is carried out, the abnormal convection influence in the crystal growth process is evaluated, and how to apply an intervention magnetic field to inhibit the influence is determined by combining the crystal contour and the crystal diffraction peak, so that the crystal growth quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal growth, and particularly to a crystal growth detection method and system for a crystal growth device. Background Art

[0002] Crystals play an important role in the semiconductor industry and are widely used in the manufacture of products such as infrared optical devices, detectors, and solar cells. Currently, crystals are generally prepared based on the Cz method. The crystal growth furnace contains a crystal melt. By controlling the continuous lifting of the seed crystal (single crystal seed) in the crystal growth furnace, high-quality single crystals are grown. However, during the crystal growth process, the melt in the growth furnace will generate abnormal convection due to hydrodynamic changes, etc., resulting in uneven solute distribution near the crystal growth interface, and further affecting the crystal growth quality. Therefore, it is crucial to perform real-time detection and control of crystal growth.

[0003] Currently, an external magnetic field is generally used to assist in stabilizing the melt convection. However, due to the complex fluid changes in the crystal growth furnace, the direction and magnitude of abnormal convection may change at any time, and the preset fixed magnetic field direction may not be able to cover different convections in a timely manner, resulting in uneven melt flow in the crystal growth furnace, and causing defects such as vacancies during the crystal growth process, affecting the crystal growth quality. Summary of the Invention

[0004] In order to solve the technical problem of poor crystal growth quality, the purpose of the present invention is to provide a crystal growth detection method and system for a crystal growth device, and the specific technical solutions adopted are as follows: A crystal growth detection method for a crystal growth device, the method comprising: At each detection moment, obtain the melt concentration at each measurement point in the crystal growth furnace, as well as the contour image and XRD pattern of the crystal interface, and the main viewing angle of the contour image is parallel to the crystal lifting direction; According to the difference in the melt concentration at different measurement points at each detection moment, and the change in the melt concentration at each measurement point between adjacent detection moments, determine the melt flow vector at each detection moment; at each detection moment, according to the crystal contour in the contour image, determine the abnormal deposition direction during the crystal growth process, and combine the difference in the melt concentration at the crystal contour position in the abnormal deposition direction to obtain the abnormal deposition vector; At each detection moment, according to the abnormal deposition vector and the melt flow vector, and in combination with the crystal contour in the contour image and the crystal diffraction peak in the XRD pattern of the adjacent previous detection moment, adjust the magnetic field in the crystal growth furnace.

[0005] Further, the method for obtaining the melt flow vector includes: Obtain the maximum concentration gradient vector at each detection moment; take any detection moment as the target moment and the adjacent previous detection moment of the target moment as the reference moment; at the reference moment, take the melt concentration of the measuring point corresponding to the maximum melt concentration at the target moment as the maximum reference concentration, and take the melt concentration of the measuring point corresponding to the minimum melt concentration at the target moment as the minimum reference concentration; According to the difference between the maximum melt concentration and the maximum reference concentration at the reference moment, and the difference between the minimum melt concentration and the minimum reference concentration at the reference moment, determine whether the maximum concentration gradient vector at the reference moment has changed; if it has changed, take the maximum concentration gradient vector at the target moment as the melt flow vector; if it has not changed, take the sum of the maximum concentration gradient vector at the target moment and the maximum concentration gradient vector at the reference moment as the melt flow vector at the target moment.

[0006] Furthermore, the method for obtaining the maximum concentration gradient vector includes: At each detection moment, cluster the measuring points based on the clustering algorithm and all melt concentrations; regard the area corresponding to all measuring points in each cluster as a concentration similarity area, and take the melt concentration of the measuring point corresponding to the cluster center as the area representative concentration; Take the range of the area representative concentration as the gradient modulus length, and take the direction from the cluster center corresponding to the maximum area representative concentration to the cluster center corresponding to the minimum area representative concentration as the gradient direction, and determine the maximum concentration gradient vector based on the gradient modulus length and the gradient direction.

[0007] Furthermore, the method for determining whether the maximum concentration gradient vector at the reference moment has changed includes: Take the difference between the maximum melt concentration and the maximum reference concentration as the first change parameter; take the difference between the minimum reference concentration and the minimum melt concentration as the second change parameter; if both the first change parameter and the second change parameter are greater than 0, determine that the maximum concentration gradient vector has changed, otherwise it has not changed.

[0008] Furthermore, the method for determining the abnormal deposition direction includes: According to the difference between the crystal contour in the contour image and the preset standard growth contour, determine the maximum convex vector and the maximum concave vector of the crystal in the contour image; take the direction of the vector corresponding to the sum of the maximum convex vector and the maximum concave vector as the abnormal deposition direction; where the preset standard growth contours are different at different detection moments.

[0009] Furthermore, the method for obtaining the maximum convex vector and the maximum concave vector includes: At each detection moment, map the preset standard growth profile onto the profile image, determine the maximum convex direction and maximum convex width of the crystal profile, as well as the maximum concave direction and maximum concave width; determine the maximum convex vector based on the maximum convex direction and maximum convex width, and determine the maximum concave vector based on the maximum concave direction and maximum concave width.

[0010] Further, the method for obtaining the abnormal deposition vector includes: At each detection moment, obtain two profile intersection points on the crystal profile along the abnormal deposition direction, respectively use the melt concentration at the measurement point closest to each profile intersection point as the reference concentration corresponding to the profile intersection point, use the difference between the two reference concentrations as the modulus length of the abnormal deposition vector, and combine the abnormal deposition direction to determine the abnormal deposition vector.

[0011] Further, the method for regulating the magnetic field in the crystal growth furnace includes: At each detection moment, use the difference between the abnormal deposition vector and the melt flow vector as the abnormal convection vector, use the opposite direction of the vector direction of the abnormal convection vector as the magnetic field regulation direction, determine the regulation weight according to the modulus length of the abnormal convection vector, and use the regulation weight to weight the preset magnetic field intensity to obtain the magnetic field regulation intensity; At each detection moment, obtain the crystal growth quality parameter according to the degree of coincidence between the area enclosed by the crystal profile in the profile image and the area enclosed by the preset standard growth profile, and the deviation of the width of the crystal diffraction peak in the XRD pattern relative to the preset standard width; take any detection moment as the target moment, and take the adjacent previous detection moment of the target moment as the reference moment; use the change rate between the crystal growth quality parameters corresponding to the target moment and the reference moment as the magnetic field regulation effect parameter at the reference moment; If the magnetic field regulation effect parameter is greater than or equal to 0, regulate the magnetic field in the crystal growth furnace based on the magnetic field regulation direction and magnetic field regulation intensity at the reference moment; if the magnetic field regulation effect parameter is less than 0, regulate the magnetic field in the crystal growth furnace based on the magnetic field regulation direction and magnetic field regulation intensity at the target moment.

[0012] Further, the method for obtaining the crystal growth quality parameter includes: Take the area coincidence area between the area enclosed by the crystal profile in the profile image and the area enclosed by the preset standard growth profile as the first quality parameter, and take the negative correlation mapping result of the absolute value of the difference between the width of the crystal diffraction peak in the XRD pattern and the preset standard width as the second quality parameter; fuse the first quality parameter and the second quality parameter to obtain the crystal growth quality parameter.

[0013] A crystal growth detection system for a crystal growth device, the system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the crystal growth detection method for the crystal growth device are implemented.

[0014] The present invention has the following beneficial effects: In the present invention, at each detection moment, the melt concentration at each measurement point in the crystal growth furnace, as well as the contour image and XRD pattern of the crystal interface are obtained. The main viewing angle of the contour image is parallel to the crystal lifting direction, preparing for subsequent crystal growth detection and analysis. Then, according to the differences in the melt concentration at different measurement points at each detection moment, and the changes in the melt concentration at each measurement point between adjacent detection moments, the melt flow vector reflecting the overall macroscopic flow of the melt at each detection moment is determined, preparing for subsequent comprehensive evaluation of abnormal convection in combination with the crystal deposition situation. At each detection moment, based on the crystal contour in the contour image, the abnormal deposition direction during the crystal growth process is determined, and by combining the differences in the melt concentration at the crystal contour positions in the abnormal deposition direction, the abnormal deposition vector reflecting the influence of abnormal convection during the crystal growth process is obtained. Furthermore, in combination with the crystal contour in the contour image of the adjacent previous detection moment and the crystal diffraction peaks in the XRD pattern, the magnetic field in the crystal growth furnace is regulated. By analyzing the melt concentration distribution in the crystal growth furnace and the morphological deviation of the crystal cross-section contour, the present invention conducts crystal growth detection, evaluates the influence of abnormal convection during the crystal growth process, and determines how to apply an intervention magnetic field to suppress the influence in combination with the crystal contour and crystal diffraction peaks, thereby improving the crystal growth quality. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a flowchart of a crystal growth detection method for a crystal growth device provided by an embodiment of the present invention; Figure 2 It is a flowchart of a method for obtaining a melt flow vector provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of a crystal contour provided by an embodiment of the present invention; Figure 4A flowchart of a method for regulating the magnetic field in a crystal growth furnace provided by an embodiment of the present invention. Detailed implementation manners

[0017] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following describes in detail the specific implementation manners, structures, features and effects of a crystal growth detection method and system for a crystal growth device according to the present invention in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0019] The following specifically describes the specific solution of a crystal growth detection method and system for a crystal growth device provided by the present invention in conjunction with the accompanying drawings.

[0020] Please refer to Figure 1 , which shows a flowchart of a method for a crystal growth detection method for a crystal growth device provided by an embodiment of the present invention, specifically including: Step S1, at each detection moment, obtain the melt concentration at each measurement point in the crystal growth furnace, as well as the contour image and XRD pattern of the crystal interface, and the main viewing angle of the contour image is parallel to the crystal lifting direction.

[0021] It should be noted that the growth detection and control methods for different crystals are the same. An embodiment of the present invention takes a germanium crystal as an example for analysis and description.

[0022] In an embodiment of the present invention, through an existing detection system in the crystal growth furnace or by evenly arranging measurement points on the inner wall of the crystal growth furnace and installing conductivity sensors, the melt concentration at each measurement point is collected in real time to prepare for subsequent analysis of the melt flow in the crystal growth furnace and evaluation of abnormal convection; at the same time, X-ray imaging technology is used to collect the contour image of the crystal interface, wherein the main viewing angle of the contour image is parallel to the crystal lifting direction, that is, it represents the circular cross-sectional contour of the crystal rod, to prepare for subsequent evaluation of abnormal deposition caused by abnormal convection in crystal growth; and X-ray diffraction technology is used to detect the crystal growth interface to obtain the XRD pattern, to prepare for subsequent evaluation of the growth quality of the crystal interface and regulation of the magnetic field to intervene in the growth.

[0023] Among them, the collection frequencies of the melt concentration, the profile image, and the XRD pattern are all set to 1 time per second, and the collection starts synchronously from the moment when the germanium seed crystal (single crystal seed) first penetrates into the melt, so as to obtain the melt concentration at each measurement point at each detection moment, as well as the profile image and the XRD pattern of the crystal interface.

[0024] It should be noted that the above collection processes are all prior arts and will not be elaborated here. The implementer can also set the collection frequency by himself.

[0025] Step S2: Determine the melt flow vector at each detection moment according to the differences in the melt concentration at different measurement points at each detection moment and the changes in the melt concentration at each measurement point between adjacent detection moments; at each detection moment, determine the abnormal deposition direction during the crystal growth process according to the crystal profile in the profile image, and combine the differences in the melt concentration at the crystal profile positions in the abnormal deposition direction to obtain the abnormal deposition vector.

[0026] During the growth process of germanium crystals, applying an external magnetic field can reduce the influence of internal abnormal convection on the crystal growth quality, so that the crystals grow according to the ideal lattice arrangement. However, since abnormal convection cannot be directly detected, and the overall macroscopic flow of the melt and abnormal convection will affect crystal growth to a certain extent, therefore, in the embodiments of the present invention, the overall macroscopic flow situation of the melt is first evaluated to prepare for evaluating abnormal convection in combination with the crystal growth situation later; Considering that the distribution of the melt concentration is closely related to the flow direction of the melt, based on the buoyancy effect, the flow direction in the melt will tend to be from the region with a higher concentration to the region with a lower concentration. Therefore, at each detection moment, the melt flow situation can be preliminarily evaluated according to the differences in the melt concentration at different measurement points; however, since the melt flow is dynamic, the above melt flow situation is preliminarily evaluated by the static data at a single detection moment, which may have errors, so it is necessary to further determine it in combination with the change in the melt concentration; Therefore, in the embodiments of the present invention, the melt flow vector at each detection moment will be determined according to the differences in the melt concentration at different measurement points at each detection moment and the changes in the melt concentration at each measurement point between adjacent detection moments; where the melt flow vector reflects the overall macroscopic flow direction of the melt in the crystal growth furnace and the concentration gradient difference in the flow direction.

[0027] Preferably, in an embodiment of the present invention, the method for obtaining the melt flow vector includes: Please refer to Figure 2 , which shows a flow chart of a method for obtaining a melt flow vector provided by an embodiment of the present invention, specifically including: Step S201: Obtain the maximum concentration gradient vector at each detection moment. Take any detection moment as the target moment and the adjacent previous detection moment of the target moment as the reference moment. At the reference moment, take the melt concentration of the measurement point corresponding to the maximum melt concentration at the target moment as the maximum reference concentration, and take the melt concentration of the measurement point corresponding to the minimum melt concentration at the target moment as the minimum reference concentration.

[0028] Considering that the maximum concentration gradient in the crystal growth furnace usually reflects the overall flow of the melt, in an embodiment of the present invention, the maximum concentration gradient vector at each detection moment is first obtained.

[0029] In a preferred embodiment of the present invention, considering that the maximum concentration gradient usually points from the region of larger melt concentration to the region of smaller melt concentration, and clustering can cluster the measurement point regions corresponding to similar melt concentrations into a cluster, thereby helping to evaluate the overall flow of the melt and determine the maximum concentration gradient. Therefore, the method for obtaining the maximum concentration gradient vector includes: At each detection moment, based on the clustering algorithm and the melt concentrations at all measurement points, cluster the measurement points. Take the regions corresponding to all measurement points in each cluster as a concentration similarity region, and take the melt concentration of the measurement point corresponding to the cluster center as the regional representative concentration. Take the range of the regional representative concentrations as the gradient modulus length, and take the direction from the cluster center corresponding to the maximum regional representative concentration, i.e., the measurement point, to the cluster center corresponding to the minimum regional representative concentration, i.e., the measurement point, as the gradient direction. Based on the gradient modulus length and the gradient direction, determine the maximum concentration gradient vector.

[0030] As an example, specifically use the ISODATA algorithm to cluster with the melt concentration difference as the metric distance. The methods of determining the vector based on the modulus length and direction are already well-known in the art. Implementers can also use other clustering means, which will not be elaborated here.

[0031] In another embodiment of the present invention, the range of the melt concentrations at different measurement points can also be directly taken as the gradient modulus length, and the direction from the measurement point corresponding to the maximum melt concentration to the measurement point corresponding to the minimum melt concentration can be taken as the gradient direction. Based on the gradient modulus length and the gradient direction, determine the maximum concentration gradient vector.

[0032] Also considering that as time goes by, the concentration difference in the direction corresponding to the maximum concentration gradient will change, that is, as the melt flows, at each detection moment, the concentration at the region or measurement point corresponding to the maximum melt concentration at the previous adjacent detection moment will decrease, while the concentration at the region or measurement point corresponding to the minimum melt concentration will increase. However, if the above situation does not occur, it indicates that the maximum concentration gradient at the previous detection moment has not changed, and other extreme concentration gradients may appear inside the melt. The extreme concentration gradient and the maximum concentration gradient at the previous detection moment jointly affect the overall flow of the melt. Therefore, it is still necessary to determine the concentrations of the measuring points corresponding to the maximum melt concentration and the minimum melt concentration at this detection moment for reference, so as to prepare for evaluating whether the maximum concentration gradient at the previous detection moment has changed and judging whether other extreme concentration gradients appear at this detection moment.

[0033] In an embodiment of the present invention, any detection moment is used as the target moment, and the previous adjacent detection moment of the target moment is used as the reference moment; at the reference moment, the melt concentration of the measuring point corresponding to the maximum melt concentration at the target moment is used as the maximum reference concentration, and the melt concentration of the measuring point corresponding to the minimum melt concentration at the target moment is used as the minimum reference concentration; by changing the target moment, the concentration references of the measuring points corresponding to the maximum melt concentration and the minimum melt concentration at the previous detection moment at each detection moment can be obtained.

[0034] Step S202: According to the difference between the maximum melt concentration and the maximum reference concentration at the reference moment, and the difference between the minimum melt concentration and the minimum reference concentration at the reference moment, judge whether the maximum concentration gradient vector at the reference moment has changed; if it has changed, use the maximum concentration gradient vector at the target moment as the melt flow vector; if it has not changed, use the sum of the maximum concentration gradient vector at the target moment and the maximum concentration gradient vector at the reference moment as the melt flow vector at the target moment.

[0035] If the concentration difference in the direction corresponding to the maximum concentration gradient has changed at the target moment, then the concentration at the area or measuring point corresponding to the maximum melt concentration at the reference moment will decrease relatively at the target moment, and the concentration at the area or measuring point corresponding to the minimum melt concentration at the reference moment will increase relatively at the target moment. Based on this, in a preferred embodiment of the present invention, the method for judging whether the maximum concentration gradient vector at the reference moment has changed includes: Take the difference obtained by subtracting the maximum reference concentration from the maximum melt concentration as the first change parameter; take the difference obtained by subtracting the minimum melt concentration from the minimum reference concentration as the second change parameter; if both the first change parameter and the second change parameter are greater than 0, it is determined that the maximum concentration gradient vector has changed, otherwise it has not changed.

[0036] Among them, the first change parameter reflects the decrease of the concentration at the area or measuring point corresponding to the maximum melt concentration at the reference moment at the target moment; the second change parameter reflects the increase of the concentration at the area or measuring point corresponding to the minimum melt concentration at the reference moment at the target moment; when the maximum concentration gradient vector at the reference moment has not changed, it indicates that there are other extreme concentration gradients, and the maximum concentration gradient at the target moment is the extreme concentration gradient.

[0037] After determining the existence of an extreme concentration gradient at the target moment, the maximum concentration gradient vector at the target moment can be further summed with the maximum concentration gradient vector at the reference moment to determine the melt flow vector at the target moment; among them, vector operations are already well-known technical means and will not be elaborated here.

[0038] By changing the target moment, the melt flow vectors at each detection moment can be obtained.

[0039] Considering that during the growth process of germanium crystals, if the melt flow direction is stable and uniform, the formed crystal will present a regular cylinder with a uniform diameter; while if abnormal convection occurs, it will cause the deposition of single-crystal germanium to shift along with the melt flow, that is, the diameter of the growth interface changes, forming abnormal deposition and resulting in uneven cylinder morphology; at the same time, if the abnormal convection promotes the melt flow at a certain position of the crystal growth interface, it will cause this position to show a protruding deposition, and vice versa, it will show a sunken deposition. Among them, the uneven growth interface is the result of the combined action of melt flow and abnormal convection. Therefore, after obtaining the melt flow vectors at each detection moment in the embodiments of the present invention, the morphological uniformity of the crystal growth interface is further analyzed based on the crystal contour in the contour image, so as to analyze the abnormal deposition situation during the crystal growth process and determine the abnormal deposition direction; further, in combination with the difference between the melt concentrations at the crystal contour positions in the abnormal deposition direction, the deposition unevenness degree of the crystal growth interface, that is, the abnormal deposition modulus length, is evaluated, so as to obtain the abnormal deposition vector.

[0040] Please refer to Figure 3 , which shows a schematic diagram of a crystal contour provided by an embodiment of the present invention; Figure 3 The thick irregular shape in represents the crystal contour, and the thin regular circle represents the preset standard growth contour.

[0041] Preferably, in an embodiment of the present invention, considering that the abnormal deposition direction usually points from the depression to the deposition, the method for determining the abnormal deposition direction includes: According to the difference between the crystal contour in the contour image and the preset standard growth contour, determine the maximum protruding vector and the maximum sunken vector of the crystal in the contour image; the direction of the corresponding vector of the sum of the maximum protruding vector and the maximum sunken vector is used as the abnormal deposition direction; among them, the preset standard growth contours at different detection moments are different.

[0042] It should be noted that when the crystal contour in the contour image completely coincides with the preset standard growth contour, it is determined that the crystal grows normally, and no additional intervention and subsequent step analysis are required.

[0043] Among them, in a preferred embodiment of the present invention, the method for obtaining the maximum protruding vector and the maximum sunken vector includes: At each detection moment, map the preset standard growth profile into the profile image, and determine the maximum convex direction and maximum convex width of the crystal profile, as well as the maximum concave direction and maximum concave width; determine the maximum convex vector based on the maximum convex direction and maximum convex width, and determine the maximum concave vector based on the maximum concave direction and maximum concave width.

[0044] As an example, first obtain the closed edge in the profile image, i.e., the crystal profile, based on the edge detection algorithm, and then map the preset standard growth profile at this detection moment into the profile image for comparison reference to determine the maximum convex region and the maximum concave region, i.e., Figure 3 the maximum convex region A and the maximum concave region B in, and determine the maximum convex width in the maximum convex region A and the maximum concave width in the maximum concave region B; where the maximum convex direction is from the preset standard growth profile to the crystal profile at the maximum convex width, and the maximum concave direction is from the preset standard growth profile to the crystal profile at the maximum concave width; then use the maximum convex direction as the vector direction and the maximum convex width as the vector modulus to determine the maximum convex vector, and similarly determine the maximum concave vector; then perform vector summation, and the direction of the resulting vector is the abnormal deposition direction.

[0045] It should be noted that obtaining the crystal profile, determining the preset standard growth profile at each detection moment and mapping it, determining the maximum convex region and the maximum concave region, obtaining the maximum convex direction and maximum convex width, obtaining the maximum concave direction and maximum concave width, vector construction and vector operation are all prior arts and will not be elaborated here.

[0046] After determining the abnormal deposition direction at each detection moment, the abnormal deposition degree can be further determined, and thus the abnormal deposition vector can be constructed.

[0047] Preferably, in an embodiment of the present invention, considering that the abnormal deposition is caused by the melt concentration difference, by evaluating the melt concentration at the measurement point closest to the crystal profile in the abnormal deposition direction, the melt concentration difference can be reflected, and thus the deposition non-uniformity degree of the crystal growth interface at this detection moment can be evaluated; therefore, the method for obtaining the abnormal deposition vector includes: At each detection moment, obtain two profile intersection points on the crystal profile along the abnormal deposition direction, respectively use the melt concentration at the measurement point closest to each profile intersection point as the reference concentration corresponding to the profile intersection point, use the difference between the two reference concentrations as the modulus of the abnormal deposition vector, and determine the abnormal deposition vector in combination with the abnormal deposition direction.

[0048] As an example, specifically, two contour points where the extension line of the abnormal deposition direction intersects the crystal contour are respectively used as contour intersection points, and the corresponding reference concentrations are obtained; then the difference is measured by the absolute value of the difference to determine the magnitude of the abnormal deposition vector, and further an abnormal deposition vector is constructed.

[0049] Step S3, at each detection moment, according to the abnormal deposition vector and the melt flow vector, and in combination with the crystal contour in the contour image and the crystal diffraction peak in the XRD pattern at the adjacent previous detection moment, the magnetic field in the crystal growth furnace is regulated.

[0050] Since the abnormal deposition is the result of the combined action of melt flow and abnormal convection, in the embodiment of the present invention, at each detection moment, the abnormal convection situation can be preliminarily evaluated according to the abnormal deposition vector and the melt flow vector, so as to regulate the magnetic field for intervention to reduce the influence of abnormal convection on crystal growth; Moreover, since the production cost of frequently adjusting the magnetic field is relatively high, when the growth quality of the crystal has been improved after adjusting the magnetic field at the previous detection moment, it indicates that the magnetic field intervention at the previous detection moment can appropriately reduce the influence of abnormal convection on crystal growth, and the magnetic field can be kept unchanged at this detection moment, so as to reduce the adjustment frequency of the magnetic field while ensuring that abnormal convection can be suppressed and optimize the cost of magnetic field regulation; therefore, in the embodiment of the present invention, the magnetic field in the crystal growth furnace is further regulated in combination with the crystal contour in the contour image and the crystal diffraction peak in the XRD pattern at the adjacent previous detection moment.

[0051] Preferably, in an embodiment of the present invention, the method for regulating the magnetic field in the crystal growth furnace includes: Please refer to Figure 4 , which shows a flowchart of a method for regulating the magnetic field in the crystal growth furnace provided by an embodiment of the present invention, specifically including: Step S301, at each detection moment, the difference between the abnormal deposition vector and the melt flow vector is used as the abnormal convection vector, the opposite direction of the vector direction of the abnormal convection vector is used as the magnetic field regulation direction, and the regulation weight is determined according to the magnitude of the abnormal convection vector, and the preset magnetic field intensity is weighted by the regulation weight to obtain the magnetic field regulation intensity.

[0052] Considering that the difference between the abnormal deposition vector and the melt flow vector can obtain the abnormal convection vector, and by applying a magnetic field in the opposite direction of the abnormal convection vector, the influence of abnormal convection on crystal growth can be suppressed, so the magnetic field regulation direction can be preliminarily determined, and further the magnetic field regulation intensity needs to be determined; also considering that the larger the abnormal convection vector, the greater the corresponding magnetic field intervention intensity to suppress the influence of abnormal convection.

[0053] As an example, the magnitude of the abnormal convection vector is used as the numerator, the magnitude of the melt flow vector is used as the denominator, the fractional ratio is used as the regulation weight, and then the regulation weight is multiplied by the preset magnetic field strength to obtain the magnetic field regulation strength; the greater the adjustment weight, the more intense the abnormal convection, and the greater the magnetic field strength is required to suppress the influence of abnormal convection.

[0054] It should be noted that during the growth process of germanium crystals, the magnetic field strength is generally set within the range of 50 - 500 gauss. In the embodiment of the present invention, the preset magnetic field strength is set to 200, and the implementer can also adjust it according to the actual situation in the crystal growth furnace.

[0055] Step S302, at each detection moment, according to the degree of coincidence between the area enclosed by the crystal contour in the contour image and the area enclosed by the preset standard growth contour, and the deviation of the width of the crystal diffraction peak in the XRD pattern relative to the preset standard width, obtain the crystal growth quality parameter; take any detection moment as the target moment, and the adjacent previous detection moment of the target moment as the reference moment; take the change rate between the crystal growth quality parameters corresponding to the target moment and the reference moment as the magnetic field regulation effect parameter at the reference moment.

[0056] Considering that after adjusting the magnetic field at the previous detection moment, if the growth quality of the crystal has improved, it means that the magnetic field intervention at the previous detection moment can appropriately reduce the influence of abnormal convection on crystal growth, and the magnetic field can be kept unchanged at this detection moment; therefore, in the embodiment of the present invention, the crystal growth quality parameters at each detection moment are first evaluated, and then the magnetic field regulation effect parameters at the previous detection moment are evaluated; Also considering that the higher the degree of coincidence between the area enclosed by the crystal contour in the contour image and the area enclosed by the preset standard growth contour, the higher the crystal growth quality; at the same time, the width of the diffraction peak in the XRD pattern of the crystal interface can reflect the vacancy defect situation in the crystal. Vacancy defects usually cause local irregularities in the crystal structure, which in turn leads to the broadening of the diffraction peak. Then, the smaller the deviation of the width of the crystal diffraction peak in the XRD pattern relative to the preset standard width, the higher the crystal growth quality.

[0057] Based on this, in a preferred embodiment of the present invention, the method for obtaining the crystal growth quality parameter includes: Take the area coincidence area between the area enclosed by the crystal contour in the contour image and the area enclosed by the preset standard growth contour as the first quality parameter, and take the negative correlation mapping result of the absolute value of the difference between the width of the crystal diffraction peak in the XRD pattern and the preset standard width as the second quality parameter; fuse the first quality parameter and the second quality parameter to obtain the crystal growth quality parameter.

[0058] As an example, specifically, the absolute value of the difference is added with a preset extremely small positive parameter 0.001 and then the reciprocal operation is performed to perform a negative correlation mapping to obtain a second quality parameter; furthermore, the first quality parameter and the second quality parameter are multiplied and fused to obtain the crystal growth quality parameter corresponding to the detection moment; Then, taking any detection moment as the target moment and the adjacent previous detection moment of the target moment as the reference moment; at the reference moment, taking the crystal growth quality parameter of the target moment as the numerator and the crystal growth quality parameter of the reference moment as the denominator, and then subtracting 1 from the fractional ratio to obtain the change rate, that is, the magnetic field regulation effect parameter at the reference moment; by changing the target moment, the magnetic field regulation effect parameters of the previous adjacent detection moment of each detection moment can be obtained, so as to evaluate the magnetic field regulation frequency.

[0059] It should be noted that the acquisition of the preset standard width is already an existing technology, and the implementer can obtain it by referring to relevant materials of germanium crystals, and the acquisition process will not be elaborated.

[0060] Step S303, if the magnetic field regulation effect parameter is greater than or equal to 0, regulate the magnetic field in the crystal growth furnace based on the magnetic field regulation direction and magnetic field regulation intensity at the reference moment; if the magnetic field regulation effect parameter is less than 0, regulate the magnetic field in the crystal growth furnace based on the magnetic field regulation direction and magnetic field regulation intensity at the target moment.

[0061] When the magnetic field regulation effect parameter is greater than or equal to 0, it indicates that the crystal growth quality is stable or improved, and further indicates that the magnetic field regulated at the reference moment can suppress the influence of abnormal convection. Therefore, at the target moment, the magnetic field regulation can be not performed, and the magnetic field regulation direction and magnetic field regulation intensity at the reference moment are maintained; When the magnetic field regulation effect parameter is less than 0, it indicates that the crystal growth quality has decreased, and further indicates that the magnetic field regulated at the reference moment is not sufficient to suppress the influence of abnormal convection, resulting in crystal growth deviation or abnormal deposition. Then, at the target moment, the magnetic field needs to be re-regulated based on the magnetic field regulation direction and magnetic field regulation intensity obtained in step S301 for regulation.

[0062] It should be noted that adjusting the magnetic field intensity and magnetic field direction in the crystal growth furnace are both existing technologies and will not be elaborated.

[0063] The present invention also proposes a crystal growth detection system for a crystal growth device. The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of a crystal growth detection method for a crystal growth device are implemented.

[0064] In summary, in each detection moment, according to the differences in the melt concentration at different measurement points and the changes in the melt concentration at each measurement point between adjacent detection moments, the melt flow vector at each detection moment is determined. Then, based on the crystal contour in the contour image, the abnormal deposition direction during the crystal growth process is determined, and by combining the differences between the melt concentrations at the crystal contour positions in the abnormal deposition direction, the abnormal deposition vector is obtained. Further, based on the abnormal deposition vector and the melt flow vector, and in combination with the crystal contour in the contour image and the crystal diffraction peak in the XRD pattern at the previous adjacent detection moment, the magnetic field in the crystal growth furnace is regulated. By analyzing the melt concentration distribution in the crystal growth furnace and the morphological deviation of the crystal cross-section contour, the present invention performs crystal growth detection, evaluates the influence of abnormal convection during the crystal growth process, and determines how to apply an intervention magnetic field to suppress the influence by combining the crystal contour and the crystal diffraction peak, thereby improving the crystal growth quality.

[0065] It should be noted that the above sequence of the embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0066] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized.

Claims

1. A crystal growth detection method for a crystal growth device, characterized in that, The method includes: At each detection moment, obtaining the melt concentration at each measurement point in the crystal growth furnace, as well as the contour image and XRD pattern of the crystal interface, wherein the main viewing angle of the contour image is parallel to the crystal lifting direction; According to the difference in the melt concentration at different measurement points at each detection moment, and the change in the melt concentration at each measurement point between adjacent detection moments, determining the melt flow vector at each detection moment; at each detection moment, according to the crystal contour in the contour image, determining the abnormal deposition direction during crystal growth, and combining the difference in the melt concentration at the crystal contour position in the abnormal deposition direction, obtaining the abnormal deposition vector; At each detection moment, according to the abnormal deposition vector and the melt flow vector, combining the crystal contour in the contour image and the crystal diffraction peak in the XRD pattern at the adjacent previous detection moment, regulating the magnetic field in the crystal growth furnace.

2. The crystal growth detection method for a crystal growth device according to claim 1, wherein The method for obtaining the melt flow vector includes: Obtaining the maximum concentration gradient vector at each detection moment; taking any detection moment as the target moment, and taking the adjacent previous detection moment of the target moment as the reference moment; at the reference moment, taking the melt concentration of the measurement point corresponding to the maximum melt concentration at the target moment as the maximum reference concentration, and taking the melt concentration of the measurement point corresponding to the minimum melt concentration at the target moment as the minimum reference concentration; According to the difference between the maximum melt concentration and the maximum reference concentration at the reference moment, and the difference between the minimum melt concentration and the minimum reference concentration at the reference moment, judging whether the maximum concentration gradient vector at the reference moment changes; if it changes, taking the maximum concentration gradient vector at the target moment as the melt flow vector; if it does not change, taking the sum of the maximum concentration gradient vector at the target moment and the maximum concentration gradient vector at the reference moment as the melt flow vector at the target moment.

3. A crystal growth detection method for a crystal growth device according to claim 2, characterized in that, The method for obtaining the maximum concentration gradient vector includes: At each detection moment, clustering the measurement points based on the clustering algorithm and all melt concentrations; taking the area corresponding to all measurement points in each cluster as a concentration similarity area, and taking the melt concentration of the measurement point corresponding to the cluster center as the area representative concentration; Taking the range of the area representative concentration as the gradient modulus length, and taking the direction from the cluster center corresponding to the maximum area representative concentration to the cluster center corresponding to the minimum area representative concentration as the gradient direction, and determining the maximum concentration gradient vector based on the gradient modulus length and the gradient direction.

4. A crystal growth detection method for a crystal growth device according to claim 2, characterized in that, The method for judging whether the maximum concentration gradient vector at the reference moment changes includes: Taking the difference between the maximum melt concentration and the maximum reference concentration as the first change parameter; taking the difference between the minimum reference concentration and the minimum melt concentration as the second change parameter; if both the first change parameter and the second change parameter are greater than 0, it is determined that the maximum concentration gradient vector changes, otherwise it does not change.

5. A crystal growth detection method for a crystal growth device according to claim 1, characterized in that, The method for determining the abnormal deposition direction includes: Determine the maximum convex vector and the maximum concave vector of the crystal in the contour image according to the difference between the crystal contour in the contour image and the preset standard growth contour; take the direction of the sum corresponding vector of the maximum convex vector and the maximum concave vector as the abnormal deposition direction; wherein, the preset standard growth contours at different detection times are different.

6. The crystal growth detection method for a crystal growth device according to claim 5, wherein The method for obtaining the maximum convex vector and the maximum concave vector includes: At each detection time, map the preset standard growth contour onto the contour image, and determine the maximum convex direction and the maximum convex width, and the maximum concave direction and the maximum concave width of the crystal contour; determine the maximum convex vector based on the maximum convex direction and the maximum convex width, and determine the maximum concave vector based on the maximum concave direction and the maximum concave width.

7. A crystal growth detection method for a crystal growth device according to claim 1, characterized in that, The method for obtaining the abnormal deposition vector includes: At each detection time, obtain two contour intersection points on the crystal contour along the abnormal deposition direction, respectively take the melt concentration at the measurement point closest to each contour intersection point as the reference concentration corresponding to the contour intersection point, take the difference between the two reference concentrations as the modulus length of the abnormal deposition vector, and determine the abnormal deposition vector in combination with the abnormal deposition direction.

8. A crystal growth detection method for a crystal growth device according to claim 5, characterized in that, The method for regulating the magnetic field in the crystal growth furnace includes: At each detection time, take the difference between the abnormal deposition vector and the melt flow vector as the abnormal convection vector, take the opposite direction of the vector direction of the abnormal convection vector as the magnetic field regulation direction, determine the regulation weight according to the modulus length of the abnormal convection vector, and use the regulation weight to weight the preset magnetic field intensity to obtain the magnetic field regulation intensity; At each detection time, obtain the crystal growth quality parameter according to the degree of coincidence between the area enclosed by the crystal contour in the contour image and the area enclosed by the preset standard growth contour, and the deviation of the width of the crystal diffraction peak in the XRD pattern relative to the preset standard width; take any detection time as the target time, and take the adjacent previous detection time of the target time as the reference time; take the change rate between the crystal growth quality parameters corresponding to the target time and the reference time as the magnetic field regulation effect parameter at the reference time; If the magnetic field regulation effect parameter is greater than or equal to 0, regulate the magnetic field in the crystal growth furnace based on the magnetic field regulation direction and the magnetic field regulation intensity at the reference time; if the magnetic field regulation effect parameter is less than 0, regulate the magnetic field in the crystal growth furnace based on the magnetic field regulation direction and the magnetic field regulation intensity at the target time.

9. A crystal growth detection method for a crystal growth device according to claim 8, characterized in that, The method for obtaining the crystal growth quality parameter includes: Take the area coincidence area between the area enclosed by the crystal contour in the contour image and the area enclosed by the preset standard growth contour as the first quality parameter, and take the negative correlation mapping result of the absolute value of the difference between the width of the crystal diffraction peak in the XRD pattern and the preset standard width as the second quality parameter; fuse the first quality parameter and the second quality parameter to obtain the crystal growth quality parameter.

10. A crystal growth detection system for a crystal growth device, the system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the crystal growth detection method for a crystal growth device according to any one of claims 1 to 9.

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