Disclosure of Invention
The present application is made based on the discovery and recognition of the following facts and problems by the inventors:
the thermal history of the ingot directly affects parameters directly or indirectly related to ingot performance such as diffusion of crystal defects, oxygen precipitation, thermal stress, and the like. The inventor finds that the cooling process of the crystal bar is simulated and calculated through computer software in the crystal growth process of a CZ method (Czochralski) single crystal furnace in the related art, and the actual monitoring of the cooling rate of the crystal bar is not performed. Further, the inventor finds that according to the actual adjustment of the cooling rate of the crystal bar in the cooling process of the crystal bar obtained by the computer software simulation, the situation that the adjustment result is inconsistent with the simulation result can occur, and a certain error exists between the cooling process of the crystal bar obtained by the computer software simulation and the actual cooling process all the time, so that the cooling rate of the crystal bar cannot be directly and accurately adjusted in the actual operation, and the crystal bar can have thermal stress in the crystal bar due to the too fast cooling rate in the process of taking out the crystal bar, so that explosion occurs, or the cooling time of the crystal bar is too long due to the too slow cooling rate, so that the productivity is seriously affected.
The present application aims to at least somewhat alleviate or solve at least one of the above mentioned problems.
In one aspect of the present application, a method for obtaining a thermal history of a boule during a boule process is provided, comprising: s1: determining the cross section of the crystal bar to be measured; s2: after the seed crystal contacts the liquid level of the molten soup, vertically lifting the seed crystal to grow crystal to obtain the crystal rod, starting timing and recording as t 0 The method comprises the steps of carrying out a first treatment on the surface of the S3: in the crystal growth process, sequentially acquiring the temperature T of the cross section of the temperature to be detected through a plurality of infrared temperature measuring devices x And sequentially recording time t when the plurality of infrared temperature measuring devices measure the temperature of the cross section to be measured x Wherein x is a positive integer not less than 2, and the maximum value of x is equal to the number of the infrared temperature measuring devices; s4: in the coordinate system at said t x Is in abscissa, T x And obtaining a plurality of coordinate points for the ordinate, and sequentially connecting the plurality of coordinate points to obtain the crystal bar heat history curve in the crystal growth process. Thus, an actual ingot heat history curve can be obtained.
According to an embodiment of the present application, the S1 further includes: determining the cross section to be measured, wherein the cross section to be measured is the cross section where the equal diameter length of the crystal bar is L; the S2 further includes: after the seed crystal is contacted with the molten soup liquid level, vertically lifting the seed crystal to obtain the crystal bar, and starting the timing when the equal diameter length of the crystal bar on the molten soup liquid level is L, and recording as t 0 . From the following componentsIn this way, a thermal history curve at any point on the ingot can be obtained.
According to an embodiment of the present application, the S2 further includes: at the beginning of the timing, the temperature T of the molten soup liquid level is measured by at least one infrared temperature measuring device 0 The method comprises the steps of carrying out a first treatment on the surface of the The S4 further includes: in the coordinate system at t x Is in abscissa, T x Obtaining a plurality of coordinate points for an ordinate, in the coordinate system, at the t 0 Is in abscissa, T 0 And obtaining a starting coordinate point for an ordinate, and sequentially connecting the starting coordinate point and a plurality of coordinate points to obtain the crystal bar heat history curve in the crystal growth process. Thus, an actual ingot heat history curve can be obtained.
According to an embodiment of the present application, the S3 further includes: acquiring the distance d between the temperature measuring point of the infrared temperature measuring device and the molten soup liquid level x The S4 further includes: in the coordinate system, with d x In abscissa, said T x And obtaining a plurality of coordinate points for an ordinate, and sequentially connecting the plurality of coordinate points to obtain the crystal bar heat history curve in the crystal growth process. Thus, various practical ingot heat history curves can be obtained.
According to an embodiment of the present application, further comprising: adjusting the thermal field of the single crystal furnace, and repeating the steps S1-S4; said adjusting said thermal field in said single crystal furnace comprises at least one of: adjusting the distance between the lower edge of the guide cylinder and the molten soup liquid level; adjusting the heat insulation coefficient of the guide cylinder material; adjusting the rate at which the seed crystal is vertically pulled; the heating power of the heater is adjusted. Thus, the thermal history of the ingot can be adjusted.
According to an embodiment of the present application, further comprising: and adjusting the speed of vertically lifting the seed crystal, and repeating the steps S1-S4. Thus, the thermal history of the ingot can be adjusted.
In another aspect of the present application, the present application provides a single crystal furnace comprising: a main furnace chamber defining an accommodation space therein; the quartz crucible is arranged in the accommodating space to melt raw materials and contain molten soup, a space capable of vertically moving a seed crystal is arranged above the quartz crucible, and the seed crystal is vertically movably arranged above the quartz crucible and can extend into the molten soup so as to grow crystals to obtain a crystal bar; the draft tube is arranged in the accommodating space, wherein a plurality of light-transmitting windows are formed in the side wall of the single crystal furnace, infrared temperature measuring devices are arranged at the light-transmitting windows, the heights of temperature measuring points of the infrared temperature measuring devices are different, and the infrared temperature measuring devices are configured to: in the crystal growth process, the temperature of the same cross section on the crystal bar can be measured sequentially. Therefore, the thermal history in the production process of the crystal bar can be accurately monitored.
According to an embodiment of the present application, the single crystal furnace further includes: the bottom end of the auxiliary chamber is connected with the furnace cover of the main furnace chamber, and a plurality of light-transmitting windows are formed in the side wall of the main furnace chamber and/or the side wall of the auxiliary chamber. Therefore, the monitoring of the thermal history in the production process of the crystal bar can be realized through a simple structural design.
According to an embodiment of the present application, a connection line between the temperature measuring point of at least one infrared temperature measuring device and the infrared temperature measuring device is perpendicular to a length direction of the crystal bar. Therefore, the infrared temperature measuring device is convenient to set.
According to an embodiment of the present application, at least one of the infrared thermometry devices is configured to: and measuring the temperature of the liquid level of the molten soup in the quartz crucible. Therefore, the complete monitoring of the heat history of the crystal bar is convenient to realize.
Detailed Description
Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.
In one aspect of the application, the application provides a method for acquiring the heat history of a crystal bar in the crystal growth process, the difference of cooling rates in different crystal growth processes can be compared through the acquired heat history curve, the heat history curve can be reversely obtained through combining the performance test of the crystal bar to be actually improved, and then the high-quality crystal bar with better heat history can be obtained through optimizing parameters such as a thermal field of a single crystal furnace.
According to some embodiments of the present application, the apparatus for obtaining the heat history of the crystal ingot in the crystal growth process is not particularly limited, for example, the obtaining method in the present application may be used for obtaining the heat history of the crystal ingot in the crystal growth process of the apparatus such as a single crystal furnace, a vacuum furnace, and the like. The method for obtaining the heat history of the crystal bar in the crystal growth process is described below by taking a single crystal furnace as an example:
specifically, referring to fig. 3, the method for obtaining the heat history of the crystal bar in the crystal growth process of the single crystal furnace comprises the following steps:
s1: determining the cross section of the crystal bar at the temperature to be measured
According to some embodiments of the application, the cross section of the crystal bar to be measured in temperature is determined in the step, so that the same cross section on the crystal bar can be measured in sequence through a plurality of infrared temperature measuring devices in the crystal growth process, and the crystal bar can be accurately monitored.
According to some embodiments of the present application, the method of determining the temperature cross section to be measured of the ingot is not particularly limited, for example, S1 may further include: the temperature cross section to be measured is determined, the temperature cross section to be measured is the cross section where the equal diameter length of the crystal bar is L, namely the cross section at the equal diameter length L position of the crystal bar, and it can be understood that the equal diameter length is the length from the beginning of the diameter reaching the preset diameter of the crystal bar, if the preset diameter is 300mm, the equal diameter length is calculated when the diameter of the crystal bar reaches 300mm in the crystal growth process after the seed crystal contacts the molten soup liquid level. Taking the preset diameter of 300mm as an example, the temperature cross section L=400 mm to be measured is taken as the position of the crystal rod diameter reaching 300mm from the starting point of the equal diameter length, and the temperature cross section to be measured when the length from the starting point is 400 mm. Taking the isodiametric length of the target crystal bar as 2800mm as an example, the change of the temperature of the cross section of the crystal bar in the crystal growth process when the length of the part to be measured is any value in the range of 0-2800mm can be measured, specifically, the length (namely, the L value) of the part to be measured can be 500mm, 1000mm, 1500mm, 2000mm and 2500mm, etc., so that the thermal history of each position point of the isodiametric length of the crystal bar can be accurately monitored by selecting different isodiametric length L positions as the temperature cross section to be measured of the crystal bar.
S2: after the seed crystal contacts the liquid level of the molten soup, the seed crystal is vertically lifted and timing is started
According to some embodiments of the present application, after the step of contacting the seed crystal with the level of the molten bath, the seed crystal is vertically pulled to obtain a ingot, the timing is started and the time is recorded as t 0 。
According to some embodiments of the present application, when it is determined that the cross section to be measured is at the ingot isodiametric stage length L, correspondingly, S2 further comprises: after the seed crystal is contacted with the liquid level of the molten steel, the seed crystal is vertically lifted to obtain a crystal bar, wherein when the equal diameter length of the crystal bar on the liquid level of the molten steel is L, the timing is started again and is marked as t 0 Therefore, the temperature change of the cross section of the temperature to be detected with the constant diameter length L in the growth process can be accurately monitored. t is t 0 Without being particularly limited, it is only used to represent the starting point in time of the thermal history curve, e.g., t 0 May be 0 or a number greater than 0.
According to some embodiments of the present application, in order to further accurately monitor the thermal history during the growth of the ingot, an infrared temperature measuring device may be used to measure the temperature of the molten liquid level in real time, where S2 further includes: when the seed crystal contacts the molten soup liquid level, the seed crystal is vertically lifted and begins to time, and the temperature T of the molten soup liquid level is measured by at least one infrared temperature measuring device 0 . Thus, the initial coordinate point (t) of the thermal history curve of the ingot can be obtained 0 ,T 0 )。
S3: in the crystal growth process, the temperature T of the cross section of the temperature to be measured is sequentially obtained through a plurality of infrared temperature measuring devices x And sequentially recording time t when the plurality of infrared temperature measuring devices measure the temperature of the cross section of the temperature to be measured x
According to some embodiments of the present invention, the temperature T of the cross section of the temperature to be measured is sequentially obtained at this step by a plurality of infrared temperature measuring devices (such as the infrared temperature measuring devices T0, T1, T2, T3, etc. shown in FIG. 2) x And sequentially recording time t when the plurality of infrared temperature measuring devices measure the temperature of the cross section of the temperature to be measured x . Specifically, referring to fig. 2 and 5, an infrared temperature measuring device is used for measuring the temperature T of the molten soup liquid level 0 The infrared temperature measuring devices T1, T2, T3 and the like are used for sequentially measuring the temperature at the same cross section in the crystal bar straight drawing process to beFor example, let t 0 The section P of the equal diameter length L of the crystal bar on the liquid level of the molten steel at the moment is the section of the temperature to be measured (namely the horizontal section of the crystal bar where the point P is located), and the temperature is measured at t 0 At the moment, the section P at the equal diameter length L of the crystal bar is positioned at the liquid level position, and the temperature at the section P is T 0 The method comprises the steps of carrying out a first treatment on the surface of the When the time t passes 1 The equal diameter length of the crystal bar is L+d 1 At this time, the temperature displayed by the infrared temperature measuring device T1 is the elapsed time T of the section P 1 From temperature T 0 Down to T 1 The method comprises the steps of carrying out a first treatment on the surface of the When time t is elapsed again 2 The equal diameter length of the crystal bar is L+d 1 +d 2 At this time, the temperature displayed by the infrared temperature measuring device T2 is the elapsed time T of the section P 2 From temperature T 1 Down to T 2 Similarly, when the section P is measured by a plurality of infrared temperature measuring devices in sequence, the section P is obtained (t 0 ,T 0 ) A plurality (t) x ,T x ) Thus, a complete crystal bar heat history time-temperature curve can be obtained, wherein x is a positive integer not less than 2, and the maximum value of x is equal to the number of infrared temperature measuring devices.
According to some embodiments of the present application, S3 further comprises: in the crystal growth process, the distance d between the temperature measuring point of the infrared temperature measuring device and the molten soup liquid level is obtained x And records the time t when the cross section to be measured passes through a plurality of infrared temperature measuring devices in turn x Specifically, referring to fig. 2 and 5, an infrared temperature measuring device T0 is used to measure the temperature T of the melt level 0 The infrared temperature measuring devices T1, T2, T3 and the like are used for sequentially measuring the temperature at the same cross section in the crystal bar pulling process, taking T as an example 0 The section P of the equal diameter length L of the crystal bar on the liquid level of the molten soup at the moment is the section of the temperature to be measured, then at t 0 At the moment, the section P of the equal diameter length L of the crystal bar is positioned at the liquid level, and the equal diameter length L and d of the crystal bar are obtained at the moment 0 =0, temperature T 0 The method comprises the steps of carrying out a first treatment on the surface of the Through t 1 Time at t 0 +t 1 At the moment, the section P rises by d 1 Corresponding to the equal diameter length L+d of the crystal bar 1 At a temperature T 1 The method comprises the steps of carrying out a first treatment on the surface of the Then pass t 2 Time at t 0 +t 1 +t 2 At the moment, the section P rises by d 1 +d 2 For a pair ofThe equal diameter length of the strain gauge bar is L+d 1 +d 2 The temperature is T2; similarly, when the section P is measured by a plurality of infrared temperature measuring devices in sequence, the section P is obtained (t 0 ,d 0 ) A plurality (t) x ,d x ) Therefore, a complete crystal bar heat history time-length change curve can be obtained, wherein x is a positive integer not smaller than 2, the maximum value of x is equal to the number of infrared temperature measuring devices, and therefore the temperature history adjustment in the crystal bar crystal growth process can be realized by changing the crystal bar lifting speed, further changing the ascending height of the section P after the same time, further changing the equal diameter length of the crystal bar corresponding to the same moment, and finally obtaining a plurality of crystal bar heat history curves through the change of the crystal bar lifting speed.
S4: in the coordinate system at t x Is of abscissa, T x Obtaining a plurality of coordinate points for the ordinate, and connecting the plurality of coordinate points in turn
According to some embodiments of the present application, at t in this step x Is of abscissa, T x And (3) obtaining a plurality of coordinate points for the ordinate, and sequentially connecting the plurality of coordinate points to draw a curve so as to obtain a crystal bar heat history curve in the crystal growth process.
According to some embodiments of the present application, when S2 further comprises: when the seed crystal contacts the molten soup liquid level, the seed crystal is vertically lifted and begins to time, and the temperature T of the molten soup liquid level is measured by at least one infrared temperature measuring device 0 When, accordingly, S4 may further include: in the coordinate system at t x Is of abscissa, T x Obtaining a plurality of coordinate points for the ordinate, and taking t as a coordinate system 0 Is of abscissa, T 0 And obtaining a starting coordinate point for the ordinate, and sequentially connecting the starting coordinate point and a plurality of coordinate points to obtain a crystal bar heat history curve in the crystal growth process. Thus, an actual ingot heat history curve can be obtained.
According to some embodiments of the present application, when S3 further comprises: in the crystal growth process, the distance d between the temperature measuring point of the infrared temperature measuring device and the molten soup liquid level is obtained x And sequentially recording time t when the plurality of infrared temperature measuring devices measure the temperature of the cross section of the temperature to be measured x Accordingly, S4 may further wrapThe method comprises the following steps: in the coordinate system, with d x T is the abscissa, T x And obtaining a plurality of coordinate points for the ordinate, and sequentially connecting the plurality of coordinate points to obtain a crystal bar heat history curve in the crystal growth process. Thus, various practical ingot heat history curves can be obtained.
According to some embodiments of the present application, the method for obtaining the heat history of the ingot in the present application is not particularly limited, for example, referring to fig. 4, the method for obtaining the heat history of the ingot may further include: and (3) adjusting the thermal field of the single crystal furnace, and repeating S1-S4. The thermal field is the temperature field distribution determined by the real object, taking a single crystal furnace as an example, wherein the real object is a graphite component (such as a graphite crucible, a heater, a guide cylinder and the like) and a heat preservation layer (such as a hard felt, a soft felt and the like), and the thermal field is also influenced by the relative position relation of the real object. Specifically, according to some embodiments of the present application, adjusting the thermal field in the single crystal furnace includes at least one of: adjusting the distance between the lower edge of the guide cylinder and the molten soup level; adjusting the heat insulation coefficient of the guide cylinder material; the heating power of the heater is adjusted. Therefore, after the thermal history curve of the crystal bar is obtained by the method, the thermal history of the crystal bar can be purposefully adjusted by adjusting the thermal field in the single crystal furnace, so that the intrinsic defects generated in the crystal growth process are reduced, and the quality of the crystal bar is improved.
According to some embodiments of the present application, the method for obtaining the heat history of the ingot in the present application is not particularly limited, and the method for obtaining the heat history of the ingot may further include: the rate of vertical pulling of the seed is adjusted and S1-S4 are repeated. Therefore, after the heat history curve of the crystal bar is obtained by the method, the heat history of the crystal bar can be purposefully adjusted by adjusting the pulling rate, so that the intrinsic defects generated in the crystal growth process are reduced, and the quality of the crystal bar is improved. The method for acquiring the heat history of the crystal bar in the crystal growth process of the single crystal furnace has at least one of the following advantages:
1. the thermal history of the crystal bar is accurately monitored in real time, so that the thermal history of the crystal bar can be accurately regulated in the growth process of the crystal bar, the distribution of crystal defects, oxygen precipitation, thermal stress and the like are improved, and the quality of the crystal bar is improved.
2. By correlating the pulling rate in the process of taking the rod/hanging the material with the thermal history of the crystal rod in the form of a thermal history curve, the pulling rate in the process of taking the rod/hanging the material can be quantitatively adjusted, so that the cooling rate of the crystal rod is controlled, and the explosion caused by the too fast pulling rate or the influence on the productivity caused by the too slow pulling rate is prevented.
3. The relation curve between each moment and the temperature at any section of the equal diameter stage of the crystal bar in the growth process can be obtained according to the heat history of the crystal bar, so that the heat field can be purposefully optimized, and the quality of the crystal bar is improved.
In another aspect of the present application, a single crystal furnace is provided, which can meet the equipment requirements required in the method for obtaining the thermal history of a crystal ingot in the crystal growth process, and specifically, referring to fig. 1 and 2, the single crystal furnace includes: a main furnace chamber 10, wherein an accommodating space is defined in the main furnace chamber 10; the quartz crucible 20 is arranged in the accommodating space to melt raw materials and contain molten soup, a space capable of vertically moving a seed crystal is arranged above the quartz crucible 20, and the seed crystal is vertically movably arranged above the quartz crucible 20 and can extend into the molten soup so as to grow crystals to obtain a crystal bar; the guide cylinder 30, the guide cylinder 30 is established in accommodation space, and the lower limb of guide cylinder 30 and the liquid level of melting soup in the quartz crucible 20 do not contact, wherein, a plurality of printing opacity windows have been seted up on the lateral wall of single crystal growing furnace, printing opacity window department is provided with infrared temperature measuring device (such as the infrared temperature measuring device such as T1, T2, T3 that show in FIG. 1), and the temperature measuring point of a plurality of infrared temperature measuring device highly differs, and a plurality of infrared temperature measuring device are configured as: in the growth process of the crystal bar, the same cross section of the crystal bar can be sequentially subjected to temperature measurement, and when the single crystal furnace is adopted for crystal growth, the infrared temperature measuring device is used for monitoring the heat history of the crystal bar, so that the heat history in the production process of the crystal bar can be accurately monitored in the crystal growth process.
According to some embodiments of the present application, the position of the infrared temperature measuring device is not particularly limited, for example, referring to fig. 2, when the single crystal furnace further includes an auxiliary chamber 40, and the bottom end of the auxiliary chamber 40 is connected to the furnace cover of the main furnace chamber 10, a plurality of light-transmitting windows are formed on the side wall of the main furnace chamber 10 and/or the side wall of the auxiliary chamber 40, and the infrared temperature measuring device (such as the infrared temperature measuring devices of T0, T1, T2, T3 and the like shown in fig. 2) may be disposed at the light-transmitting windows. Specifically, the original metal material of the single crystal furnace body can be replaced by the high temperature resistant glass part to form a light transmission window, and the infrared temperature measuring device can comprise an infrared thermometer and the like.
According to some embodiments of the present application, the temperature measurement angle of the infrared temperature measurement device is not particularly limited, for example, referring to fig. 1, there may be at least one temperature measurement point of the infrared temperature measurement device (such as T3, T4, T5 shown in fig. 1) and a line connecting the infrared temperature measurement device to the length direction of the ingot, so as to facilitate the setting of the infrared temperature measurement device and calculate the distance between the adjacent temperature measurement points of the infrared temperature measurement device.
According to some embodiments of the present application, the temperature measurement angle of the infrared temperature measurement device is not particularly limited, for example, referring to fig. 2, at least one infrared temperature measurement device (e.g., T0 shown in fig. 2) may be configured to: the temperature of the liquid level of the molten soup in the quartz crucible 20 is measured, so that the whole-process monitoring of the heat history of the crystal bar can be realized, and a more complete cooling rate curve can be obtained.
According to the single crystal furnace, the side walls of the main furnace chamber 10 and/or the auxiliary chamber 40 of the conventional CZ single crystal furnace device are provided with the plurality of light transmission windows, the infrared temperature measuring devices are correspondingly arranged at the light transmission windows, the temperature of each part in the crystal bar Czochralski growth process is measured through the infrared temperature measuring devices, the curve of the time T-temperature T in the crystal bar Czochralski growth process can be obtained according to the process, the actual cooling rate of the crystal bar can be directly obtained through the curve, the cooling rate of the crystal bar can be purposefully adjusted according to the curve, the temperature distribution of a melt can be precisely controlled, the oxygen content of the crystal bar is reduced, the crystal defect distribution is improved, and the high-quality crystal bar is obtained.
The following description of the present application is made by way of specific examples, which are given for illustration only and should not be construed as limiting the scope of the present application. The examples are not to be construed as limiting the specific techniques or conditions described in the literature in this field or as per the specifications of the product. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
Example 1
The guide cylinder is internally provided with a hard graphite felt as a heat insulation material, and the distance between the lower edge of the guide cylinder and the liquid level of molten soup in the embodiment 1 is 15mm. The pulling speed of the crystal bar is 0.65mm/min, the structure of the single crystal furnace is shown in fig. 2, the temperature of the molten soup liquid level is 1420 ℃ measured by an infrared temperature measuring device T0, and the cross section of the crystal bar at the side close to the liquid level at the moment is taken as a cross section P to be measured; the temperature of the section P to be measured is 1100 ℃ after 2 hours, and the temperature of the section P to be measured is 1020 ℃ after 2 hours.
Example 2:
example 2 was consistent with example 1 except that soft felt was used as a heat insulation material inside the guide cylinder, the infrared temperature measuring device T0 measured the liquid level temperature of 1420 ℃, the infrared temperature measuring device T1 measured the temperature of the temperature section P to be measured at 1000 ℃ for 2 hours, and the infrared temperature measuring device T2 measured the temperature of the temperature section P to be measured at 920 ℃ for 2 hours.
Example 3:
example 3 was identical to example 1 except that the lower edge of the guide shell of example 3 was spaced 30mm from the level of the melt. The infrared temperature measuring device T0 measures the temperature of the liquid level of molten soup to be 1420 ℃, and takes the cross section of the crystal bar at the side close to the liquid level at the moment as a cross section P to be measured; after 2 hours, the temperature of the cross section P to be measured is 1120 ℃ measured by the infrared temperature measuring device T1, and after 2 hours, the temperature of the cross section P to be measured is 1025 ℃ measured by the infrared temperature measuring device T2.
Example 4:
as shown in FIG. 2, when the single crystal furnace is used for lifting materials, the lifting speed is 3mm/min, wen Jiemian P to be detected is lifted to the position of an infrared temperature measuring device T5 through 5.55 hours, the temperature measuring point of the infrared temperature measuring device T5 is perpendicular to the lifting direction, and the temperature of the section P to be detected is 700 ℃ measured by the infrared temperature measuring device T5.
The lifting speed is 5mm/min, the Wen Jiemian P to be detected is lifted to the position of the infrared temperature measuring device T5 after 3 hours, the temperature measuring point of the infrared temperature measuring device T5 is perpendicular to the lifting direction, the temperature of the section P to be detected is 740 ℃ measured by the infrared temperature measuring device T5, and the crystal bar is cracked, particularly, the explosion test curves in fig. 10 and 11 are seen.
Example 5:
example 5 was consistent with example 4 except that the initial pull-up speed was set to 3mm/min, and maintained at that speed for 2 hours; and (3) increasing the lifting speed to 5mm/min, and then after 2.1 hours, increasing the temperature to be measured Wen Jiemian P to the position of the infrared temperature measuring device T5, wherein the temperature of the section P to be measured is 690 ℃ measured by the infrared temperature measuring device T5.
The test results show that: the heat history curves of the ingot in example 1 are shown in fig. 6, and the heat history curves of the ingot in example 1 and example 2 are shown in fig. 7, in example 1, since the cooling capacity of the ingot is weak, when the pulling speed is not less than 0.65mm/min, the ingot is distorted, and the production efficiency is affected. In the embodiment 2, the material of the guide cylinder with better heat insulation effect is selected, the cooling rate of the crystal bar is high, the pulling rate of the crystal bar is increased to be more than 0.65mm/min of the limiting pulling rate, and the crystal bar is not distorted even if the pulling rate reaches 0.7 mm/min. It is known from the combination of examples 1 and 2 that by enhancing the heat insulating capability of the guide cylinder, the cooling rate of the ingot is increased, which is beneficial to improving the problem of deformation of the ingot with high pulling rate.
The ingot heat history curves of example 1 and example 3 are shown in fig. 8, and the ingot longitudinal defect distributions of example 1 and example 3 are shown in fig. 9. In embodiment 1, the radial defect distribution of the finally obtained ingot is too large due to the too fast cooling rate of the ingot, so that a complete perfect crystal window cannot be grown (i.e. a cross section exists in the ingot, crystals at the cross section are all perfect crystals), and in embodiment 3, the cooling rate of the ingot is moderate, the radial defect distribution of the finally obtained ingot is relatively uniform, so that a complete perfect crystal window is grown, and a perfect wafer is further formed. As can be seen from the combination of example 3 and example 1, when the defect distribution in the ingot is similar to that of example 1, a perfect wafer cannot be grown, and the defect distribution can be improved by increasing the distance between the guide cylinder and the molten steel level and reducing the cooling rate of the ingot.
As shown in fig. 10 for the heat history curves of the ingot in example 4 and fig. 11 for the heat history curves of the ingot in example 4 and example 5, the cooling rate of the ingot in example 4 was slow and the operation time was long, and by adjusting the heat history curves of the ingot in fig. 10, it was found that the hanging ingot did not crack when the cooling rate of example 5 was performed in combination with example 4 and example 5, and the time was saved by 1.45 hours as compared with example 4. That is to say, if the situation of cracking of the crystal bar exists in actual production, the method can be adopted to obtain a cracking test curve first, then the heat history of the crystal bar is purposefully adjusted, and as long as the cooling rate of the adjusted crystal bar is smaller than the cooling rate of the cracking test, the occurrence of cracking can be avoided, so that the product yield is improved, and the production efficiency is improved.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. All patents and publications referred to in this application are incorporated herein by reference in their entirety. The terms "comprising" or "including" are used in an open-ended fashion, i.e., including what is indicated in the present application, but not excluding other aspects.
In the description of the present application, "a and/or B" may include any of the cases of a alone, B alone, a and B, wherein A, B is merely for example, which may be any technical feature of the present application using "and/or" connection.
In the description of the present specification, reference to the term "one embodiment," "another embodiment," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Although embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives, and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.