A CZ single crystal furnace static thermal field measurement device and a static thermal field measurement method

Abstract

The invention discloses a static thermal field measuring device and a method for measuring the static thermal field of a CZ single crystal furnace. The static thermal field measuring device of a CZ single crystal furnace comprises a furnace barrel, a furnace cover is arranged on the top of the furnace barrel, a crucible is arranged in the furnace barrel, a seed crystal rod that can be raised and lowered is arranged on the inner side of the furnace cover, and a graphite measuring strip and a thermometer are also included; the graphite measuring strip is in the shape of a long strip, and the graphite measuring strip is movably hung on the seed crystal rod, and the length direction of the graphite measuring strip is perpendicular to the axial direction of the furnace barrel; the upper surface of the graphite measuring strip is provided with notch marks arranged along the length direction and at equal intervals; an observation hole is arranged on the furnace cover, and the thermometer is installed in the observation hole through a joint bearing, and the temperature measuring probe of the thermometer points to the furnace barrel. The above device can obtain three-dimensional temperature distribution data in the furnace through the arrangement of the graphite measuring strip with notch marks and the thermometer, and then the thermal field in the furnace can be adjusted according to the measurement results; the operation is simple, and data can be obtained at any time through experiments; there is no waste of raw materials, only a small amount of electricity is consumed, and the cost is low.

Description

Technical Field

[0001] The invention relates to a CZ single crystal furnace static thermal field measuring device and a static thermal field measuring method, belonging to the technical field of Z single crystal furnace static thermal field measurement. Background Art

[0002] When growing single crystals by the CZ method (direct stretching), it is often necessary to adjust the thermal field in the furnace according to different customer requirements (such as special diameter requirements, resistivity range requirements, or requirements for a small amount of native point defects). There are two common methods: one is to test the furnace by adding materials, replacing testing with production, but there is a possibility of failure and the risk of raw materials is relatively large; the second is to use professional thermal field simulation software for adjustment. The disadvantage is that it is expensive. The rental cost of some products alone is as high as 3 million yuan per year, which is too costly. Summary of the invention

[0003] In order to solve the problem of waste of raw materials in single crystal furnace thermal field adjustment by production instead of testing, and the problem of high cost of using professional software to simulate the thermal field adjustment, the present invention provides a CZ single crystal furnace static thermal field measurement device and a static thermal field measurement method.

[0004] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0005] A static thermal field measuring device for a CZ single crystal furnace comprises a furnace barrel, a furnace cover is arranged on the top of the furnace barrel, a crucible is arranged in the furnace barrel, a seed crystal rod that can be raised and lowered is arranged on the inner side of the furnace cover, and also comprises a graphite measuring strip and a thermometer; the graphite measuring strip is in the shape of a long strip, the graphite measuring strip is movably hung on the seed crystal rod, and the length direction of the graphite measuring strip is perpendicular to the axial direction of the furnace barrel; notch marks are arranged along the length direction and at equal intervals on the upper surface of the graphite measuring strip; an observation hole is arranged on the furnace cover, the thermometer is installed in the observation hole through a joint bearing, and the temperature measuring probe of the thermometer points into the furnace barrel.

[0006] The applicant has found through research that the above-mentioned graphite measuring strip has the advantages of not introducing metal ions to pollute the thermal system, fast thermal conductivity, and good thermal stability, and can accurately reflect the thermal field in the furnace; the upper surface of the graphite measuring strip is provided with notch marks arranged along the length direction and at equal intervals, and combined with the rise and fall of the graphite measuring strip driven by the seed crystal rod, three-dimensional temperature distribution data can be obtained; the thermometer is used to test the temperature at each notch mark of the graphite measuring strip; the thermometer is installed in the observation hole through a joint bearing, so that the thermometer can adjust the test angle, which is convenient for measuring the temperature at different positions of the graphite measuring strip.

[0007] The above-mentioned CZ single crystal furnace is an existing equipment, and the seed crystal rod can be raised and lowered as an existing technology.

[0008] The static thermal field measuring device of the CZ single crystal furnace is used to measure the static thermal field. A graphite measuring strip is used to simulate the spatial position in the furnace. The temperature at each notch mark on the graphite measuring strip is measured through the observation hole with a thermometer and recorded to obtain the distribution of the overall thermal field.

[0009] In order to accurately reflect the distribution of the overall thermal field, the above method for measuring the static thermal field includes the following steps in sequence:

[0010] 1) Load the graphite measuring bar onto the seed crystal rod and load the thermometer onto the observation hole;

[0011] 2) Sealing the furnace, heating and maintaining constant temperature;

[0012] 3) Lower the graphite measuring bar to the bottom of the crucible and keep the temperature constant for 8 to 12 minutes;

[0013] 4) Slide the torsion thermometer from left to right or from right to left to record the temperature value of each notch mark on the graphite measuring strip;

[0014] 5) Raise the seed crystal rod by 0.8 to 1.2 cm, keep the temperature constant for 8 to 12 minutes, and repeat the measurement in step 4);

[0015] 6) Repeat step 5) until the graphite measuring bar reaches the top of the CZ single crystal furnace insulation system to obtain three-dimensional temperature distribution data.

[0016] The above method can obtain three-dimensional temperature distribution data, which fully meets the requirements of static thermal field measurement and can adjust the thermal field in the furnace according to the measurement results; the operation is simple and data can be obtained at any time; it does not waste raw materials, consumes only a small amount of electricity, and has a low cost.

[0017] In order to improve the accuracy of measurement, the interval between two adjacent notch marks is 0.8 to 1.2 cm.

[0018] In order to improve the test efficiency, the length of the graphite measuring strip is 450-550 mm, the width is 15-25 mm, and the thickness is 4-6 mm.

[0019] To facilitate installation, a mounting tube is connected to the outside of the observation hole, and the temperature meter is installed on the inside of the mounting tube through a spherical bearing.

[0020] The top of the thermometer is an observation eyepiece, and the bottom is provided with a temperature probe. The thermometer is preferably a RAYTEK infrared thermometer.

[0021] For easy control, a tightening screw is provided on the spherical bearing. As common sense, the inner ring of the spherical bearing can be rotated and adjusted relative to the outer ring. When the tightening screw is rotated to contact the inner ring, the position of the thermometer is fixed. When the tightening screw is rotated outward to separate it from the inner ring, the thermometer can flexibly adjust the angle.

[0022] In order to improve the stability of the measurement, the central position of the graphite measuring strip in the length direction is movably hung on the seed crystal rod.

[0023] The technologies not mentioned in the present invention are all referred to the prior art.

[0024] The static thermal field measuring device for a CZ single crystal furnace of the present invention can obtain three-dimensional temperature distribution data in the furnace by setting a graphite measuring strip with a notch mark and a thermometer, and can further adjust the thermal field in the furnace according to the measurement result; no metal ions are introduced; the operation is simple, and data can be obtained at any time by experiment; there is no waste of raw materials, only a small amount of electricity is consumed, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A top view of the graphite measuring strip of the present invention;

[0026] Figure 2 It is a schematic structural diagram of a static thermal field measuring device for a CZ single crystal furnace according to the present invention;

[0027] Figure 3 It is a structural schematic diagram of the thermometer of the present invention;

[0028] In the figure, 1 is a graphite measuring strip, 11 is a notch mark, 2 is a furnace barrel, 3 is a furnace cover, 31 is an observation hole, 32 is a mounting tube, 33 is a spherical bearing, 4 is a crucible, 5 is a seed crystal rod, 6 is a thermometer, 61 is an observation eyepiece, 62 is a temperature measuring probe, and 63 is a tightening screw. DETAILED DESCRIPTION

[0029] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0030] In this application, directional words such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings or in use, and are only for the convenience of describing this application, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0031] Example 1

[0032] like Figure 2 As shown, a CZ single crystal furnace static thermal field measurement device includes a furnace barrel, a furnace cover is provided on the top of the furnace barrel, a crucible is provided in the furnace barrel, a seed crystal rod that can be raised and lowered is provided on the inner side of the furnace cover, and also includes a graphite measuring bar and a temperature measuring instrument; Figure 1As shown, the graphite measuring strip is in the shape of a long strip, and the central position of the graphite measuring strip in the length direction is movably hung on the seed crystal rod, and the length direction of the graphite measuring strip is perpendicular to the axial direction of the furnace barrel; the upper surface of the graphite measuring strip is provided with notch marks arranged along the length direction and at equal intervals; the furnace cover is provided with an observation hole, such as Figure 2 As shown, the thermometer is installed in the observation hole through a spherical bearing, and the temperature probe of the thermometer points to the furnace barrel.

[0033] Through practice, the above-mentioned graphite measuring strip has the advantages of not introducing metal ions to pollute the thermal system, heating quickly, and having good thermal stability, and can accurately reflect the thermal field in the furnace; the upper surface of the graphite measuring strip is provided with notch marks arranged along the length direction and at equal intervals. Combined with the rise and fall of the graphite measuring strip driven by the seed crystal rod, three-dimensional temperature distribution data can be obtained; the thermometer is used to test the temperature at each notch mark of the graphite measuring strip; the thermometer is installed in the observation hole through a joint bearing, so that the thermometer can adjust the test angle, which is convenient for measuring the temperature at different positions of the graphite measuring strip.

[0034] The method for measuring the static thermal field using the static thermal field measuring device of the CZ single crystal furnace comprises the following steps connected in sequence:

[0035] 1) Load the graphite measuring bar onto the seed crystal rod and load the thermometer onto the observation hole;

[0036] 2) Sealing the furnace, heating and maintaining constant temperature;

[0037] 3) Lower the graphite measuring bar to the bottom of the crucible and keep the temperature constant for 10 minutes;

[0038] 4) Slide the torsion thermometer from left to right or from right to left to record the temperature value of each notch mark on the graphite measuring strip;

[0039] 5) Raise the seed crystal rod by 1 cm, keep the temperature constant for 10 minutes, and repeat the measurement in step 4);

[0040] 6) Repeat step 5) until the graphite measuring bar reaches the top of the CZ single crystal furnace insulation system to obtain three-dimensional temperature distribution data.

[0041] The above method can obtain three-dimensional temperature distribution data, which fully meets the requirements of static thermal field measurement and can adjust the thermal field in the furnace according to the measurement results; the operation is simple and data can be obtained at any time; it does not waste raw materials, consumes only a small amount of electricity, and has a low cost.

[0042] Example 2

[0043] Based on Example 1, the following improvements were made: To improve the accuracy of the measurement, the interval between two adjacent notch marks was 1 cm. To improve the test efficiency, the length of the graphite measuring strip was 500 mm, the width was 20 mm, and the thickness was 5 mm.

[0044] Example 3

[0045] On the basis of Example 2, the following improvements were made: Figure 2 As shown, to facilitate installation, a mounting tube is connected to the outside of the observation hole, and the temperature meter is installed on the inside of the mounting tube through a spherical bearing.

[0046] Example 4

[0047] On the basis of Example 3, the following improvements were made: Figure 3 As shown, the thermometer is a RAYTEK infrared thermometer, the top of the thermometer is an observation eyepiece, and the bottom is provided with a temperature measuring probe.

[0048] Actual case: The customer needs a zero-dislocation germanium single crystal, which cannot be produced using the existing thermal field in the single crystal furnace. Using the above device and method, after measuring the thermal field distribution in the furnace as shown in Table 1, the radial average temperature gradient exceeds 3°C / cm, and a zero-dislocation single crystal cannot be grown.

[0049] Table 1 Thermal field distribution in the furnace before adjustment

[0050]

[0051]

[0052] According to the measured thermal field distribution in the furnace, after several adjustments, the new thermal field distribution was measured as shown in Table 2. The average radial temperature gradient was about 2°C / cm, which basically met the process requirements. The expected effect was achieved after production. The growth cycle of zero-dislocation germanium single crystal is generally about one week. This method saves a lot of trial and error costs.

[0053] Table 2 Adjusted heat field distribution in the furnace

[0054]

[0055] In Table 1-2, the units of radial and longitudinal directions are both cm, and the unit of temperature is °C.

[0056] Example 5

[0057] On the basis of Example 4, the following improvements were made: Figure 2-3 As shown in the figure, for the convenience of control, a tightening screw is provided on the spherical bearing. The inner ring of the spherical bearing can be rotated and adjusted relative to the outer ring. When the tightening screw is rotated to contact the inner ring, the position of the thermometer is fixed. When the tightening screw is rotated outward to separate it from the inner ring, the thermometer can flexibly adjust the angle.

[0058] The static thermal field measuring device of a CZ single crystal furnace of the present invention can obtain three-dimensional temperature distribution data in the furnace by setting a graphite measuring strip with a notch mark and a thermometer, and then adjust the thermal field in the furnace according to the measurement result; the operation is simple, and data can be obtained at any time by experiment; there is no waste of raw materials, only a small amount of electricity is consumed, and the cost is low.

Claims

1. A static thermal field measuring device for a CZ single crystal furnace, comprising a furnace barrel, a furnace cover is arranged on the top of the furnace barrel, a crucible is arranged in the furnace barrel, and a seed crystal rod which can be raised and lowered is arranged on the inner side of the furnace cover, characterized in that: It also includes a graphite measuring strip and a thermometer; the graphite measuring strip is in the shape of a long strip, and is movably hung on the seed crystal rod, and the length direction of the graphite measuring strip is perpendicular to the axial direction of the furnace barrel; the upper surface of the graphite measuring strip is provided with notch marks arranged along the length direction and at equal intervals; an observation hole is provided on the furnace cover, and the thermometer is installed in the observation hole through a joint bearing, and the temperature measuring probe of the thermometer points to the furnace barrel.

2. The CZ single crystal furnace static thermal field measurement device according to claim 1, characterized in that: The interval between two adjacent notch marks is 0.8~1.2cm.

3. The CZ single crystal furnace static thermal field measuring device according to claim 1 or 2, characterized in that: The length of the graphite measuring strip is 450~550mm, the width is 15~25mm, and the thickness is 4~6mm.

4. The CZ single crystal furnace static thermal field measuring device according to claim 1 or 2, characterized in that: A mounting tube is butt-jointed to the outer side of the observation hole, and the temperature measuring instrument is mounted on the inner side of the mounting tube through a spherical bearing.

5. The CZ single crystal furnace static thermal field measuring device according to claim 1 or 2, characterized in that: The top of the thermometer is an observation eyepiece and the bottom is provided with a temperature measuring probe.

6. The CZ single crystal furnace static thermal field measuring device according to claim 1 or 2, characterized in that: The thermometer is a RAYTEK infrared thermometer.

7. The CZ single crystal furnace static thermal field measuring device according to claim 1 or 2, characterized in that: The spherical bearing is provided with a tightening screw.

8. The CZ single crystal furnace static thermal field measuring device according to claim 1 or 2, characterized in that: The central position of the graphite measuring strip in the length direction is movably hung on the seed crystal rod.

9. A method for measuring a static thermal field using the CZ single crystal furnace static thermal field measuring device according to any one of claims 1 to 8, characterized in that: A graphite measuring strip is used to simulate the spatial position in the furnace. The temperature at each notch mark on the graphite measuring strip is measured through the observation hole with a thermometer and recorded to obtain the distribution of the overall thermal field.

10. The method according to claim 9, characterized in that: The method comprises the following steps in sequence: 1) Load the graphite measuring strip onto the seed crystal rod and load the thermometer onto the observation hole; 2) Sealing the furnace, heating and maintaining constant temperature; 3) Lower the graphite measuring bar to the bottom of the crucible and keep the temperature constant for 8 to 12 minutes; 4) Slide the torsion thermometer from left to right or from right to left to record the temperature value of each notch mark on the graphite measuring strip; 5) Raise the seed crystal rod by 0.8~1.2cm, keep the temperature constant for 8~12 minutes, and repeat the measurement in step 4); 6) Repeat step 5) until the graphite measuring bar reaches the top of the CZ single crystal furnace insulation system to obtain three-dimensional temperature distribution data.

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