Precise small single crystal pulling furnace device

Abstract

The invention discloses a precise small single crystal pulling furnace device, and relates to the field of wood fiber material preparation. The problems that an existing large single crystal furnace is large in size, heavy and high in cost, a large amount of laboratory space is occupied, and much inconvenience is brought in the aspects of movement, placement and daily maintenance are solved. A heating unit is installed on the side face of a furnace body control cabinet through a lifting unit, one end of a connecting piece is connected with the upper end of the furnace body control cabinet, and the other end of the connecting piece is connected with a quartz tube in the heating unit; the furnace body control cabinet comprises a cabinet body, a temperature control instrument, an ampere meter, a touch screen and a power switch, the cabinet body is a rectangular cabinet body, and the temperature control instrument, the ampere meter, the touch screen and the power switch are sequentially installed on the cabinet body from top to bottom; wherein the length of the cabinet body is 300mm, the width of the cabinet body is 270mm, and the diameter of the electric furnace heating area of the heating unit is 40mm, and the height of the electric furnace heating area of the heating unit is 150mm. The method is used for preparing the single crystal.

Description

Technical Field

[0001] The invention relates to the technical field of crystal growth, and in particular to a small-scale precision single crystal pulling furnace device. Background Art

[0002] A single crystal furnace is a device that uses a graphite heater to melt polycrystalline materials such as polysilicon in an inert gas (mainly nitrogen and helium) environment and grows dislocation-free single crystals using the Czochralski method.

[0003] In the field of single crystal furnaces, large-scale single crystal furnaces on the market have always dominated, but their inherent defects have become increasingly prominent. Zone melting is an advanced material purification technology that uses the segregation effect of impurities at the solid-liquid interface through repeated melting and solidification processes to effectively remove impurities in the material and improve the purity of the material. In the design of single crystal furnaces, the introduction of zone melting technology can further improve the quality and purity of single crystal growth. Compared with traditional large-scale single crystal furnaces, the single crystal furnace of the present invention has achieved significant optimization in cost, efficiency and volume, providing a new solution for high-precision experiments such as laboratory single crystal pulling.

[0004] Large single crystal furnaces are large and heavy, which not only takes up a lot of laboratory space, but also brings many inconveniences in terms of movement, placement and daily maintenance. More importantly, the price of these large single crystal pulling equipment is extremely expensive, and the specific price is also affected by factors such as equipment specifications, technical level and brand. For example, some high-end large single crystal furnaces, due to their advanced temperature control systems and sophisticated mechanical structures, cost up to millions of RMB, which not only increases the cost burden of scientific research projects, but also limits the flexibility and diversity of laboratories.

[0005] In summary, the existing large-scale single crystal furnaces are bulky, heavy, and costly, which not only takes up a large amount of laboratory space, but also brings many inconveniences in terms of movement, placement, and daily maintenance. Summary of the invention

[0006] The purpose of the present invention is to solve the problems that the existing large single crystal furnaces are bulky, heavy and costly, which not only occupy a large amount of laboratory space but also bring many inconveniences in movement, placement and daily maintenance, and thus provide a precise small single crystal pulling furnace device.

[0007] The technical solution of the present invention is:

[0008] A precision small single crystal pulling furnace device includes a furnace control cabinet, a heating unit, a lifting unit and a connecting piece. The heating unit is installed on the side of the furnace control cabinet through the lifting unit. One end of the connecting piece is connected to the upper end of the furnace control cabinet, and the other end of the connecting piece is connected to the quartz tube in the heating unit. The furnace control cabinet includes a cabinet, a temperature control instrument, an ammeter, a touch screen and a power switch. The cabinet is a rectangular cabinet. The temperature control instrument, the ammeter, the touch screen and the power switch are installed on the cabinet in sequence from top to bottom. Among them, the length of the cabinet is 300mm and the width is 270mm. The dimensions of the electric furnace heating zone of the heating unit are 40mm in diameter and 150mm in height.

[0009] Furthermore, the heating unit includes a quartz tube, a heating resistance wire, a furnace chamber and an outer shell. The outer wall of the outer shell is connected to the lifting unit and is lifted and lowered by the lifting unit. The furnace chamber is installed inside the outer shell. The heating resistance wire is embedded in the furnace chamber and is located in the middle of the furnace chamber. The quartz tube vertically passes through the heating resistance wire and the furnace chamber and extends downward.

[0010] Furthermore, the furnace is a fiber insulation furnace.

[0011] Preferably, the diameter of the quartz tube is 35-50 mm.

[0012] Furthermore, a gap is left between the outer edge of the heating resistance wire and the quartz tube, and the gap is 8-12 mm.

[0013] Furthermore, when the heating unit is at the vertex position, the distance between the lower end of the quartz tube and the base is 130-140 mm.

[0014] Preferably, the housing is made of cold-rolled steel plate by electrostatic spraying.

[0015] Preferably, the heating resistance wire is an iron-chromium-aluminum alloy heating wire.

[0016] Furthermore, the lifting unit includes two linear guides and a ball screw pair. The two linear guides are vertically installed on the side of the cabinet, and the outer shell is slidingly connected to the linear guides. The ball screw pair is vertically installed on the side of the cabinet and is located between the two linear guides. The outer shell is connected to the nut seat on the ball screw pair.

[0017] Preferably, the motor of the ball screw pair is a servo motor.

[0018] Compared with the prior art, the present invention has the following effects:

[0019] 1. In order to overcome the defects of existing large-scale single crystal furnaces, the present invention proposes a compact and efficient single crystal furnace design. Compared with the traditional large-scale single crystal furnace, the single crystal furnace of the present invention has been greatly reduced in size. For example, the overall length is 620mm, and the structure of the furnace is compact and exquisite, which makes it extremely convenient to move or place. This not only saves laboratory space, but also reduces the maintenance cost of the equipment.

[0020] 2. The present invention adopts a touch key program controller as a temperature controller (referring to the temperature control instrument 4), which supports digital setting and LED display from room temperature to 1150°C, and the temperature control accuracy can reach ±1°C. In addition, the system is also equipped with a modular switch over-temperature protector, which can be digitally set according to the experimental requirements to ensure the safety and stability of the experimental process. More importantly, the temperature control system supports program-controlled operation (1-8 mode), and can compile up to 50 temperature curves to achieve precise control of the heating rate, insulation time and cooling process.

[0021] 3. The fast-heating high-temperature electric furnace (referring to the heating unit) of the present invention has excellent performance in heating rate. By using HRE furnace wire as a heating element as a heating source, it can heat up from room temperature to 1150°C in about 50 minutes, which is significantly energy-saving compared to the 2-3 hours heating time of a traditional electric furnace. In the constant temperature stage, its power consumption is only half of that of a traditional electric furnace, which greatly reduces the experimental cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention;

[0023] Figure 2 yes Figure 1 A top view of

[0024] Figure 3 is a cross-sectional view of the heating unit.

[0025] The following are marked in the figure:

[0026] 1. Furnace control cabinet, 2. Quartz tube, 3. Cabinet, 4. Temperature control instrument, 5. Ammeter, 6. Touch screen, 7. Power switch, 8. Heating resistance wire, 9. Furnace, 10. Shell, 11. Linear guide, 12. Ball screw pair. DETAILED DESCRIPTION

[0027] Specific implementation method 1: Combination Figures 1 to 3The present embodiment is described. The present embodiment comprises a furnace control cabinet 1, a heating unit, a lifting unit and a connecting piece. The heating unit is installed on the side of the furnace control cabinet 1 through the lifting unit. One end of the connecting piece is connected to the upper end of the furnace control cabinet 1, and the other end of the connecting piece is connected to the quartz tube 2 in the heating unit. The furnace control cabinet 1 comprises a cabinet 3, a temperature control instrument 4, an ammeter 5, a touch screen 6 and a power switch 7. The cabinet 3 is a rectangular cabinet. The temperature control instrument 4, the ammeter 5, the touch screen 6 and the power switch 7 are sequentially installed on the cabinet 3 from top to bottom. The length of the cabinet 3 is 300 mm, the width is 270 mm, and the dimensions of the electric furnace heating zone of the heating unit are 40 mm in diameter and 150 mm in height.

[0028] The miniaturized precision small single crystal pulling furnace device of the present invention not only achieves significant improvements in pulling speed and temperature range, but also achieves breakthroughs in structural design, perfectly adapting to the high-precision single crystal pulling requirements in laboratory environments. Specifically, the size of the heating zone (referring to the heating unit) of this electric furnace is Φ40×150mm, which is suitable for heating treatment of a variety of small experimental materials and has excellent heat preservation and energy-saving characteristics.

[0029] The furnace control cabinet 1 structure of the present invention adopts a furnace control integrated (opening and closing) design, the cabinet 3 is made of cold-rolled steel plate electrostatically sprayed, and mullite fiber is used as the thermal insulation material inside the furnace to ensure good thermal insulation effect and temperature uniformity.

[0030] The structural design of the furnace control integrated cover opening and closing not only makes the electric furnace look more novel, but also makes it easy to match with other instruments and equipment, improving the overall coordination of the laboratory. At the same time, the small and exquisite furnace structure also makes the electric furnace easy to move and place, meeting the needs of different experimental environments.

[0031] The temperature control system of this embodiment supports program-controlled operation and multi-stage temperature curve setting, realizes precise control of heating rate, holding time and cooling process, and improves experimental efficiency and flexibility.

[0032] The structural design of the furnace control integrated upper cover opening and closing and the compact and exquisite furnace body structure of this embodiment make the electric furnace superior in appearance, ease of operation and environmental adaptability.

[0033] Specific implementation method 2: Combination Figure 3 To illustrate this embodiment, the heating unit of this embodiment includes a quartz tube 2, a heating resistance wire 8, a furnace chamber 9 and a shell 10. The outer wall of the shell 10 is connected to the lifting unit and is lifted and lowered by the lifting unit. The furnace chamber 9 is installed inside the shell 10. The heating resistance wire 8 is embedded in the furnace chamber 9 and is located in the middle of the furnace chamber 9. The quartz tube 2 vertically passes through the heating resistance wire 8 and the furnace chamber 9 and extends downward.

[0034] Such arrangement facilitates providing a heating environment and a heating source for the preparation of a single crystal. Other components and connection relationships are the same as those in the first specific embodiment.

[0035] Specific implementation method three: Combination Figure 3 To explain this embodiment, the furnace 9 of this embodiment is a fiber insulation furnace. In this way, this embodiment preferably uses mullite fiber as the furnace insulation material, which significantly improves the temperature uniformity inside the furnace and ensures the accuracy of the experimental data. Other components and connection relationships are the same as those of the specific embodiment one or two.

[0036] Specific implementation method four: Combination Figure 3 This embodiment is described. The diameter of the quartz tube 2 of this embodiment is 35-50 mm. This arrangement can simultaneously meet the needs of laboratory small-scale single crystal synthesis and industrial production of large-scale single crystals. Other components and connection relationships are the same as those of the first, second or third embodiments.

[0037] Specific implementation method five: Combination Figure 3 To explain this embodiment, a gap is left between the outer edge of the heating resistance wire 8 and the quartz tube 2 in this embodiment, and the gap is 8-12 mm.

[0038] Such an arrangement can effectively ensure a uniform temperature field and avoid direct contact between the heating resistor wire and the outer quartz tube, thereby generating large thermal stress and causing the quartz tube to crack. Other components and connection relationships are the same as those of the first, second, third or fourth specific implementations.

[0039] Specific implementation method six: Combination Figure 1 To explain this embodiment, when the heating unit of this embodiment is at the apex position, the distance between the lower end of the quartz tube 2 and the base 10 is 130-140 mm.

[0040] Such an arrangement can keep the tip of the quartz bottom at the thermocouple position in the center of the heating furnace as much as possible when the heating furnace body descends to the bottom, ensuring that the heating temperature of the sample is uniform and an effective temperature difference from the center to the bottom of the furnace body is established. The other components and connection relationships are the same as any one of the specific embodiments 1 to 5.

[0041] Specific implementation method seven: Combination Figure 1 To explain this embodiment, the housing 10 of this embodiment is made of cold-rolled steel plate electrostatically sprayed. This arrangement can ensure that the coating has good corrosion resistance, wear resistance and insulation, can effectively isolate oxygen and moisture in the air, prevent metal from rusting, and has a good appearance and decorative properties. Other components and connection relationships are the same as any one of the specific embodiments 1 to 6.

[0042] Specific implementation method eight: Combination Figure 3The present embodiment is described. The heating resistance wire 8 of the present embodiment is an iron-chromium-aluminum alloy heating wire.

[0043] In this way, the heating system uses HRE furnace wire as the heating element, and with the advanced power management system, it can work stably at a voltage of 220V 50Hz, with a rated power of 1.5KW. Other components and connection relationships are the same as any one of the specific embodiments 1 to 7.

[0044] Specific implementation method nine: Combination Figure 2 To illustrate this embodiment, the lifting unit of this embodiment includes two linear guides 11 and a ball screw pair 12. The two linear guides 11 are vertically installed on the side of the cabinet 3, and the housing 10 is slidingly connected to the linear guides 11. The ball screw pair 12 is vertically installed on the side of the cabinet 3 and is located between the two linear guides 11. The housing 10 is connected to the nut seat on the ball screw pair 12.

[0045] With this arrangement, the propulsion device is responsible for the inlet and outlet and positioning of the experimental materials. Its delivery speed can be adjusted within 0-200 mm / hour. The input method and display are completed through the touch screen, and the operation is simple and intuitive. At the same time, the device also has a digitally set over-temperature protection function, which further improves the safety of the experimental process. The other components and connection relationships are the same as any one of the specific implementation methods one to eight.

[0046] Specific implementation method ten: Combination Figure 2 This embodiment is described. The motor of the ball screw pair 12 of this embodiment is a servo motor. With this arrangement, the precession speed of the furnace body rising and falling can be more accurately controlled, and can be set to 1-10000mm / h according to the program, effectively meeting the different requirements of laboratory preparation of single crystals and industrial production of rapid batch preparation of crystals. The other components and connection relationships are the same as any one of the specific embodiments one to nine.

[0047] Combination Figures 1 to 3 The working principle of the present invention is described:

[0048] The present invention combines the advantages of the Bridgman growth method and the zone melting method, constructs a temperature gradient through the heating body 10 and the external environment of the furnace body, and realizes the controllable precession of the furnace body through the servo motor, accelerating the crystal growth from the bottom to the top of the quartz tube. Multi-stage temperature program control and variable speed precession of the furnace body can meet the needs of both laboratory and industrial production, and realize high-quality batch preparation of single crystal materials.

[0049] The prefabricated polycrystalline material is placed in a quartz tube, protected by vacuum, and then heated to the melting point by an HRE furnace wire, at which point the polycrystalline material turns into a liquid state. Subsequently, a temperature difference is established between the furnace body and the environment, and the furnace body is controlled to advance upward at a slow rate. At this time, the bottom of the pointed quartz tube will first reach the solidification temperature, and the seed crystal will precipitate from the bottom of the quartz tube. As the furnace body continues to move upward, at a small degree of supercooling, the crystal will grow along the direction of the furnace body advance until the entire advance process is completed. The temperature and speed need to be precisely controlled during the stretching process to ensure that the quality and size of the single crystal meet the requirements.

[0050] The invention adopts mullite fiber, an advanced refractory material, as furnace lining and thermal insulation material, and has an experimental electric furnace with excellent thermal insulation performance and temperature uniformity.

[0051] The control system of the small experimental electric furnace of the present invention mainly includes: a power control module, a temperature display and setting module, a program control module and a lifting and conveying operation module. Among them, the power control module is responsible for the switch and power management of the electric furnace; the temperature display and setting module is used to display the furnace temperature and set the heating program; the program control module automatically adjusts the heating power and time according to the set program; and the lifting and conveying operation module is responsible for the lifting and positioning of the experimental materials.

[0052] Press the power button, the internal contactor closes and the instrument is powered on. The upper display "PV" of the instrument shows the furnace temperature, and the lower display "SV" alternately shows "Stop" and the first stage starting temperature.

[0053] Press the left key once and then release it, the instrument will enter the program setting state. At this time, the upper display "PV" shows SP1, and the lower display "SV" shows the first segment starting temperature. The temperature value can be modified by the direction key, and the first segment starting temperature value can be set to the ambient temperature or set to "10℃".

[0054] Press the "Refresh" button on the instrument, the upper display "PV" on the instrument shows T-1, and the lower display "SV" shows the time required for the first program, which can be modified according to actual needs. Press the "Refresh" button repeatedly to set the temperature and time of the subsequent sections in sequence, until tx is set to -121.0 in the next time period (indicating the end of the program and stop running). For example, it takes 25 minutes to rise from room temperature to 800℃, and the constant temperature is 10 minutes. The parameter settings are: SP110℃T-125, SP2800℃T-210, SP3800℃T-3-121.0.

[0055] After the program is set, press the "left key" and "refresh key" at the same time, or wait for about 20 seconds, the instrument returns to the initial state. Press the "down key" for about 2 seconds, and the program starts after the lower display "SV" displays "run". At this time, the program temperature value on the lower display begins to increase, the ammeter pointer displays the current current, and then the furnace temperature displayed on the upper display also increases.

[0056] After powering on, click on the screen to enter the operation interface. Click "Origin Return Operation", and click "OK" in the pop-up dialog box. The support rod will be pulled to the origin position and stop automatically. This step is recommended to be performed once before each use to ensure accurate positioning.

[0057] Click "Alarm View" to view each alarm record for troubleshooting. Click "Operation Log" to view the operation records used for traceability and management. Click "User Login" in the upper right corner, enter the user password (such as 360), and click "Login". After a successful login, you can perform more advanced settings and operations. In the interface after a successful login, enter "Position Calibration", click "Position Edit", and you can set the required working points, such as the rising positioning position and the descending positioning position. After the settings are completed, click "OK".

[0058] In the "Position Calibration" interface, you can also manually jog down and jog up (this operation can be used in an emergency). Speed ​​setting: Also in the "Position Calibration" interface, you can adjust the rising positioning speed, the descending positioning speed, the jog descent speed, the jog rise speed, the origin return speed and the creeping speed (adjustable from 1 to 1000). After the adjustment is completed, click "Update" and then click "OK" to complete the speed setting. Finally, click "Home Page" to return to the main operation interface.

[0059] During the program running, the instrument will automatically perform the heating task according to the set temperature and time. After the program is finished, the lower display will alternately display "STOP" and the first section starting temperature value. At this time, you can turn off the power button and disconnect the main power switch.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A small precision single crystal pulling furnace device, characterized in that: The invention comprises a furnace control cabinet (1), a heating unit, a lifting unit and a connecting piece. The heating unit is installed on the side of the furnace control cabinet (1) through the lifting unit. One end of the connecting piece is connected to the upper end of the furnace control cabinet (1), and the other end of the connecting piece is connected to a quartz tube (2) in the heating unit. The furnace control cabinet (1) comprises a cabinet (3), a temperature control instrument (4), an ammeter (5), a touch screen (6) and a power switch (7). The cabinet (3) is a rectangular cabinet. The temperature control instrument (4), the ammeter (5), the touch screen (6) and the power switch (7) are installed on the cabinet (3) in sequence from top to bottom. The cabinet (3) has a length of 300 mm and a width of 270 mm. The dimensions of the electric furnace heating zone of the heating unit are a diameter of 40 mm and a height of 150 mm.

2. A small precision single crystal pulling furnace device according to claim 1, characterized in that: The heating unit comprises a quartz tube (2), a heating resistance wire (8), a furnace (9) and a housing (10). The outer wall of the shell (10) is connected to the lifting unit and is lifted and lowered by the lifting unit. The furnace (9) is installed inside the shell (10). The heating resistance wire (8) is embedded in the furnace (9) and located in the middle of the furnace (9). The quartz tube (2) vertically passes through the heating resistance wire (8) and the furnace (9) and extends downward.

3. A small precision single crystal pulling furnace device according to claim 2, characterized in that: The furnace (9) is a fiber heat-insulating furnace.

4. A small precision single crystal pulling furnace device according to claim 1 or 3, characterized in that: The diameter of the quartz tube (2) is 35-50 mm.

5. A small precision single crystal pulling furnace device according to claim 4, characterized in that: A gap is left between the outer edge of the heating resistance wire (8) and the quartz tube (2), and the gap is 8-12 mm.

6. The small precision single crystal pulling furnace device according to claim 5, characterized in that: When the heating unit is at the vertex position, the distance between the lower end of the quartz tube (2) and the base (10) is 130-140 mm.

7. A small precision single crystal pulling furnace device according to claim 6, characterized in that: The housing (10) is made of cold-rolled steel plate by electrostatic spraying.

8. The small precision single crystal pulling furnace device according to claim 7, characterized in that: The heating resistance wire (8) is an iron-chromium-aluminum alloy heating wire.

9. The small precision single crystal pulling furnace device according to claim 8, characterized in that: The lifting unit comprises two linear guide rails (11) and a ball screw pair (12); the two linear guide rails (11) are vertically mounted on the side of a cabinet (3); a housing (10) and the linear guide rails (11) are slidably connected; the ball screw pair (12) is vertically mounted on the side of the cabinet (3) and is located between the two linear guide rails (11); and the housing (10) is connected to a nut seat on the ball screw pair (12).

10. The small precision single crystal pulling furnace device according to claim 9, characterized in that: The motor of the ball screw pair (12) is a servo motor.

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