Graphite heating device of silicon carbide PVT method crystal growth equipment
By adopting the design of spiral graphite resistor sheet and fan ring electrode pin, the high current density and ignition problems at the corners of the heater in the silicon carbide PVT method crystal growth device are solved, and a more uniform current distribution and longer heater life are achieved, and crystal quality is improved.
Patent Information
- Application Number
- CN202422467778.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2025-08-15
- Estimated Expiration
- 2034-10-12
AI Technical Summary
In the existing silicon carbide PVT crystal growth device, the current density at the corners of the heater is high, and peeling and blacking are prone to occur, which affects the life of the heater and easily causes ignition.
The spiral graphite resistor plate design is adopted, the electrode pins are fan-ring-shaped, the current distribution is more uniform, corners are reduced, and the repulsion between the spiral graphite plates is changed to vertical, reducing shear stress and increasing the contact area to avoid deformation and ignition.
It extends the service life of the heater, improves the crystal quality, reduces the ignition phenomenon, and avoids the heater deformation.
Smart Images
Figure CN223226227U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a graphite heating device, in particular to a graphite heating device for silicon carbide PVT method crystal growth equipment. Background Art
[0002] With the rapid development of information technology, innovation in semiconductor technology is becoming increasingly important. Wide-bandgap semiconductor materials, represented by silicon carbide (SiC) and gallium nitride (GaN), are the third generation of semiconductors, following silicon (Si) and gallium arsenide (GaAs). Silicon carbide offers advantages such as high breakdown field strength, high thermal conductivity, high saturation drift electron velocity, and high bonding energy, making it one of the most promising materials in the semiconductor field.
[0003] In the prior art, the heaters used in silicon carbide PVT crystal growth devices are generally strip heaters, which generate mutually repulsive forces between adjacent graphite resistor sheets in the heater. This phenomenon causes radial shear forces at the heater pins, which can easily cause sparks at the electrode pins. The heater's excessive deformation in the hot state compared to the cold state affects the heater's life. On the other hand, the current density at the corners of the strip heater is high, and in actual production, peeling and blackening are often observed at the corners. This affects the life of the graphite at the corners, which in turn affects the life of the heater, and is also prone to sparks. Utility Model Content
[0004] The utility model provides a graphite heating device for silicon carbide PVT method crystal growth equipment, which aims to overcome the above-mentioned shortcomings of the prior art, reduce the sparking phenomenon and extend the service life.
[0005] The present utility model provides a technical solution for a graphite heating device used in silicon carbide PVT crystal growth equipment. The device comprises a spiral graphite resistor in the shape of a hollow cylinder. Electrode pins A and B are located on either side of the top of the spiral graphite resistor, connecting to the positive and negative poles of a power supply, respectively. A uniform spiral gap is formed on the spiral graphite resistor. The A and B electrode pins are fan-shaped, with the inner arc of the fan-shaped ring coinciding with the inner arc of the spiral graphite resistor and the outer arc of the fan-shaped ring protruding from the outer arc of the spiral graphite resistor. The spiral design shifts the direction of repulsive force between the graphite sheets to a vertical direction, reducing shear stress at the electrode pins. Compared to strip heaters, this design avoids corners, resulting in more uniform current distribution, extended heater life, and improved crystal quality. The fan-shaped electrode pins increase the contact area, reducing the possibility of sparking and preventing heater deformation.
[0006] Preferably, the gap size is 8-20 mm.
[0007] Preferably, the fan-shaped A electrode pin and B electrode pin protrude from the outer arc portion of the spiral graphite resistor sheet and have several screw holes evenly spaced circumferentially, and the positive and negative poles of the power supply are fixed to the screw holes of the A electrode pin and the B electrode pin through graphite screws.
[0008] Advantages of this utility model: Its rational structural design utilizes a spiral heater with equally spaced graphite resistor sheets, shifting the repulsive force between the sheets to a vertical direction, reducing shear stress at the electrode pins. This eliminates the appearance of corners found in strip heaters, resulting in more uniform current distribution, extending heater life, and improving crystal quality. The fan-shaped design of the electrode pins increases contact area, reduces the risk of sparking, and prevents heater deformation. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 It is a structural schematic diagram of a heater in a prior art silicon carbide PVT method crystal growth device.
[0010] Figure 2 The utility model is a structural schematic diagram of a graphite heating device of silicon carbide PVT method crystal growth equipment.
[0011] Figure 3 yes Figure 2 Top view of .
[0012] In the figure, 1 is the A electrode pin, 2 is the B electrode pin, 3 is the spiral graphite resistor, 4 is the gap, and 5 is the screw hole. DETAILED DESCRIPTION
[0013] The present invention will be further described in detail below with reference to the embodiments and specific implementation methods.
[0014] like Figure 2 、 3 As shown, a graphite heating device for silicon carbide PVT method crystal growth equipment includes a spiral graphite resistor 3 that is generally hollow cylindrical. An A electrode pin 1 and a B electrode pin 2 are respectively provided on both sides of the top of the spiral graphite resistor 3. The A electrode pin 1 and the B electrode pin 2 are respectively connected to the positive and negative poles of the power supply (copper electrodes with a water-cooling structure inside). A uniform spiral gap 4 is provided on the spiral graphite resistor 3. The gap 4 is 8-20 mm in size. The A electrode pin 1 and the B electrode pin 2 are fan-shaped. The inner arc of the fan-shaped ring coincides with the inner arc of the spiral graphite resistor 3, and the outer arc of the fan-shaped ring protrudes from the outer arc of the spiral graphite resistor 3.
[0015] The spiral-shaped graphite resistor 3, as described above, shifts the direction of repulsive forces between the graphite sheets to a vertical direction, reducing shear stress at the electrode pins. This also avoids corners in strip heaters, resulting in more uniform current distribution, extending heater life, and improving crystal quality. The fan-shaped electrode pins increase contact area, reducing the risk of sparks and preventing heater deformation.
[0016] During specific installation, the fan-shaped A electrode pin 1 and B electrode pin 2 protrude from the outer arc part of the spiral graphite resistor sheet 3, and a number of screw holes 5 are evenly spaced circumferentially. The positive and negative poles of the power supply are fixed to the screw holes 5 of the A electrode pin 1 and the B electrode pin 2 through graphite screws.
[0017] In the specific design, the ratio of the overall height of the spiral graphite resistor 3 to the height of the matching graphite crucible is 3:1, and the center of the graphite crucible is located near 1 / 3 of the overall height of the spiral graphite resistor 3 from bottom to top. The heating power is 30-50kW, the maximum temperature is 2100℃-2250℃, and the heating time is 5-10h.
[0018] The components described above are all prior art, and those skilled in the art can use any model and existing design that can achieve their corresponding functions.
[0019] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, which all fall within the scope of protection of the present invention.
Claims
1. A graphite heating device for silicon carbide PVT crystal growth equipment, characterized in that: The invention comprises a spiral graphite resistor (3) which is in the shape of a hollow cylinder as a whole. An electrode pin A (1) and an electrode pin B (2) are respectively provided on both sides of the top of the spiral graphite resistor (3). The electrode pin A (1) and the electrode pin B (2) are respectively connected to the positive electrode and the negative electrode of the power supply. A uniform spiral gap (4) is provided on the spiral graphite resistor (3). The electrode pin A (1) and the electrode pin B (2) are in the shape of a fan ring. The inner arc of the fan ring coincides with the inner arc of the spiral graphite resistor (3), and the outer arc of the fan ring protrudes from the outer arc of the spiral graphite resistor (3).
2. The graphite heating device for silicon carbide PVT crystal growth equipment according to claim 1, characterized in that: The size of the gap (4) is 8-20 mm.
3. The graphite heating device for silicon carbide PVT crystal growth equipment according to claim 1, characterized in that: The fan-shaped A electrode pin (1) and B electrode pin (2) protrude from the outer arc portion of the spiral graphite resistor sheet (3) and have a plurality of screw holes (5) evenly spaced in the circumferential direction. The positive and negative poles of the power supply are fixed to the screw holes (5) of the A electrode pin (1) and the B electrode pin (2) through graphite screws.