Mocvd apparatus and its resistance wire heater

Abstract

This invention relates to an MOCVD apparatus and its resistance wire heater. The resistance wire heater includes: a heating wire, which is a double-wire wound structure and is formed by two sets of concentric arc segments with different centers alternately joined together in a planar layout; a multi-layer reflector, a negative electrode plate, a partition, and a positive electrode plate disposed below the heating wire; multiple furnace feet, each with a helical connection structure at its upper part, through which the heating wire is detachably connected to the furnace foot, and the multiple furnace feet respectively connect the heating wire to the positive and negative electrode plates; and multiple heating wire supports, which support the heating wire, and are fitted with support insulation kits on their outer sides. Both the support insulation kits pass sequentially through the multi-layer reflector, the negative electrode plate, and the partition and are supported on the positive electrode plate, with the top of the support insulation kits higher than the top surface of the multi-layer reflector. Furthermore, the MOCVD apparatus includes the aforementioned resistance wire heater. This invention can improve the service life and heating uniformity of the resistance wire heater.

Description

Technical Field

[0001] This invention belongs to the field of MOCVD technology, and more specifically, relates to an MOCVD apparatus and its resistance wire heater. Background Technology

[0002] Metal-organic chemical vapor deposition (MOCVD) is a key piece of equipment for the mass production of high-quality epitaxial thin films of various III-V and II-VI compound semiconductors and other novel semiconductors. The heater is a critical and extremely valuable core component of MOCVD equipment. The heating rate directly affects the growth rate of the epitaxial thin film, while the uniformity of the heating temperature directly determines the wavelength uniformity of the epitaxial thin film, and its lifespan determines the production cost.

[0003] Typically, heaters operate for extended periods in extremely harsh environments, such as high temperatures of 1400-1500℃ and corrosive atmospheres of NH3, placing extremely high demands on their performance. Currently, commonly used heater types for MOCVD include high-frequency induction heaters, resistive element heaters, and resistance wire heaters. However, each type has its own drawbacks. For example, high-frequency induction heaters are prone to electromagnetic interference with other precision electronic equipment and suffer from the "skin effect," causing the induced current to concentrate on the graphite substrate surface, which can easily damage the substrate. Resistive element heaters require a high-speed rotating mechanism with a rotation speed greater than 1000 rpm, increasing the complexity and cost of the MOCVD reaction chamber. They also have a more concentrated heating range, require higher power, and are prone to heating element deformation. While traditional resistance wire heaters do not require a complex high-speed rotating mechanism and exhibit less heating element deformation compared to resistive elements, their slow heating and cooling rates affect the growth rate. Furthermore, the uneven distribution of the heating elements can lead to uneven localized heating and damage, resulting in a limited lifespan and requiring periodic replacement, which increases the cost of epitaxial thin film material preparation.

[0004] Therefore, existing resistance wire heaters still have significant drawbacks and cannot meet the stringent requirements of MOCVD equipment for high performance and long-term stable operation. In view of this, there is an urgent need for a new type of resistance wire heater that can significantly improve heating efficiency, temperature uniformity, and long service life while maintaining a simple structure and high reliability, thereby reducing the fabrication cost of semiconductor epitaxial materials and improving product consistency. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a resistance wire heater for MOCVD equipment, and in particular, a high-temperature long-life resistance wire heater for MOCVD equipment, which aims to solve the problems of limited life and poor heating temperature uniformity of resistance wire heaters in the prior art.

[0006] To solve the above-mentioned technical problems or achieve the above-mentioned objectives, the present invention adopts the following technical solution: According to one aspect of the present invention, a resistance wire heater for an MOCVD apparatus is provided, comprising: The heating element is a double-wire wound structure, and in its planar layout, it is composed of two sets of concentric arc segments with different centers that are alternately connected. A multi-layered reflector plate, negative electrode plate, partition plate, and positive electrode plate are arranged below the heating element; Multiple furnace feet, each with a spiral connection structure on its upper part, the heating wire is detachably connected to the furnace foot through the spiral connection structure, and the multiple furnace feet connect the heating wire to the positive electrode plate and the negative electrode plate respectively; Multiple heating wire supports support the heating wires. An insulating kit is fitted around the outside of the heating wire supports. The heating wire supports, together with the insulating kit, pass through multiple reflectors, a negative electrode plate, and a partition in sequence and are supported on the positive electrode plate. The top of the insulating kit is higher than the top surface of the multiple reflectors.

[0007] In one embodiment of the present invention, the heating wire is arranged in a planar layout as follows: two sets of concentric circular arc segments are a first set of concentric semicircular arc segments and a second set of concentric semicircular arc segments. The first set of concentric semicircular arc segments shares a first center, and the second set of concentric semicircular arc segments shares a second center. The line connecting the first center and the second center forms a 45° angle with both the horizontal centerline and the vertical centerline. Furthermore, the spacing between any two adjacent semicircular arc segments in the first set of concentric semicircular arc segments and the spacing between any two adjacent semicircular arc segments in the second set of concentric semicircular arc segments are the same, and the spacing is 7-19 mm.

[0008] In one embodiment of the present invention, the heating wire is made of tungsten wire, and the pitch of the heating wire is 3-6 mm, the wire diameter is 1-2 mm, and the inner cross-sectional diameter is 3-7 mm.

[0009] In one embodiment of the present invention, the upper part of the furnace foot is a cylinder, and the cylinder has a cone angle of 2-5° from top to bottom. A spiral fitting structure is provided on the cylinder. The spiral fitting structure includes an outer spiral double groove, and the inner diameter of the first turn of the outer spiral double groove is 3-7 mm.

[0010] In one embodiment of the present invention, the pitch of the outer spiral double groove is adapted to the pitch of the heating wire, and the spiral direction of the outer spiral double groove is the same as the spiral direction of the heating wire. The heating element is rotated into the outer spiral double groove with the central axis of the furnace foot as the rotation center, and the inner spiral surface of the heating element is in close contact with the side wall of the outer spiral double groove.

[0011] In one embodiment of the present invention, the furnace foot is fitted with a furnace foot insulating ring after being connected to the heating wire.

[0012] In one embodiment of the invention, the top of the bracket insulating kit is 2-5 mm above the top surface of the multilayer reflector.

[0013] In one embodiment of the present invention, the bracket insulation kit takes the form of a bracket insulation ring.

[0014] In one embodiment of the present invention, the multilayer reflector, the negative electrode plate, the partition plate and the positive electrode plate are connected and fixed by their respective corresponding screws and nuts, and each screw is fitted with its own corresponding screw insulating ring to make the multilayer reflector, the negative electrode plate, the partition plate and the positive electrode plate electrically insulated from each other.

[0015] In one embodiment of the present invention, the resistance wire heater further includes: The positive electrode rod and the negative electrode rod are connected to the positive electrode plate. The negative electrode rod passes through the positive electrode plate and the partition and is connected to the negative electrode plate. The negative electrode rod has an insulating ring fitted on its body between the positive electrode plate and the negative electrode plate to achieve electrical insulation.

[0016] In one embodiment of the present invention, the multilayer reflector, negative electrode plate, partition, positive electrode plate, furnace foot, and heating wire support are all made of pure molybdenum.

[0017] According to another aspect of the present invention, an MOCVD apparatus is provided, comprising: reaction chamber; As described above, the resistance wire heater is installed inside the reaction chamber.

[0018] The technical solution provided by this invention has the following advantages compared with the prior art: The innovative planar layout of the heating wires in this invention can improve the heating uniformity of the resistance wire heater; the heating wires are double-wound tungsten wires and are connected to the furnace feet through an external spiral double groove, which can improve the service life of the heating wires; all heating wire supports are covered with support insulation kits, which can significantly reduce the risk of damage to the resistance wire heater and improve the service life and heating uniformity of the resistance wire heater. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0020] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0021] Figure 1 This diagram illustrates the structure of the connection between the cold-pressed furnace foot and the heating wires provided in the prior art. Figure 2 A schematic diagram of the structure of the furnace wire support assembly of a resistance wire heater in the prior art is shown; Figure 3 The prior art is shown Figure 2 A schematic diagram of the structure after long-term high-temperature use; Figure 4 The prior art is shown Figure 3 A schematic diagram of the state structure used in the resistance wire heater structure; Figure 5 The prior art is shown Figure 3 A schematic diagram of the current loop distribution of the heating element in the state structure; Figure 6 A schematic diagram of the resistance wire heater provided in an embodiment of the present invention is shown; Figure 7 A schematic diagram of the heating wire planar layout provided in an embodiment of the present invention is shown; Figure 8 A schematic diagram of a partial structure of the heating element in an embodiment of the present invention is shown; Figure 9 The embodiments of the present invention are shown. Figure 6 A magnified plan view of point A; Figure 10 The embodiments of the present invention are shown. Figure 6 A magnified isometric view of a portion of point A; Figure 11 The embodiments of the present invention are shown. Figure 6 A magnified view of a portion of point B.

[0022] The components are as follows: 1. Heating wire; 2. Positive and negative electrode plate fixing screws; 3. Heating wire bracket; 4. Bracket insulation kit; 5. Reflector plate fixing screws; 6. Multi-layer reflector plate; 7. Negative electrode plate; 8. Positive electrode rod; 9. Partition plate; 10. Positive electrode plate; 11. Furnace foot; 11-1. External spiral double groove; 12. Furnace foot insulation ring; 13. Negative electrode rod insulation ring; 14. Negative electrode rod; 15. Snap-on heating wire bracket; 16. Molybdenum gasket; 17. Snap-on bracket insulation ring; 18. Molybdenum rod; 19. Cold-pressed furnace foot; 20. Positive and negative electrode plate fixing screw insulation ring; 21. Reflector plate fixing screw insulation ring. Detailed Implementation

[0023] To better understand the above-described objectives, features, and advantages of this disclosure, embodiments of this disclosure will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0024] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways than those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0025] like Figure 6-11 As shown, an embodiment of the present invention provides a resistance wire heater for an MOCVD device, comprising: Heating wire 1 has a double-wire parallel winding structure and is composed of two sets of concentric arc segments with different centers connected alternately in a planar layout. A multi-layered reflector plate 6, a negative electrode plate 7, a partition plate 9, and a positive electrode plate 10 are disposed below the heating coil 1; Multiple furnace feet 11, each furnace foot 11 has a spiral engagement structure on its upper part (e.g., an outer spiral double groove 11-1), the heating wire 1 is detachably connected to the furnace foot 11 through the spiral engagement structure, and the multiple furnace feet 11 connect the heating wire 1 to the positive electrode plate 10 and the negative electrode plate 7 respectively; Multiple heating wire supports 3 support heating wires 1. The outer side of the heating wire supports 3 is fitted with a support insulation kit 4. The heating wire supports 3 and the support insulation kit 4 pass through the multi-layer reflector 6, the negative electrode plate 7, and the partition 9 in sequence and are supported on the positive electrode plate 10. The top of the support insulation kit 4 is higher than the top surface of the multi-layer reflector 6.

[0026] The technical advantages of this invention are primarily reflected in its systematic structural innovation, which significantly improves the overall performance of resistance wire heaters in harsh environments with high temperatures and corrosive conditions. The unique planar layout of the heating wire in this invention—composed of two sets of concentric arc segments with different centers alternately joined together—creates a uniform and stable thermal field distribution, effectively improving the wavelength uniformity of the epitaxial film. This invention uses double-wound tungsten wires as the heating wires, effectively reducing the current density per unit length and extending the service life of the heating wires. This invention creatively employs an externally spiral double-grooved furnace foot to achieve a detachable spiral connection with the heating wires, which not only significantly increases the contact area and reduces local current density and overheating risk, but its combined structure can also adaptively release thermal stress at high temperatures, greatly suppressing the generation and propagation of microcracks. Simultaneously, all heating wire supports are fitted with support insulation kits that extend above the multi-layer reflectors. This design achieves rigid isolation electrically, completely eliminating arcing discharge or short-circuit paths caused by high-temperature thermal deformation, and mechanically effectively constrains the thermal deformation of each layer, maintaining a stable safety gap. Furthermore, the detachable connection method allows for the individual replacement of the heating wire and furnace feet, significantly reducing maintenance costs and downtime. Therefore, this invention, through a synergistic design of optimized layout, innovative connections, and enhanced insulation, systematically solves the inherent defects of traditional resistance wire heaters, such as uneven heating, limited lifespan, and inconvenient maintenance, achieving a combined improvement in heating uniformity, long-term reliability, and economy under extreme operating conditions.

[0027] In the above embodiment, the heating wire is arranged in a planar layout as follows: two sets of concentric arc segments are a first set of concentric semicircular arc segments and a second set of concentric semicircular arc segments. The first set of concentric semicircular arc segments shares a first center, and the second set of concentric semicircular arc segments shares a second center. The line connecting the first center and the second center forms a 45° angle with both the horizontal centerline and the vertical centerline. Furthermore, the spacing between any two adjacent semicircular arc segments in the first set of concentric semicircular arc segments and the spacing between any two adjacent semicircular arc segments in the second set of concentric semicircular arc segments are the same, and the spacing is 7-19 mm.

[0028] In this embodiment, such as Figure 7As shown, in this invention, the planar layout of the heating wire 1 is such that heating wire 1-1 is geometrically connected to heating wire 1-2, heating wire 1-3 to heating wire 1-4, heating wire 1-5 to heating wire 1-6, heating wire 1-7 to heating wire 1-8, and heating wire 1-8 to heating wire 1-9. Heating wire 1-1, heating wire 1-3, heating wire 1-5, heating wire 1-7, and heating wire 1-9 are concentric semicircles sharing a common center C2. Heating wire 1-2, heating wire 1-4, heating wire 1-6, and heating wire 1-8 are concentric semicircles sharing a common center C1. The line connecting the centers C1 and C2 forms a 45° angle with both the horizontal and vertical center lines, ensuring that the spacing S between the heating wires is completely uniform along the radial position of the resistance wire heater, thus improving the heating uniformity of the resistance wire heater.

[0029] In the above embodiments, the heating wire is made of tungsten wire, and the pitch of the heating wire is 3-6 mm, the wire diameter is 1-2 mm, and the inner cross-sectional diameter is 3-7 mm.

[0030] In this embodiment, such as Figure 8 As shown, in this invention, the heating wire 1 is a tungsten wire with two wires wound in parallel. The parallel winding of the two wires reduces the current density per unit length of the heating wire, thereby improving the service life of the heating wire. The pitch L of the heating wire 1 is 3 mm to 6 mm, the wire diameter d of the heating wire 1 is 1 mm to 2 mm, and the inner cross-sectional diameter D1 of the heating wire 1 is 3 mm to 7 mm.

[0031] In the above embodiment, the upper part of the furnace foot is a cylinder, and the cylinder has a 2-5° tapered angle from top to bottom. A spiral fitting structure is provided on the cylinder. The spiral fitting structure includes an outer spiral double groove. The inner diameter of the first turn of the outer spiral double groove is 3-7 mm. The pitch of the outer spiral double groove is adapted to the pitch of the heating wire. The spiral direction of the outer spiral double groove is the same as the spiral direction of the heating wire. The heating wire is screwed into the outer spiral double groove with the central axis of the furnace foot as the rotation center. The inner spiral surface of the heating wire is tightly fitted with the side wall of the outer spiral double groove.

[0032] In this embodiment, such as Figure 9 and 10 As shown, in this invention, the upper part of the furnace foot 11 is a cylinder and is provided with an outer spiral double groove 11-1. The cone angle 11-2 (α°) is 2° to 5°. The inner diameter D2 of the first ring of the outer spiral double groove 11-1 on the upper part of the furnace foot 11 is 3mm to 7mm. The pitch of the outer spiral double groove 11-1 of the furnace foot 11 is adapted to the pitch of the heating wire 1, and the spiral direction of the outer spiral double groove 11-1 is the same as the spiral direction of the heating wire 1.

[0033] In this embodiment, the heating element 1 is screwed in with the central axis of the furnace foot 11 as the rotation center, so that its inner spiral surface is tightly fitted with the side wall of the outer spiral double groove 11-1 of the furnace foot 11. The spiral fit achieves a detachable fixation between the two. This detachable fixing structure has significant advantages: on the one hand, when either the furnace foot 11 or the heating element 1 is damaged, only the damaged part needs to be replaced, unlike the non-detachable structure which requires the entire structure to be replaced, greatly reducing production and usage costs; on the other hand, the disassembly and assembly process is convenient and quick, effectively improving disassembly and assembly efficiency as well as subsequent maintenance efficiency.

[0034] Meanwhile, the upper part of the furnace foot 11 is a cylinder with a cone angle 11-2 of 2° to 5°, and the cylinder has an external spiral double groove 11-1. Its function is reflected in three aspects: First, when tightening the heating wire 1 and the furnace foot 11, the pre-tightening force can be adjusted to an appropriate range, which can ensure that the connection between the two is tight, and avoid excessive external force causing the heating wire 1 to break or generate micro-cracks that are not easily detected, thereby improving the product manufacturing yield; Second, the cross-section of the heating wire 1 is unconstrained radially, and the thermal expansion force can be continuously released in the high temperature heating scenario of 1400-1500℃, avoiding the accumulation of internal stress and effectively extending the service life of the resistance wire heater; Third, the assembly and adjustment efficiency in the manufacturing stage is higher, and the heating wire 1 and the furnace foot 11 can be quickly separated when disassembling them later.

[0035] Furthermore, the heating wire 1 and the furnace foot 11 are fixed together by a spiral fit, forming a face-to-face contact, which significantly increases the contact area between the two and reduces the current density per unit area at the contact point. This design can prevent the accumulation of thermal expansion and internal stress caused by local overheating during the use of the resistance wire heater, thereby preventing the heating wire 1 from breaking or developing micro-cracks, and further ensuring the service life of the resistance wire heater.

[0036] In the above embodiment, the furnace foot is fitted with a furnace foot insulating ring after being connected to the heating wire.

[0037] In this embodiment, such as Figure 6 As shown, in this invention, after the furnace foot 11 is attached and fixed to the heating wire 1, a furnace foot insulating ring 12 is fitted on it. This can prevent the resistance wire heater from being damaged due to the compact structure of the resistance wire heater, the small distance between adjacent furnace feet 11, the large current passing through the furnace feet 11 at high temperatures, and the tendency for arcing discharge to occur between them. Moreover, in this embodiment, the wall thickness of the furnace foot insulating ring 12 is 0.5 mm to 1 mm.

[0038] In the above embodiment, the top of the bracket insulation kit is 2-5 mm higher than the top surface of the multilayer reflector.

[0039] In this embodiment, such as Figure 11As shown, the heating wire support 3 supports the heating wire 1, and the heating wire support 3 is sleeved with the support insulation kit 4. The support insulation kit 4 is 2 mm to 5 mm higher than the top surface of the multi-layer reflector 6. After the heating wire support 3 is sleeved with the support insulation kit 4, it passes through the multi-layer reflector 6, the negative electrode plate 7, and the partition plate 9 respectively, and is finally placed on the positive electrode plate 10.

[0040] In this embodiment, the heating wire support 3 is sleeved with the support insulation kit 4. Firstly, the electrical insulation of the support insulation kit 4 can prevent arcing or short circuits caused by the multilayer reflector 6 shrinking the gap or physical contact with the heating wire support 3 due to high-temperature thermal deformation, thereby significantly reducing the risk of damage to the resistance wire heater and improving its service life. Secondly, the support insulation kit 4 can serve as a support reinforcement for the heating wire 1 to enhance the heating wire support 3's resistance to high-temperature thermal deformation. In addition, the fixed support insulation kit 4 can constrain the high-temperature thermal deformation of the multilayer reflector 6, thereby significantly reducing the risk of shrinking gap or physical contact between the heating wire support 3 and the multilayer reflector 6. Thirdly, the support insulation kit 4 can prevent a local complete circuit from appearing in a single heating wire after the heating wire support 3 contacts the multilayer reflector 6, causing inconsistent current density per unit length between the local circuit part and the rest of the single heating wire 1, affecting the heating uniformity of the heating wire 1, thereby affecting the wavelength uniformity of the epitaxial thin film material and reducing the performance and yield of the epitaxial thin film material.

[0041] In the above embodiments, preferably, the bracket insulation kit 4 takes the form of a bracket insulation ring.

[0042] In this embodiment, the support insulation kit 4 is preferably designed as a support insulation ring, which can significantly improve the overall performance and operational reliability of the resistance wire heater. The support insulation kit 4, with its ring-shaped structure, is fitted onto the outside of the heating wire support 3, uniformly wrapping the heating wire support 3 circumferentially. This creates a complete and continuous insulating layer between the heating wire support 3 and the multi-layer reflector 6, effectively avoiding the risk of arcing and short circuits caused by high-temperature thermal deformation. It optimizes electrical insulation performance and improves electrical safety and stability under high-temperature conditions. Simultaneously, this ring-shaped structure can serve as a support reinforcement, enhancing its high-temperature bending and creep resistance. It can also constrain the thermal deformation of the multi-layer reflector 6 to maintain safe clearances between each layer, reducing mechanical interference and contact, and strengthening the overall structure. It provides structural rigidity and resistance to deformation, extending service life. In addition, its insulation function can prevent the heating wire support 3 from forming an unintended electrical connection with the multilayer reflector 6, prevent local current loops in the heating wire 1, ensure uniform current density distribution in each section of the heating wire 1, maintain thermal field uniformity, improve wavelength uniformity of epitaxial thin film materials and product yield, and the ring structure facilitates standardized manufacturing and assembly, which can reduce processing costs, improve assembly efficiency, and simplify the structure of the heating wire support 3. No additional complex accessories are required, which is conducive to later maintenance and component replacement and reduces usage costs.

[0043] In the above embodiments, such as Figure 6 As shown, the multilayer reflector 6, negative electrode plate 7, partition plate 9 and positive electrode plate 10 are connected and fixed to nuts by their respective corresponding screws (e.g., positive and negative electrode plate fixing screw 2, reflector fixing screw 5), and each screw is fitted with its own corresponding screw insulating ring (e.g., positive and negative electrode plate fixing screw insulating ring 20 and reflector fixing screw insulating ring 21) to make the multilayer reflector 6, negative electrode plate 7, partition plate 9 and positive electrode plate 10 electrically insulated from each other.

[0044] In the above embodiments, such as Figure 6 As shown, the resistance wire heater also includes: Positive electrode rod 8 and negative electrode rod 14 are provided. Positive electrode rod 8 is connected to positive electrode plate 10. Negative electrode rod 14 passes through positive electrode plate 10 and partition 9 and is connected to negative electrode plate 7. Negative electrode rod 14 is fitted with a negative electrode rod insulating ring 13 on its rod body between positive electrode plate 10 and negative electrode plate 7 (to achieve electrical insulation).

[0045] In the above embodiments, such as Figure 6 As shown, the heating element 1 is connected to the positive electrode plate 10 and the negative electrode plate 7 through the furnace foot 11 as an intermediate medium. One end of the furnace foot 11 is attached and fixed to the heating element 1, and the other end is fastened to the positive electrode plate 10 or the negative electrode plate 7 by a molybdenum nut.

[0046] In the above embodiments, such as Figure 6As shown, the multi-layer reflector 6, negative electrode plate 7, partition 9, positive electrode plate 10, furnace foot 11, and heating wire support 3 are all made of pure molybdenum.

[0047] Therefore, embodiments of the present invention provide a resistance wire heater for MOCVD equipment, particularly a high-temperature, long-life resistance wire heater for MOCVD equipment. This resistance wire heater mainly includes: a heating wire 1, serving as the heating element of the resistance wire heater; multiple furnace feet 11, for connecting the heating wire 1 to the positive electrode plate 10 and the negative electrode plate 7; multiple heating wire supports 3, for supporting the heating wire 1; a multi-layer reflector 6, placed below the heating wire 1, for reflecting the heat generated by the heating wire 1 upwards; a positive electrode plate 10, a negative electrode plate 7, and a partition 9; a positive electrode rod 8 and a negative electrode rod 14, which are respectively connected to the positive electrode plate 10, the negative electrode plate 7, and an external power supply electrode (not shown in the figure).

[0048] In the embodiments of the present invention, the multi-layer reflector 6, negative electrode plate 7, partition plate 9, and positive electrode plate 10 are fixed together by molybdenum screws and molybdenum nuts. They are then separated from the reflector by their respective corresponding positive and negative electrode plate fixing screws and insulating rings 20 and 21, giving them different electrical properties. All the insulating components and insulating rings used in this invention are made of high-purity alumina ceramic, possessing extremely strong electrical insulation properties, remaining stable and undeformed at high temperatures, not easily broken, and resistant to chemical corrosion. The multi-layer reflector 6 uses a pure molybdenum metal plate, which can quickly reflect the downward heat from the heating wire 1 upwards, improving the heating and cooling rate and reducing energy consumption and cost.

[0049] Furthermore, embodiments of the present invention also provide an MOCVD apparatus, comprising: reaction chamber; As described above, the resistance wire heater is installed inside the reaction chamber.

[0050] The technical solutions of the present invention will be described in detail below through specific embodiments.

[0051] The inventors of this invention discovered during their research that in MOCVD equipment, traditional resistance wire heaters often experience a significant reduction in lifespan due to short circuits. This not only increases the cost of epitaxial thin film material preparation but also wastes considerable time due to frequent heater replacements. To improve the lifespan of the resistance wire heater, this invention innovates the connection method between the heating wire and the furnace foot, and extensively utilizes various insulating kits and rings to ensure complete electrical isolation or insulation between the various metal components. This prevents breakage caused by localized overheating between the heating wire and the furnace foot, and avoids arcing or short circuits caused by reduced gaps or physical contact between the multilayer reflector and the heating wire support due to high-temperature thermal deformation. Furthermore, the heating wire uses a double-wound tungsten wire, which reduces the current density per unit length of the heating wire. These features significantly reduce the risk of damage to the resistance wire heater and improve its lifespan.

[0052] Reference Figure 1 As shown, Figure 1 A schematic diagram of the connection between the cold-pressed furnace foot and the heating wire provided in the prior art is shown. In this scheme, a molybdenum rod 18 is inserted into the vertically downward inner wall of the heating wire 1, and then the whole is placed into the inner wall of the cold-pressed furnace foot 19. Pressure is applied to the outer surface of the cold-pressed furnace foot 19 by hydraulic clamps and a cold-pressing mold, so that the cold-pressed furnace foot 10 deforms 19-1(H) due to the external force, and the heating wire 1 is also deformed by pressure, ultimately achieving the effect of line contact between the heating wire 1 inside the cold-pressed furnace foot 19 and the inner wall of the cold-pressed furnace foot 19. This technical solution will cause four adverse effects: First, it is difficult to control the pressure applied to the outer surface of the cold-pressed furnace foot 19 to an appropriate value. During the assembly stage, excessive pressure can easily cause the cold-pressed furnace foot 19 and the heating wire 1 to break or develop micro-cracks that are difficult to detect. If either of the two parts breaks or is damaged, since the heating wire 1 is already attached and fixed to the cold-pressed furnace foot 19 and cannot be removed, both will be scrapped, resulting in a significant increase in usage costs. Second, the cold-pressed furnace foot 19 and the heating wire 1 are fixed by cold pressing deformation. After the cold pressing deformation and fixing, a large amount of Internal stress: As the cold-pressed furnace foot 19 and heating wire 1 expand at high temperature, thermal expansion forces continue to accumulate, and because these internal stresses cannot be released due to the fixed connection, they continue to accumulate, thus accelerating damage; Third, the fixed connection between the heating wire 1 and the cold-pressed furnace foot 19 is a line contact connection, and the current density per unit area at the contact point is high. During the use of the resistance wire heater, local overheating is likely to occur, which will increase the accumulation of thermal expansion and generate internal stress, resulting in a shorter life of the resistance wire heater; Fourth, this cold-pressed connection method is non-removable, and the assembly and adjustment are complicated and inefficient.

[0053] Reference Figure 2 As shown, Figure 2A schematic diagram of a wire support assembly for a resistance wire heater in the prior art is shown. This wire support assembly includes a multi-layer reflector 6, a snap-fit ​​wire support 15, a molybdenum gasket 16, and a snap-fit ​​insulating ring 17. The snap-fit ​​wire support 15 has two protrusions on both sides of its middle section. The lower part of the snap-fit ​​wire support 15 is fitted into the molybdenum gasket 16, which is flush with the protrusions. Finally, the lower part of the snap-fit ​​wire support 15 is inserted into the inner wall of the snap-fit ​​insulating ring 17, and the upper surface of the insulating ring 17 is flush with the molybdenum gasket 16. In this technical solution, there are no protective measures between the snap-fit ​​wire support 15 and the multi-layer reflector 6. (Refer to...) Figure 3 As shown, Figure 3 The prior art is shown Figure 2 The diagram shows the state of the structure after long-term high-temperature use. After the heater has been used at a high temperature of 1400-1500℃ for a long time, the distance between the snap-fit ​​heating wire support 15 and the multi-layer reflector 6 will become smaller or even come into direct contact due to deformation.

[0054] Continue to refer to Figure 3 and further combine Figure 4 , Figure 5 As shown, the multi-layer reflector 6 and the negative electrode plate 7 are fixedly connected by the reflector fixing screw 5, therefore the electrical property of the multi-layer reflector 6 is negative. When the distance between the snap-fit ​​heating wire bracket 15 and the multi-layer reflector 6 is reduced to a critical range or they come into direct contact, two major problems will occur: Firstly, this contact or close proximity condition is very likely to induce arcing discharge under high temperature conditions, which will accelerate the wear and damage of the resistance wire heater and significantly shorten its service life. Secondly, after the snap-on heating wire bracket 15 comes into contact with the multi-layer reflector 6, it will cause a single heating wire to form multiple independent and complete circuits (such as...). Figure 4 , Figure 5 (The diagram illustrates the CDE and CDF circuits). This leads to a difference in current density per unit length between the CD heating wire segment corresponding to the CDE local circuit and the DF heating wire segment corresponding to the CDF circuit in a single heating wire, resulting in uneven temperature field distribution in the resistance wire heater. This uneven temperature field directly affects the wavelength uniformity of the epitaxial thin film material, ultimately leading to a decrease in the performance of the epitaxial thin film material and a reduction in product yield.

[0055] To address the shortcomings of existing technologies, this invention provides a resistance wire heater for MOCVD equipment, particularly a high-temperature, long-life resistance wire heater for MOCVD equipment. (Refer to...) Figure 6 As shown, the resistance wire heater specifically includes the following components: Heating element 1: As the core heating element of the heater, it provides the required heat to the equipment; Furnace foot 11: Used to connect the heating wire 1 to the positive electrode plate 10 and the negative electrode plate 7, serving the dual purpose of circuit conduction and component fixation; Heating wire support 3: Specifically designed to support heating wire 1 and ensure its stable installation position; Multi-layer reflector 6: Arranged below the heating element 1, its core function is to reflect the heat generated by the heating element 1 upwards, thereby improving heat utilization. Positive electrode plate 10, negative electrode plate 7 and partition plate 9: These are key components that form the circuit connection and ensure safe and stable circuit conduction. Positive electrode rod 8 and negative electrode rod 14: respectively connected to positive electrode plate 10, negative electrode plate 7 and external power supply electrode to realize the transmission of external electrical energy to the heater.

[0056] Further reference Figure 7 As shown, the planar layout design of the heating wire 1 in this embodiment of the invention is as follows: heating wire segments 1-1 and 1-2, 1-3 and 1-4, 1-5 and 1-6, 1-7 and 1-8, and 1-8 and 1-9 are geometrically connected sequentially; among them, heating wire segments 1-1, 1-3, 1-5, 1-7, and 1-9 form a concentric semicircle structure, sharing the same center C2; heating wire segments 1-2, 1-4, 1-6, and 1-8 form another set of concentric semicircles, sharing the same center C1. The line connecting center C1 and center C2 forms a 45° angle with both the horizontal and vertical center lines. This layout design ensures that the spacing S between each heating wire is completely consistent along the radial direction of the resistance wire heater, thereby significantly improving the heating uniformity of the heater; wherein the value of the spacing S ranges from 7 mm to 19 mm.

[0057] Reference Figure 8 As shown, the heating wire 1 in this embodiment of the invention adopts a double-wire wound tungsten wire structure. This design can effectively reduce the current density per unit length of the heating wire, thereby significantly improving the service life of the heating wire. The key structural parameters of the heating wire 1 are as follows: the pitch L ranges from 3 mm to 6 mm, the wire diameter d is from 1 mm to 2 mm, and the inner cross-sectional diameter D1 is from 3 mm to 7 mm. It should be noted that the heating wire 1 will undergo thermal expansion under high-temperature conditions. If the pitch L is too small, the thermal expansion will easily cause adjacent wire coils to be squeezed and deformed, or even cause a short circuit; if the pitch L is too large, it will reduce the heating wire's resistance to high-temperature creep and sagging, thereby affecting the heating uniformity. Therefore, the above-mentioned range of pitch L is an optimized choice that balances structural stability and heating effect.

[0058] Further reference Figure 9 , Figure 10 As shown, the furnace foot 11 structure used in this embodiment of the invention is similar to... Figure 1 The structures shown differ, and their specific designs are as follows: The upper cylinder of the furnace foot 11 has an outer spiral double groove 11-1. The pitch of the groove is adapted to the pitch of the heating wire 1, and the number of groove turns is not less than four. At the same time, the inner diameter D2 of the first outer spiral double groove on the upper part of the furnace foot 11 is 3 mm to 7 mm. The upper part of the cylinder of the furnace foot 11 presents a certain expansion cone angle 11-2 (denoted as α°) from top to bottom, where the value of α° ranges from 2° to 5°.

[0059] During the assembly process of the heating wire 1 and the furnace foot 11, the heating wire 1 is screwed in with the central axis of the furnace foot 11 as the center of rotation, so that the inner spiral surface of the heating wire 1 is tightly fitted with the side wall of the outer spiral double groove 11-1 of the furnace foot 11, and the two are detachably fixed together through the spiral fit. This structural design has multiple advantages: Firstly, the heating element 1 and the outer spiral double groove 11-1 form a face-to-face contact, which significantly increases the contact area between the two. This reduces the current density per unit area at the contact point when the resistance wire heater is working, effectively avoiding the problem of heat expansion accumulation and internal stress caused by local overheating, which could lead to damage to the heating element and shorten the life of the heater. Secondly, the 2° to 5° cone angle set from top to bottom on the upper part of the furnace foot 11, combined with the inner diameter D2 parameter of the first outer spiral double groove, can precisely control the pre-tightening force during the process of the heating wire 1 being screwed into the groove. This not only ensures the tightness of the connection between the heating wire 1 and the furnace foot 11, but also avoids the heating wire 1 from breaking or developing micro-cracks that are not easily detected due to excessive external force, thereby improving the product manufacturing yield. Third, the cross-section of heating wire 1 is radially unconstrained, and under high-temperature heating scenarios of 1400-1500℃, the thermal expansion force can be continuously released, avoiding the accumulation of internal stress and further extending the service life of the resistance wire heater. Fourth, the spiral-fit detachable fixing structure not only improves the assembly and adjustment efficiency during the manufacturing stage, but also enables the rapid disassembly of the heating element 1 and the furnace foot 11. Moreover, thanks to the cone angle design, the disassembly process can achieve non-destructive separation rather than destructive disassembly, which greatly improves the convenience of maintenance.

[0060] In the above-described embodiments of the present invention, the spiral direction of the outer spiral double groove 11-1 of the furnace foot 11 is the same as the spiral direction of the heating wire 1.

[0061] In the above-described embodiments of the present invention, the pitch of the outer spiral double groove 11-1 of the furnace foot 11 is adapted to the pitch of the heating wire 1, which can make them fit together more fully.

[0062] In the above embodiments of the present invention, the heating element 1 and the furnace foot 11 are fixed in a detachable manner to avoid the other being scrapped due to the damage of one.

[0063] In the above embodiments, such as Figure 6 As shown, after the furnace foot 11 is attached and fixed to the heating wire 1, an insulating ring 12 is fitted around its exterior. Given the compact overall structure of the heater and the small distance between adjacent furnace feet 11, arcing or short circuits are easily caused under high temperature and high heat operating conditions. The insulating ring 12 can effectively avoid the above risks, thereby preventing the resistance wire heater from being damaged faster due to such electrical faults and ensuring its stable operation.

[0064] Reference Figure 11 As shown, the structure of the embodiment of the present invention is similar to... Figure 2 , Figure 3 The structures shown differ. The core design is as follows: all heating wire supports 3 are sleeved with support insulation kits 4 (in the form of support insulation rings), and the height of the support insulation kits 4 is higher than that of the multi-layer reflector 6, thereby achieving reliable electrical insulation between the heating wire supports 3 and the multi-layer reflector 6. This structure does not require the addition of too many auxiliary materials, simplifies the structural design of the heating wire supports 3, and effectively reduces processing costs and the overall operating cost of the resistance wire heater.

[0065] exist Figure 11 In the assembly structure, after the heating wire bracket 3 is sleeved with the bracket insulation kit 4, it sequentially passes through the multi-layer reflector plate 6, the negative electrode plate 7, and the partition plate 9, and is finally fixed on the positive electrode plate 10. Preferably, the top surface of the bracket insulation kit 4 is 2 mm to 5 mm higher than the top surface of the multi-layer reflector plate 6. This design has three key functions: (1) Electrical insulation protection: avoids the gap between the multi-layer reflector 6 and the heating wire support 3 shrinking due to high temperature thermal deformation, which may lead to arcing and discharge problems, significantly reducing the risk of damage to the resistance wire heater and extending its service life; (2) Structural reinforcement and deformation constraint: The bracket insulation kit 4 can serve as a reinforcement for the heating wire bracket 3, improving its resistance to high-temperature thermal deformation; at the same time, the fixed bracket insulation kit 4 can constrain the high-temperature thermal deformation of the multi-layer reflector 6, greatly reducing the risk of the gap between the two narrowing or physical contact. (3) Ensure heating uniformity: Avoid the formation of a local complete circuit by a single heating wire after the heating wire support 3 comes into contact with the multilayer reflector 6. If a local circuit occurs, the current density per unit length of the local circuit section of the heating wire will be inconsistent with that of the other sections, which will destroy the heating uniformity and ultimately affect the wavelength uniformity of the epitaxial thin film material, resulting in a decrease in its performance and product yield.

[0066] It should be noted that the heating wire support 3 and the multi-layer reflector 6 have different electrical properties, which further strengthens the necessity of insulation protection.

[0067] In addition, such as Figure 6 As shown, the resistance wire heater of this embodiment includes a positive electrode rod 8 and a negative electrode rod 14, which are respectively connected to the positive electrode plate 10, the negative electrode plate 7, and the external power supply electrode. When the negative electrode rod 14 passes through the positive electrode plate 10 and the partition plate 9 and is fixedly connected to the negative electrode plate 7, electrical insulation is achieved through the negative electrode rod insulating ring 13, preventing short circuits between different electrodes.

[0068] In the overall assembly, the multi-layer reflector 6, negative electrode plate 7, partition plate 9, and positive electrode plate 10 are fixedly connected by molybdenum screws and molybdenum nuts, and are isolated by various insulating rings to ensure that each component has independent electrical properties. All insulating kits and insulating rings are made of high-purity alumina ceramic material, which is dimensionally stable and not easily deformed or broken in high-temperature environments, and has excellent chemical corrosion resistance, making it suitable for the high-temperature working environment of the heater.

[0069] Furthermore, in the above embodiments of the present invention, the multilayer reflector 6 is made of pure molybdenum metal plate, which can reflect the heat radiated downward by the heating wire upward, effectively improving the heating and cooling rate of the heater and reducing energy consumption and operating costs.

[0070] In the above embodiments of the present invention, apart from the heating wire and various insulating kits and insulating rings, all other metal parts are made of pure molybdenum material, which has multiple advantages in adapting to high-temperature scenarios: High melting point: The melting point is approximately 2623℃, ensuring stable operation in high-temperature environments; Low coefficient of thermal expansion: approximately 5.2 × 10⁻ 6 / ℃, which matches the thermal expansion characteristics of semiconductor materials such as silicon, and can reduce structural deformation caused by thermal stress; Excellent corrosion resistance: Stable to most acids such as hydrochloric acid and sulfuric acid and organic solvents at room temperature, and resistant to corrosion by corrosive gases such as HCl and Cl2 and molten metal at high temperatures; High purity and low volatility: Electronic-grade high-purity molybdenum has extremely low impurity content (such as Fe, Ni, C, etc.), which can avoid contaminating semiconductor films, and has low volatility at high temperatures, making it suitable for high-cleanliness working environments; Excellent thermal shock resistance: It can be used as a high-temperature insulation material to reflect heat and reduce heat loss, while also being able to withstand periodic temperature changes and not easily damaged by thermal shock.

[0071] Therefore, the resistance wire heater of the MOCVD equipment provided in this embodiment of the invention achieves performance improvement through multiple creative designs. The core innovations and advantages are as follows: Innovative heating element layout: A planar layout with two sets of concentric semicircular heating elements geometrically connected is adopted. The line connecting the centers of the two sets of semicircles forms a 45° angle with both the horizontal and vertical center lines, ensuring that the spacing S of each heating element in the radial direction of the heater is completely consistent, significantly improving heating uniformity. Heating wire structure optimization: Tungsten wire with double wires wound in parallel is selected as the heating wire, which effectively reduces the current density per unit length and extends the service life of the heating wire; Improved connection structure: The heating element and the furnace foot are connected by a spiral double groove, which increases the contact area between the two and avoids the risk of the heating element breaking due to excessive external force during assembly, thus further extending the life of the heater. Upgraded insulation protection: All heating wire supports are fitted with support insulation kits. The ingeniously optimized structural design not only solves the problem of arcing caused by high temperature deformation of multi-layer reflectors and narrowing gaps in the supports, but also avoids the decrease in heating uniformity caused by local circuits, while improving the deformation resistance of the supports and reflectors. High material adaptability: The core metal components are made of pure molybdenum, and the insulation kit and insulation ring are made of high-purity alumina ceramic, which is perfectly adapted to high-temperature, high-cleanliness and highly corrosive working environments, ensuring the long-term stable operation of the heater.

[0072] In summary, the resistance wire heater of the present invention has the characteristics of long life, high heating uniformity and high reliability, and is especially suitable for MOCVD equipment scenarios with high heating temperature and compact structure.

[0073] Of course, the embodiments of the present invention are merely illustrative and are not intended to limit the invention. For example, the bracket insulation kit, furnace foot insulation ring, screw insulation ring, etc., used in the embodiments of the present invention are specific examples, and other similar insulation kits and insulation rings with similar structures or functions can also be used. The multi-layer reflector of the present invention shows three layers, but of course, reflectors with other multi-layers can also be used. In addition, the heating wire can be made of materials other than tungsten wire, and other metal parts can be made of materials other than pure molybdenum, as long as the same or similar effects or functions can be achieved.

[0074] It should be noted that, in the embodiments provided in this application, it should be understood that the disclosed device structure can also be implemented in other ways. The device embodiments described above are merely illustrative. Furthermore, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to the process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0075] The above description is merely an embodiment of the present invention, which enables those skilled in the art to understand and implement the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

1. A resistance wire heater for an MOCVD apparatus, characterized by, include: The heating element is a double-wire wound structure, and in its planar layout, it is composed of two sets of concentric arc segments with different centers that are alternately connected. A multi-layered reflector plate, negative electrode plate, partition plate and positive electrode plate are arranged below the heating element; Multiple furnace feet, each with a spiral engagement structure on its upper part, wherein the heating element is detachably connected to the furnace foot through the spiral engagement structure, and the multiple furnace feet respectively connect the heating element to the positive electrode plate and the negative electrode plate; Multiple heating wire supports support the heating wires. An insulating sleeve is fitted around the outer side of each heating wire support. The heating wire supports, together with the insulating sleeve, pass through the multi-layer reflector, the negative electrode plate, and the partition in sequence and are supported on the positive electrode plate. The top of the insulating sleeve is higher than the top surface of the multi-layer reflector.

2. The resistance wire heater of claim 1, wherein, The heating element is arranged in a planar layout with two sets of concentric semicircular arc segments, namely a first set of concentric semicircular arc segments and a second set of concentric semicircular arc segments. The first set of concentric semicircular arc segments shares a first center, and the second set of concentric semicircular arc segments shares a second center. The line connecting the first center and the second center forms a 45° angle with both the horizontal centerline and the vertical centerline. Furthermore, the spacing between any two adjacent semicircular arc segments in the first set of concentric semicircular arc segments and the spacing between any two adjacent semicircular arc segments in the second set of concentric semicircular arc segments are the same, and the spacing is 7-19 mm.

3. The resistance wire heater of claim 1, wherein, The heating wire is made of tungsten wire, and the pitch of the heating wire is 3-6 mm, the wire diameter is 1-2 mm, and the inner cross-sectional diameter is 3-7 mm.

4. The resistance wire heater of claim 1, wherein, The upper part of the furnace foot is a cylinder, and the cylinder has a cone angle of 2-5° from top to bottom. The spiral fitting structure is provided on the cylinder, and the spiral fitting structure includes an outer spiral double groove. The inner diameter of the first turn of the outer spiral double groove is 3-7 mm.

5. The resistance wire heater of claim 4, wherein, The pitch of the outer spiral double groove is adapted to the pitch of the heating wire, and the spiral direction of the outer spiral double groove is the same as the spiral direction of the heating wire; The heating element is screwed into the outer spiral double groove with the central axis of the furnace foot as the rotation center, and the inner spiral surface of the heating element is in close contact with the side wall of the outer spiral double groove.

6. The resistance wire heater of claim 1, wherein, The furnace foot is fitted with a furnace foot insulating ring after being connected to the heating wire.

7. The resistance wire heater of claim 1, wherein, The top of the bracket insulation kit is 2-5 mm higher than the top surface of the multilayer reflector.

8. The resistance wire heater of claim 1, wherein, The multi-layer reflector, the negative electrode plate, the partition plate, and the positive electrode plate are connected and fixed by their respective screws and nuts, and each screw is fitted with its own corresponding screw insulating ring to ensure that the multi-layer reflector, the negative electrode plate, the partition plate, and the positive electrode plate are electrically insulated from each other.

9. The resistance wire heater of claim 1, wherein, The resistance wire heater further includes: A positive electrode rod and a negative electrode rod are provided. The positive electrode rod is connected to the positive electrode plate. The negative electrode rod passes through the positive electrode plate and the partition and is connected to the negative electrode plate. An insulating ring is fitted on the rod between the positive electrode plate and the negative electrode plate to achieve electrical insulation.

10. The resistance wire heater according to claim 1, characterized in that, The multi-layer reflector, the negative electrode plate, the partition, the positive electrode plate, the furnace foot, and the heating wire support are all made of pure molybdenum.

11. An MOCVD apparatus, characterized in that, include: reaction chamber; The resistance wire heater as described in any one of claims 1-10, wherein the resistance wire heater is installed inside the reaction chamber.

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