Polysilicon reduction high-efficiency vapor deposition reaction system
By setting up a plasma reaction chamber and an accelerator in front of the reduction furnace, and combining the synergistic effect of a microwave source and a bias source, the problem of low reduction efficiency of polycrystalline silicon in the Siemens process was solved, achieving low-temperature and high-efficiency deposition, and reducing energy consumption and production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHONGQING DAQUAN TAILAI ELECTRIC CO LTD
- Filing Date
- 2025-08-29
- Publication Date
- 2026-07-21
AI Technical Summary
The existing Siemens process for polysilicon reduction via vapor deposition has low efficiency, resulting in high power consumption and high costs, making it uncompetitive in the market.
Before the SiHCl3 and H2 mixed gas enters the reduction furnace, a plasma reaction chamber is set up for ionization to generate high-energy electrons and ions. A plasma accelerator is used to maintain the transport of active groups, and electromagnetic energy is provided by a microwave source with multi-angle distribution. Combined with a DC/RF bias source, a directional electric field is formed to drive deposition, suppress the generation of by-products, and achieve low-temperature and high-efficiency deposition.
It significantly improves the deposition efficiency and purity of polycrystalline silicon, reduces energy consumption, and optimizes production costs and quality.
Smart Images
Figure CN224530628U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of polycrystalline silicon technology, and in particular to a high-efficiency vapor deposition reaction system for polycrystalline silicon reduction. Background Technology
[0002] The improved Siemens process for polysilicon reduction, which uses vapor deposition, generally has low efficiency, with a deposition rate of 10%-12%, resulting in high power consumption and thus making it uncompetitive in the market due to high costs. This puts the Siemens process on the verge of being replaced by particulate silicon production processes. However, since 80% of polysilicon production facilities in reality use the Siemens process, changing the production process would require a huge investment.
[0003] Therefore, how to provide a high-efficiency polycrystalline silicon reduction vapor deposition reaction system with high production efficiency and low production energy consumption cost has become an urgent problem to be solved. Utility Model Content
[0004] The purpose of this invention is to provide a high-efficiency vapor deposition reaction system for polycrystalline silicon reduction, which solves the technical problems of low production efficiency and high energy consumption cost in polycrystalline silicon preparation.
[0005] To achieve the above objectives, this utility model provides a high-efficiency vapor deposition reaction system for polycrystalline silicon reduction, comprising:
[0006] The plasma reaction chamber has its inlet end connected to a mixed gas pipeline to receive a mixture of SiHCl3 and H2 gas, so as to generate a plasma-state mixed gas from the mixture of SiHCl3 and H2 gas.
[0007] A plasma accelerator, connected to the outlet of the plasma reaction chamber, is used to accelerate the plasma-state mixed gas and maintain its activity.
[0008] A reduction furnace is connected to the outlet of the plasma accelerator. The reduction furnace is equipped with several silicon rods for receiving the plasma-state mixed gas and performing a vapor-phase deposition reaction.
[0009] A microwave transmitter assembly, mounted on the reduction furnace, is used to provide high-energy electromagnetic waves into the reduction furnace;
[0010] The bias source and heating components are connected to the silicon rod.
[0011] Preferably, the plasma reaction chamber includes:
[0012] Stainless steel housing shielding cover;
[0013] A high-purity quartz tube is installed inside the stainless steel outer shell shield, with one end connected to the mixed gas pipeline and the other end connected to the plasma accelerator inlet.
[0014] An induction coil is sleeved outside the high-purity quartz tube, and the induction coil is electrically connected to a microwave power supply or a radio frequency power supply.
[0015] Preferably, the inner wall of the high-purity quartz tube is provided with a chlorine-resistant coating, and the thickness of the chlorine-resistant coating is greater than 50 μm.
[0016] Preferably, the chlorine-resistant coating is a high-purity quartz coating or a stainless steel coating treated with Al2O3.
[0017] Preferably, it further includes an RF matching unit connected between the induction coil and the microwave power supply or the RF power supply.
[0018] Preferably, the output power range of the microwave power supply or the radio frequency power supply is 100W to 6000W.
[0019] Preferably, the energy density of the microwave power supply or the radio frequency power supply is greater than 1 W / cm².
[0020] Preferably, the bias source is a DC bias source or an RF bias source.
[0021] Preferably, the microwave transmitter assembly includes a first microwave transmitter, a second microwave transmitter, a third microwave transmitter, a fourth microwave transmitter, and a fifth microwave transmitter, which are respectively arranged on the top, upper left side, front side, rear side, and right side of the reduction furnace.
[0022] Preferably, the reduction furnace is equipped with a temperature sensor and a pressure sensor.
[0023] Compared to the aforementioned background technology, the polycrystalline silicon reduction high-efficiency vapor deposition reaction system provided by this utility model sets up a plasma reaction chamber before SiHCl3 and H2 enter the reduction furnace for ionization, generating high-energy electrons and ions, reducing the reaction activation energy, and enabling SiHCl3 to efficiently dissociate at low temperature, generating active groups to provide highly active raw materials for silicon deposition. A plasma accelerator directs the plasma jet into the reduction furnace, ensuring the efficient transport of active groups. Inside the reduction furnace, multi-angle distributed microwave sources continuously provide electromagnetic energy to maintain the plasma state of the material and avoid energy decay. Furthermore, a DC / RF bias source on the silicon rod forms a directional electric field, driving the positively charged... Rapid deposition significantly improves deposition efficiency while inhibiting [the process]. Byproduct generation and gas-phase nucleation reduce dust pollution, improve product purity and deposition uniformity, and through plasma-assisted and electric field synergy, achieve low-temperature and high-efficiency deposition, reduce energy consumption, and optimize the cost and quality of polycrystalline silicon production. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0025] Figure 1 This is a process flow diagram of a high-efficiency vapor deposition reaction system for polycrystalline silicon reduction provided in an embodiment of the present invention;
[0026] Figure 2 A top view of the reduction furnace in a high-efficiency vapor deposition reaction system for polycrystalline silicon reduction provided in an embodiment of this utility model;
[0027] Figure 3 This is a cross-sectional electric field distribution diagram of the microwave-assisted cavity in a polycrystalline silicon reduction high-efficiency vapor deposition reaction system provided in an embodiment of the present invention.
[0028] in:
[0029] 1-Plasma reaction chamber, 11-Stainless steel outer shell shield, 12-High-purity quartz tube, 13-Induction coil, 2-Plasma accelerator, 3-Reduction furnace, 4-Silicon rod, 5-First microwave transmitter, 6-Second microwave transmitter, 7-Third microwave transmitter, 8-Fourth microwave transmitter, 9-Fifth microwave transmitter. Detailed Implementation
[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0031] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0032] See Figure 1This application provides a high-efficiency vapor deposition reaction system for polycrystalline silicon reduction, comprising a plasma reaction chamber 1, the inlet of which is connected to a mixed gas pipeline for receiving a mixture of SiHCl3 and H2 gas to generate a plasma-state mixed gas; a plasma accelerator 2, connected to the outlet of the plasma reaction chamber 1, for accelerating the plasma-state mixed gas and maintaining its activity; a reduction furnace 3, connected to the outlet of the plasma accelerator 2, wherein a plurality of silicon rods 4 are provided inside the reduction furnace 3 for receiving the plasma-state mixed gas and performing a vapor deposition reaction; a microwave transmitter assembly, mounted on the reduction furnace 3, for providing high-energy electromagnetic waves into the reduction furnace 3; and a bias source and heating assembly, connected to the silicon rods 4.
[0033] Specifically, the inlet of the plasma reaction chamber 1 is connected to the SiHCl3 and H2 mixed gas delivery pipeline to receive the reaction gas in a specific ratio (H2 / SiHCl3 volume ratio is 5:1 to 10:1). A radio frequency or microwave excitation source is set in the chamber to excite the gas molecules to ionize and generate a plasma mixed gas rich in high-energy electrons, ions and active free radicals.
[0034] The cavity adopts a coaxial resonant structure design to ensure uniform electromagnetic field distribution (field strength distribution error <5%) and improve ionization efficiency.
[0035] Plasma accelerator 2 is connected to the outlet end of plasma reaction chamber 1 and is used to directionally accelerate the ionized plasma mixture and maintain its highly active state during transport.
[0036] The reduction furnace 3 is sealed to the outlet end of the plasma accelerator 2. Several silicon rods 4 arranged in an array are placed inside the furnace as the deposition substrate. The reduction furnace has high temperature resistance, corrosion resistance and microwave transmission performance. The furnace body is made of high-purity quartz or ceramic composite material.
[0037] After the plasma gas enters the furnace, the active silicon species undergo an adsorption-diffusion-crystallization reaction on the surface of silicon rod 4 to form a high-purity polycrystalline silicon layer.
[0038] The microwave emitter assembly installed in reduction furnace 3 is used to continuously inject microwave energy into the furnace during the deposition process to maintain or further excite the plasma state of the reactive gases. Each silicon rod 4 is connected to a bias source via a conductive clamp, applying a negative bias voltage (-10V to -200V) during deposition to form a local electric field. This drives positively charged silicon-based ions to migrate directionally and accelerate their impact on the silicon rod surface, promoting ordered deposition, suppressing gas nucleation and dust generation, and simultaneously reducing... The formation of by-products improves product purity and density.
[0039] The heating element is used to maintain the initial heating of the silicon rod and process temperature control. Since the plasma reduces the activation energy required for the decomposition of SiHCl3, the deposition temperature of >1000℃ in the traditional process can be significantly reduced to 300-800℃ (preferably 710℃), thereby reducing heating energy consumption and achieving a substantial reduction in reduction power consumption.
[0040] Working principle:
[0041] The SiHCl3 and H2 mixed gas first enters the plasma reaction chamber 1, where it is efficiently ionized by radio frequency or microwave to generate active plasma. Subsequently, it is injected at high speed into the reduction furnace 3 via the plasma accelerator 2. The external microwave emission component maintains the plasma activity, and the bias source guides the ions to be deposited directionally on the surface of the silicon rod 4.
[0042] Based on the above embodiments, the plasma reaction chamber 1 includes a stainless steel outer shell shield 11; a high-purity quartz tube 12, which is disposed inside the stainless steel outer shell shield 11, with one end connected to the mixed gas pipeline and the other end connected to the inlet of the plasma accelerator 2; and an induction coil 13, which is sleeved on the outside of the high-purity quartz tube 12 and is electrically connected to a microwave power supply or a radio frequency power supply.
[0043] In other words, the stainless steel outer shell shield 11 is made of 316L stainless steel, which has good mechanical strength and radio frequency / microwave shielding performance.
[0044] A high-purity quartz tube 12 is coaxially mounted inside a stainless steel outer shell shield 11, forming a reaction channel for plasma generation. The quartz tube has a purity of not less than 99.999%, i.e., HPQ grade, and can withstand temperatures up to 1100℃ or higher. It has excellent dielectric properties and microwave / radio frequency permeability, and also has good resistance to strong corrosive gases such as hydrogen chloride and chlorine. One end of the quartz tube is connected to a mixed gas pipeline through a sealed interface to receive the premixed gas of SiHCl3 and H2; the other end is sealed to the inlet of the plasma accelerator 2 to directionally output the generated plasma gas.
[0045] The induction coil 13 is wound around the outer wall of the high-purity quartz tube 12 in a spiral or spiral-solenoid composite structure, with 5 to 20 turns and uniform spacing to ensure a uniform distribution of the electromagnetic field along the axial direction of the quartz tube. The induction coil 13 is electrically connected to an external radio frequency power supply or microwave power supply through an impedance matching network, such as an RF matching device. When a high-frequency current passes through the induction coil, an alternating electromagnetic field is generated inside the quartz tube, causing the current entering the chamber to... The mixed gas is broken down and ionized, forming a high-temperature non-equilibrium plasma with electron temperatures reaching [missing value]. The above, while the overall gas temperature remains at a low level, effectively breaks the Si–Cl bond energy of approximately 381 kJ / mol and the Si–H bond.
[0046] Based on the above embodiments, the inner wall of the high-purity quartz tube 12 is provided with a chlorine corrosion resistant coating, the thickness of which is greater than 50 μm; the chlorine corrosion resistant coating is a high-purity quartz coating or a stainless steel coating treated with Al2O3.
[0047] In some embodiments, the thickness of the chlorine corrosion resistant coating is greater than any value within a range of 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, or 100μm. The chlorine corrosion resistant coating forms a dense protective barrier, effectively resisting the erosion of active chloride ions in the plasma environment, thus extending the service life of the quartz tube under strong corrosion conditions. Secondly, the ultra-thick coating completely covers the micro-defects on the surface of the quartz substrate, eliminating the risk of metal impurities leaching out and ensuring that the purity of the polycrystalline silicon product consistently meets electronic grade standards.
[0048] High-purity quartz coating or Al2O3-coated stainless steel coating has excellent chemical inertness and interfacial compatibility, and can form a defect-free continuous protective layer to prevent corrosion of the inner wall of the high-purity quartz tube.
[0049] In some implementations, the power range of the microwave power supply or radio frequency power supply is any range of values from 100W, 500W, 1000W, 1500W, 2000W, 2500W, 3000W, 3500W, 4000W, 4500W, 5000W, 5500W, or 6000W, or any value within that range.
[0050] In some implementations, the energy density of the microwave or radio frequency power supply is >1W / cm².
[0051] In some implementations, the energy density of the microwave or radio frequency power supply is greater than any value within the range of 1W / cm², 1.5W / cm², 2W / cm², 2.5W / cm², 3W / cm², 3.5W / cm², 4W / cm², and 4.5W / cm².
[0052] In some embodiments, the electromagnetic field distribution uniformity error of the plasma reaction chamber is <5%.
[0053] In some implementations, the electromagnetic field distribution uniformity error of the plasma reaction chamber is within a range or any value within a range of any of the following values: <5%, <4.5%, <4%, <3.5%, <3%, <2.5%, <2%, <1.5%, <1%, or <0.5%.
[0054] Based on the above embodiments, the bias source is a DC bias source or an RF bias source. That is, the bias source is a switchable or optional DC bias source or an RF bias source, which is connected to each group of silicon rods 4 in the reduction furnace 3 to apply a controllable potential to the silicon rods during the vapor deposition process, thereby regulating the movement behavior of charged particles in the plasma and realizing directional accelerated deposition and interface quality optimization.
[0055] Based on the above embodiments, see Figure 2 The microwave transmitter assembly includes a first microwave transmitter 5, a second microwave transmitter 6, a third microwave transmitter 7, a fourth microwave transmitter 8, and a fifth microwave transmitter 9, which are respectively arranged on the top, upper left side, front side, rear side, and right side of the reduction furnace 3.
[0056] The first microwave transmitter 5 is located at the top center of the furnace cylinder of the reduction furnace 3, with its emission port facing the inside of the furnace cylinder of the reduction furnace 3, and its emission axis extending downward along the vertical axis of the furnace cylinder of the reduction furnace.
[0057] The second microwave transmitter 6 is located at the uppermost position on the left side wall of the reduction furnace 3, with its emission port facing the inside of the reduction furnace cylinder and its emission axis running horizontally through the reduction furnace cylinder.
[0058] The fourth microwave transmitter 8 is located on the rear side wall of the furnace cylinder of the reduction furnace 3, forming a height difference of 500mm-1000mm with the second microwave transmitter 6 in the vertical direction. Its emission port faces the inside of the furnace cylinder of the reduction furnace 3, and is spatially intersected with the emission port of the second microwave transmitter 6 at a 90-degree angle.
[0059] The third microwave transmitter 7 is located on the front side wall of the furnace cylinder of the reduction furnace 3, and forms a height difference of 500mm-1000mm with the fourth microwave transmitter 8 in the vertical direction. Its emission port faces the inside of the furnace cylinder of the reduction furnace 3.
[0060] The fifth microwave transmitter 9 is located on the right side wall of the furnace cylinder of the reduction furnace 3, forming a height difference of 500mm-1000mm with the third microwave transmitter 7 in the vertical direction. Its emission port faces the inside of the furnace cylinder of the reduction furnace 3, and is spatially distributed at a 90° angle to the emission port of the third microwave transmitter 7.
[0061] Achieving a three-dimensional uniform distribution of microwave energy within the reduction furnace 3: The top transmitter provides axial energy input, which, combined with four sets of transmitters arranged at 90° intervals on the side walls, maintains a gradient height difference of 500mm-1000mm in the vertical direction, forming a three-dimensional interlaced electromagnetic field network. Multi-angle microwave interference effectively eliminates energy dead zones, thus improving the uniformity of plasma excitation. Figure 3It can be seen that the 90° intersecting spatial arrangement combined with the height difference design achieves electromagnetic wave phase optimization, which greatly reduces the reflected power; and the small standard deviation of microwave intensity distribution in the furnace ensures the efficient maintenance of the plasma state of materials in the large-volume reaction zone.
[0062] Based on the above embodiments, the reduction furnace 3 is equipped with temperature sensors and pressure sensors. In other words, in order to monitor and regulate the internal environment of the reduction furnace 3, temperature sensors and pressure sensors are configured inside the reduction furnace 3, which helps to monitor process conditions in real time, optimize temperature and pressure parameters during the deposition process, and ensure production stability and product consistency.
[0063] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.
[0064] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.
Claims
1. A high-efficiency vapor deposition reaction system for polycrystalline silicon reduction, characterized in that, include: The plasma reaction chamber (1) has its inlet end connected to the mixed gas pipeline to receive the SiHCl3 and H2 mixed gas, so as to generate the SiHCl3 and H2 mixed gas into a plasma mixed gas. The plasma accelerator (2) is connected to the outlet end of the plasma reaction chamber (1) and is used to accelerate the plasma-state mixed gas and maintain its activity. The reduction furnace (3) is connected to the outlet end of the plasma accelerator (2). The reduction furnace (3) is provided with several silicon rods (4) for receiving the plasma mixed gas and performing a vapor deposition reaction. A microwave transmitter assembly is installed on the reduction furnace (3) for providing high-energy electromagnetic waves into the reduction furnace (3); The bias source and heating components are connected to the silicon rod (4).
2. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 1, characterized in that, The plasma reaction chamber (1) includes: Stainless steel housing shielding cover (11); A high-purity quartz tube (12) is installed inside the stainless steel outer shell shield (11), with one end connected to the mixed gas pipeline and the other end connected to the inlet of the plasma accelerator (2); An induction coil (13) is sleeved outside the high-purity quartz tube (12), and the induction coil (13) is electrically connected to a microwave power supply or a radio frequency power supply.
3. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 2, characterized in that, The inner wall of the high-purity quartz tube (12) is provided with a chlorine corrosion resistant coating, the thickness of which is greater than 50 μm.
4. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 3, characterized in that, The chlorine-resistant coating is a high-purity quartz coating or a stainless steel coating treated with Al2O3.
5. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 4, characterized in that, It also includes an RF matching unit connected between the induction coil (13) and the microwave power supply or the RF power supply.
6. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 5, characterized in that, The output power range of the microwave power supply or the radio frequency power supply is 100 W to 6000 W.
7. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 6, characterized in that, The energy density of the microwave power supply or the radio frequency power supply is greater than 1 W / cm².
8. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 1, characterized in that, The bias source is a DC bias source or an RF bias source.
9. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 1, characterized in that: The microwave transmitter assembly includes a first microwave transmitter (5), a second microwave transmitter (6), a third microwave transmitter (7), a fourth microwave transmitter (8), and a fifth microwave transmitter (9), which are respectively arranged on the top, upper left side, front side, rear side, and right side of the reduction furnace (3).
10. The high-efficiency vapor deposition reaction system for polycrystalline silicon reduction according to claim 1, characterized in that, The reduction furnace (3) is equipped with a temperature sensor and a pressure sensor.