A method and apparatus for growing a CVD-SiC single crystal

Abstract

The application provides a CVD-SiC single crystal growth method and device. The method comprises the following steps: setting a seed crystal in a growth cavity, heating, and introducing carbon source gas, silicon source gas purified in a third reaction cavity and hydrogen, and growing CVD-SiC single crystal; introducing the tail gas of the growth cavity into a first reaction cavity for filtration and adsorption; introducing the adsorbed gas into a second reaction cavity, placing a silicon source supplementing material in the second reaction cavity, introducing HCl gas, and performing disproportionation reaction to generate silicon source gas and hydrogen; introducing the gas in the second reaction cavity into the third reaction cavity for separation and purification, introducing the purified high-purity silicon source gas and hydrogen into the growth cavity for CVD-SiC single crystal growth, and returning the separated gas to the second reaction cavity for reaction. The application also relates to a CVD-SiC single crystal growth device which applies the above CVD-SiC single crystal growth method. The application solves the technical problem of how to reduce the cost of CVD-SiC single crystal growth, improve resource utilization efficiency and reduce environmental pollution.

Description

Technical Field

[0001] This invention relates to the technical field of semiconductor material preparation, and in particular to a CVD-SiC single crystal growth method and apparatus. Background Technology

[0002] Silicon carbide (SiC), as a wide-bandgap semiconductor material, plays a crucial role in high-performance electronic devices, especially in applications under high-temperature, high-voltage, and high-frequency environments, due to its excellent thermal stability, superior electrical properties, and high electric field tolerance. Currently, the main methods for growing single-crystal SiC include the following three: high-temperature sublimation (PVT), liquid phase growth (LPE), and chemical vapor deposition (CVD).

[0003] Currently, vapor phase reaction deposition (CVD-SiC) is the most common method for preparing single-crystal SiC. CVD-SiC single-crystal growth typically occurs in a low-pressure hydrogen atmosphere, where silicon and carbon sources are introduced to grow single-crystal SiC on a substrate surface maintained at a high temperature. CVD-SiC single-crystal growth offers advantages such as faster growth rate, lower growth temperature, controllable single-crystal SiC thickness, and fewer crystal defects, enabling the production of high-quality crystals.

[0004] However, in actual production, silicon / chlorosilanes are expensive, require a continuous supply of high-purity gas during the reaction, and incomplete reactions result in unreacted silicon / chlorosilanes in the tail gas, making this method costly. Furthermore, the reaction tail gas contains some harmful gases, and inadequate treatment of the tail gas can damage the environment.

[0005] Therefore, how to reduce the cost of CVD-SiC single crystal growth, improve resource utilization efficiency, and reduce environmental pollution has become a pressing technical problem to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a CVD-SiC single crystal growth method and apparatus, which solves the technical problems of how to reduce the cost of CVD-SiC single crystal growth, improve resource utilization efficiency, and reduce environmental pollution.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows.

[0008] In a first aspect, the present invention provides a CVD-SiC single crystal growth method, the method comprising the following steps: placing a seed crystal at the top of a growth chamber, heating the growth chamber, and introducing carbon source gas, silicon source gas purified and refluxed from a third reaction chamber, and hydrogen gas to perform CVD-SiC single crystal growth; introducing the tail gas generated in the growth chamber into a first reaction chamber, and using the separation and adsorption material in the first reaction chamber to filter and adsorb impurities in the tail gas; introducing the gas filtered and adsorbed in the first reaction chamber into a second reaction chamber, placing high-purity Si particles in the second reaction chamber as a silicon source supplement material, and introducing HCl gas to cause the filtered and adsorbed gas to undergo a disproportionation reaction with the silicon source material to generate silicon source gas and hydrogen gas required for CVD-SiC single crystal growth; introducing the gas after the reaction in the second reaction chamber into a third reaction chamber for separation and purification, inputting the purified high-purity silicon source gas and hydrogen gas into the growth chamber for continued CVD-SiC single crystal growth, and returning the separated gas to the second reaction chamber for further reaction.

[0009] Furthermore, the carbon source gas is methane.

[0010] Furthermore, the silicon source gas is silane and chlorosilane gas.

[0011] Furthermore, high-purity Si particles are placed in the second reaction chamber as a silicon source supplement material.

[0012] Furthermore, the separation and adsorption material employs multi-stage activated carbon material for multi-stage filtration and adsorption.

[0013] Furthermore, the multi-stage activated carbon material sequentially comprises an activated carbon layer that has undergone activation treatment, a nitrogen-rich functional group activated carbon layer, and another activated carbon layer that has undergone activation treatment.

[0014] Furthermore, the separation and purification are carried out using distillation purification.

[0015] Secondly, the present invention also provides a CVD-SiC single crystal growth apparatus, applying the CVD-SiC single crystal growth method described in any one of the above claims. The apparatus includes a basic growth mechanism, a first reaction mechanism, a second reaction mechanism, and a third reaction mechanism. The basic growth mechanism includes a growth chamber with a carbon source replenishment path, a silicon source replenishment path, a tail gas outlet, and a seed crystal, and a heating coil disposed outside the growth chamber. The first reaction mechanism includes a first reaction chamber, a first chamber inlet connected to the tail gas outlet, a separation and adsorption material disposed within the chamber, and a first chamber outlet. The second reaction mechanism includes a second reaction chamber, a second chamber inlet connected to the first chamber outlet, a silicon source replenishment material disposed within the chamber, an HCl gas inlet, a recovery gas inlet, and a second chamber outlet. The third reaction mechanism includes a third reaction chamber, a third chamber inlet connected to the second chamber outlet, a recovery gas outlet connected to the recovery gas inlet, a third chamber outlet connected to the silicon source replenishment path, and a distillation heating device acting on the third reaction chamber.

[0016] Furthermore, the separation and adsorption material adopts multi-stage activated carbon material for graded filtration and adsorption, wherein the multi-stage activated carbon material sequentially adopts an activated carbon layer with activated treatment, a nitrogen-rich functional group activated carbon layer, and an activated carbon layer with activated treatment.

[0017] Furthermore, the basic growth mechanism also includes a heat insulation layer structure disposed outside the growth cavity and the heating coil for heat preservation during heating.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects.

[0019] This invention enables the recycling of silicon / chlorosilane gas by incorporating efficient and simple filtration, reaction, and purification / regeneration processes in an external cavity, eliminating the need for external replenishment of expensive silicon / chlorosilane and reducing raw material costs. Furthermore, only a single alkane gas needs to be introduced into the growth chamber to achieve high-quality CVD-SiC crystal growth.

[0020] The exhaust gas generated in the growth chamber of this invention is filtered and adsorbed in the first reaction chamber, reacted in the second reaction chamber to generate silicon / chlorosilane gas, and purified by distillation in the third reaction chamber. The high-purity silicon / chlorosilane gas and hydrogen are then returned to the growth chamber for continued use. The separated unreacted substances and products can also be returned to the second reaction chamber for further reaction, thus realizing the full recovery and effective utilization of process exhaust gas and improving resource utilization efficiency.

[0021] In this invention, impurities in the exhaust gas are adsorbed by an adsorption material in the first reaction chamber, and the effective components are recovered and reused. This reduces the emission of unreacted gases and harmful gases in the reaction products, and solves the problem of environmental pollution caused by improper exhaust gas treatment in traditional methods. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the CVD-SiC single crystal growth apparatus provided in this embodiment.

[0024] Figure 2 This is a schematic diagram of the basic growth mechanism provided in this embodiment.

[0025] Figure 3 This is a schematic diagram of the first reaction mechanism provided in this embodiment.

[0026] Figure 4 This is a schematic diagram of the second reaction mechanism provided in this embodiment.

[0027] Figure 5 This is a schematic diagram of the third reaction mechanism provided in this embodiment.

[0028] icon:

[0029] 1-Insulation layer structure; 2-Heating coil; 3-Growth chamber; 4-Seed crystal; 5-Carbon source replenishment path; 6-Silicon source replenishment path; 7-Exhaust gas outlet; 8-First reaction chamber; 9-Adsorbent material; 10-First chamber inlet; 11-First chamber outlet; 12-Second reaction chamber; 13-Silicon source replenishment material; 14-HCl gas inlet; 15-Second chamber inlet; 16-Second chamber outlet; 17-Recovery gas inlet; 18-Third reaction chamber; 19-Third chamber inlet; 20-Recovery gas outlet; 21-Third chamber outlet. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0033] This embodiment provides a CVD-SiC single crystal growth method. Please refer to [link / reference]. Figure 1-5 As shown, the method includes the following steps.

[0034] Seed crystal 4 is placed at the top of the growth chamber 3. The growth chamber 3 is heated and a single carbon source gas (such as methane) and a silicon source gas (such as silicon / chlorosilane) purified from the third reaction chamber 18 and hydrogen are introduced to carry out CVD-SiC single crystal growth.

[0035] The exhaust gas generated in the growth chamber 3 is introduced into the first reaction chamber 8, and the impurities in the exhaust gas are filtered and adsorbed by the multi-stage activated carbon material in the first reaction chamber 8.

[0036] The gas filtered and adsorbed in the first reaction chamber 8 is introduced into the second reaction chamber 12. High-purity Si particles are placed in the second reaction chamber 12 as silicon source supplement material 13, and HCl gas is introduced to cause the filtered and adsorbed gas to undergo a disproportionation reaction with the Si silicon source material to generate silicon source gas and hydrogen required for CVD-SiC single crystal growth.

[0037] The gas produced after the reaction in the second reaction chamber 12 is passed into the third reaction chamber 18 for distillation and purification. The purified high-purity silicon source gas and hydrogen are then fed into the growth chamber 3 for further CVD-SiC single crystal growth. The separated gases (products, unreacted substances such as hydrogen chloride (HCl) and chlorosilanes (SiH)) are then separated. m Cl n (etc.) Return to the second reaction chamber 12 for further reaction.

[0038] This embodiment also provides a growth apparatus that applies the above-described CVD-SiC single crystal growth method. Please refer to [link / reference]. Figure 1-5 As shown, the device specifically relates to the following.

[0039] 1. Specific implementation of basic growth mechanisms and reaction steps.

[0040] The basic growth structure includes an insulation layer structure 1, a heating coil 2, a growth chamber 3 (crucible body), a seed crystal 4, a carbon source (such as methane) replenishment path 5, a silicon source (such as silicon / chlorosilane) replenishment path 6, and an exhaust gas outlet 7.

[0041] The growth chamber 3 primarily facilitates CVD-SiC single crystal growth through the reaction of alkanes with silicon / chlorosilanes. The growth apparatus prepares high-purity SiC single crystals by vapor-phase deposition of carbon (methane) and silicon (silicon / chlorosilane) sources onto the seed crystal surface. The specific reactions are as follows.

[0042] SiH4 + CH4 → SiC + H 2； SiCl4 + CH4 → SiC + HCl.

[0043] The gases emitted from tail gas outlet 7 after the reaction are completed mainly include: unreacted methane (CH4), silicon / chlorosilane gas (SiH4 / SiCl4), hydrogen (H2), hydrogen chloride (HCl), and chlorosilane (SiH2). m Cl n ), light hydrocarbons with more than two carbons (C 2+ It contains fine particles such as carbon monoxide (CO), carbon dioxide (CO2), water (H2O), silicon dioxide (SiO2), and trace amounts of Si powder / clusters or carbon powder (C).

[0044] 2. The specific implementation of the first reaction mechanism and reaction steps.

[0045] The first reaction mechanism includes a first reaction chamber 8, an adsorbent material 9, a first chamber inlet 10 (connected to the exhaust gas outlet 7), and a first chamber outlet 11.

[0046] The primary reaction chamber 8 is used for filtering impurity gases. The adsorbent material 9 consists of three different types of activated carbon, capable of adsorbing various impurity gases in stages. First, the gases pass through an activated carbon layer (pore size <1 nm, specific surface area up to 800-1000 m²). 2 / g), for methane (CH4), light hydrocarbons with more than two carbons (C2 and above) 2+ The process involves strong adsorption of fine particles such as silicon dioxide (SiO2) and trace amounts of Si powder / clusters or carbon powder (C), followed by strong adsorption of carbon monoxide (CO) and carbon dioxide (CO2) by nitrogen-rich functional group activated carbon (Xu Yingjie, Zhang Jing, Wang Dongdong, et al. Preparation of nitrogen-rich functional group activated carbon and its CO2 adsorption performance. Journal of Engineering Thermophysics, (5) 2023, 1405-1412.). Finally, the activated carbon layer is re-activated to strongly adsorb residual impurity gases, with a gas adsorption rate of up to 99.999%. The remaining gases are silicon / chlorosilane gas (SiH4 / SiCl4), hydrogen (H2), hydrogen chloride (HCl), and chlorosilane (SiH2). mCl n It enters the second reaction chamber 12.

[0047] 3. The specific implementation of the second reaction mechanism and reaction steps.

[0048] The second reaction mechanism includes a second reaction chamber 12, a silicon source supplement material 13, an HCl gas inlet 14, a second chamber inlet 15 (connected to the first chamber outlet 11), a second chamber outlet 16, and a (distillation) recovery gas inlet 17.

[0049] The second reaction chamber 12 is mainly used for the production of silicon / chlorosilane gas. High-purity Si particles are placed in the reaction chamber to replenish the Si element for the disproportionation reaction, and HCl gas is introduced at the same time to ensure the continuous progress of the reaction. The specific reaction is as follows.

[0050] Si+HCl→SiHCl3+SiCl4+SiH2Cl2+H 2； SiCl4 + H2 + Si → SiHCl 3。

[0051] SiHCl3→SiCl4+SiH2Cl 2； SiH₂Cl₂→SiHCl₃+SiH 4。

[0052] The exhaust gases after the reaction mainly include high-concentration silicon / chlorosilane gases (SiH4 / SiCl4), hydrogen (H2), hydrogen chloride (HCl), and chlorosilanes (SiH2). m Cl n ).

[0053] 4. The specific implementation of the third reaction mechanism and reaction steps.

[0054] The third reaction mechanism includes a third reaction chamber 18, a third chamber inlet 19 (connected to the second chamber outlet 16), a recovery gas outlet 20 (connected to the recovery gas inlet 17), and a third chamber outlet 21 (connected to the silicon source replenishment path 6).

[0055] The third reaction chamber 18 primarily involves the distillation and separation of silicon / chlorosilane gases. After distillation and gas recovery, high-purity silicon / chlorosilane gases (SiH4 / SiCl4) and hydrogen (H2) are obtained, which are then returned to the growth chamber 3 for further crystal growth. The separated products, unreacted hydrogen chloride (HCl), and chlorosilanes (SiH4 / SiCl4) are further separated. m Cl n The contents can be recycled to the second reaction chamber 12 for further reaction.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A CVD-SiC single crystal growth method, characterized in that, The method includes the following steps: A seed crystal is placed at the top of the growth chamber, the growth chamber is heated, and carbon source gas, as well as silicon source gas and hydrogen gas purified and refluxed from the third reaction chamber, are introduced to carry out CVD-SiC single crystal growth. The exhaust gas generated in the growth chamber is introduced into the first reaction chamber, and the impurities in the exhaust gas are filtered and adsorbed by the separation and adsorption material in the first reaction chamber. The separation and adsorption material adopts multi-stage activated carbon material for multi-stage filtration and adsorption. The multi-stage activated carbon material consists of an activated carbon layer with activation treatment, a nitrogen-rich functional group activated carbon layer, and an activated carbon layer with activation treatment in sequence. The gas filtered and adsorbed in the first reaction chamber is introduced into the second reaction chamber. High-purity Si particles are placed in the second reaction chamber as silicon source supplement material, and HCl gas is introduced to cause the filtered and adsorbed gas to undergo a disproportionation reaction with the silicon source supplement material to generate silicon source gas and hydrogen required for CVD-SiC single crystal growth. The gas produced after the reaction in the second reaction chamber is passed into the third reaction chamber for separation and purification. The purified high-purity silicon source gas and hydrogen are then fed into the growth chamber for further CVD-SiC single crystal growth. The separated gas, including unreacted hydrogen chloride and chlorosilane, is returned to the second reaction chamber for further reaction.

2. The CVD-SiC single crystal growth method according to claim 1, characterized in that, The carbon source gas is methane.

3. The CVD-SiC single crystal growth method according to claim 1, characterized in that, The silicon source gas is silane and chlorosilane gas.

4. The CVD-SiC single crystal growth method according to claim 1, characterized in that, The separation and purification process employs distillation.

5. A CVD-SiC single crystal growth apparatus, employing the CVD-SiC single crystal growth method according to any one of claims 1-4, characterized in that, The device includes a basic growth mechanism, a first reaction mechanism, a second reaction mechanism, and a third reaction mechanism; The basic growth mechanism includes a growth cavity with a carbon source replenishment path, a silicon source replenishment path, an exhaust gas outlet path and a seed crystal, as well as a heating coil disposed outside the growth cavity. The first reaction mechanism includes a first reaction chamber, a first chamber inlet connected to the exhaust gas outlet, a separation and adsorption material disposed in the chamber, and a first chamber outlet; The separation and adsorption material adopts a multi-stage activated carbon material for graded filtration and adsorption. The multi-stage activated carbon material consists of an activated carbon layer that has undergone activation treatment, a nitrogen-rich functional group activated carbon layer, and an activated carbon layer that has undergone activation treatment in sequence. The second reaction mechanism includes a second reaction chamber, a second chamber inlet connected to the outlet of the first chamber, a silicon source replenishment material disposed in the chamber, an HCl gas inlet, a recovery gas inlet, and a second chamber outlet; The third reaction mechanism includes a third reaction chamber, a third chamber inlet connected to the outlet of the second chamber, a recovery gas outlet connected to the recovery gas inlet, a third chamber outlet connected to the silicon source replenishment path, and a distillation heating device acting on the third reaction chamber.

6. The CVD-SiC single crystal growth apparatus according to claim 5, characterized in that, The basic growth mechanism also includes a heat insulation layer structure disposed outside the growth cavity and the heating coil for heat preservation during heating.

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