A quartz furnace tube and a chemical vapor deposition apparatus including the same.

Abstract

This invention provides a quartz furnace tube, comprising: a tube body, including an inner wall and an outer wall; an adhesion layer disposed on the surface of the inner wall; an expansion layer disposed on the side of the adhesion layer away from the inner wall; and a buffer layer disposed on the side of the expansion layer away from the adhesion layer. The thermal expansion coefficients of the tube body, adhesion layer, expansion layer, and buffer layer increase sequentially, with the thickness of the expansion layer being greater than the thickness of the adhesion layer and also greater than the thickness of the buffer layer. This invention, by setting three layers with varying thermal expansion coefficients and thicknesses in a "thin-thick-thin" manner on the inner wall of the quartz furnace tube, not only ensures good bonding between the layers and with the tube body but also avoids stress concentration, thereby improving the stability and service life of the quartz furnace tube, while also ensuring that the composite layer structure is not excessively thick. This invention also provides a chemical vapor deposition apparatus including the aforementioned quartz furnace tube.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, and in particular to a quartz furnace tube. Background Technology

[0002] In the field of crystalline silicon solar cell manufacturing, low-pressure chemical vapor deposition (LPCVD) is the core process for preparing tunneling polycrystalline silicon oxide (PCO) and intrinsic polycrystalline silicon (IPS) films. This deposition process is typically performed in a quartz furnace tube for LPCVD. During the deposition process, PCO and IPS films are deposited not only on the surface of the cell wafer but also inevitably on the inner wall of the quartz furnace tube.

[0003] The coefficient of thermal expansion (CTE) of intrinsic polycrystalline silicon is 2.5×10⁻⁶ / ℃ (T=300K), while that of quartz is 0.5×10⁻⁶ / ℃ (T=300K). Due to the close contact between the two materials and the significant difference in their coefficients of thermal expansion, when the intrinsic polycrystalline silicon deposited on the inner wall of the quartz furnace tube reaches a certain thickness, even a slight change in the temperature inside the furnace tube or a slight external force will cause the quartz furnace tube to crack. This further leads to problems such as easy cracking and short service life of LPCVD quartz furnace tubes, which seriously restricts the stability of the equipment and production efficiency.

[0004] Currently, the lifespan of LPCVD quartz furnace tubes used in the photovoltaic field is typically less than 3 months, and the lifespan is not fixed, making regular maintenance or preventative replacement impossible. Frequent furnace tube breakage or replacement not only significantly increases the cost of spare parts for battery manufacturing equipment but also introduces production safety risks, such as process gas leaks and debris contamination.

[0005] Therefore, improving the stability and service life of LPCVD quartz furnace tubes has become a technical challenge that urgently needs to be solved in the photovoltaic manufacturing field. Utility Model Content

[0006] In view of this, the present invention provides a novel quartz furnace tube with improved stability and service life.

[0007] Specifically, according to a first aspect of the present invention, a quartz furnace tube is provided, comprising: a tube body, including an inner wall and an outer wall; an adhesion layer disposed on the surface of the inner wall; an expansion layer disposed on the side of the adhesion layer away from the inner wall; and a buffer layer disposed on the side of the expansion layer away from the adhesion layer; wherein the coefficients of thermal expansion of the tube body, the adhesion layer, the expansion layer and the buffer layer increase sequentially, and the thickness of the expansion layer is greater than the thickness of the adhesion layer and greater than the thickness of the buffer layer.

[0008] In this invention, by sequentially setting an adhesion layer, an expansion layer, and a buffer layer with progressively increasing coefficients of thermal expansion on the inner wall of the quartz furnace tube, the stress is gradually decomposed due to the reduced difference in the coefficients of thermal expansion between the layers. This results in a smooth transition of stress during temperature changes, effectively preventing stress concentration and stress mismatch caused by excessive differences in the coefficients of thermal expansion between the tube body and the layers in direct contact. This, in turn, prevents the quartz furnace tube from cracking and increases its stability and service life. Furthermore, the thickness of the three layers is set such that the thickness of the intermediate expansion layer is greater than the thickness of the adhesion layer and greater than the thickness of the buffer layer, i.e., in a "thin-thick-thin" form. The thinner adhesion layer can achieve good bonding with the quartz tube body, while the thicker expansion layer, as an intermediate transition layer, can coordinate the deformation difference between the adhesion layer and the buffer layer, absorb the expansion of the adhesion layer and the buffer layer, reduce stress, and the subsequent thinner buffer layer can achieve good bonding with the intermediate expansion layer and with subsequent deposited layers, such as polycrystalline silicon layers. This invention, by setting three layers with varying coefficients of thermal expansion and varying thicknesses in a "thin-thick-thin" manner on the inner wall of the quartz furnace tube, not only ensures good bonding between the layers and between the layers and the tube body, but also avoids stress concentration, thereby improving the stability and service life of the quartz furnace tube, while also ensuring that the composite layer structure is not too thick.

[0009] In some embodiments, the adhesion layer, expansion layer, and buffer layer each include one or more sublayers, wherein, in the case of multiple sublayers, the coefficients of thermal expansion of each of the multiple sublayers of the adhesion layer, expansion layer, and buffer layer increase sequentially in the direction from the inner wall to the central axis of the tube.

[0010] In some implementations, the porosity of the expansion layer is greater than that of the adhesion layer and also greater than that of the buffer layer.

[0011] In some implementations, the surface roughness of the buffer layer is less than that of the adhesion layer and less than that of the expansion layer.

[0012] In some implementations, the coefficient of thermal expansion of the adhesion layer is 0.8×10⁻⁶ / ℃-1.2×10⁻⁶ / ℃, the coefficient of thermal expansion of the expansion layer is 1.3×10⁻⁶ / ℃-2.0×10⁻⁶ / ℃, and the coefficient of thermal expansion of the buffer layer is 2.1×10⁻⁶ / ℃-2.5×10⁻⁶ / ℃.

[0013] In some implementations, the thickness of the adhesion layer is 10μm-90μm, the thickness of the expansion layer is 70μm-160μm, and the thickness of the buffer layer is 20μm-100μm.

[0014] In some implementations, the thickness of the expansion layer is at least 50% of the total thickness of the adhesion layer, expansion layer, and buffer layer.

[0015] In some implementations, the total thickness of the adhesion layer, expansion layer, and buffer layer is 100 μm to 350 μm.

[0016] In some implementations, the density of the adhesion layer is 2.5-3.2 g / cm3, the density of the expansion layer is 2.2-2.6 g / cm3, and the density of the buffer layer is 3.0-3.5 g / cm3.

[0017] In some implementations, the coefficient of thermal expansion of the buffer layer is smaller than that of the polysilicon layer.

[0018] In some embodiments, the material of the adhesion layer includes one or more of silicon-doped silicon dioxide, silicon-doped aluminum oxide, silicon-doped silicon nitride, and silicon-doped silicon carbide, wherein the silicon doping ratio is 5wt%-20wt%; the material of the expansion layer includes one or more of silicon-doped silicon nitride and silicon-doped silicon carbide, wherein the silicon doping ratio is 5wt%-25wt%; and the material of the buffer layer includes one or more of silicon-doped silicon nitride and silicon-doped silicon carbide, wherein the silicon doping ratio is 30wt%-70wt%.

[0019] According to a second aspect of the present invention, a chemical vapor deposition apparatus is provided, comprising the quartz furnace tube described in the first aspect of the present invention. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other implementation schemes can be obtained based on these drawings without creative effort.

[0021] Figure 1 A cross-sectional schematic diagram of a quartz furnace tube according to some embodiments of the present invention is shown.

[0022] Among them, 1-quartz furnace tube, 11-tube body, 111-outer wall, 112-inner wall, 12-attachment layer, 13-expansion layer, 14-buffer layer. Detailed Implementation

[0023] The present invention will now be clearly and completely described with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments that can be obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0024] The accompanying drawings show various structural schematic diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0025] It should be noted that the technical features of the various embodiments exemplified in the specification can be freely combined to form new solutions without conflict. In addition, each claim can be a separate implementation or the technical features in the various claims can be combined to form a new implementation.

[0026] In the context of this invention, when describing a layer / element as being "above" another layer / element, it means that the layer / element can be directly located on the other layer / element, or it can be indirectly located on the other layer / element; that is, there can be an intermediate layer / element between them. Furthermore, if in one orientation a lower layer / element is "above" another layer / element, then when the orientation is reversed, it can be considered that the lower layer / element is "below" the other layer / element.

[0027] Furthermore, the terms "first" and "second" are used for descriptive or distinguishing purposes only and should not be construed as indicating, explicitly or implicitly, the order or relative importance of the indicated technical features or the number of indicated technical features. Thus, a technical feature modified by the terms "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0028] In the description of this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that the specific features, structures, materials, or characteristics described in that embodiment or example can be included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] In this invention, the coefficient of thermal expansion (CTE) refers to the relative change in material length caused by a unit change in temperature, and its unit is ×10⁻⁶. 6 / °C (ppm / °C), which is measured by optical methods or dial gauge methods; thickness refers to the average thickness, which is obtained by taking the arithmetic mean of the thickness after measuring the thickness at multiple points (e.g., 3, 4, 5, 6 or more points) along the length direction; porosity refers to the ratio of the pore volume to the total volume of the material, usually expressed as a percentage or decimal, which is measured by water saturation methods or image analysis methods; surface roughness refers to the arithmetic mean roughness (Ra) of the surface roughness, which is measured by scanning electron microscopy; density refers to the apparent density, which is measured by a tap density meter.

[0030] As mentioned above, existing quartz furnace tubes suffer from problems such as easy breakage, poor stability, and short service life due to the intrinsic polycrystalline silicon deposited on the inner wall.

[0031] Therefore, this utility model provides a novel quartz furnace tube 1, which includes: a tube body 11, including an inner wall 112 and an outer wall 111; an adhesion layer 12, disposed on the surface of the inner wall 112; an expansion layer 13, disposed on the side of the adhesion layer 12 away from the inner wall 112; and a buffer layer 14, disposed on the side of the expansion layer 13 away from the adhesion layer 12; wherein, the coefficient of thermal expansion (CTE) of the tube body 11, the adhesion layer 12, the expansion layer 13 and the buffer layer 14 increases sequentially, and the thickness of the expansion layer 13 is greater than the thickness of the adhesion layer 12 and greater than the thickness of the buffer layer 14.

[0032] It is understood that in this invention, the purpose of sequentially providing an adhesion layer 12, an expansion layer 13, and a buffer layer 14 on the inner wall 112 of the quartz furnace tube 1 is to reduce the CTE difference between the material of the tube body 11 with a smaller coefficient of thermal expansion, such as fused silica, and the material of the subsequent deposited layer with a larger coefficient of thermal expansion, such as a polycrystalline silicon layer, which may be deposited on its inner wall 112, when performing a deposition process such as low-pressure chemical vapor deposition (LPCVD) in the quartz furnace tube 1. Therefore, the coefficient of thermal expansion of the adhesion layer 12 is greater than that of the material of the tube body 11, and the coefficient of thermal expansion of the buffer layer 14 is less than that of the subsequent deposited layer.

[0033] In this invention, by sequentially providing an adhesion layer 12, an expansion layer 13, and a buffer layer 14 with progressively increasing coefficients of thermal expansion on the inner wall 112 of the quartz furnace tube 1, the stress is gradually decomposed due to the reduced difference in the coefficients of thermal expansion between the layers. This results in a smooth transition of stress during temperature changes, effectively preventing stress concentration and thus avoiding stress mismatch caused by excessive differences in the coefficients of thermal expansion between the tube body 11 and the layers in direct contact. Consequently, the quartz furnace tube 1 is prevented from cracking, increasing its stability and service life. Furthermore, the thickness of the three layers is set such that the thickness of the intermediate expansion layer 13 is greater than the thickness of the attachment layer 12 and greater than the thickness of the buffer layer 14, i.e., in a "thin-thick-thin" form. The thinner attachment layer 12 can achieve good bonding with the quartz tube body 11, while the thicker expansion layer 13, as an intermediate transition layer, can coordinate the deformation difference between the attachment layer 12 and the buffer layer 14, absorb the expansion of the attachment layer 12 and the buffer layer 14, reduce stress, and the subsequent thinner buffer layer 14 can achieve good bonding with the intermediate expansion layer 13 and with subsequent deposited layers, such as polycrystalline silicon layers. This utility model, by setting three layers with a gradient of thermal expansion coefficients and a "thin-thick-thin" thickness on the inner wall 112 of the quartz furnace tube 1, not only ensures good bonding between the layers and with the tube body 11, but also avoids stress concentration, thereby improving the stability and service life of the quartz furnace tube 1, while also ensuring that the composite layer structure is not too thick.

[0034] In some embodiments, the porosity of the expansion layer 13 is greater than that of the adhesion layer 12 and also greater than that of the buffer layer 14. The porosity of the intermediate expansion layer 13 is designed to be maximum, allowing the elastic deformation of its relatively numerous pores to absorb volume changes caused by thermal expansion, thereby reducing stress due to the mismatch in thermal expansion coefficients between different layers. Simultaneously, the lower porosity of the adhesion layer 12 ensures a certain bonding strength with the tube body 11 and the expansion layer 13, while the lower porosity of the buffer layer 14 maintains the rigidity of the composite structure and disperses some stress.

[0035] In some embodiments, the surface roughness of the buffer layer 14 is less than that of the adhesion layer 12 and less than that of the expansion layer 13. Minimizing the surface roughness of the buffer layer 14 reduces gas adsorption and flow resistance, thereby improving the efficiency of vacuuming during deposition. Simultaneously, the relatively high surface roughness of the adhesion layer 12 and the expansion layer 13 helps to provide better surface adhesion for their respective expansion layers 13 and buffer layers 14, thereby increasing the interfacial bonding between adjacent layers and improving the stability and service life of the quartz furnace tube 1.

[0036] In some embodiments, the thickness of the expansion layer 13 is at least 50% of the total thickness of the adhesion layer 12, expansion layer 13, and buffer layer 14, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85%. The higher porosity of the expansion layer 13 results in a significantly lower elastic modulus than the adjacent adhesion layer 12 and buffer layer 14. Therefore, when the thickness percentage is ≥50%, this layer can absorb most of the thermal expansion strain of the entire composite structure through pore compression deformation, thereby reducing the residual stress transmitted to the adhesion layer 12 and buffer layer 14 and preventing peeling or cracking at the interface due to CTE mismatch.

[0037] In some embodiments, the total thickness of the adhesion layer 12, the expansion layer 13, and the buffer layer 14 is 100μm-350μm, for example, 100, 150, 200, 250, 300, and 350μm. Controlling the total thickness within the above range ensures the bonding strength between the layers and with the inner wall 112 of the tube body 11, while maximizing the release of interlayer stress and improving the stability and service life of the quartz furnace tube 1.

[0038] In this invention, the tube body 11 of the quartz furnace tube 1 is made of quartz, with a coefficient of thermal expansion of approximately 0.5 × 10⁻⁶. -6 / ℃ (T=300K). The tube body 11 of the quartz furnace tube 1 includes an outer wall 111, wherein the present invention improves the stability and service life of the quartz furnace tube 1 by designing a multi-layer composite structure on the inner wall 112.

[0039] In some embodiments, the surface roughness of the inner wall 112 of the tube body 11 is 0.8-5.6 μm, for example, 0.8, 0.9, 1.0, 1.2, 1.5, 1.8, 2.0, 2.3, 2.5, 2.7, 3.0, 3.3, 3.6, 3.8, 4.0, 4.3, 4.5, 4.8, 5.0, 5.2, 5.5, and 5.6 μm. Controlling the surface roughness of the inner wall 112 of the tube body 11 within the above range can provide better adhesion for the subsequently applied adhesion layer 12, allowing the adhesion layer 12 to better bond to the inner wall 112, thereby enhancing the stability and service life of the quartz furnace tube 1.

[0040] In this invention, the adhesion layer 12 is disposed on the surface of the inner wall 112, and is in direct contact with and bonded to the pipe body 11. The coefficient of thermal expansion of the adhesion layer 12 is greater than that of the pipe body 11. In some embodiments, the coefficient of thermal expansion of the adhesion layer 12 is 0.8×10⁻⁶ / ℃ to 1.2×10⁻⁶ / ℃, for example, 0.8×10⁻⁶ / ℃, 0.85×10⁻⁶ / ℃, 0.9×10⁻⁶ / ℃, 0.95×10⁻⁶ / ℃, 1×10⁻⁶ / ℃, 1.05×10⁻⁶ / ℃, 1.1×10⁻⁶ / ℃, 1.15×10⁻⁶ / ℃, 1.2×10⁻⁶ / ℃, or any value within a range of both.

[0041] In some implementations, the thickness of the adhesion layer 12 is 10μm-90μm, for example, 10, 20, 30, 40, 50, 60, 70, 80, or 90μm. If it is too thin, i.e., less than 10μm, it will result in insufficient interfacial bonding and an inability to effectively coordinate CTE differences, leading to thermal stress concentration and accelerating coating cracking. If it is too thick, i.e., greater than 90μm, it may lead to increased internal stress, causing coating cracking or peeling. Controlling the thickness within the above range can ensure the interlayer bonding strength and provide stress buffering, thereby improving the stability and service life of the quartz furnace tube 1.

[0042] In some embodiments, the porosity of the adhesion layer 12 is 3%-10%, for example 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. Such porosity ensures that the adhesion layer 12 can maintain a certain bonding strength with the pipe body 11 and the expansion layer 13, while dispersing a certain amount of stress.

[0043] In some embodiments, the density of the adhesion layer 12 is 2.5-3.2 g / cm³, for example, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2 g / cm³, or any value between the two. In this invention, density refers to apparent density. Controlling the density of the adhesion layer 12 within the above range ensures a certain bonding strength with the pipe body 11, while also providing stress buffering.

[0044] In some embodiments, the surface roughness Ra of the adhesion layer 12 is 1.3-2.3 μm, for example, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3 μm, or any value in between. Controlling the surface roughness of the adhesion layer 12 within the above range can provide a good adhesion surface for the subsequently applied expansion layer 13 and improve the interfacial bonding strength.

[0045] In some embodiments, the bonding force between the adhesion layer 12 and the expansion layer 13 is 30N-70N, for example, 30N, 35N, 40N, 45N, 50N, 55N, 60N, 65N, or 70N. This ensures a good bond between the two layers, prevents delamination, and improves the stability of the quartz furnace tube 1.

[0046] In some embodiments, the material of the adhesion layer 12 includes one or more of silicon-doped silicon dioxide, silicon-doped aluminum oxide, silicon-doped silicon nitride, and silicon-doped silicon carbide, wherein the silicon doping ratio is 5wt%-20wt%, for example, 5wt%, 10wt%, 15wt%, and 20wt%. By doping silicon and controlling different doping concentrations, adhesion layers 12 with different coefficients of thermal expansion can be obtained.

[0047] In some embodiments, the adhesion layer 12 comprises one or more sublayers, wherein, in the case of multiple sublayers, the coefficients of thermal expansion of the multiple sublayers of the adhesion layer 12 increase sequentially in the direction from the inner wall 112 to the central axis of the tube body 11. In some embodiments, the multiple sublayers increase sequentially in the range of 0.8 × 10⁻⁶ / ℃ to 1.2 × 10⁻⁶ / ℃. It is understood that the more sublayers the adhesion layer 12 has, the gentler the gradient change of the coefficient of thermal expansion, the higher the stress matching degree between the layers, the lower the risk of rupture of the quartz furnace tube 1 caused by the adhesion layer 12, and the longer the service life; however, the manufacturing cost is also higher.

[0048] In some embodiments, the adhesion layer 12 includes 2 to 10 sublayers, for example, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Controlling the number of sublayers to 2 to 10 layers can achieve an optimal balance between stress matching and manufacturing cost.

[0049] In this invention, the expansion layer 13 is disposed on the side of the attachment layer 12 away from the inner wall 112. It is in direct contact with and bonded to the attachment layer 12 and the subsequently disposed buffer layer 14. The thermal expansion coefficient of the expansion layer 13 is greater than that of the attachment layer 12 and less than that of the subsequently disposed buffer layer 14. In some embodiments, the thermal expansion coefficient of the expansion layer 13 is 1.3×10⁻⁶ / ℃ - 2.0×10⁻⁶ / ℃, for example, 1.3×10⁻⁶ / ℃, 1.4×10⁻⁶ / ℃, 1.5×10⁻⁶ / ℃, 1.6×10⁻⁶ / ℃, 1.7×10⁻⁶ / ℃, 1.8×10⁻⁶ / ℃, 1.9×10⁻⁶ / ℃, 2.0×10⁻⁶ / ℃, or any value in the range between the two.

[0050] In some embodiments, the thickness of the expansion layer 13 is 70μm-160μm, for example, 70, 80, 90, 100, 110, 120, 130, 140, 150, and 160μm. In this invention, the expansion layer 13 is the main layer that bears thermal expansion. Its thickness is designed within the above range so that the expansion layer 13 has sufficient volume to accommodate thermal expansion deformation (absorbing most of the strain through pore compression or elastic deformation of the material), thereby effectively reducing the residual stress transmitted to adjacent layers and significantly improving the thermal stress buffering capacity of the multilayer composite structure.

[0051] In some embodiments, the porosity of the expansion layer 13 is 10%-30%, for example 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, and 30%. Such porosity allows the intermediate expansion layer 13 to have greater elastic deformation, thereby absorbing more volume changes caused by thermal expansion and reducing stress caused by the mismatch of thermal expansion coefficients between different layers.

[0052] In some embodiments, the density of the expansion layer 13 is 2.2-2.6 g / cm³, for example, 2.2, 2.3, 2.4, 2.5, 2.6 g / cm³, or any value in between. Controlling the density of the expansion layer 13 within the above range allows it to fully exert its stress-buffering effect.

[0053] In some embodiments, the surface roughness Ra of the expansion layer 13 is 2.0 μm-5.6 μm, for example, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6 μm. Controlling the surface roughness of the expansion layer 13 within the above range provides a good adhesion surface for the subsequently applied buffer layer 14, improving interfacial bonding. In some embodiments, the bonding force between the expansion layer 13 and the buffer layer 14 is 30N-70N, for example 30N, 35N, 40N, 45N, 50N, 55N, 60N, 65N, or 70N.

[0054] In some embodiments, the material of the expansion layer 13 includes one or more of silicon-doped silicon nitride and silicon-doped silicon carbide, with a silicon doping ratio of 5wt%-25wt%, for example, 5wt%, 10wt%, 15wt%, 20wt%, and 25wt%. By doping silicon and controlling different doping concentrations, expansion layers 13 with different coefficients of thermal expansion can be obtained.

[0055] In some embodiments, the expansion layer 13 comprises one or more sublayers, wherein, in the case of multiple sublayers, the coefficients of thermal expansion of the multiple sublayers of the expansion layer 13 increase sequentially in the direction from the inner wall 112 to the central axis of the tube body 11. In some embodiments, the multiple sublayers increase sequentially in the range of 1.3 × 10⁻⁶ / ℃ to 2.0 × 10⁻⁶ / ℃. It is understood that the more sublayers the expansion layer 13 has, the gentler the gradient change of the coefficient of thermal expansion, the higher the stress matching degree between the layers, the lower the risk of rupture of the quartz furnace tube 1 caused by the expansion layer 13, and the longer the service life; however, the manufacturing cost is also higher.

[0056] In some embodiments, the expansion layer 13 includes 2 to 10 sublayers, for example, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Controlling the number of sublayers to 2 to 10 layers achieves an optimal balance between stress matching and fabrication cost.

[0057] In this invention, the buffer layer 14 is disposed on the side of the expansion layer 13 away from the attachment layer 12, and is in direct contact with and bonded to the expansion layer 13. The buffer layer 14 has a thermal expansion coefficient greater than that of the expansion layer 13 and less than that of subsequent layers disposed thereon. In some embodiments, the thermal expansion coefficient of the buffer layer 14 is 2.1×10⁻⁶ / ℃ to 2.5×10⁻⁶ / ℃, for example, 2.1×10⁻⁶, 2.2×10⁻⁶, 2.3×10⁻⁶, 2.4×10⁻⁶, 2.5×10⁻⁶, or any value in between.

[0058] As described above, the coefficient of thermal expansion of the buffer layer 14 is less than that of the subsequently deposited layers. In some embodiments, when the subsequently deposited layer is a polysilicon layer, the coefficient of thermal expansion of the buffer layer 14 is less than that of the polysilicon layer. In some embodiments, the polysilicon layer is intrinsic polysilicon with a coefficient of thermal expansion (CTE) of 2.5 × 10⁻⁶ / ℃ (T = 300 K).

[0059] In some embodiments, the thickness of the buffer layer 14 is 20 μm to 100 μm, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 μm, or any value in between. Controlling the thickness within the above range can ensure the bonding strength between layers, while also dispersing certain stresses and improving the stability and service life of the quartz furnace tube 1.

[0060] In some embodiments, the porosity of the buffer layer 14 is 3%-10%, for example 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. Such porosity allows the buffer layer 14 to maintain a certain bonding strength with the expansion layer 13 and the subsequently deposited layers, and provides a certain rigidity to the composite layer structure while dispersing certain stresses.

[0061] In some embodiments, the density of the buffer layer 14 is 3.0-3.5 g / cm³, for example, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 g / cm³, or any value in between. Controlling the density of the buffer layer 14 within the above range ensures a certain bonding strength with its adjacent layers and also disperses some thermal stress.

[0062] In some embodiments, the surface roughness Ra of the buffer layer 14 is 1.0 μm to 2.0 μm, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 μm, or any value in between. Controlling the surface roughness of the buffer layer 14 within the above range can provide a good adhesion surface for the subsequently deposited layers and improve the interfacial bonding.

[0063] In some embodiments, the bonding strength between the buffer layer 14 and the subsequently deposited layer, such as the polysilicon layer, is 30N-70N, for example, 30N, 35N, 40N, 45N, 50N, 55N, 60N, 65N, or 70N. This ensures good bonding between the two layers, avoids delamination, and improves the stability of the quartz furnace tube 1.

[0064] In some embodiments, the material of the buffer layer 14 includes one or more of silicon-doped silicon nitride and silicon-doped silicon carbide, with a silicon doping ratio of 30wt%-70wt%, for example 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt%, and 70wt%. By doping silicon and controlling different doping concentrations, buffer layers 14 with different coefficients of thermal expansion can be obtained.

[0065] In some embodiments, the buffer layer 14 comprises one or more sublayers, wherein, in the case of multiple sublayers, the coefficients of thermal expansion of each of the multiple sublayers of the buffer layer 14 increase sequentially in the direction from the inner wall 112 to the central axis of the tube body 11. In some embodiments, the multiple sublayers increase sequentially in the range of 2.1 × 10⁻⁶ / ℃ to 2.5 × 10⁻⁶ / ℃. It is understood that the more sublayers the buffer layer 14 has, the gentler the gradient change of the coefficient of thermal expansion, the higher the stress matching degree between the layers, the lower the risk of rupture of the quartz furnace tube 1 caused by the buffer layer 14, and the longer the service life; however, the manufacturing cost is also higher.

[0066] In some implementations, the buffer layer 14 includes 2 to 10 sublayers, for example, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Controlling the number of sublayers to 2 to 10 layers achieves an optimal balance between stress matching and fabrication cost.

[0067] In this invention, the metal impurity content of the adhesion layer 12, expansion layer 13, and buffer layer 14 is ≤50ppm. This strict limitation is mainly due to the fact that if the content of metal impurities (such as Fe, Cu, Ni, etc.) exceeds the limit during the high-temperature battery manufacturing process (such as sintering, annealing, etc.), these impurities may vaporize and migrate or precipitate at the interface at high temperatures, thereby forming recombination defect centers on the battery surface. Such defects will significantly increase the probability of carrier recombination and affect the photoelectric conversion efficiency of the battery. By controlling the impurity content to no more than 50ppm, the chemical stability of these three layers at higher process temperatures can be ensured, avoiding the adverse effects of impurity diffusion on battery performance.

[0068] The quartz furnace tube 1 provided by this utility model can be prepared by the following process, which includes the following steps:

[0069] S1: An adhesion layer 12 is prepared on the inner wall 112 of the tube body 11 of the quartz furnace tube 1, for example by coating processes such as chemical vapor deposition (CVD), chemical vapor infiltration (CVI), and atmospheric plasma spraying (ASP).

[0070] S2: An expansion layer 13 is prepared on the adhesion layer 12, for example by coating processes such as chemical vapor deposition (CVD), chemical vapor infiltration (CVI), and atmospheric plasma spraying (ASP);

[0071] S3: Prepare a buffer layer 14 on the expansion layer 13, for example by coating processes such as chemical vapor deposition (CVD), chemical vapor infiltration (CVI), atmospheric plasma spraying (ASP), etc., to obtain the quartz furnace tube 1 provided in the first aspect of this utility model.

[0072] Optionally, the above preparation method further includes roughening the inner wall 112 of the tube body 11 before preparing the adhesion layer 12, for example, by sandblasting roughening, so that the inner wall 112 has a certain roughness.

[0073] It is understood that the above-described processes for preparing the quartz furnace tube 1 are all conventional processes in the art. Those skilled in the art can select appropriate operating methods, such as cleaning methods or etching methods, at each step as needed. Furthermore, those skilled in the art can omit or add one or more steps in the above-described preparation process, or adjust the order of the steps, as needed. This utility model does not limit this.

[0074] Furthermore, the various features of the quartz furnace tube 1 provided in the first aspect of this utility model can be obtained through the above-described preparation process and can achieve the same technical effect, which will not be repeated here.

[0075] According to a second aspect of the present invention, a chemical vapor deposition apparatus is provided, comprising a quartz furnace tube 1 according to the first aspect of the present invention.

[0076] The beneficial effects of the second aspect of this utility model can be analyzed by referring to the beneficial effects of the first aspect of the utility model and its various embodiments, and will not be repeated here.

[0077] Example

[0078] Example 1

[0079] Preparation of quartz furnace tube 1:

[0080] The inner wall 112 of the tube body 11 is roughened by sandblasting: the surface of the inner wall 112 of the quartz furnace tube 1 is roughened by sandblasting with white corundum with a particle size of 250μm-280μm. The surface roughness Ra after sandblasting is 2.0μm.

[0081] Deposition of the adhesion layer 12: A silicon-doped silicon dioxide coating (silicon doping ratio of 15wt%) with a thermal expansion coefficient of 1.0×10-6 / ℃ is formed on the surface of the inner wall 112 of the roughened quartz furnace tube 1 using a chemical vapor infiltration (CVI) coating process as the adhesion layer 12. The thickness of this layer is 15μm, the porosity is 6%, the density is 2.7g / cm3, the adhesion force with the inner wall 112 is 55N, the surface roughness Ra is 2.0μm, and the metal impurity content is ≤15ppm.

[0082] Deposition of expansion layer 13: An atmospheric plasma spraying (ASP) coating process is used to form a silicon-doped silicon carbide coating (silicon doping ratio of 10wt%) with a thermal expansion coefficient of 1.8×10-6 / ℃ on the adhesion layer 12 as expansion layer 13. The thickness of this layer is 150μm, the porosity is 30%, the density is 2.5g / cm3, the adhesion force with the adhesion layer 12 is 45N, the surface roughness Ra is 4.6μm, and the metal impurity content is ≤20ppm.

[0083] Deposition of buffer layer 14: A silicon-doped silicon nitride coating (silicon doping ratio of 40wt%) with a thermal expansion coefficient of 2.4×10-6 / ℃ is formed on the expansion layer 13 using a chemical vapor deposition (CVD) coating process as buffer layer 14. The thickness of this layer is 60μm, the porosity is 3%, the density is 3.5g / cm3, the bonding force with the expansion layer 13 is 55N, the surface roughness Ra is 1.5μm, and the metal impurity content is ≤10ppm. According to the test, the service life of the quartz furnace tube 1 in Example 1 is about 6-7 months, and the vacuuming time is about 1-2h.

[0084] Example 2

[0085] Preparation of quartz furnace tube 1:

[0086] The inner wall 112 of the tube body 11 is roughened by sandblasting with quartz sand or garnet with a particle size of 200μm-250μm. The surface roughness Ra after sandblasting is 0.8μm.

[0087] Deposition of the adhesion layer 12: An atmospheric plasma spraying (ASP) coating process is used to form a silicon-doped aluminum oxide coating (silicon doping ratio of 5wt%) with a thermal expansion coefficient of 0.8×10-6 / ℃ on the surface of the inner wall 112 of the roughened quartz furnace tube as the adhesion layer 12. The thickness of this layer is 40μm, the porosity is 3%, the surface roughness Ra is 1.6μm, the density is 3.1g / cm3, and the metal impurity content is ≤10ppm.

[0088] The expansion layer 13 is deposited using an atmospheric plasma spraying (ASP) coating process. A silicon-doped silicon nitride coating with a thermal expansion coefficient of 1.3×10-6 / ℃ (silicon doping ratio of 5wt%-25wt%) is formed on the adhesion layer 12 as the expansion layer 13. The expansion layer has a thickness of 100μm, a porosity of 10%, a surface roughness Ra of 2.0μm, a density of 2.2g / cm3, and a metal impurity content of ≤15ppm.

[0089] Deposition of buffer layer 14: An atmospheric plasma spraying (ASP) coating process is used to form a silicon coating with a thermal expansion coefficient of 2.1×10-6 / ℃ on the expansion layer 13 as buffer layer 14. The thickness of this layer is 50μm, the porosity is 7.5%, the surface roughness Ra is 1.0μm, the density is 3.3g / cm3, and the metal impurity content is ≤10ppm. According to the test, the service life of the quartz furnace tube of Example 2 is about 6-7 months, and the vacuuming time is about 1-2h.

[0090] Example 3

[0091] Preparation of quartz furnace tube 1:

[0092] The difference from Example 1 is that the thickness of the adhesion layer 12 is 10 μm, the thickness of the expansion layer 13 is 70 μm, and the thickness of the buffer layer 14 is 20 μm. Testing showed that the service life of the quartz furnace tube in Example 3 is approximately 5 months, and the vacuuming time is approximately 1-2 hours.

[0093] Example 4

[0094] Preparation of quartz furnace tube 1:

[0095] The difference from Example 1 is that the thickness of the adhesion layer 12 is 90 μm, the thickness of the expansion layer 13 is 160 μm, and the thickness of the buffer layer 14 is 100 μm. Testing showed that the service life of the quartz furnace tube in Example 4 is approximately 6 months, and the vacuuming time is approximately 1-2 hours.

[0096] Example 5

[0097] The difference from Example 1 is that the coefficient of thermal expansion of the adhesion layer 12 is 1.2 × 10⁻⁶ / ℃, the coefficient of thermal expansion of the expansion layer 13 is 2.0 × 10⁻⁶ / ℃, and the coefficient of thermal expansion of the buffer layer 14 is 2.5 × 10⁻⁶ / ℃. Testing showed that the service life of the quartz furnace tube in Example 5 is approximately 6 months, and the vacuuming time is approximately 1-2 hours.

[0098] Comparative Example 1

[0099] The difference from Example 1 is that the thickness of the adhesion layer 12, the expansion layer 13 and the buffer layer 14 is the same, which is 40 μm.

[0100] Comparative Example 2

[0101] The difference from Example 1 is that the thickness of the adhesion layer 12, the expansion layer 13 and the buffer layer 14 is the same, which is 150 μm.

[0102] Comparative Example 3

[0103] The difference from Example 1 is that the porosity of the expansion layer 13 is the same as that of the attachment layer 12 and the buffer layer 14, which is 10%.

[0104] Tests showed that the service life of the quartz furnace tube in Comparative Example 1 was about 3-4 months, the service life of the quartz furnace tube in Comparative Example 2 was about 4 months, and the service life of the quartz furnace tube in Comparative Example 3 was about 3-4 months. The vacuuming time for all of them was about (1-2 hours).

[0105] Comparative Example 4

[0106] The difference from Example 1 is that the surface roughness of the adhesion layer 12 and the expansion layer 13 is the same as that of the buffer layer 14, which is 1.0 μm.

[0107] According to the test, the service life of the quartz furnace tube in Comparative Example 4 is 5-6 months, and the vacuuming time is about 3-4 hours.

[0108] The above description does not provide detailed explanations of the technical aspects of each layer's patterning and etching. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various implementation schemes have been described separately above, this does not mean that the measures in these implementation schemes cannot be advantageously combined.

Claims

1. A quartz furnace tube characterized by, include: Pipe body, including inner wall and outer wall; An adhesion layer is provided on the surface of the inner wall; An expansion layer is disposed on the side of the adhesion layer away from the inner wall; A buffer layer is disposed on the side of the expansion layer away from the adhesion layer; The coefficients of thermal expansion of the tube body, the attachment layer, the expansion layer, and the buffer layer increase sequentially, and the thickness of the expansion layer is greater than the thickness of the attachment layer and also greater than the thickness of the buffer layer.

2. The quartz furnace tube of claim 1, wherein The adhesion layer, the expansion layer, and the buffer layer each include one or more sublayers, wherein, when multiple sublayers are included, the coefficients of thermal expansion of each of the multiple sublayers of the adhesion layer, the expansion layer, and the buffer layer increase sequentially in the direction from the inner wall to the central axis of the tube.

3. The quartz furnace tube of claim 1, wherein The porosity of the expansion layer is greater than that of the adhesion layer and also greater than that of the buffer layer.

4. The quartz furnace tube of claim 1, wherein The surface roughness of the buffer layer is less than that of the adhesion layer and less than that of the expansion layer.

5. The quartz furnace tube of claim 1, wherein The coefficient of thermal expansion of the adhesion layer is 0.8×10⁻⁶ / ℃-1.2×10⁻⁶ / ℃, the coefficient of thermal expansion of the expansion layer is 1.3×10⁻⁶ / ℃-2.0×10⁻⁶ / ℃, and the coefficient of thermal expansion of the buffer layer is 2.1×10⁻⁶ / ℃-2.5×10⁻⁶ / ℃.

6. The quartz furnace tube of claim 1, wherein The thickness of the adhesion layer is 10μm-90μm, the thickness of the expansion layer is 70μm-160μm, and the thickness of the buffer layer is 20μm-100μm.

7. The quartz furnace tube of claim 1, wherein The thickness of the expansion layer is at least 50% of the total thickness of the adhesion layer, the expansion layer, and the buffer layer.

8. The quartz furnace tube of claim 1, wherein The total thickness of the adhesion layer, the expansion layer, and the buffer layer is 100μm-350μm.

9. The quartz furnace tube of claim 1 wherein, The density of the adhesion layer is 2.5-3.2 g / cm3, the density of the expansion layer is 2.2-2.6 g / cm3, and the density of the buffer layer is 3.0-3.5 g / cm3.

10. The quartz furnace tube of claim 1, wherein The coefficient of thermal expansion of the buffer layer is less than that of the polycrystalline silicon layer.

11. The quartz furnace tube of claim 1, wherein The material of the adhesion layer includes one or more of silicon-doped silicon dioxide, silicon-doped aluminum oxide, silicon-doped silicon nitride, and silicon-doped silicon carbide, wherein the proportion of silicon doping is 5wt%-20wt%. The expansion layer is made of one or more of silicon-doped silicon nitride and silicon-doped silicon carbide, with a silicon doping ratio of 5 wt% to 25 wt%; and The material of the buffer layer includes one or more of silicon-doped silicon nitride and silicon-doped silicon carbide, with the silicon doping ratio being 30wt%-70wt%.

12. A chemical vapor deposition apparatus characterized by comprising: Includes the quartz furnace tube according to any one of claims 1-11.

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