Crucible and manufacturing method thereof

Abstract

The invention relates to the technical field of crystalline silicon manufacturing, and provides a crucible and a manufacturing method thereof, which are at least beneficial to improving the quality of a monocrystalline silicon ingot and prolonging the service life of the crucible. The crucible comprises an inner base material layer, materials of the inner base material layer comprise yttrium oxide, zirconium oxide and silicon oxide, the inner base material layer comprises a surface functional layer, a transition layer and a matrix binding layer which are sequentially arranged in a stacked mode from inside to outside, and the mass ratio of the yttrium oxide in the surface functional layer, the transition layer and the matrix binding layer is gradually reduced; the mass ratio of the zirconium oxide in the surface functional layer, the transition layer and the matrix bonding layer is gradually increased; the outer base material layer is located on the outer side of the inner base material layer, materials of the outer base material layer comprise zirconium oxide, aluminum oxide and silicon oxide, and the mass ratio of the silicon oxide in the outer base material layer is larger than that of the silicon oxide in the inner base material layer.

Description

Technical Field

[0001] The present application relates to the technical field of crystalline silicon manufacturing, and in particular to a crucible and a method for manufacturing the same. Background Art

[0002] Crystalline silicon, the starting material for most processes used to manufacture many electronic components, such as semiconductor devices and solar cells, is typically produced via batch Czochralski (CZ) or continuous Czochralski (CCZ) processes. These processes typically involve loading a solid feedstock material, such as polycrystalline silicon, into a quartz crucible, heating and melting it, bringing a single seed crystal into contact with the molten silicon, and slowly extracting it to form a single crystal ingot.

[0003] In the current process of manufacturing single crystal silicon ingots, polycrystalline silicon is typically melted in a quartz crucible. Due to the high melting point of polycrystalline silicon, the quartz crucible must be heated to a sufficiently high temperature and maintained for a sufficiently long time to produce a silicon melt. However, at high temperatures, the quartz crucible tends to transform into silicon dioxide crystals (cristobalite). This process is called recrystallization, also known as "devitrification."

[0004] Severe crystallization significantly impacts the manufacturing process of single-crystal silicon ingots. Crystallization can damage the inner wall of a quartz crucible, causing the bubble layer to react with the silicon melt, leading to the ingress of granular silicon oxide into the melt. This can distort the growing crystal structure and prevent normal crystal growth. Crystallization also reduces the original thickness of the quartz crucible, weakening its strength and potentially causing deformation, shortening its service life.

[0005] Therefore, there is a need to improve the crucible to improve the quality of single crystal silicon ingots and increase the service life of the crucible. Summary of the Invention

[0006] The embodiments of the present application provide a crucible and a method for manufacturing the same, which are at least beneficial for improving the quality of single crystal silicon ingots while increasing the service life of the crucible.

[0007] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a crucible, comprising: an inner substrate layer, the material of the inner substrate layer comprising yttrium oxide, zirconium oxide and silicon oxide, the inner substrate layer comprising a surface functional layer, a transition layer and a matrix bonding layer stacked in sequence from the inside to the outside, the mass proportion of yttrium oxide in the surface functional layer, the transition layer and the matrix bonding layer gradually decreases, and the mass proportion of zirconium oxide in the surface functional layer, the transition layer and the matrix bonding layer gradually increases; an outer substrate layer, the outer substrate layer is located on the outside of the inner substrate layer, the material of the outer substrate layer comprises zirconium oxide, aluminum oxide and silicon oxide, the mass proportion of silicon oxide in the outer substrate layer is greater than the mass proportion of silicon oxide in the inner substrate layer.

[0008] In some embodiments, in the inner substrate layer, the mass proportions of yttrium oxide, zirconium oxide, and silicon oxide are 5 wt % to 20 wt %, 30 wt % to 60 wt %, and 20 wt % to 65 wt %, respectively.

[0009] In some embodiments, in the inner substrate layer, the total weight of yttria and zirconium oxide accounts for more than 40 wt %.

[0010] In some embodiments, the surface functional layer includes 85wt% to 92wt% of yttrium oxide, 2wt% to 8wt% of zirconium oxide and 2wt% to 8wt% of silicon oxide in a mass ratio; the transition layer includes 30wt% to 50wt% of yttrium oxide, 30wt% to 40wt% of zirconium oxide and 10wt% to 25wt% of silicon oxide in a mass ratio; and the substrate bonding layer includes 0wt% to 5wt% of yttrium oxide, 50wt% to 70wt% of zirconium oxide and 30wt% to 40wt% of silicon oxide in a mass ratio.

[0011] In some embodiments, in the outer substrate layer, the mass proportions of zirconium oxide, aluminum oxide, and silicon oxide are 3 wt% to 15 wt%, 2 wt% to 10 wt%, and 75 wt% to 95 wt%, respectively.

[0012] In some embodiments, the outer substrate layer includes multiple sub-outer substrate layers, and in the direction of diffusion from the inner substrate layer to the outer substrate layer, the mass proportions of zirconium oxide and aluminum oxide in the sub-outer substrate layers increase successively in each sub-outer substrate layer.

[0013] In some embodiments, in the sub-outer substrate layer closest to the inner substrate layer, the mass proportion of zirconium oxide is greater than or equal to 5wt%, and the mass proportion of aluminum oxide is greater than or equal to 3wt%; in the sub-outer substrate layer farthest from the inner substrate layer, the mass proportion of zirconium oxide is greater than or equal to 5wt%, and the mass proportion of aluminum oxide is less than or equal to 8wt%.

[0014] In some embodiments, the method further includes: an intermediate layer located between the inner substrate layer and the outer substrate layer, wherein the material of the intermediate layer includes nano zirconium silicate, mullite whiskers, yttria-zirconia sol and β-quartz glass powder.

[0015] In some embodiments, the mass proportions of nano zirconium silicate, mullite whiskers, yttria-zirconia sol, and β-quartz glass powder are 40wt% to 65wt%, 15wt% to 30wt%, 10wt% to 25wt%, and 5wt% to 15wt%, respectively.

[0016] According to some embodiments of the present application, on the other hand, the embodiments of the present application also provide a method for manufacturing a crucible, including: providing a crucible mold; forming an initial outer substrate layer in the crucible mold by centrifugal deposition, the material of the initial outer substrate layer including zirconium oxide, aluminum oxide and silicon oxide; forming an initial inner substrate layer on the inner side of the initial outer substrate layer, the material of the initial inner substrate layer including yttrium oxide, zirconium oxide and silicon oxide, the initial inner substrate layer including a surface functional layer, a transition layer and a matrix bonding layer stacked in sequence from the inside to the outside, the mass proportion of yttrium oxide in the surface functional layer, the transition layer and the matrix bonding layer gradually decreases, the mass proportion of zirconium oxide in the surface functional layer, the transition layer and the matrix bonding layer gradually increases, and the mass proportion of silicon oxide in the initial outer substrate layer is greater than the mass proportion of silicon oxide in the initial inner substrate layer; performing a gradient sintering process on the initial outer substrate layer and the initial inner substrate layer to convert the initial outer substrate layer into a substrate layer, and to convert the initial inner substrate layer into an inner substrate layer; performing hot isostatic pressing densification treatment on the inner substrate layer and the outer substrate layer; and obtaining a crucible consisting of an inner substrate layer and an outer substrate layer without damage after testing.

[0017] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0018] The crucible provided in the embodiment of the present application includes an inner substrate layer and an outer substrate layer, and the inner substrate layer includes a surface functional layer, a transition layer, and a matrix bonding layer stacked in sequence from the inside to the outside. The surface functional layer contains a relatively high mass fraction of yttrium oxide. As the first layer in direct contact with the molten silicon, the surface functional layer can reduce the risk of melt contamination by utilizing the good chemical inertness of yttrium oxide, while also preventing the melt from corroding the crucible. The yttrium oxide content in the transition layer is reduced and the zirconium oxide content is increased to achieve a gradient transition. Due to the difference in thermal expansion coefficients between yttrium oxide and zirconium oxide, if they are in direct contact at high temperatures or during cooling, large thermal stress will be generated at the interface, leading to cracking or peeling. The gradient transition causes the thermal expansion coefficient to change gradually, effectively dispersing and buffering thermal stress, enhancing interlayer bonding, and preventing the surface functional layer from contacting the matrix. The problem of delamination failure occurs between the body bonding layers; the higher content of zirconia in the base bonding layer has good strength, toughness and thermal shock resistance, and the higher zirconia content makes it closer in composition to the outer substrate layer containing zirconia, which is conducive to achieving a strong bond between the inner substrate layer and the outer substrate layer; the alumina in the outer substrate layer has high hardness, high melting point and good chemical stability, and the cost is relatively low. During the sintering process, the higher content of silicon oxide molten phase can effectively wet and bond zirconia and alumina, enhance the bonding strength within the layer, and provide a solid backing for the inner substrate layer to withstand the weight of the crucible and the static pressure of the melt. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present application or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the structure of a quartz crucible in the related art;

[0021] Figure 2 A schematic diagram of the structure of the crucible provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] As known from the background art, when a quartz crucible is heated to a high temperature and kept for a long time, crystallization problem may occur.

[0023] Figure 1 Schematic diagram of the structure of a quartz crucible in the related art.

[0024] refer to Figure 1 Currently, commonly used quartz crucibles generally have an inner and outer layer structure: an inner, transparent layer 101 (high-purity silicon dioxide) with fewer bubbles, and an outer, non-transparent layer 102 (graphite or polycrystalline alumina) with more bubbles. The inner wall of transparent layer 101, away from non-transparent layer 102, has a coating 103 (silicon nitride, aluminum oxide, or calcium oxide). Non-transparent layer 102 uniformly radiates the heat source provided by the heater, transparent layer 101 reduces bubble density in the area in contact with the melt, and coating 103 prevents chemical reactions in the quartz crucible, thereby improving the success rate of single crystal growth and the quality of the crystal ingot.

[0025] Crystallization in a quartz crucible occurs when the quartz in the transparent layer 101 undergoes a phase transition, from glass to cristobalite, destroying its original structure and the coating 103 on the crucible's inner wall. Alternatively, it can cause the non-transparent layer 102 to react with molten silicon, causing some granular silicon oxide to enter the molten silicon and flow to the crystal growth front, which can easily lead to the loss of the single crystal structure of the silicon single crystal, commonly known as crystal growth breakage. Crystallization also reduces the original thickness of the quartz crucible, weakening its strength and causing changes in its structure, morphology, and density, leading to fragmentation and mechanical failure.

[0026] An embodiment of the present application provides a crucible and a method for manufacturing the same. The crucible includes an inner substrate layer and an outer substrate layer. The inner substrate layer includes a surface functional layer, a transition layer, and a base bonding layer stacked sequentially from the inside to the outside. The surface functional layer can reduce the risk of melt contamination while also preventing melt erosion of the crucible; the transition layer can prevent delamination failure between the surface functional layer and the base bonding layer; the base bonding layer facilitates a strong bond between the inner substrate layer and the outer substrate layer; and the outer substrate layer provides a solid backing for the inner substrate layer, bearing the crucible's own weight and the melt's static pressure. The special design of the inner and outer substrate layers can not only prevent melt contamination but also increase the service life of the crucible.

[0027] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0028] In the description of the embodiments of the present application, “multiple” means more than two, unless otherwise clearly and specifically defined.

[0029] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] In the description of the embodiments of the present application, technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the embodiments of the present application.

[0031] In the description of the embodiments of the present application, when a component “includes” another component, unless otherwise stated, other components are not excluded, and other components may be further included.

[0032] The terms used in the description of the various embodiments described herein are for describing specific embodiments only and are not intended to be limiting. As used in the description of the various embodiments described and the appended claims, "components" are also intended to include plural forms unless the context clearly indicates otherwise.

[0033] The embodiments of the present application will be described in detail below with reference to the drawings. However, those skilled in the art can understand that, in the embodiments of the present application, many technical details are presented in order to enable the reader to better understand the present application. However, the technical solutions claimed by the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0034] Figure 2 A schematic structural diagram of a crucible provided by the embodiments of the present application is shown in FIG. 1.

[0035] Reference Figure 2 The crucible provided by the embodiments of the present application comprises an inner base material layer 210 and an outer base material layer 220.

[0036] The material of the inner base material layer 210 comprises yttrium oxide, zirconium oxide and silicon oxide. The inner base material layer 210 comprises a surface functional layer 211, a transition layer 212 and a base material bonding layer 213 which are sequentially stacked from inside to outside. The mass percentage of yttrium oxide in the surface functional layer 211, the transition layer 212 and the base material bonding layer 213 gradually decreases. The mass percentage of zirconium oxide in the surface functional layer 211, the transition layer 212 and the base material bonding layer 213 gradually increases.

[0037] The outer base material layer 220 is located outside the inner base material layer 210. The material of the outer base material layer 220 comprises zirconium oxide, aluminum oxide and silicon oxide. The mass percentage of silicon oxide in the outer base material layer 220 is greater than the mass percentage of silicon oxide in the inner base material layer 210.

[0038] The crucible provided in the embodiment of the present application includes an inner substrate layer 210 and an outer substrate layer 220. The inner substrate layer 210 includes a surface functional layer 211, a transition layer 212, and a substrate bonding layer 213 stacked in sequence from the inside to the outside. The surface functional layer 211 contains a relatively high mass percentage of yttrium oxide. As the first layer in direct contact with the molten silicon, the surface functional layer 211 can reduce the risk of melt contamination by utilizing the good chemical inertness of yttrium oxide, while also preventing the melt from corroding the crucible. The yttrium oxide content in the transition layer 212 is reduced and the zirconium oxide content is increased, thereby achieving a gradient transition. Due to the difference in thermal expansion coefficients between yttrium oxide and zirconium oxide, if they are in direct contact at high temperatures or during cooling, large thermal stress will be generated at the interface, leading to cracking or peeling. The gradient transition causes the thermal expansion coefficient to change gradually, effectively dispersing and buffering thermal stress, enhancing the bonding force between layers, and preventing the surface functional layer 211 from bonding with the substrate bonding layer. 213; the higher content of zirconium oxide in the base bonding layer 213 has good strength, toughness and thermal shock resistance, and the higher content of zirconium oxide makes it closer in composition to the outer substrate layer 220 containing zirconium oxide, which is conducive to achieving a strong bond between the inner substrate layer 210 and the outer substrate layer 220; the alumina in the outer substrate layer 220 has high hardness, high melting point and good chemical stability, and the cost is relatively low. During the sintering process, the higher content of silicon oxide molten phase can effectively wet and bond zirconium oxide and alumina, enhance the bonding strength within the layer, and provide a solid backing for the inner substrate layer 210 to withstand the weight of the crucible and the static pressure of the melt.

[0039] The thickness of the surface functional layer 211 is 0.05 mm to 0.15 mm, for example, 0.05 mm, 0.07 mm, 0.09 mm, 0.1 mm, 0.13 mm or 0.15 mm.

[0040] The thickness of the transition layer 212 is 0.1 mm to 0.25 mm, for example, 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.13 mm or 0.25 mm.

[0041] The thickness of the substrate bonding layer 213 is 0.6 mm to 1 mm, for example, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm.

[0042] The thickness of the outer base layer 220 is 15 mm to 65 mm, for example, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm or 65 mm.

[0043] In some embodiments, the mass percentage of yttrium oxide in the inner substrate layer 210 is 5 wt% to 20 wt%, preferably 8 wt% to 12 wt%; the mass percentage of zirconium oxide is 30 wt% to 60 wt%, preferably 45 wt% to 55 wt%; and the mass percentage of silicon oxide is 20 wt% to 65 wt%, preferably 35 wt% to 45 wt%. The mass percentage of yttrium oxide, zirconium oxide, and silicon oxide in the inner substrate layer 210 refers to the mass percentage of yttrium oxide, zirconium oxide, and silicon oxide in the total mass of the surface functional layer 211, the transition layer 212, and the substrate bonding layer 213.

[0044] In the inner substrate layer 210, the mass proportion of yttrium oxide can be specifically 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt% or 20wt%; the mass proportion of zirconium oxide can be specifically 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt% or 60wt%; the mass proportion of silicon oxide is 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt% or 65wt%.

[0045] Wherein, the purity of silicon oxide is greater than or equal to 99.99%.

[0046] In the inner substrate layer 210, the total weight of yttrium oxide and zirconium oxide is greater than 40 wt%. Zirconia (thermal expansion coefficient 7×10 -6 / K~10×10 -6 / K) is the core of improving heat and shock resistance. Yttrium oxide is conducive to the formation of a yttrium silicate (Y2Si2O7 has a melting point of 1975°C) barrier layer. The total mass of yttrium oxide and zirconium oxide is greater than 40wt%, which is conducive to maintaining a high density of the inner substrate layer 210.

[0047] Furthermore, the mass proportion of yttrium oxide in the inner substrate layer 210 is greater than 5 wt %, which is conducive to forming continuous protection.

[0048] In some embodiments, the surface functional layer 211 includes yttrium oxide, 2wt% to 8wt% zirconium oxide and 2wt% to 8wt% silicon oxide in a mass ratio of 85wt% to 92wt%; the transition layer 212 includes yttrium oxide, 30wt% to 40wt% zirconium oxide and 10wt% to 25wt% silicon oxide in a mass ratio of 30wt% to 50wt%; and the substrate bonding layer 213 includes yttrium oxide, 50wt% to 70wt% zirconium oxide and 30wt% to 40wt% silicon oxide in a mass ratio of 0wt% to 5wt%.

[0049] In some embodiments, in the direction from the top to the bottom of the crucible, in at least one of the surface functional layer 211, the transition layer 212 or the substrate bonding layer 213, the mass ratio of yttrium oxide gradually decreases and the mass ratio of zirconium oxide gradually increases, so as to suppress gas-phase oxidation, stabilize the sample, and improve the ability to resist thermal shock and impurity corrosion.

[0050] In the outer substrate layer 220 , the mass proportion of zirconium oxide is 3% to 15%, preferably 5% to 10%; the mass proportion of aluminum oxide is 2% to 10%, preferably 3% to 5%; the mass proportion of silicon oxide is 75% to 95%, preferably 85% to 95%.

[0051] In the outer substrate layer 220, the mass proportion of zirconium oxide can be specifically 3%, 5%, 8%, 10%, 13% or 15%; the mass proportion of aluminum oxide can be specifically 2%, 3%, 4%, 5%, 7%, 9% or 10%; the mass proportion of silicon oxide can be 75%, 80%, 85% or 90%.

[0052] In some embodiments, the outer substrate layer 220 may include multiple sub-external substrate layers (not shown). The mass percentages of zirconium oxide and aluminum oxide in the sub-external substrate layers increase in descending order from the inner substrate layer 210 to the outer substrate layer 220. This gradual increase in the mass percentages of zirconium oxide (high expansion) and aluminum oxide (lower expansion) within the sub-external substrate layers from the inner substrate layer 210 to the outer substrate layer 220 creates a gradient in the coefficient of thermal expansion (CTE), preventing sudden changes in composition that could cause cracking between the inner and outer substrate layers 210, 220 due to concentrated thermal stress during drastic temperature fluctuations.

[0053] In some embodiments, in the sub-outer substrate layer closest to the inner substrate layer 210, the mass percentage of zirconium oxide is greater than or equal to 5%, and the mass percentage of aluminum oxide is greater than or equal to 3%. In the sub-outer substrate layer farthest from the inner substrate layer 220, the mass percentage of zirconium oxide is greater than or equal to 5%, and the mass percentage of aluminum oxide is less than or equal to 8%. This facilitates matching of thermal expansion coefficients, avoids delamination at the interface, and helps suppress crystallization.

[0054] In some embodiments, the crucible further includes an intermediate layer (not shown in the figure), which is located between the inner substrate layer 210 and the outer substrate layer 220. The materials of the intermediate layer include nano-zirconium silicate, mullite whiskers, yttria-zirconia sol, and β-quartz glass powder. The nano-zirconium silicate in the intermediate layer can serve as a transition of the thermal expansion coefficient, the mullite whiskers play a role in crack bridging, and the yttria-zirconia sol generates a YAG phase (Y3Al5O 12 ) has a high melting point (melting point 1970℃), and β-quartz glass powder is used for low-temperature flow filling of micropores.

[0055] Among them, in the middle layer, the mass proportions of nano zirconium silicate, mullite whiskers, yttria-zirconia sol and β-quartz glass powder are 40% to 65%, 15% to 30%, 10% to 25% and 5% to 15% respectively.

[0056] In some embodiments, in the direction from the top to the bottom of the crucible, in the middle layer, the mass proportion of mullite whiskers in the middle layer gradually increases, and the mass proportion of nano zirconium silicate gradually increases, which is beneficial for resisting thermal shock peeling and absorbing mechanical stress.

[0057] The crucible may have a diameter of 12 inches to 40 inches, such as 12 inches, 15 inches, 18 inches, 20 inches, 23 inches, 26 inches, 28 inches, 30 inches, 33 inches, 35 inches, 37 inches, or 40 inches.

[0058] In the inner substrate layer 210, as the crucible diameter increases from 12 inches to 40 inches, the amount of yttrium oxide in the inner substrate layer 210 increases by 0.18% for each inch increase to increase the contact angle of the melt and reduce the erosion rate of the melt; the amount of zirconium oxide in the inner substrate layer 210 increases by 0.32% to increase the proportion of tetragonal zirconium oxide and improve thermal shock cycle performance; and the amount of silicon oxide in the inner substrate layer 210 decreases by 0.45% to increase the density of nanopore filling.

[0059] The crucible provided in the embodiment of the present application includes an inner substrate layer 210 and an outer substrate layer 220. The inner substrate layer 210 includes a surface functional layer 211, a transition layer 212, and a substrate bonding layer 213 stacked in sequence from the inside to the outside. The surface functional layer 211 contains a relatively high mass percentage of yttrium oxide. As the first layer in direct contact with the molten silicon, the surface functional layer 211 can reduce the risk of melt contamination by utilizing the good chemical inertness of yttrium oxide, while also preventing the melt from corroding the crucible. The yttrium oxide content in the transition layer 212 is reduced and the zirconium oxide content is increased, thereby achieving a gradient transition. Due to the difference in thermal expansion coefficients between yttrium oxide and zirconium oxide, if they are in direct contact at high temperatures or during cooling, large thermal stress will be generated at the interface, leading to cracking or peeling. The gradient transition causes the thermal expansion coefficient to change gradually, effectively dispersing and buffering thermal stress, enhancing the bonding force between layers, and preventing the surface functional layer 211 from bonding with the substrate bonding layer. 213; the higher content of zirconium oxide in the base bonding layer 213 has good strength, toughness and thermal shock resistance, and the higher content of zirconium oxide makes it closer in composition to the outer substrate layer 220 containing zirconium oxide, which is conducive to achieving a strong bond between the inner substrate layer 210 and the outer substrate layer 220; the alumina in the outer substrate layer 220 has high hardness, high melting point and good chemical stability, and the cost is relatively low. During the sintering process, the higher content of silicon oxide molten phase can effectively wet and bond zirconium oxide and alumina, enhance the bonding strength within the layer, and provide a solid backing for the inner substrate layer 210 to withstand the weight of the crucible and the static pressure of the melt.

[0060] Accordingly, another embodiment of the present application further provides a method for manufacturing a crucible, which can be used to manufacture the crucible provided in the above embodiment. For the same or corresponding parts as the previous embodiment, please refer to the corresponding description of the previous embodiment, and will not be described in detail below.

[0061] The crucible manufacturing method includes:

[0062] S11. Provide a crucible mold.

[0063] S12. Forming an initial outer substrate layer in the crucible mold by centrifugal deposition. The material of the initial outer substrate layer includes zirconium oxide, aluminum oxide, and silicon oxide.

[0064] For example, zirconium oxide, aluminum oxide and silicon oxide are mixed with a solvent, a binder and a dispersant to form a slurry with a solid content of 40 wt% to 60 wt%; an initial outer substrate layer is deposited layer by layer on the inner surface of a crucible mold at a rotation speed of 500 rpm to 3000 rpm and a temperature of 25° C. to 60° C.

[0065] When the outer substrate layer includes multiple sub-outer substrate layers, and the mass fraction of zirconium oxide and aluminum oxide in the sub-outer substrate layers gradually increases in the direction of diffusion from the inner substrate layer to the outer substrate layer. A plurality of slurries with different mass fractions of zirconium oxide and aluminum oxide can be pre-configured, and the slurries are sequentially deposited on the inner surface of the crucible mold according to the order of gradually decreasing mass fractions of zirconium oxide and aluminum oxide, so as to realize the structure of the outer substrate layer composed of multiple sub-outer substrate layers.

[0066] In some embodiments, when the crucible further includes an intermediate layer, after forming the initial outer substrate layer, before forming the initial inner substrate layer, the method further includes: forming an initial intermediate layer inside the initial outer substrate layer; during the formation of the initial inner substrate layer, the initial inner substrate layer is located inside the initial intermediate layer; and during the subsequent gradient sintering process, the initial intermediate layer is converted into the intermediate layer.

[0067] For example, the nano-zirconium silicate, mullite whiskers, yttrium oxide-zirconium oxide sol, and beta-quartz glass powder are configured into a slurry with a solid content of 40wt%-60wt% together with a solvent, a binder, and a dispersant; and the initial intermediate layer is sequentially deposited on the inner surface of the initial outer substrate layer at a rotation speed of 500rpm-3000rpm and a temperature of 25℃-60℃.

[0068] S13, an initial inner substrate layer is formed inside the initial outer substrate layer, the material of the initial inner substrate layer includes yttrium oxide, zirconium oxide, and silicon oxide, the initial inner substrate layer includes a surface functional layer, a transition layer, and a matrix bonding layer which are sequentially stacked from inside to outside, the mass fraction of yttrium oxide in the surface functional layer, the transition layer, and the matrix bonding layer gradually decreases, the mass fraction of zirconium oxide in the surface functional layer, the transition layer, and the matrix bonding layer gradually increases, and the mass fraction of silicon oxide in the initial outer substrate layer is greater than that in the initial inner substrate layer.

[0069] For example, the matrix bonding layer, the transition layer, and the surface functional layer are sequentially formed on the inner surface of the initial outer substrate layer by using a plasma spraying process. The spraying power for forming the surface functional layer is greater than that for forming the transition layer, and the spraying power for forming the transition layer is greater than that for forming the matrix bonding layer. Since the content of yttrium oxide in the surface functional layer is high, a higher spraying power is needed to provide a higher enthalpy value to completely melt the yttrium oxide. The spraying power for forming the transition layer is moderate to avoid overheating and cause the volatilization of silicon dioxide. The spraying power for forming the matrix bonding layer needs to balance the melting and the inhibition of thermal decomposition.

[0070] Specifically, the spraying power for forming the matrix bonding layer is 35kW-40kW; the spraying power for forming the transition layer is 35kW-45kW; and the spraying power for forming the surface functional layer is 40kW-50kW.

[0071] S14, performing a gradient sintering process on the initial outer substrate layer and the initial inner substrate layer to transform the initial outer substrate layer into a substrate layer, and to transform the initial inner substrate layer into an inner substrate layer.

[0072] The gradient sintering process includes: in the first stage, heating from room temperature to 800℃ at a rate of 5℃ / min to expel organic matter; in the second stage, heating to 1400℃ at a rate of 3℃ / min; in the third stage, keeping at 1350℃~1450℃ for 3h~6h to promote the formation of solid solution; in the fourth stage, cooling to 300℃ with the furnace and then taking it out to avoid cracks caused by rapid cooling.

[0073] In some embodiments, after the gradient sintering process and before the hot isostatic pressing densification process, the process further includes: performing interface strengthening treatment on the inner substrate layer and the outer substrate layer, for example, using chemical vapor deposition (CVD) to form a SiC coating on the inner surface of the inner substrate layer and the outer surface of the outer substrate layer to improve the interface strength of the crucible.

[0074] S15, performing hot isostatic pressing densification treatment on the inner substrate layer and the outer substrate layer. Hot isostatic pressing can eliminate pores and increase interface density.

[0075] The process parameters of hot isostatic pressing include a temperature of 1350° C. to 1450° C., a time of 2 h to 3 h, and a pressure of 100 MPa to 150 MPa (Ar atmosphere).

[0076] S16. After testing, a crucible consisting of an inner substrate layer and an outer substrate layer without damage is obtained.

[0077] The present embodiment provides a specific crucible, which is prepared using the crucible manufacturing method provided in the above embodiment. The specific process steps are as follows:

[0078] S21. Provide a crucible mold, wherein the crucible mold has a diameter of 20 inches.

[0079] S22. Mix 8% zirconium oxide, 5% aluminum oxide and 87% aluminum oxide in a mass ratio with water, polyvinyl alcohol and ammonium polyacrylate to form a slurry with a solid content of 55%; at a rotation speed of 1500 rpm and a temperature of 50°C, deposit an initial outer substrate layer layer by layer on the inner surface of the crucible mold.

[0080] S23. A substrate bonding layer, a transition layer, and a surface functional layer are sequentially formed on the inner surface of the initial outer substrate layer using a plasma spraying process. The surface functional layer comprises 90 wt% yttrium oxide, 5 wt% zirconium oxide, and 5 wt% silicon oxide; the transition layer comprises 50 wt% yttrium oxide, 40 wt% zirconium oxide, and 10 wt% silicon oxide; and the substrate bonding layer comprises 5 wt% yttrium oxide, 60 wt% zirconium oxide, and 35 wt% silicon oxide. The spraying power for forming the substrate bonding layer is 35 kW; the spraying power for forming the transition layer is 40 kW; and the spraying power for forming the surface functional layer is 45 kW.

[0081] S24. Perform a gradient sintering process on the initial outer substrate layer and the initial inner substrate layer, heating from room temperature to 800°C at a rate of 5°C / min; heating to 1400°C at a rate of 3°C / min; keeping at 1400°C for 6 hours; and cooling to 300°C in the furnace before taking out.

[0082] S25, performing hot isostatic pressing densification treatment on the inner substrate layer and the outer substrate layer. The process parameters of the hot isostatic pressing include temperature of 1400° C., time of 3 hours, and pressure of 100 MPa (Ar atmosphere).

[0083] S26. After testing, a crucible consisting of an inner substrate layer and an outer substrate layer without damage is obtained.

[0084] After the crucible provided in the embodiment of the present application is kept at 1400 degrees Celsius for 6 hours, the thickness of the crystallization layer is 0 μm. Compared with the average thickness of the crystallization layer of a conventional quartz crucible of 50 μm after being kept at 1400 degrees Celsius for 6 hours, the crucible provided in the embodiment of the present application has the effect of inhibiting crystallization. The oxygen content of the single crystal silicon prepared by the crucible provided in the embodiment of the present application can be as low as 7.2×10 17 atoms / cm 3 The density of the crucible provided in the embodiment of the present application can reach 98.5% as measured by the Archimedean measurement method.

[0085] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A crucible, characterized in that: include: An inner substrate layer, wherein the material of the inner substrate layer includes yttrium oxide, zirconium oxide, and silicon oxide, and the inner substrate layer includes a surface functional layer, a transition layer, and a matrix bonding layer stacked in sequence from the inside to the outside, wherein the mass proportion of yttrium oxide in the surface functional layer, the transition layer, and the matrix bonding layer gradually decreases, and the mass proportion of zirconium oxide in the surface functional layer, the transition layer, and the matrix bonding layer gradually increases; An outer substrate layer is located outside the inner substrate layer, and the material of the outer substrate layer includes zirconium oxide, aluminum oxide and silicon oxide, and the mass proportion of silicon oxide in the outer substrate layer is greater than the mass proportion of silicon oxide in the inner substrate layer.

2. The crucible according to claim 1, characterized in that In the inner substrate layer, the mass proportions of yttrium oxide, zirconium oxide and silicon oxide are 5wt% to 20wt%, 30wt% to 60wt% and 20wt% to 65wt% respectively.

3. The crucible according to claim 2, characterized in that In the inner substrate layer, the total mass of yttrium oxide and zirconium oxide accounts for more than 40 wt%.

4. The crucible according to claim 1 or 2, characterized in that The surface functional layer comprises 85wt% to 92wt% of yttrium oxide, 2wt% to 8wt% of zirconium oxide, and 2wt% to 8wt% of silicon oxide in a mass ratio; the transition layer comprises 30wt% to 50wt% of yttrium oxide, 30wt% to 40wt% of zirconium oxide, and 10wt% to 25wt% of silicon oxide in a mass ratio; and the substrate bonding layer comprises 0wt% to 5wt% of yttrium oxide, 50wt% to 70wt% of zirconium oxide, and 30wt% to 40wt% of silicon oxide in a mass ratio.

5. The crucible according to claim 1, characterized in that In the outer substrate layer, the mass proportions of zirconium oxide, aluminum oxide and silicon oxide are 3wt% to 15wt%, 2wt% to 10wt% and 75wt% to 95wt% respectively.

6. The crucible according to claim 1 or 5, characterized in that The outer substrate layer includes multiple sub-outer substrate layers. In the direction of diffusion from the inner substrate layer to the outer substrate layer, the mass proportions of zirconium oxide and aluminum oxide in the sub-outer substrate layers increase successively.

7. The crucible according to claim 6, characterized in that In the sub-outer substrate layer located closest to the inner substrate layer, the mass proportion of zirconium oxide is greater than or equal to 5wt%, and the mass proportion of aluminum oxide is greater than or equal to 3wt%; in the sub-outer substrate layer located farthest from the inner substrate layer, the mass proportion of zirconium oxide is greater than or equal to 5wt%, and the mass proportion of aluminum oxide is less than or equal to 8wt%.

8. The crucible according to claim 1, wherein Also includes: An intermediate layer is located between the inner substrate layer and the outer substrate layer. The material of the intermediate layer includes nano zirconium silicate, mullite whiskers, yttria-zirconia sol and β-quartz glass powder.

9. The crucible according to claim 8, characterized in that The mass proportions of nano zirconium silicate, mullite whiskers, yttria-zirconia sol and beta-quartz glass powder are 40wt% to 65wt%, 15wt% to 30wt%, 10wt% to 25wt% and 5wt% to 15wt% respectively.

10. A method for manufacturing a crucible, characterized in that: include: Provide crucible molds; forming an initial outer substrate layer in the crucible mold by centrifugal deposition, wherein the material of the initial outer substrate layer comprises zirconium oxide, aluminum oxide and silicon oxide; An initial inner substrate layer is formed inside the initial outer substrate layer, wherein the material of the initial inner substrate layer includes yttrium oxide, zirconium oxide, and silicon oxide. The initial inner substrate layer includes a surface functional layer, a transition layer, and a matrix bonding layer stacked in sequence from the inside to the outside. The mass proportion of yttrium oxide in the surface functional layer, the transition layer, and the matrix bonding layer gradually decreases, and the mass proportion of zirconium oxide in the surface functional layer, the transition layer, and the matrix bonding layer gradually increases. Moreover, the mass proportion of silicon oxide in the initial outer substrate layer is greater than the mass proportion of silicon oxide in the initial inner substrate layer. performing a gradient sintering process on the initial outer substrate layer and the initial inner substrate layer to convert the initial outer substrate layer into a substrate layer, and to convert the initial inner substrate layer into an inner substrate layer; performing hot isostatic pressing densification treatment on the inner substrate layer and the outer substrate layer; The crucible consisting of the inner base material layer and the outer base material layer was found to be undamaged after testing.

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