Use of quartz grain arrays in the production of single crystal silicon.

Abstract

A method of producing a single crystal silicon ingot is disclosed in which an array of quartz grains is added to a crucible assembly prior to ingot growth. The array may be located in the outer melt zone of the crucible assembly, such as in the Continuous Czochralski (CCz) process. The array may be made of quartz grains interconnected by connecting members.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 276,969, filed November 08, 2021, which is incorporated by reference in its entirety.

[0002] The field of the disclosure relates to methods for producing continuous Czochralski (CCz) single crystal silicon ingots, and in particular, to adding an array of quartz grains to a crucible assembly prior to ingot growth. [Background technology]

[0003] Continuous Czochralski (CCz) is suitable for forming 300mm and 200mm diameter monocrystalline silicon ingots, including ingots that are relatively highly doped with arsenic or phosphorus. The continuous Czochralski process forms monocrystalline silicon ingots from a silicon melt while adding solid polycrystalline silicon to the melt continuously or intermittently to replenish the melt while the ingot is growing. This method may involve forming multiple ingots from the same melt while the hot zone remains at temperature (i.e., melt is continuously present in the crucible assembly while multiple ingots are grown). Summary of the Invention [Problem to be solved by the invention]

[0004] Customers have come to expect that wafers grown on a continuous Czochralski process will have a relatively low void count, similar to wafers grown on a standard batch Czochralski process. A continuous Czochralski process may include a crucible assembly that contains at least two, and often three, melt zones separated by physical barriers: an outer melt zone where the solid polycrystalline silicon is delivered, an intermediate melt zone where the melt stabilizes, and an inner melt zone where the silicon ingot is drawn. The addition of solid polycrystalline silicon to the melt introduces inert gas bubbles (such as argon bubbles) into the melt, which affect the void count.

[0005] A need exists for a method of forming a silicon ingot that reduces the number of defects in silicon wafers sliced ​​from the ingot and / or facilitates dissipation of inert gas bubbles.

[0006] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure that are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to better understand the various aspects of the present disclosure. As such, it should be read in this light and understood as admissions of prior art. [Means for solving the problem]

[0007] One aspect of the present disclosure is directed to a method of forming a single crystal silicon ingot. Solid phase polycrystalline silicon is added to a crucible assembly. An array of quartz grains is added to the crucible assembly. The array includes a plurality of quartz grains and a plurality of connecting members interconnecting the quartz grains. The polycrystalline silicon is heated to form a silicon melt. The silicon melt is contacted with a seed crystal. The seed crystal is withdrawn from the silicon melt to form a silicon ingot.

[0008] There are various refinements of the features mentioned in relation to the above-mentioned aspects of the disclosure. Additional features may be incorporated into the above-mentioned aspects of the disclosure as well. These refinements and additional features may exist individually or in any combination. For example, the various features described below in relation to any of the illustrated embodiments of the disclosure may be incorporated alone or in any combination into any of the above-mentioned aspects of the disclosure. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of an example of an ingot puller having a solid polycrystalline silicon charge disposed therein.

[0010] [Diagram 2] FIG. 2 is a cross-sectional view of an ingot puller having an array of quartz particles disposed on the surface of a polycrystalline silicon charge.

[0011] [Diagram 3] FIG. 3 is a cross-sectional view of an ingot extraction apparatus having a melt disposed in a crucible assembly with an array disposed in the melt.

[0012] [Figure 4] FIG. 4 is a cross-sectional view of an ingot extraction apparatus showing a silicon ingot being extracted from a silicon melt.

[0013] [Diagram 5] FIG. 5 is a top view of a crucible assembly of an ingot puller having an array of quartz grains disposed in the outer melting zone.

[0014] [Figure 6] FIG. 6 is a schematic diagram of a process for forming an array of quartz particles.

[0015] [Figure 7] FIG. 7 is a schematic diagram of a quartz structure that can be incorporated into the array.

[0016] [Figure 8] FIG. 8 is one embodiment of an array of quartz particles.

[0017] [Figure 9] FIG. 9 is another embodiment of an array of quartz particles.

[0018] [Figure 10] FIG. 10 is another embodiment of an array of quartz particles.

[0019] [Figure 11] FIG. 11 is a schematic diagram of quartz cullet in a silicon melt.

[0020] [Figure 12] FIG. 12 is a schematic diagram of quartz cullet after partial melting.

[0021] [Figure 13] FIG. 13 is a schematic diagram of the quartz cullet after fusion.

[0022] [Figure 14] FIG. 14 is a graph of the relative concentration of dissolved SiO in the silicon melt for the cullet spacings shown in each of FIGS. 11-13.

[0023] [Figure 15] FIG. 15 is a graph showing the increase in the number of moles of SiO(g) produced as a function of the immersion time in the silicon melt for four different lengths and diameters of the quartz rod. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Corresponding reference characters indicate corresponding parts throughout the drawings.

[0025] The present disclosure provides a method for growing a monocrystalline silicon ingot in a continuous Czochralski (CCz) process. An array of quartz grains is added to a crucible assembly. The array may be made of quartz grains connected within the array by connecting members. The array may be placed in the crucible assembly with solid polycrystalline silicon prior to melting.

[0026] An example of an ingot withdrawal apparatus 5 for producing an ingot 60 by a continuous Czochralski process is shown in FIG. 4. The ingot withdrawal apparatus 5 includes a crucible assembly 10 that contains a melt 6 of semiconductor or solar grade silicon material. A susceptor 13 supports the crucible assembly 10. The crucible assembly 10 has a sidewall 40 and one or more fluid barriers 20, 30 or "weirs" that separate the melt into different melt zones. In the illustrated embodiment, the crucible assembly 10 includes a first weir 20. The first weir 20 and the sidewall 40 define an outer melt zone 42 of the silicon melt 6 and the crucible assembly 10. The crucible assembly 10 includes a second weir 30 radially inward relative to the first weir 20 that defines an inner melt zone 22 of the silicon melt and the crucible assembly 10. The inner melt zone 22 is a growth region in which the single crystal silicon ingot 60 grows. The first weir 20 and the second weir 30 define an intermediate melt zone 32 of the crucible assembly 10 and the silicon melt where the melt 6 may stabilize as it travels toward the inner melt zone 22. The first weir 20 and the second weir 30 each have at least one opening defined therein to allow molten silicon to flow radially inward toward the growth region of the inner melt zone 22.

[0027] In the illustrated embodiment, the first weir 20, the second weir 30, and the sidewall 40 each have a generally annular shape. The first weir 20, the second weir 30, and the sidewall 40 may be part of three nested crucibles that are joined at the bottom or floor 45 of the crucible assembly 10 (i.e., the first weir 20 and the second weir 30 are sidewalls of two crucibles nested within a larger crucible). The crucible assembly configurations illustrated in Figures 1-4 are exemplary. In other embodiments, the crucible assembly 10 has a single floor with the weirs extending upward from the floor 45 (i.e., no nested crucibles). Optionally, the floor 45 may be flat rather than curved, and / or the weirs 20, 30 and / or the sidewall 40 may have straight sides. Additionally, although the illustrated crucible assembly 10 is shown with two dams, in other embodiments the crucible assembly may have one dam or even no dams.

[0028] Supply tube 46 supplies polycrystalline silicon, which may be, for example, in granular, chunk, chip, or combinations thereof, to outer melt zone 42 at a rate sufficient to maintain a substantially constant melt height level and volume during growth of ingot 60.

[0029] Generally, the melt 6 from which the ingot 60 is drawn is formed by loading polycrystalline silicon into a crucible to form an initial silicon charge 27 (FIG. 1). Typically, the initial charge is about 10 kilograms to about 200 kilograms of polycrystalline silicon and may be in granular, chunk, chip, or combinations thereof. The mass of the initial charge depends on the desired crystal diameter and hot zone design. Because polycrystalline silicon is continuously fed during crystal growth, the initial charge does not reflect the length of the ingot crystal.

[0030] A variety of sources of polycrystalline silicon can be used, such as, for example, granular polycrystalline silicon produced by pyrolysis of silane or halosilane in a fluidized bed reactor, polycrystalline silicon produced in a Siemens reactor, etc. As described below, an array of quartz particles (i.e., sometimes referred to herein as quartz particles or glass particles, and meant to include fused quartz particles) may be added to the initial charge of solid phase polycrystalline silicon 27 in the outer melt zone 42 or inner melt zone 32 of the crucible assembly 10 prior to melting the initial charge of polycrystalline silicon 27 (or after, if smaller arrays are added, such as in systems capable of supplying larger chunks of silicon).

[0031] Once the polycrystalline silicon (and the array of quartz particles) is added to the crucible assembly 10 to form the charge 27, the charge 27 is heated to a temperature above about the melting temperature of silicon (e.g., about 1412°C) to melt the charge, thereby forming a silicon melt 6 (FIG. 3) having molten silicon. The silicon melt 6 has an initial volume of molten silicon and has an initial melt height level, with these parameters being determined by the size of the initial charge 27. In some embodiments, the crucible assembly 10 with the silicon melt 6 is heated to a temperature of at least about 1425°C, at least about 1450°C, or even at least about 1500°C.

[0032] The ingot extraction apparatus 5 includes an extraction mechanism 114 ( FIG. 4 ) for growing and extracting an ingot 60 from the melt in the inner melt zone 22. The extraction mechanism 114 includes an extraction cable 118, a seed holder or seed chuck 120 coupled to one end of the extraction cable 118, and a seed crystal 122 coupled to the seed holder or seed chuck 120 for initiating crystal growth. One end of the extraction cable 118 is connected to a lifting mechanism (e.g., a driven pulley or drum, or other suitable type of lifting mechanism) and the other end is connected to the chuck 120 that holds the seed crystal 122. During operation, the seed crystal 122 is lowered into contact with the melt 6 in the inner melt zone 22. Activating the extraction mechanism 114 raises the seed crystal 122 along the extraction axis A. This causes the single crystal ingot 60 to be extracted from the melt 6.

[0033] As the charge of polycrystalline silicon 27 (FIG. 1) liquefies to form a silicon melt 6 (FIG. 3) having molten silicon, a silicon seed crystal 122 (FIG. 4) is lowered into contact with the melt 6 within the inner melt zone 22. The silicon seed crystal 122 is then pulled out of the melt 6 with the silicon attached to it, forming a neck 52, thereby forming a melt-solid interface near or at the surface of the melt 6.

[0034] The extraction mechanism 114 may rotate the seed crystal 122 and the ingot 60 connected thereto. The crucible drive unit 44 may rotate the susceptor 13 and the crucible assembly 10. In some embodiments, the silicon seed crystal 122 and the crucible assembly 10 are rotated in opposite directions, i.e., counter-rotated. The counter-rotation provides convection in the silicon melt 6. The rotation of the seed crystal 122 is primarily used to provide a symmetrical temperature profile, reduce impurity angular variation, and control the crystal-melt interface shape.

[0035] After the neck 52 is formed, an outwardly bulging seed cone section 54 (or "crown") adjacent the neck 52 is grown. Typically, the drawing speed is slowed from the neck pull speed to a speed suitable for growing the outwardly bulging seed cone section 54. Once the seed cone section reaches a target diameter, the body 56 or "constant diameter section" of the ingot 60 is grown. In some embodiments, the body 56 of the ingot 60 has a diameter of about 150 mm, at least about 150 mm, about 200 mm, at least about 200 mm, about 300 mm, at least about 300 mm, about 450 mm, or even at least about 450 mm.

[0036] While ingot 60 is being withdrawn from melt 6, solid polysilicon feedstock is added to outer melt zone 42 through tube 46 or other channel to replenish melt 6 in ingot growth apparatus 5. Solid polycrystalline silicon may be added from polycrystalline silicon supply system 66 and may be added continuously or intermittently to ingot withdrawal apparatus 5 to maintain the melt level. In general, polycrystalline silicon may be metered to ingot withdrawal apparatus 5 by any method available to one of ordinary skill in the art.

[0037] In some embodiments, dopants are also added to the melt 6 during ingot growth. The dopants may be introduced from a dopant supply system 72. The dopants may be added as a gas or a solid, and may be added to the outer melt zone 42.

[0038] The apparatus 5 may include a heat shield 116 disposed around the growing ingot 60 to allow the ingot 60 to radiate its latent heat of solidification and heat flux from the melt 6. The heat shield 116 may be at least partially conical in shape and angled obliquely downward to form an annular opening in which the ingot 60 is placed. A flow of inert gas, such as argon, is typically provided along the length of the growing crystal. The ingot 60 is drawn through a growth chamber 78 that is sealed from the surrounding atmosphere.

[0039] Multiple independently controlled annular bottom heaters 70 may be arranged in a radial pattern below the crucible assembly 10. The annular bottom heaters 70 apply heat in a relatively controlled distribution across the base surface of the crucible assembly 10. The annular bottom heaters 70 may be individually controlled planar resistive heating elements. The apparatus 5 may include one or more side heaters 74 positioned radially outward of the crucible assembly 10 to control the temperature distribution through the melt 6.

[0040] The ingot growth apparatus 5 shown in Figures 1-4 and described herein is exemplary, and in general, unless otherwise noted, any system in which a crystalline ingot is prepared by the continuous Czochralski process may be used.

[0041] According to an embodiment of the present disclosure, an array 31 (FIG. 2) of quartz grains is attached to the crucible assembly 10 prior to growing the ingot 60. The array 31 may be added to the crucible assembly 10 prior to heating the polycrystalline silicon 27 to form the silicon melt 6. The array 31 may be located above the initial charge 27 of polycrystalline silicon 27 or may be disposed within the charge 27 (e.g., with polycrystalline silicon disposed above and below the charge).

[0042] An example of an array 31 of quartz particles disposed in the outer melt zone 42 is shown in FIG. 5. The array 31 includes a plurality of quartz particles 33 and a plurality of connecting members 37 connecting adjacent quartz particles 33. The connecting members 37 may be made of quartz. The array 31 may be fabricated by 3D printing or other suitable methods. In methods involving 3D printing, the array is built from the base up, and the structure is connected or fused layer by layer. In 3D printing methods, the deposition head or melt source may be capable of translating in the xy plane to effect connection of the array to its final or "green" state. Examples of suitable 3D printing methods that may be used include von Witzendorff et al., “Additive Manufacturing of Glass: CO2-Laser Glass Deposition Printing,” Procedia CIRP 74 (2018), 272-275, and Luo et al., “Additive Manufacturing of Glass,” Journal of Manufacturing Science and Engineering, Vol. 136, 061024:1-6 (2014), both of which are incorporated by reference herein for all relevant consistent purposes.

[0043] In some embodiments, 3D printing is used to form arrays that are composite and / or incorporate doped materials. For example, array 31 may be made of quartz doped with silicon to reduce surface crystallization of fused silica.

[0044] Another embodiment of the array 31 is shown in FIG. 6. The array 31 includes connecting members 37 constructed as a scaffold. The connecting members 37 of the array 31 may be made of unit cells 49 (e.g., parallelepipeds) that may be stacked and connected to form a 3D scaffold. Each scaffold may incorporate a second structure (e.g., by porosity or another structure) having a surface area of ​​quartz. The connecting members 37 of the unit cells 49 may include structures within the connecting members (i.e., not solid rods). For example, the structure 41 shown in FIG. 7 having quartz grains 33 formed therein may be incorporated within the connecting members 37.

[0045] Other embodiments of the array 31 include monolithic disks incorporating quartz grain. The array 31 may also incorporate porous patterns such as a "basket weave" pattern or a "bird's nest" pattern (FIG. 5).

[0046] In general, the quartz particles 33 incorporated into the array 31 may have any suitable size and shape that enables the array 31 to function as described herein. For example, the quartz particles 33 may be shaped into rods, tubes, spheres, or irregular shapes. In some embodiments, the particles have a size (i.e., largest dimension) between 10 μm and 500 mm. The particles may be sized based on erosion by the melt and survivability of the scaffold, which depends on desired conditioning of the melt.

[0047] In some embodiments, the quartz particles 33 of the array 31 have a relatively high surface area. For example, the quartz particles have a surface area of ​​at least 0.1 cm 2 Quartz / gram of quartz or at least 0.5 cm 2 Quartz / gram of quartz (e.g. 0.1 cm 2 Quartz / gram to 10cm 2 In some embodiments, the quartz particles 33 of the array 31 may have a surface area to mass ratio of at least 10 cm 2 kg of quartz / silicon or at least 50 cm 2 kg of quartz / silicon (e.g. 10 cm2 kg to 250cm of quartz / silicon 2 It has a relatively high surface area relative to the amount of silicon in the crucible, such as 10 ...

[0048] Array 31 may be of any size and shape that enables the array to function as described herein. According to some embodiments of the present disclosure, array 31 of quartz grains may have a sufficient width such that array 31 extends continuously from sidewall 40 of crucible assembly 10 to first weir 20. In other embodiments, array 31 has a width that is less than the distance between sidewall 40 and first weir 20 of crucible assembly 10. In some embodiments, array 31 has a width between about 50 mm and about 75 mm and / or a height (i.e., depth) between 6 mm and 100 mm.

[0049] One embodiment of quartz particles 33 for use in array 31 is shown in Figure 7. The quartz particles 33 are shaped as hollow spheres with openings 51 formed therein. In the embodiment shown in Figure 8, the quartz particles 33 include points extending from the core of the structure. In the embodiment shown in Figure 9, the quartz particles include dimples that increase the surface area of ​​the particles 33.

[0050] The array 31 may be of a lower density then the melt 6, thereby allowing the array 31 to float on the melt with a portion of the array 31 disposed above the melt 6. In other embodiments, the array 31 may have a density more similar to the melt, such that the array 31 is immersed (or partially immersed) in the melt 6.

[0051] In some continuous Czochralski processes, multiple ingots are grown while the hot zone (i.e., the lower portion of the apparatus 5, such as the crucible assembly 10 and susceptor 13) remains heated with the silicon melt 6 being continuous within the crucible assembly 10. In such methods, a first ingot is grown to a target length, growth is terminated, the ingot is removed from the ingot puller, and then a seed crystal is lowered into the melt to begin growing a second single crystal silicon ingot (i.e., using the same melt from which the first ingot was pulled). Subsequent ingots may be grown with the hot zone intact and at a temperature where a continuous melt of silicon is present within the crucible assembly 10 (e.g., until one or more components of the hot zone degrade, such as requiring cooling of the crucible assembly and replacement of the degraded components). For example, at least one, two, three, four, five, six, ten, or twenty or more ingots may be grown. The array 31 of ingot particles 33 may be present within the crucible assembly 10 during the growth of one or more of the subsequently grown ingots (or all of the subsequently grown ingots while the hot zone remains intact).

[0052] In some embodiments, after the array 31 is located within the crucible assembly, no additional quartz (e.g., a second array of quartz particles or free-floating quartz) is added to the crucible assembly 10. For example, no additional quartz is added during the entire period during which the hot zone is intact (e.g., during the growth of subsequent ingots). In other embodiments, additional amounts of quartz are added during ingot growth (e.g., after the initial ingot is grown).

[0053] Compared to conventional methods of forming monocrystalline silicon ingots, the disclosed method has several advantages. Without being bound to any particular theory, it is believed that the addition of polycrystalline silicon to the outer melt zone of the crucible assembly creates relatively small bubbles (e.g., less than 10 μm) of inert gas (e.g., argon) that are carried by the melt through the openings in each weir, allowing the bubbles to reach the silicon-melt interface. The array of quartz particles provides surface area and nucleation points for the inert gas bubbles to coalesce, thereby increasing the size of the bubbles and allowing the bubbles to become more buoyant. The array or particles provide a monolithic layer of quartz on the surface of the melt (e.g., less interstices compared to non-arrayed quartz cullet). The array melts to a certain extent after melt formation, and the dissolved quartz helps remove the inert gas from the melt. The array may be relatively easily placed in the crucible assembly (e.g., placed on top of an initial charge of polycrystalline silicon) before the hot zone is ramped up to temperature. The use of an array disperses the quartz particles, increasing the surface area exposed to the melt, thereby removing the argon melt. The quartz particles may be configured to have a relatively high surface area compared to quartz cullet. The interconnected small feature size allows for increased SiO2 dissolution (due to increased surface area), but limited fusion.

[0054] In embodiments where the array is created by 3D printing, the surface area of ​​the quartz particles may be increased and the particles may be interconnected within the array. 3D printing allows the removal of binders used in glass production. 3D printing allows the regions of the array that dissolve faster due to their proximity to the free surface of the melt to be tailored along the thickness of the array so that they can be optimized for structural integrity and SiO generation, while the parts that are immersed by the melt may also be tailored to have spacing and cross-sections such that dissolution by the melt does not destabilize the structure. The taper of the cross-section may be tailored to maintain the connectivity of the structure (e.g., thicker at the junctions and thinner at the periphery, thereby keeping the array intact and maintaining the spacing of the array) to provide a sufficient surface to optimize silica production. Larger wall structures can be produced by 3D printing, where the actual structure of the wall can act as a SiO(g) generator and particle filter. Conversely, smaller macro-dimensional spheres can be produced, thereby maintaining the porosity to generate SiO(g) at a high rate. 3D printing could potentially be used to obtain fully dense materials that may be integrated with porous structures (e.g., a fully dense outer shell with a porous inner core, or conversely, a fully dense inner shell with a porous outer shell, depending on the evolution of the array during crystal growth). EXAMPLES

[0055] The processes of the present disclosure are further illustrated by the following examples, which should not be construed in a limiting sense. Example 1: Increasing the spacing between quartz particles in the conventional method

[0056] 11-13 show schematics of conventional cylindrical quartz particles after addition to a silicon melt (e.g., the outer melt zone of a crucible assembly). In FIG. 11, after addition of the cullet, there is a deep section of quartz with open porosity due to natural packing of the surface. As the crystal pull-out growth progresses (FIG. 12), the cross section of the quartz surface decreases and the distance between the quartz pieces increases. As the quartz dissolves into the melt (FIG. 13), the cullet begins to fuse. Fusion provides a more open passageway for the silicon melt.

[0057] Since quartz (SiO2) melts and produces dissolved SiO, which can nucleate SiO bubbles, an interaction volume can be defined, as shown in the highlighted area between the quartz shapes in Figures 11 and 12. The so-called interaction volume allows enough to trap argon and produce SiO bubbles that disappear at the free surface of the melt. As the shapes melt, their cross-sectional area decreases, and when they become small enough to be mobile, they are seen to fuse (Figure 13). This causes spacing between the features and results in clusters. The physical phenomena of melting and fusion result in a change in the concentration of dissolved SiO in the melt, represented by the interaction volume, which changes the effectiveness of argon removal by bubble nucleation.

[0058] Schematic diagrams of hypothetical profiles consistent with the three cases in Figures 11-13 ("a", "b", and "c", respectively) are shown in Figure 14. Figure 14 shows the relative concentration of dissolved SiO in the silicon melt for varying spacing of quartz features. There is a critical concentration ([SiO]*critical) at which bubbles cannot nucleate, grow, collect argon gas, and reduce growth in the voids. As shown in Figure 14, the spatial layout of the dissolving quartz features affects the ability of the particles to maintain a viable mechanism for void reduction.

[0059] The production of SiO proceeds via the following reaction between quartz forms and silicon liquid: Si(l) + SiO2(s) => 2SiO(g)

[0060] The mass of SiO2 dissolved in the silicon melt is proportional to the amount of SiO(g) produced. Using a literature average rate of 10 μm / hr for SiO2 dissolution in silicon liquid, the molar production increase rate was calculated as a function of the total mass of added quartz shapes and the surface area of ​​the shapes over the entire immersion time. In the simulation in Figure 15, a total mass of 5 kg quartz shapes was used, and the feature sizes in terms of rod diameter and length are shown as D and L, respectively. Four cases are shown for L and D: 2 cm, 1.2 cm, 0.6 cm, and 0.3 cm. The production rate of SiO(g) increases with smaller feature sizes. However, a compromise situation exists where the fusion effect allows for areas in the silicon melt that can bypass the conditioning action of SiO(g) and reduce large area void defects.

[0061] As used herein, when used in conjunction with a range of dimensions, concentrations, temperatures, or other physical or chemical properties or characteristics, the terms "about," "substantially," "essentially," and "approximately" are meant to cover the variation that may exist at the upper and / or lower limits of the range of the property or characteristic, including, for example, the variation due to rounding, measurement method or other statistical variation.

[0062] When introducing elements of the disclosure or embodiments thereof, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," "containing," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. Use of specific directional terms (e.g., "top," "bottom," "side," etc.) is for convenience of description and does not require a particular orientation of the articles being described.

[0063] Since various changes may be made in the above structures and methods without departing from the scope of the present disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

Claims

1. 1. A method of forming a single crystal silicon ingot, comprising: adding solid phase polycrystalline silicon to the crucible assembly; adding an array of quartz grains to the crucible assembly, wherein the array includes a plurality of quartz grains and a plurality of connecting members connecting adjacent quartz grains, each quartz grain in the array being connected to a connecting member; heating the polycrystalline silicon to form a silicon melt; contacting the silicon melt with a seed crystal; withdrawing the seed crystal from the silicon melt to form a silicon ingot. Including, The method wherein said array of quartz grains maintains the dispersion of the quartz grains during ingot growth.

2. the array is added to the crucible assembly prior to heating the polycrystalline silicon to form the silicon melt; The method of claim 1.

3. the array having a width of between about 50 mm and about 75 mm and a depth of between 6 mm and 100 mm; The method of claim 1.

4. The connecting member is made of quartz. The method of claim 3.

5. The quartz particles have a rod-like, tubular, spherical, or irregular shape; The method of claim 1.

6. wherein the array is produced by 3D printing; The method of claim 1.

7. the array having a 3D scaffold; The method of claim 1.

8. The quartz particles are at least 0.1 cm ２ Quartz / quartz has a surface area to mass ratio in grams, The method of claim 1.

9. The quartz particles are at least 0.5 cm ２ Quartz / quartz has a surface area to mass ratio in grams, The method of claim 1.

10. The quartz particles are 0.1 cm ２ Quartz / grams of quartz to 10 cm ２ having a surface area to mass ratio of grams of quartz / grams of quartz; The method of claim 1.

11. The quartz particles are at least 10 cm ２ having a surface area ratio of quartz / silicon to kg of silicon charge; The method of claim 1.

12. The quartz particles are at least 50 cm ２ having a surface area ratio of quartz / silicon to kg of silicon charge; The method of claim 1.

13. The quartz particles are 10 cm ２ kg of quartz / silicon to 250 cm ２ having a surface area to silicon charge ratio of quartz / kg of silicon; The method of claim 1.

14. the crucible assembly includes a weir and a sidewall defining an outer melt zone between the weir and the sidewall, and the array is added to the outer melt zone; The method of claim 1.

15. the weir is a first weir, the crucible assembly includes a second weir radially inward from the first weir, the first weir and the second weir define an intermediate melt zone between the first weir and the second weir, and the second weir defines an inner melt zone within the second weir; 15. The method of claim 14.

16. the crucible assembly comprises a first weir, a second weir radially inward from the first weir, and a sidewall, the first weir and the sidewall defining an outer melt zone between the first weir and the sidewall, the first weir and the second weir defining an intermediate melt zone between the first weir and the second weir, the second weir defining an inner melt zone within the second weir, and the array being added to the intermediate melt zone; The method of claim 1.

17. the silicon ingot is grown in a continuous Czochralski process in which polycrystalline silicon is added to the melt during ingot growth; The method of claim 1.

18. No quartz is added to the melt during ingot growth; 18. The method of claim 17.

19. A method of forming a single crystal silicon ingot, comprising: adding solid phase polycrystalline silicon to the crucible assembly; adding an array of quartz grains to the crucible assembly, wherein the array includes a plurality of quartz grains and a plurality of connecting members connecting adjacent quartz grains, the connecting members being solid rods; heating the polycrystalline silicon to form a silicon melt; contacting the silicon melt with a seed crystal; withdrawing the seed crystal from the silicon melt to form a silicon ingot. A method comprising:

20. A method of forming a single crystal silicon ingot, comprising: adding solid phase polycrystalline silicon to the crucible assembly; adding an array of quartz grains to the crucible assembly, wherein the array includes a plurality of quartz grains and a plurality of connecting members connecting adjacent quartz grains, the connecting members forming a scaffold, the scaffold incorporating a second structure having a surface area of ​​quartz within the scaffold; heating the polycrystalline silicon to form a silicon melt; contacting the silicon melt with a seed crystal; withdrawing the seed crystal from the silicon melt to form a silicon ingot. A method comprising:

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