Synthetic crucible with edge coating

Abstract

A consensus quartz crucible for holding a silicon melt during growth of a monocrystalline silicon ingot is disclosed. The crucible may include a coating disposed along an edge on the inner and other surfaces of the crucible body. The coating extends only downwardly along a sidewall portion of the crucible and may extend to or beyond a melt line of the crucible.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. non-provisional patent application No. 17 / 897,677, filed on August 29, 2022, the entirety of which is incorporated herein by reference. Technical Field

[0003] The field of the present disclosure relates to crucibles for growing single crystal silicon ingots by the Czochralski process, and in particular, to synthetic crucibles including an edge coating. Background Art

[0004] Quartz crucibles are commonly used to hold silicon melt during the Czochralski silicon single crystal growth process. During ingot growth, the crucible softens and, in some cases, deforms. This crucible deformation can cause the crucible to contact components of the hot zone including the heat shield, which can cause loss of the zero-dislocation ingot.

[0005] Synthetic quartz can be used as a liner in the crucible to reduce impurities introduced into the melt during ingot growth.Synthetic quartz crucibles can be characterized by increased melt vibrations, which cause additional neck thrusts and increase retests.

[0006] There is a need for synthetic quartz crucibles that resist deformation and improve crucible smoothness and increase zero dislocation success rate.

[0007] This section is intended to introduce the reader to various aspects of the technology that may be related to the various aspects of the present disclosure that will be described and / or claimed below. We believe that this discussion is helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Therefore, it should be understood that these statements should be interpreted in this light and should not be interpreted as an admission of the prior art. Summary of the invention

[0008] One aspect of the present disclosure relates to a crucible for holding a silicon melt. The crucible includes a body having a bottom surface and a sidewall extending upward from the bottom surface. The bottom surface and the sidewall define a cavity for holding the silicon melt. The sidewall has a top, an inner surface, and an outer surface. The sidewall has a height extending from the bottom surface to the top of the sidewall. The body includes synthetic quartz. A coating is disposed on a first inner surface region of the inner surface of the sidewall. The coating includes magnesium, calcium, strontium, or barium. The first inner surface region extends only from the top of the sidewall to a distance D1 from the top of the sidewall. The distance D1 is less than the height of the sidewall.

[0009] Another aspect of the present disclosure relates to a method for producing a crucible. A body is provided having a bottom surface and a sidewall extending upward from the bottom surface. The bottom surface and the sidewall define a cavity for holding a silicon melt. The sidewall has a top, an inner surface, and an outer surface. The sidewall has a height extending from the bottom surface to the top of the sidewall. The body comprises synthetic quartz. A coating is applied to a first inner surface region of the inner surface of the sidewall. The coating comprises magnesium, calcium, strontium, or barium. The first inner surface region extends only from the top of the sidewall to a distance D1 from the top of the sidewall. The distance D1 is less than the height of the sidewall.

[0010] Yet another aspect of the present disclosure relates to a method for forming a single crystal silicon ingot. An initial charge of polycrystalline silicon is added to a crucible. The crucible includes a body having a bottom surface and a sidewall extending upward from the bottom surface. The bottom surface and the sidewall define a cavity for holding the silicon melt. The sidewall has a top, an inner surface, and an outer surface. The sidewall has a height extending from the bottom surface to the top of the sidewall. The body includes synthetic quartz. A coating is disposed on a first inner surface region of the inner surface of the sidewall. The coating includes magnesium, calcium, strontium, or barium. The first inner surface region extends only from the top of the sidewall to a distance D1 from the top of the sidewall. The distance D1 is less than the height of the sidewall. The initial charge of polycrystalline silicon is heated to cause a silicon melt to form in the crucible. A silicon seed crystal is brought into contact with the silicon melt. The silicon seed crystal is extracted to grow a single crystal silicon ingot.

[0011] There are various improvements with respect to the features mentioned in the above aspects of the present disclosure. Further features may also be incorporated into the above aspects of the present disclosure. These improvements and additional features may exist independently or in any combination. For example, various features discussed below with respect to any illustrative embodiment of the present disclosure may be incorporated into any of the above aspects of the present disclosure alone or in any combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a cross section of an ingot puller apparatus prior to silicon ingot growth;

[0013] Figure 2 During the growth of silicon ingots Figure 1 A cross section of an ingot puller device;

[0014] Figure 3 yes Figure 1 A perspective view of a crucible body of a crucible of an ingot puller apparatus;

[0015] Figure 4 is a perspective view of a crucible body with melt line and edge coating distances D1 and D2 shown;

[0016] Figure 5 is a perspective view of another embodiment of a crucible body with melt line and edge coating distances D1 and D2 shown;

[0017] Figure 6 yes Figure 1 A cross section of a crucible of an ingot puller apparatus;

[0018] Figure 7 is a cross-section of another embodiment of a crucible;

[0019] Figure 8 including a graph showing the neck tests and the number of protrusions for a crucible having an edge coating that did not extend to the melt line and a crucible having an edge coating that did extend to the melt line;

[0020] Fig. 9 comprising a histogram showing the frequency of depletion zero dislocation states in the crown / early body of a crucible having an edge coating that does not extend to the melt line and a crucible having an edge coating that does extend to the melt line; and

[0021] Fig.10 Included are bar graphs showing the normalized population ratios and attempts for crucibles having edge coatings that do not extend to the melt line and crucibles having edge coatings that do extend to the melt line.

[0022] Corresponding reference characters indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION

[0023] refer to Figure 1 , the present disclosure relates to a coated crucible 102 (e.g., an edge-coated crucible) for holding a silicon melt in an ingot puller apparatus 100. The ingot puller apparatus 100 and its crucible 102 are suitable for growing a single crystal silicon ingot 113 ( Figure 2 ).

[0024] Crucible 102 includes a crucible body 103 ( Figure 3 ), as will be further described below. The crucible body 103 has a bottom surface 101 and a side wall 114 extending from the bottom surface 101. The bottom surface 101 and the side wall 114 define a cavity 144 for holding silicon melt.

[0025] The side wall 114 is substantially vertical and cylindrical. The side wall 114 of the crucible body 103 has an inner surface 112 and an outer surface 120. The side wall 114 has a top 115 and a height H extending from the bottom surface 101 to the top 115. 114 The bottom surface 101 of the crucible body includes a curved portion 147 of the crucible body 103 that extends below the sidewall 131. The portion of the top 115 of the crucible body 103 adjacent to the sidewall 114 may be referred to herein as the "rim" of the crucible.

[0026] The crucible body 103 may be made of any material suitable for holding a silicon melt. For example, the crucible body 103 may be made of quartz. In some embodiments, the crucible body may contain synthetic quartz. For example, the crucible body 103 may include a synthetic quartz lining, so that the inner surface 112 of the crucible body 103 that contacts the melt is synthetic quartz. Synthetic quartz can be made by a synthetic process, such as quartz being made by hydrothermal synthesis. To form a synthetic quartz crucible, natural sand can be arc fused to form a crucible body shell and synthetic sand can be arc fused to the inner surface of the shell as a lining. The synthetic sand lining can have a relatively smaller impurity level than the natural sand shell (e.g., 5 to 10 times smaller). For example, natural sand may have an impurity concentration of at least 5 ppm aluminum, at least 0.1 ppm calcium, at least 0.1 ppm iron, at least 0.1 ppm potassium, at least 0.05 lithium, at least 0.3 ppm sodium, and at least 0.5 ppm titanium, while synthetic sand may have a concentration of less than 0.01 ppm aluminum, less than 0.01 ppm calcium, less than 0.075 ppm iron, less than 0.01 ppm potassium, less than 0.01 ppm lithium, less than 0.01 ppm potassium, and less than 0.01 ppm titanium. Crucible body 103 (including any lining thereof) may have any thickness that allows the crucible to function as described herein.

[0027] At least a portion of the inner and outer surfaces 112, 120 of the sidewall 114 of the crucible body 103 described above may be coated with a coating composition. The coating composition may include an oxide or carbonate of magnesium, calcium, strontium, or barium (e.g., a hydroxide thereof, such as Ba(OH)). In some embodiments, the coating composition includes barium hydroxide or barium carbonate, such as Ba(OH)2 or BaCO3.

[0028] The oxide may be dissolved or suspended in a solution or carrier (e.g., deionized water). The coating composition may be applied to the first inner surface region 121 of the inner surface 112 of the body 103 and to the first outer surface region 123 of the outer surface 120 of the body 103. The hydroxide or carbonate may be dissolved or suspended in a solution or carrier (e.g., deionized water or a mixture of water and isopropyl alcohol). The coating composition may be applied to the first inner surface region 121 of the inner surface 112 of the body 103 and to the first outer surface region 123 of the outer surface 120 of the body 103.

[0029] The first inner surface area 121 to which the coating is applied extends only from the top 115 of the side wall 114 to a distance D1 from the top of the side wall. This distance D1 is less than the height H of the side wall 114. 114 The first outer surface area 123 extends only from the top 115 of the side wall 114 to a distance D2 from the top of the side wall 114. This distance D2 is less than the height H of the side wall 114. 114 D1 and D2 can be Figures 3 to 5 The same distance is shown in , or different distances as in other embodiments.

[0030] In some embodiments, D1 (and optionally D2) corresponds to the melt line ML ( Figure 1 ). The melt line ML is the location of the inner surface 112 of the sidewall at which the surface 111 of the melt 104 interfaces with the crucible 102 during the "steady phase" of the ingot growth process (i.e., the coating extends down to the melt line ML). Figure 4 As shown in FIG. 5 , the melt line ML has a width W (i.e., the melt line is a band formed on the inner surface of the crucible), which is the width where the crucible is eroded at the interface during the stable phase. This width is caused by the different centrifugal forces, neck growth, and crown growth applied to the melt during different crucible rotation rates in the stable phase. This width can be at least 1 mm, at least 5 mm, or at least 10 mm (e.g., 1 mm to 20 mm or 5 mm to 15 mm). The coating can extend down to the top of the melt line ML, the bottom of the melt line ML, to a point between the top and bottom of the melt line ML, or even below the melt line ML, as will be described below ( Figure 5 ).

[0031] In some embodiments and Figure 5 , the coating extends from the top 115 of the crucible to a distance D1 (and optionally the coating extends to a distance D2 on the first outer surface area 123) below the melt line ML. For example, the length that distance D1 extends below the melt line (i.e., below the bottom of the melt line ML) can be at least 1 times the width of the melt line ML, or at least 5 times the width of the melt line ML, from 1 to 10 times the width of the melt line ML, or from 1 to 5 times the width of the melt line ML. This length that the coating extends below the melt line ML can be at least 5 mm, at least 10 mm, at least 25 mm, at least 50 mm, at least 100 mm, or from 5 mm to 100 mm, from 10 mm to 100 mm, or 10 mm to 25 mm below the melt line.

[0032] The inner surface 112 of the crucible body 103 can include a second inner surface region 125 extending from D1 to the bottom surface 101 of the crucible body 103. In some embodiments, the second inner surface region 125 (or optionally 101) does not have a coating disposed on the region 125 (i.e., other than the synthetic quartz lining of the crucible body 103). In other embodiments (e.g., natural sand crucibles), at least a portion of the second inner surface region 125 (and optionally 101) does have a coating disposed thereon, wherein the coating is different from the coatings described above.

[0033] The coating composition may be applied to the first inner surface region 121 and the first outer surface region 123 by dipping the crucible into the coating composition. In other embodiments, the coating is applied by chemical vapor deposition, plasma spraying, brushing, aerosol spraying, pouring, or any combination thereof. The coating may be applied in a single coating or multiple times to achieve the desired thickness. The final coating may have a thickness of at least about 1 μm.

[0034] After applying the coating composition to the first inner surface region 121 and the first outer surface region 123, the composition can be dried to evaporate its carrier (e.g., water). In general, the crucible can be dried under any atmosphere, including, for example, atmospheric air, nitrogen, argon, or mixtures thereof. In general, when atmospheric air is utilized, most, if not all, of the carrier evaporates after about 20 minutes, and in other embodiments after about 30 minutes or even 40 minutes. The drying time can be substantially reduced by increasing ventilation, such as by using circulating air. In general, the coating is dried when the coating does not adhere to or transfer material to a person's fingers that come into contact with the coating.

[0035] The coating composition may be applied and dried several times to increase the thickness of the coating. Each coating may be air dried to remove the carrier before applying another coating. Alternatively or additionally, heating may be utilized. In some embodiments, the crucible is heated to at least about 150° C., to at least about 200° C., to at least about 300° C., to at least about 400° C., or even to at least about 750° C. to dry and sinter the coating composition. The crucible may be heated for at least about 1 hour, and in other embodiments, at least about 2 hours, at least about 3 hours, or from about 1 hour to about 5 hours.

[0036] The crucible can be heated in the presence of an inert gas such as, for example, nitrogen, helium, or argon. Atmospheric air can also be used as the atmosphere during heating but is less preferred because it introduces oxygen into the coating. Furthermore, as will be appreciated by those skilled in the art, the materials of construction of the furnace and the gas flow can be controlled to avoid oxidation of the coating.

[0037] In some embodiments, prior to applying the coating described above (which may be referred to herein as the "first" coating), a second coating is disposed on one or more portions of the inner and outer surfaces 112, 120. For example, the second coating 133 ( Figure 6 ) can be disposed on at least a portion of the outer surface of the crucible. The second coating 133 can be disposed on a second outer surface region 127 of the outer surface 120 of the sidewall 114. The second outer surface region 127 is formed from the first outer surface region 123 ( Figure 3) extends to the bottom surface 101. The second coating 133 may also be disposed on the first outer surface region 123 (i.e., between the crucible body 103 and the first coating 109. The second coating 133 is different from the first coating 109. For example, the second coating 133 may include aluminum. In some embodiments, the second coating 133 including aluminum is not applied over the melt line ML.

[0038] Reference Figure 7 In other embodiments, the crucible 102 does not include a second coating on the outer surface 120 of the sidewall (or the inner surface 112 of the sidewall). The coating 109 described above is applied directly to the outer surface 120 and / or directly to the inner surface 112.

[0039] The coated crucible 102 described above can be used to prepare a single crystal silicon ingot by the Czochralski process. The crucible can generally be used in any ingot puller apparatus configured to pull a single crystal silicon ingot. An example ingot puller apparatus (or more simply, an "ingot puller") is Figure 1 The ingot puller apparatus 100 includes a crucible 102 described above for holding a melt 104 of silicon. The crucible 102 is supported by a susceptor 106. The ingot puller apparatus 100 includes a crystal puller housing 108 that defines a portion of a silicon ingot 113 ( Figure 2 )'s growth chamber 152.

[0040] Crucible 102 has a bottom surface 129 and a side wall 117 extending from a base or bottom surface 129. Side wall 117 is generally vertical and cylindrical. Bottom surface 129 of crucible 102 includes a curved portion of crucible 102 extending below side wall 131. Crucible 102 is supported by susceptor 106. Susceptor 106 is supported by shaft 105. Susceptor 106, crucible 102, shaft 105, and ingot 113 ( Figure 2 ) have a common longitudinal axis A or "pulling axis" A.

[0041] A pulling mechanism 132 is disposed within the ingot puller apparatus 100 for growing and pulling an ingot 113 from the melt 104. The pulling mechanism 132 includes a pulling cable 118, a seed crystal holder or chuck 155 coupled to an end of the pulling cable 118, and a silicon seed crystal 122 coupled to the seed crystal holder or chuck 155 for initiating crystal growth. One end of the pulling cable 118 is connected to a pulley (not shown) or a roller (not shown) or any other suitable type of lifting mechanism (such as a shaft), and the other end is connected to the chuck 155 that holds the seed crystal 122. In operation, the seed crystal 122 is lowered to contact the melt 104. The pulling mechanism 132 is operated to cause the seed crystal 122 to rise. This causes the single crystal ingot 133 ( Figure 2 ).

[0042] During heating and crystal pulling, crucible drive unit 107 (e.g., a motor) rotates crucible 102 and susceptor 106. Lift mechanism 132 raises and lowers crucible 102 along pull axis A during the growth process. Figure 1 , crucible 102 may be in the lowest position (near bottom heater 126) where an initial charge of solid polycrystalline silicon previously added to crucible 102 is melted. Crystal growth is initiated by contacting melt 104 with seed crystal 122 and lifting seed crystal 122 by pulling mechanism 132. As the ingot grows, silicon melt 104 is consumed and the height of the melt in crucible 102 decreases. Crucible 102 and susceptor 106 may be raised to maintain melt surface 111 at or near a position relative to ingot puller apparatus 100 ( Figure 2 ) in the same location.

[0043] The crystal drive unit (not shown) can also rotate the pulling cable 118 and the ingot 113 ( Figure 2 ) rotation (e.g., counter-rotation). In embodiments using co-rotation, the crystal drive unit can rotate the pull cable 118 in the same direction that the crucible drive unit 107 rotates the crucible 102. In addition, the crystal drive unit raises and lowers the ingot 113 relative to the melt surface 111 as needed during the growth process.

[0044] The ingot puller apparatus 100 may include an inert gas system to introduce and extract an inert gas, such as argon, from the growth chamber 152. The ingot puller apparatus 100 may also include a dopant feed system (not shown) for introducing dopants into the melt 104.

[0045] According to the Czochralski single crystal growth process, a certain amount of polycrystalline silicon or polysilicon is fed into the crucible 102. The initial semiconductor or solar grade material introduced into the crucible is melted by heat provided from one or more heating elements to form a silicon melt in the crucible. The ingot puller apparatus 100 includes a bottom insulation 110 and a side insulation 124 to keep the heat in the puller apparatus. In the illustrated embodiment, the ingot puller apparatus 100 includes a bottom heater 126 disposed below the bottom surface 129 of the crucible. The crucible 102 can be moved into relatively close proximity to the bottom heater 126 to melt the polycrystalline silicon fed to the crucible 102.

[0046] Before ingot growth, melt 104 may be stabilized in a stationary phase to cool the melt. During the stationary phase (and subsequent neck and crown growth), a melt line ML forms in the crucible due to corrosion at the interface between surface 111 of melt 104 and crucible 102.

[0047] To form an ingot after the stable phase, the seed crystal 122 is brought into contact with the surface 111 of the melt 104. The pulling mechanism 132 is operated to pull the seed crystal 122 from the melt 104. Figure 2 , ingot 113 includes a crown portion 142 where the ingot tapers and decreases outward from seed crystal 122 to reach a target diameter. Ingot 113 includes a constant diameter portion 145 or cylindrical "body" of the crystal that grows by increasing the pull rate. The body 145 of ingot 113 has a relatively constant diameter. Ingot 113 includes a tail or tail cone (not shown) where the diameter of the ingot tapers after the body 145. When the diameter becomes sufficiently small, ingot 113 is then separated from melt 104. Once ingot 113 has grown, the ingot is cut into multiple silicon substrates (i.e., wafers).

[0048] The ingot puller apparatus 100 includes side heaters 135 and a susceptor 106 surrounding the crucible 102 to maintain the temperature of the melt 104 during crystal growth. The crucible 102 moves upward and downward along the pulling axis A and the side heaters 135 are radially disposed outside the crucible sidewall 131. The side heaters 135 and the bottom heater 126 can be any type of heater that allows the side heaters 135 and the bottom heater 126 to operate as described herein. In some embodiments, the heaters 135, 126 are resistive heaters. The side heaters 135 and the bottom heater 126 can be controlled by a control system (not shown) so that the temperature of the melt 104 is controlled during the entire pulling process.

[0049] The ingot puller apparatus 100 may include a heat shield 151. The heat shield 151 may cover the ingot 113 and may be disposed within the crucible 102 during crystal growth ( Figure 2 ).

[0050] The ingot growth process may be a batch process, in which polysilicon is not added to the crucible 102 during ingot growth. In other embodiments, a continuous Czochralski process is used, in which polysilicon is added to the crucible 102 during ingot growth (e.g., in which the crucible has one or more fluid barriers that divide the crucible into various zones). In some embodiments, a devitrification promoter (e.g., a barium source) is added to the feed of polysilicon or the silicon melt to modify the properties of the crucible below the melt line ML during ingot growth. The devitrification promoter modifies the region below the melt line, while the coating described above stiffens the crucible matrix above the melt line. The growth process may use magnetic Czochralski growth (e.g., HMCZ) or non-magnetic Czochralski growth. In some embodiments, no magnetic field is applied during ingot growth.

[0051] The high temperature ingot growth process can modify the coating. For example, in embodiments where barium is used, the barium in the barium oxide coating can react with the material of the quartz crucible and the barium can dissolve into the quartz crucible body 103.

[0052] The crucible and ingot growth process of the present disclosure has several advantages over conventional crucible and ingot growth processes. The stiffness of the upper portion of the crucible is enhanced by coating the upper portion of the crucible above the melt line, which reduces deformation. A deformed crucible may contact the heat shield, which may cause loss of zero dislocations (ZD) in the crucible. Cavitation is reduced by not coating in the area below the coated area. The coating may extend below the melt line (e.g., from 1 to 10 times the width of the melt line) to reduce vibrations caused by the wavy surface just below the melt line, which is more pronounced in synthetic quartz crucibles. The coating maintains crucible smoothness even over longer run times. Extended edge coatings bring more stable neck control, which helps remove dislocations in the neck. This brings an increased crown and early body zero dislocation success rate and a higher incidence of zero dislocations in the body. Extended coatings result in fewer neck attempts and improve the re-feeding capacity of the crucible. Extended coatings reduce melt vibrations during neck growth, which reduces neck advances in both magnetic Czochralski and non-magnetic Czochralski. The coating can reduce crucible dissolution at the melt line and / or fracture of quartz crucible particles into the melt, which improves the zero dislocation success rate.

[0053] Examples

[0054] The process of the present disclosure is further illustrated by the following examples. These examples should not be considered as limiting.

[0055] Example 1: Comparison of Crucibles with Barium Coatings Not Extending to the Fusion Line and Those Extending to the Fusion Line

[0056] Synthetic quartz crucibles were used to grow three single crystal silicon ingots: an older generation ingot (R0), an ingot grown after a recharge of polysilicon (R1), and an ingot grown after a second recharge of polysilicon (R2). The number of neck trials (i.e., the number of neck attempts) and the number of zero dislocation loss breakthrough events are shown for each ingot attempt. The first set of crucibles had a barium edge coating (inside and outside the surface) that stopped about 0 mm to 5 mm above the melt line ("short edge coating"), while the second set included a barium edge coating that extended to about 1 inch below the melt line (about 3 times the width of the melt line) on the inside and outside of the surface ("extended edge coating"). As Figure 8 As shown in , the extended edge coating reduces neck attempt and thrust events by reducing melt vibrations, especially in re-feed ingots. Such re-feed ingots are more susceptible to time-dependent crucible damage, which is aggravated by increased attempts and thrusts. If these events are reduced, the overall cycle time is reduced resulting in less overall crucible damage.

[0057] Fig. 9Compare the crown / early body frequencies of the depleted (normalized) zero dislocation state. Fig. 9 As shown in , the crucible with an extended edge coating maintains zero dislocation more frequently than with a short edge coating.

[0058] Fig.10 Respectfully, the overall ratio of short edge coating to extended edge coating and attempts. Fig.10 As shown in , for a crucible with an extended edge coating, fewer attempts are required to form a whole.

[0059] As used herein, the terms "about," "substantially," "substantially," and "approximately" when used in conjunction with ranges of size, concentration, temperature, or other physical or chemical properties or characteristics are meant to encompass variations that may exist in the upper and / or lower limits of the range of the property or characteristic, including variations resulting, for example, from rounding, measurement method, or other statistical variations.

[0060] When introducing elements of the present disclosure or embodiments thereof, the articles "a," "an," and "the" are intended to mean that there are one or more 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. The use of terms indicating a particular orientation (e.g., "top," "bottom," "side," etc.) is for convenience of description and does not require any particular orientation of the items being described.

[0061] As various changes could be made in the above constructions 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 shall be interpreted as illustrative rather than limiting.

Claims

1. A crucible for holding a silicon melt, the crucible comprising: a body having a bottom surface and sidewalls extending upward from the bottom surface, the bottom surface and the sidewalls defining a cavity for holding the silicon melt, the sidewall having a top, an inner surface, and an outer surface, the sidewall having a height extending from the bottom surface to the top of the sidewall, the body comprising synthetic quartz; and A coating disposed on a first inner surface region of the inner surface of the sidewall, the coating comprising magnesium, calcium, strontium or barium, the first inner surface region extending only from the top of the sidewall to a distance D1 from the top of the sidewall, wherein the distance D1 is less than the height of the sidewall.

2. The crucible of claim 1, wherein a second inner surface region of the inner surface of the sidewall extends from the first inner surface region to the bottom surface of the crucible, the second inner surface region not comprising a coating.

3. The crucible of claim 1 or claim 2, wherein the coating is disposed on a first outer surface region of the outer surface of the sidewall, the first outer surface region extending only from the top of the sidewall to a distance D2 from the top of the sidewall, wherein the distance D2 is less than the height of the sidewall.

4. The crucible of claim 3 , wherein the coating is a first coating, a second outer surface region of the outer surface of the sidewall extends from the first outer surface region to the bottom surface of the body, a second coating is disposed on the first outer surface region and the second outer surface region, the second coating comprises aluminum, and the second coating is disposed between the crucible body and the first coating.

5. The crucible of claim 3, wherein the coating is the only coating disposed on the outer surface of the sidewall.

6. The crucible of any one of claims 1 to 5, wherein the first inner surface region extends at least to the melt line.

7. The crucible of any one of claims 1 to 5, wherein the first inner surface region extends below the melt line.

8. The crucible of claim 7, wherein the coating extends at least 5 mm below the melt line, or at least 10 mm, at least 25 mm, at least 50 mm, at least 100 mm, or from 5 mm to 100 mm, from 10 mm to 100 mm, or from 10 mm to 25 mm below the melt line.

9. The crucible of any one of claims 1 to 8, wherein the coating comprises an oxide or carbonate of magnesium, calcium, strontium or barium.

10. The crucible of any one of claims 1 to 8, wherein the coating comprises barium oxide.

11. The crucible of any one of claims 1 to 10, wherein the coating has a thickness of at least about 1 μm.

12. A method for producing a crucible, the method comprising: Providing a body having a bottom surface and sidewalls extending upward from the bottom surface, the bottom surface and the sidewalls defining a cavity for holding silicon melt, the sidewall having a top, an inner surface, and an outer surface, the sidewall having a height extending from the bottom surface to the top of the sidewall, the body comprising synthetic quartz; and A coating is applied to a first inner surface region of the inner surface of the sidewall, the coating comprising magnesium, calcium, strontium or barium, the first inner surface region extending only from the top of the sidewall to a distance D1 from the top of the sidewall, wherein the distance D1 is less than the height of the sidewall.

13. The method of claim 12, comprising applying the coating to a first outer surface region of the outer surface of the sidewall, the first outer surface region extending only from the top of the sidewall to a distance D2 from the top of the sidewall, wherein the distance D2 is less than the height of the sidewall.

14. The method of claim 13, wherein the coating is a first coating, a second outer surface region of the outer surface of the sidewall extends from the first outer surface region to the bottom surface of the crucible, a second coating is disposed on the first outer surface region and the second outer surface region, the second coating comprises aluminum, and the second coating is disposed between the crucible body and the first coating after applying the first coating.

15. The method of claim 13, wherein the coating is the only coating disposed on the exterior surface of the sidewall.

16. The method of any one of claims 12 to 15, wherein the first inner surface region extends at least to a melt line.

17. The method of claim 16, wherein the coating extends at least 5 mm below the melt line, or at least 10 mm, at least 25 mm, at least 50 mm, at least 100 mm, or from 5 mm to 100 mm, from 10 mm to 100 mm or from 10 mm to 25 mm below the melt line.

18. The method of any one of claims 12 to 17, wherein the coating comprises an oxide or carbonate of magnesium, calcium, strontium or barium.

19. The method of any one of claims 12 to 17, wherein the coating comprises barium oxide.

20. The method of any one of claims 12 to 19, wherein the coating is applied to a thickness of at least about 1 μm.

21. The method of any one of claims 12 to 20, wherein the inner surface is coated with the coating by dipping, chemical vapor deposition, plasma spraying, brushing, aerosol spraying, or pouring.

22. A method for forming a single crystal silicon ingot, comprising: An initial charge of polycrystalline silicon is added to a crucible comprising: a body having a bottom surface and sidewalls extending upward from the bottom surface, the bottom surface and the sidewalls defining a cavity for holding the silicon melt, the sidewall having a top, an inner surface, and an outer surface, the sidewall having a height extending from the bottom surface to the top of the sidewall, the body comprising synthetic quartz; and a coating disposed on a first inner surface region of the inner surface of the sidewall, the coating comprising magnesium, calcium, strontium, or barium, the first inner surface region extending only from the top of the sidewall to a distance D1 from the top of the sidewall, wherein the distance D1 is less than the height of the sidewall; heating the initial charge of polycrystalline silicon to cause a silicon melt to form in the crucible; contacting a silicon seed crystal with the silicon melt; and The silicon seed crystal is extracted to grow a single crystal silicon ingot.

23. The method of claim 22, wherein the coating is disposed on a first outer surface region of the outer surface of the sidewall, the first outer surface region extending only from the top of the sidewall to a distance D2 from the top of the sidewall, wherein the distance D2 is less than the height of the sidewall.

24. The method of claim 22 or claim 23, wherein the silicon melt is stabilized in a stable phase before contacting the silicon melt with the silicon seed crystal, the silicon melt forms a melt line in the crucible at an interface between a surface of the melt and the crucible, and the first inner surface area extends at least to the melt line.

25. The method of claim 22 or claim 23, wherein the silicon melt is stabilized in a stable phase before contacting the silicon melt with the silicon seed crystal, the silicon melt forms a melt line in the crucible at an interface between a surface of the melt and the crucible, and the first inner surface area extends below the melt line.

26. The method of claim 25, wherein the melt line has a width, and the coating extends below the melt line to a degree at least 1 times the width of the melt line or at least 5 times the width of the melt line, from 1 to 10 times the width of the melt line, or from 1 to 5 times the width of the melt line.

27. The method of claim 26, wherein the coating extends at least 5 mm below the melt line or at least 10 mm below the melt line, at least 25 mm, at least 50 mm, at least 100 mm, or from 5 mm to 100 mm, from 10 mm to 100 mm or from 10 mm to 25 mm.

28. The method of any one of claims 22 to 27, wherein the coating comprises an oxide or carbonate of magnesium, calcium, strontium or barium.

29. The method of any one of claims 22 to 27, wherein the coating comprises barium oxide.

30. The method of any one of claims 22 to 29, wherein the coating is applied to a thickness of at least about 1 μm.

31. The method of any one of claims 22-30, wherein the coating is a first coating and the crucible includes a second coating disposed on at least a portion of the outer surface of the body.

32. The method of claim 31 , wherein the second coating comprises aluminum.

33. The method of any one of claims 22-30, wherein the coating is the only coating disposed on the outer surface of the body.

34. The method of any one of claims 22 to 33, comprising adding a barium source to the feed of polycrystalline silicon or the silicon melt prior to pulling the silicon melt to modify properties of the crucible during ingot growth.

Images