JP7820140B2 - Quartz glass crucible - Google Patents

Description

The present invention relates to a quartz glass crucible used for pulling silicon single crystal ingots.

The Czochralski method (CZ method) is widely used for growing silicon single crystals. In this method, a seed crystal is brought into contact with the surface of molten silicon formed in a quartz glass crucible (hereinafter sometimes simply referred to as the "crucible"), and while the crucible is rotated, the seed crystal is pulled upward while rotating in the opposite direction, forming a single crystal at the bottom of the seed crystal.

The quartz glass crucible used to contain this silicon melt typically has a two-layer structure, with a transparent layer made of high-purity synthetic quartz glass on the inner surface and an opaque layer made of natural quartz glass with excellent thermal properties on the outer surface.

The rotating mold method is known as one example of a method for manufacturing such quartz glass crucibles. In the rotating mold method, natural quartz glass raw material powder is first layered on the inner surface of a rotating crucible-forming mold, and then synthetic quartz glass raw material powder is layered on the surface of this raw material powder layer to form a raw material powder layer. Next, this raw material powder layer is heated and melted from the inside to the outside using arc discharge, and then cooled, resulting in a two-layered quartz glass crucible with a synthetic quartz glass layer (transparent layer) formed on the inner surface and a natural quartz glass layer (opaque layer) formed on the outer surface (see Patent Document 1 below).

In the production of silicon single crystal ingots using a quartz glass crucible obtained by the manufacturing method described in Patent Document 1 below, the silicon melt descends from the bottom of the silicon single crystal toward the bottom of the crucible, then rises from the bottom of the crucible along the inner wall to near the melt surface, and then moves again toward the bottom of the silicon single crystal due to convection (Marangoni convection) within the crucible. During this process, microscopic bubbles are generated on the inner surface of the crucible, and the microscopic bubbles in the silicon melt rise to the melt surface along the inner wall of the crucible due to Marangoni convection. Most of the bubbles are released into the reduced-pressure Ar atmosphere, but some remaining bubbles move due to convection from the inner wall toward the silicon single crystal and are incorporated into the silicon single crystal. These bubbles can then become air pockets (pinholes).

Meanwhile, Patent Document 2 below discloses a quartz glass crucible that can reduce the number of bubbles that travel toward a silicon single crystal and thereby reduce the occurrence of air pockets in the silicon single crystal. The quartz glass crucible described in Patent Document 2 has a two-layer structure consisting of an outer layer and an inner layer. The inner layer has a corrugated inner surface formed by peaks and valleys between the silicon melt surface's silicon single crystal pulling start line and pulling end line. Furthermore, during the manufacturing process of the quartz glass crucible, a ring-shaped truncated portion containing 0.01 to 1 mass % of a crystallization accelerator (aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO), barium oxide (BaO), calcium carbonate (CaCO ₃ ), barium carbonate (BaCO ₃ ), etc.) is provided at the top of the opening. Crystallization is promoted by carrying out a melting process in this state. After the melting process is completed, the truncated portion containing the crystallization accelerator is removed to obtain the quartz glass crucible.

In the quartz glass crucible described in Patent Document 2 below, microbubbles in the silicon melt remain on the wavy inner surface of the crucible (grooves formed in the valleys) and are held in the grooves until they combine with successively generated microbubbles and grow to a size that is not affected by Marangoni convection. Once the bubbles that have combined in the grooves gain sufficient buoyancy, they escape the grooves and rise rapidly toward the silicon melt surface, where they are released into the reduced-pressure Ar gas atmosphere. This reduces the number of bubbles that move toward the silicon single crystal due to Marangoni convection, thereby reducing the occurrence of air pockets in the silicon single crystal.

JP 2012-17246 A WO 2009/107834

Patent Document 2 discloses that the corrugated inner surface (trap surface) of the crucible enlarges microbubbles, and these enlarged bubbles are then released into a reduced-pressure Ar gas atmosphere, thereby reducing the number of bubbles trapped in the silicon single crystal.

However, the manufacturing of the quartz glass crucible described in Patent Document 2 uses grinding as a method for forming the trap surface, which inevitably leads to tool contamination and problems such as tool marks impairing the smoothness of the inner surface. Furthermore, when smoothing the ground surface using an oxygen burner, there is a risk of normal processing contamination. In other words, there is a problem in that the quality of the quartz glass crucible is reduced by the grinding process and the burner-fired finish.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a quartz glass crucible that can reduce the occurrence of air pockets in silicon single crystals without using grinding as a method for forming trap surfaces.

The quartz glass crucible of the present invention is a quartz glass crucible used for pulling silicon single crystals, and is characterized by having a coating target area on the inner surface of the body, where a compound containing aluminum, an alkali metal element, or an alkaline earth metal element as a crystallization accelerator is applied in stripes.

In the quartz glass crucible of the present invention, heating during silicon single crystal formation causes thermal deformation of the coating target area due to the difference in viscosity between the coated and uncoated surfaces, forming an uneven trap surface on the inner surface. That is, on the trap surface formed in the coating target area, the low-viscosity uncoated surface sandwiched between the high-viscosity coated surfaces rises due to heating during silicon single crystal formation, forming at least one convex portion. Microbubbles in the silicon melt generated during silicon single crystal formation remain on the convex portion formed on the trap surface and are retained in the convex portion until they combine with other microbubbles that subsequently occur and grow larger. Bubbles that grow larger in the convex portion escape from the convex portion and rise (float) toward the silicon melt surface, where they are released from the silicon melt. This reduces the number of bubbles that travel toward the silicon single crystal via Marangoni convection in the silicon melt, thereby reducing the occurrence of air pockets in the silicon single crystal.

In the quartz glass crucible of the present invention, the coating target area is the area on the inner surface other than the silicon single crystal projection area and below the position of the silicon melt surface at the start of pulling the silicon single crystal.

In addition, in the quartz glass crucible according to the present invention, the spacing between the striped crystallization promoter coatings is preferably 5 mm or more and 50 mm or less. The crystallization promoter preferably contains at least one compound containing Al, Ba, Ca, Mg, or Sr. The element concentration of the crystallization promoter is preferably 0.1 μg/ ^cm2 or more and 1000 μg/ ^cm2 or less.

The quartz glass crucible of the present invention can reduce the occurrence of air pockets in silicon single crystals without using grinding processes to form trapping surfaces for retaining air bubbles.

FIG. 1 is a schematic diagram showing an example of a vitreous silica crucible manufacturing apparatus used to manufacture a vitreous silica crucible according to the present invention. FIG. 2 is a flow chart showing an example of a method for manufacturing a silica glass crucible according to the present invention. FIG. 3 is a cross-sectional view showing an example of the structure of a quartz glass crucible according to the present invention. FIG. 4 is a diagram showing an example of the shape of a trap surface formed on the inner surface of a silica glass crucible according to the present invention. FIG. 5 is a schematic cross-sectional view of a single crystal pulling apparatus.

An embodiment of a quartz glass crucible according to the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to this embodiment.

<Crucible manufacturing equipment>

Figure 1 is a schematic diagram showing an example of a quartz glass crucible manufacturing apparatus used to manufacture a quartz glass crucible according to the present invention. The quartz glass crucible manufacturing apparatus 1 of this embodiment uses a rotational mold method to manufacture, as an example, a quartz glass crucible with a two-layer structure, which has a transparent layer (inner layer) formed on the inner surface from high-purity synthetic quartz glass and an opaque layer (outer layer) formed on the outer surface from natural quartz glass with excellent thermal properties.

In Figure 1, the crucible molding die 2 of the silica glass crucible manufacturing apparatus 1 is composed of an inner member 3, which is made up of, for example, a mold with multiple through holes (not shown), and a holder 5 that holds the inner member 3 and has a ventilation section 4 on its outer periphery.

A rotating shaft 6 connected to a rotary drive source (not shown) is fixed to the lower part of the holder 5, and rotatably supports the crucible forming mold 2. The ventilation section 4 is connected to an exhaust port 8 provided in the center of the rotating shaft 6 via an opening 7 provided in the lower part of the holder 5, and is further connected to a pressure reduction mechanism 9. The quartz glass crucible manufacturing apparatus 1 of this embodiment is configured to suck the atmosphere inside the inner member 3 from the inner peripheral surface by operating the pressure reduction mechanism 9.

The silica glass crucible manufacturing apparatus 1 of this embodiment is also provided with a raw material powder supply mechanism for supplying silica glass raw material powder into the interior of the inner member 3, including a raw material supply nozzle 11 that sprays the silica glass raw material powder and a raw material cartridge (not shown) that contains the silica glass raw material powder. Examples of silica glass raw material powder that can be contained in the raw material cartridge include natural silica glass raw material powder and synthetic silica glass raw material powder.

A carrier gas such as air, nitrogen, oxygen, or argon is supplied to the raw material supply nozzle 11. By using a carrier gas, the silica glass raw material powder can be sprayed onto the inner member 3 or onto an already sprayed layer of silica glass raw material powder. Furthermore, spraying the silica glass raw material powder using a carrier gas can produce a denser raw material powder layer. The flow rate of the supplied carrier gas is preferably in the range of 0.5 m/s to 6.5 m/s.

Furthermore, by operating the pressure reducing mechanism 9, the atmosphere inside the inner member 3 is evacuated, and the pressure on the inner surface of the inner member 3 is set to a range of 1 kPa to 101.3 kPa. If silica glass raw material powder is sprayed under such a pressure environment, an even denser raw material powder laminate can be obtained.

In this embodiment, the raw material powder stack is formed by spraying silica glass raw material powder onto the inner surface of the inner member 3 of the rotating crucible forming mold 2 in an unheated, non-melting environment.

The quartz glass crucible manufacturing apparatus 1 of this embodiment is also provided with a heating and melting mechanism that heats and melts the raw material powder stack formed by the raw material powder supply mechanism. This mechanism includes an arc electrode 21 for arc discharge at the top facing the inner member 3, and a gas supply nozzle 22 that sprays gas such as air, nitrogen, oxygen, or argon onto a predetermined portion of the crucible.

<Method for manufacturing crucible>
Next, a method for manufacturing a silica glass crucible according to this embodiment will be described in detail. Fig. 2 is a flowchart showing an example of the method for manufacturing a silica glass crucible according to this embodiment.

First, the rotary drive source (not shown) of the quartz glass crucible manufacturing apparatus 1 is operated to rotate the rotary shaft 6 in the direction of the arrow (see Figure 1), thereby rotating the crucible forming mold 2 at a predetermined speed. The pressure reducing mechanism 9 is also operated to evacuate the atmosphere inside the inner member 3, bringing the pressure on the inner surface of the inner member 3 to between 1 kPa and 101.3 kPa.

Then, a raw material powder stack is formed by spraying silica glass raw material powder from the raw material supply nozzle 11 onto the inner member 3. When spraying silica glass raw material powder into the rotating crucible forming mold 2 as described above, for example, coarse-grained natural silica glass raw material powder is sprayed first, and then fine-grained synthetic silica glass raw material powder is sprayed onto the surface.

Specifically, natural silica glass raw material powder is first sprayed into the crucible mold 2, and is layered on the inner surface of the inner member 3 of the crucible mold 2 by the centrifugal force of the rotary drive source and the suction force of the vacuum mechanism 9. This forms a layer of natural silica glass raw material powder (outer layer). Then, following the natural silica glass raw material powder, synthetic silica glass raw material powder is sprayed into the crucible mold 2, and this synthetic silica glass raw material powder is layered on the inner surface of the natural silica glass raw material powder layer by the centrifugal force of the rotary drive source and the suction force of the vacuum mechanism 9. This forms a layer of synthetic silica glass raw material powder (inner layer), and a two-layer raw material powder layer having an inner layer and an outer layer is obtained (Step S1).

Then, in an atmospheric environment, while maintaining the reduced pressure by the pressure reducing mechanism 9 and the predetermined rotation speed of the crucible mold 2, electricity is passed through the arc electrode 21 to heat the raw material powder stack from the inside. In this embodiment, when electricity is passed through the arc electrode 21, the raw material powder stack is heated and melted from the inside, and the surface layer is first vitrified (a synthetic silica glass layer is formed). The pressure reduction by the pressure reducing mechanism 9, the rotation of the crucible mold 2, and the heating and melting by the arc electrode 21 continue, until the raw material powder stack is vitrified all the way to the outer surface (a natural silica glass layer is formed), and a two-layered crucible molded body is formed (Step S2).

Then, nitrogen gas or oxygen gas is sprayed from the gas supply nozzle 22 to cool the crucible molded body, and after cooling, the upper end of the crucible molded body is cut off to obtain the main body of the quartz glass crucible (step S3).

Finally, a crystallization accelerator is applied in stripes to the inner surface of the body obtained in step S3; specifically, a barium (Ba) coating is applied in stripes to obtain the quartz glass crucible of this embodiment (step S4). Figure 3 is a cross-sectional view showing an example of the structure of the quartz glass crucible 40 of this embodiment. The quartz glass crucible 40 of this embodiment has a two-layer structure, with a transparent layer (inner layer) 40a formed on the inner surface from high-purity synthetic quartz glass, and an opaque layer (outer layer) 40b formed on the outer surface from natural quartz glass with excellent thermal properties.

In the quartz glass crucible 40 of this embodiment, the Ba-coated area on the inner surface includes at least the range from the silicon melt surface at the start of pulling the silicon single crystal to the boundary between the body and corners (the corner start position) (the required coating area shown in Figure 3). For example, this is the area on the crucible inner surface other than the silicon single crystal projection area and below the silicon melt surface at the start of pulling the silicon single crystal. The Ba coating is applied in stripes without interruption in the circumferential direction in the Ba-coated area on the inner surface of the crucible. In this embodiment, as an example, the Ba coating is applied in stripes without interruption in the circumferential direction in the required coating area. The application interval of the striped Ba coating is set to 5 mm to 50 mm, and at least one Ba-uncoated area (uncoated surface) is formed in the Ba-coated area. This means that at least two Ba-coated areas (coated surfaces) are formed.

Furthermore, in the quartz glass crucible 40 of this embodiment, the Ba concentration of the crystallization accelerator is set to a range of 0.1 μg/cm ² to 1000 μg/cm ^2. However, the Ba concentration of the crystallization accelerator is set on the condition that the Ba concentration in the silicon melt in the crucible is below 30 ppm in the process of forming a silicon single crystal. This is because if the Ba concentration in the silicon melt exceeds a certain value, crystallization will also be promoted in areas (non-coated surfaces) other than the Ba-coated area (coated surface).

Furthermore, in the quartz glass crucible 40 of this embodiment, it is desirable to apply a uniform Ba coating to the entire area ranging from the silicon melt surface to the mouth of the main body at the start of pulling the silicon single crystal, rather than in stripes (the uniformly coated area shown in Figure 3). This is because, as crystallization progresses, the area to be Ba-coated is not supported by the silicon melt, and deformation due to the striped Ba coating on the Ba-coated area may lead to problems such as the mouth of the crucible collapsing.

In the quartz glass crucible 40 of this embodiment, the width of the Ba-coated area (coated surface) and the width of the Ba-uncoated area (uncoated surface) do not need to be uniform and can be any width. Furthermore, the width of the coated surface can be any dimension determined by parameters such as the crucible size, number of stripes, and coating spacing.

Furthermore, in this embodiment, Ba is used as an example of the crystallization accelerator used in the coating, but this is not limited thereto, and any compound containing aluminum (Al), an alkali metal element, or an alkaline earth metal element may be used. For example, one or more oxides of elements such as Ba, Al, Ca, Mg, and Sr may be used. However, some compounds such as barium carbonate (BaCO ₃ ) are not preferred because they tend to uniformly crystallize the silicon melt contact surface due to diffusion. For example, it is preferable to use a compound such as barium hydroxide (Ba(OH) ₂ ), which tends to crystallize only the surface to which the crystallization accelerator is applied.

<Formation of trap surface>
Furthermore, in the quartz glass crucible 40 of this embodiment manufactured as described above, a trap surface for retaining microbubbles generated in the silicon melt is formed in the Ba-coated area on the inner surface during the process of growing a silicon single crystal.

The process for forming a trap surface in the Ba-coated region will now be described. For example, when growing a silicon single crystal ingot using a quartz glass crucible 40, raw polysilicon is first loaded into the quartz glass crucible 40, and the furnace housing the crucible is filled with a predetermined atmosphere (mainly an inert gas such as argon gas) to melt the raw polysilicon by heating, producing a silicon melt. A seed crystal is then brought into contact with the surface of the silicon melt, and while the crucible is rotated, the seed crystal is pulled upward while rotating in the opposite direction, forming a silicon single crystal ingot at the bottom of the seed crystal.

In this case, the quartz glass crucible 40 of this embodiment undergoes thermal deformation in the Ba-coated region due to the difference in viscosity between the coated and uncoated surfaces when heated during silicon single crystal formation. This results in a quartz glass crucible 50 with an uneven trap surface formed on its inner surface. Figure 4 is a diagram showing an example of the shape of the trap surface formed on the inner surface of the quartz glass crucible of this embodiment. In Figure 4, the trap surface formed in the Ba-coated region is heated during silicon single crystal formation, causing the low-viscosity uncoated surface sandwiched between the high-viscosity coated surfaces to bulge, forming at least one continuous protrusion 51 in the circumferential direction. In this embodiment, as an example, protrusions 51 are formed on three uncoated surfaces sandwiched between four coated surfaces.

In the quartz glass crucible 50 shown in Figure 4 after the formation of the trapping surface, the silicon melt descends from the bottom of the silicon single crystal toward the bottom of the crucible, then rises from the bottom of the crucible along the inner wall to near the melt surface, and then moves again toward the bottom of the silicon single crystal by convection (Marangoni convection). During this process, the silicon melt (Si) reacts with the inner surface of the crucible ( _SiO2 ), generating SiO gas (microbubbles). The microbubbles in the silicon melt remain on the convex portions 51 formed on the trapping surface and are retained there until they combine with other microbubbles that are generated and grow to a size that is not affected by Marangoni convection. When the bubbles that combine and grow large at the convex portions 51 gain sufficient buoyancy, they escape from the convex portions 51 and rise (float) rapidly toward the silicon melt surface and are released into the reduced-pressure Ar gas atmosphere. This reduces the number of bubbles that travel on the Marangoni convection toward the silicon single crystal, suppressing the number of bubbles that are captured by the silicon single crystal, thereby reducing the occurrence of air pockets in the silicon single crystal.

Next, we will explain examples of quartz glass crucibles according to the present invention. Note that the present invention is not limited to the following examples.

<Production of quartz glass crucible>
Using the quartz glass crucible manufacturing apparatus 1 shown in Figure 1, the crucible forming mold 2 was rotated at a rotation speed of 70 rpm while the pressure reducing mechanism 9 was operated, thereby evacuating the atmosphere inside the inner member 3 and setting the pressure on the inner surface of the inner member 3 to 80 kPa.

Subsequently, a total weight of 80 kg of natural silica glass raw material powder was sprayed from the nozzle 11 onto the inner surface of the inner member 3. The natural silica glass raw material powder was layered by the centrifugal force of the rotary drive source and the suction force of the pressure reducing mechanism 9, thereby forming a natural silica glass raw material powder layer (outer layer) on the inner surface of the inner member 3 of the crucible forming mold 2. Next, under the same environment as above, a total weight of 12 kg of synthetic silica glass raw material powder was sprayed onto the inner surface of the natural silica glass raw material powder layer (outer layer). This formed a synthetic silica glass raw material powder layer (inner layer) on the inner surface of the natural silica glass raw material powder layer, resulting in a two-layer raw material powder laminate. The flow rate of the carrier gas during raw material powder layer formation was 2.8 m/s.

Thereafter, the pressure reduction by the pressure reduction mechanism 9 and the rotation speed of the crucible forming mold 2 were maintained, and under conditions to obtain the melting temperature of _SiO2 (estimated 2000°C), current was passed through the arc electrode 21 to melt and vitrify the above-mentioned raw material powder stack sequentially from the inside, and the specified cooling and cutting processes were performed to obtain the main body of the quartz glass crucible.

The inner surface of the quartz glass crucible body obtained above was then coated under the following coating conditions to obtain a 32-inch quartz glass crucible (quartz glass crucible coated under the conditions of Comparative Example 1 and Examples 1 to 4). Note that the conditions other than the crystallization accelerator and coating interval were kept constant.
(Application conditions)
Crystallization accelerator: Barium hydroxide (Ba(OH) ₂ )
・Element concentration: 100μg/cm ²
Coating interval: Comparative example 1 → full surface coating
Example 1 → 4 mm (striped)
Example 2 → 5 mm (striped)
Example 3 → 50 mm (striped)
Example 4 → 51 mm (striped)
・Application width: 50 mm
- Coating range: The range from the silicon melt surface at the start of silicon single crystal pulling to the boundary between the body and corner (starting position of the corner)

<Manufacturing of silicon single crystal ingots>
Next, using the quartz glass crucibles manufactured under the above conditions (Comparative Example 1 and Examples 1 to 4), silicon single crystal ingots having a diameter of 370 mm were pulled and manufactured in the single crystal pulling apparatus shown in FIG.

Figure 5 is a schematic diagram showing a cross section of a single crystal pulling apparatus. In Figure 5, the single crystal pulling apparatus 70 includes a furnace body 81, and within this furnace body 81, there is a carbon susceptor (or graphite susceptor) 82 that is rotatable about a vertical axis and capable of being raised and lowered, and a quartz glass crucible (quartz glass crucible of Example 1) held by the carbon susceptor 82. This quartz glass crucible can rotate about a vertical axis together with the rotation of the carbon susceptor 82.

The single crystal pulling apparatus 70 also includes a side heater 83 that heats and melts the raw material (raw material polysilicon) loaded into the quartz glass crucible to form silicon melt M, and a pulling mechanism 85 that pulls up the grown silicon single crystal C by winding up a wire 84. A seed crystal P is attached to the tip of the wire 84 of the pulling mechanism 85. The single crystal pulling apparatus 70 also includes a magnetic field application electromagnetic coil 86 installed outside the furnace body 81. When a predetermined current is applied to this magnetic field application electromagnetic coil 86, a horizontal magnetic field of a predetermined strength is applied to the silicon melt M in the quartz glass crucible.

In this example, in the single crystal pulling apparatus 70 described above, 250 kg of raw polysilicon was placed in a quartz glass crucible, and the raw material was heated in an argon gas atmosphere while the quartz glass crucible was rotated to produce silicon melt M. For Examples 1 to 4, at this stage, a quartz glass crucible having a trapping surface shaped as shown in Figure 4 was obtained.

Then, using the quartz glass crucibles manufactured under the conditions of Comparative Example 1 and Examples 1 to 4, a silicon seed crystal P was brought into contact with silicon melt M to form a neck and shoulder (crown) portion, and then a silicon single crystal ingot having a straight body portion with a diameter of 370 mm and a length of 800 mm was pulled.

The magnetic flux density of the horizontal magnetic field applied during pulling was set to 2500 Gauss. The furnace pressure was set to 20 Torr. The crucible rotation speed was set to 1 rpm, and the silicon single crystal rotation speed was set to 9 rpm (the rotation directions were opposite to each other).

<Observation results>
The air pocket occurrence rate was then determined for each example (Comparative Example 1 and Examples 1 to 4) for wafers sliced from the produced silicon single crystal ingots. Table 1 shows the measurement results for the air pocket occurrence rate. Specifically, the total number of air pockets in wafers obtained by slicing the linear motion portion of the silicon single crystal ingot was measured, and the air pocket occurrence rate was calculated by dividing this total number of air pockets by the number of wafers. The total number of air pockets was obtained by measuring the wafer surface with a thickness of 0.775 mm after wafer polishing using a CCD camera. As a result, the air pocket occurrence rate in Examples 2 and 3 was 0.0% (none occurred), and the air pocket occurrence rate in Examples 1 and 4 was 0.8%, confirming that both had fewer air pockets than the comparative example (1.5%).

In addition, the crystallization accelerator applied was changed to other crystallization accelerators (Al(OH) ₃ , Mg(OH) ₂ , Sr(OH) ₂ , Ca(OH) ₂ ), and the air pocket occurrence rate (%) was confirmed using the same procedure as above. Specifically, five types of quartz glass crucibles (Comparative Example 1 and Examples 1-4) were manufactured under the same manufacturing and application conditions as above (only the crystallization accelerator was changed (element concentration of Al, Mg, Sr, Ca: 100 μg/cm ² )). Furthermore, silicon single crystal ingots with a diameter of 370 mm were pulled under the same pulling conditions as above, and the air pocket occurrence rate was confirmed for each Example (Comparative Example 1 and Examples 1-4) for wafers sliced from the resulting ingots. As a result, it was confirmed that, as with Ba, air pockets were reduced in all Examples compared to the Comparative Example.

REFERENCE SIGNS LIST 1 quartz glass crucible manufacturing apparatus 2 crucible forming mold 3 inner member 4 ventilation section 5 holder 6 rotating shaft 7 opening 8 exhaust port 9 pressure reducing mechanism 11 raw material supply nozzle 21 arc electrode 22 gas supply nozzle 40, 50 quartz glass crucible 40a transparent layer (inner layer)
40b Opaque layer (outer layer)
51 convex part

Claims (5)

A quartz glass crucible used for pulling silicon single crystals,
The body has an inner surface on which a coating target region is formed, the inner surface being coated with a compound containing any one of aluminum, an alkali metal element, and an alkaline earth metal element as a crystallization promoter in the form of continuous stripes in the circumferential direction .
A quartz glass crucible characterized by: the coating target area is an area on the inner surface other than the silicon single crystal projection area and an area below the position of the silicon melt surface at the start of pulling up the silicon single crystal;
2. The quartz glass crucible according to claim 1 . The application interval of the applied surface of the crystallization accelerator applied in stripes is 5 mm or more and 50 mm or less;
3. The quartz glass crucible according to claim 1 or 2. The crystallization promoter contains at least one compound containing an element of Al, Ba, Ca, Mg, or Sr.
4. The quartz glass crucible according to claim 1, 2 or 3. The element concentration of the crystallization accelerator is 0.1 μg/cm ² or more and 1000 μg/cm ² or less,
5. The quartz glass crucible according to claim 4.