JP2023016453A - quartz glass crucible - Google Patents

Abstract

To provide a quartz glass crucible on which surface layer of an inner layer a generation of a bubble is preferably suppressed over an entire surface.SOLUTION: A quartz glass crucible constructed by a bottom part, a curved part, and a straight trunk part has an outer layer composed of an opaque quartz glass containing a bubble and an inner layer composed of a transparent quartz glass. When an ultraviolet light is irradiated to the quartz glass crucible as an excitation light, a blue fluorescent light is generated in a boundary region between the outer layer and the inner layer, the blue fluorescent light being generated in a whole region of the bottom part, the curved part, and the straight trunk part.SELECTED DRAWING: Figure 1

Description

The present invention relates to quartz glass crucibles.

In the production of silicon single crystals (silicon single crystal ingots), the so-called Czochralski method (CZ method) is widely used. In this CZ method, a silicon melt is contained in a quartz glass crucible, a seed crystal is brought into contact with the surface of the silicon melt, the quartz glass crucible is rotated, and the seed crystal is pulled upward while rotating in the opposite direction. By raising the seed crystal, a silicon single crystal is grown on the lower end of the seed crystal.

This quartz glass crucible is generally manufactured by a method called an arc rotary melting method as described below. First, silicon dioxide powder (silica powder, quartz powder) is supplied as raw material powder into a rotating mold, and is molded into a crucible-shaped compact by centrifugal force. After that, the molded body is heated and melted from the inside by an arc flame to form a translucent quartz glass crucible base (outer layer) (base forming step). Further, during or after formation of the crucible base, silicon dioxide powder is newly supplied to the heating atmosphere in the crucible base to form an inner layer made of transparent quartz glass on the inner surface side of the crucible base (inner layer forming step). A method of forming an inner layer made of transparent quartz glass by heating while sprinkling quartz powder is also called a sprinkling method.

Further, the outer layer of the quartz glass crucible is often formed using natural silicon dioxide powder, and the inner layer is formed using synthetic silicon dioxide powder.

By the way, when pulling up a silicon single crystal from a silicon melt contained in a quartz glass crucible, if there are bubbles in the inner layer of the quartz glass crucible under reduced pressure, high temperature, or the like, they expand and are released into the silicon melt. However, there has been a problem that the crystallinity of the silicon single crystal is deteriorated due to the entrapment of the bubbles and the flakes generated during the ejection into the silicon single crystal. To address such problems, it is known in the manufacture of quartz glass crucibles to dope the inner layer of the quartz glass crucible with hydrogen. Such hydrogen doping has the effect of suppressing the generation of air bubbles. For example, Patent Literature 1 discloses a manufacturing method for obtaining a silica glass crucible by supplying quartz raw material powder into a mold to form a silica powder molded body having a crucible shape, and heating and melting the silica powder molded body by arc discharge. describes supplying hydrogen gas to the inner surface of the silica powder compact during heating and melting by arc discharge. Further, Patent Document 2 describes heating and holding a quartz glass crucible manufactured by an arc rotary melting method in hydrogen or a hydrogen-containing atmosphere.

Further, as a method of hydrogen-doping a quartz glass crucible, it is also known to dope raw material powder with hydrogen (Patent Documents 3 and 4). Such hydrogen-doped silica powder (often synthetic silica powder) is used to form a transparent silica glass layer, which is the inner layer of a silica glass crucible, using the above-described spraying method.

It is also known to introduce water vapor into a quartz glass crucible in manufacturing a quartz glass crucible (Patent Document 5). Patent Document 5 describes that the introduction of such water vapor can also suppress expansion of bubbles near the inner surface of the quartz glass crucible.

JP 2014-65622 A JP-A-05-208838 Japanese Patent Application Laid-Open No. 2003-335513 Japanese Patent Application Laid-Open No. 2017-031007 Japanese Patent Application Laid-Open No. 2001-348240 JP 2013-014518 A JP 2018-35029 A Japanese Patent Application Laid-Open No. 2006-89301

As noted above, a typical fused silica crucible consists of an outer layer of opaque fused silica containing air bubbles and an inner layer of transparent fused silica. However, the transparency of the inner layer (transparent layer) made of transparent quartz glass is not perfect, and more than a few bubbles are included. In order to suppress this foam, prior art documents such as those exemplified above have been published. In particular, in the "spraying method" performed during melting for manufacturing quartz glass crucibles, by using hydrogen-doped silica powder as described in Patent Documents 3 and 4, a transparent layer with few bubbles (synthetic quartz glass raw material A synthetic transparent layer formed from powder) is formed. However, in the transparent quartz glass layer (inner layer) formed by the spraying method, there were cases where hydrogen doping was not sufficiently performed at intended locations (that is, the state of hydrogen doping varies depending on the location).

SUMMARY OF THE INVENTION An object of the present invention is to provide a quartz glass crucible in which the generation of air bubbles in the surface layer of the inner layer is satisfactorily suppressed over the entire surface.

The present invention has been made to solve the above problems, and is a quartz glass crucible comprising a bottom portion, a curved portion, and a straight body portion, wherein the outer layer is made of opaque quartz glass containing air bubbles, and the quartz glass crucible is made of transparent quartz glass. When the quartz glass crucible is irradiated with ultraviolet rays as excitation light, blue fluorescence is generated in a boundary region between the outer layer and the inner layer of the quartz glass crucible, and the blue fluorescence is emitted from the quartz glass. Provided is a quartz glass crucible characterized in that it occurs in the entirety of the bottom portion, the curved portion and the straight body portion of the crucible.

With such a quartz glass crucible, it is possible to obtain a quartz glass crucible in which the generation of air bubbles in the surface layer of the inner layer is satisfactorily suppressed over the entire surface.

In this case, in the quartz glass crucible of the present invention, the outer layer contains natural quartz glass, the inner layer contains synthetic quartz glass, and the blue fluorescence is generated in a region where the natural quartz glass contacts the synthetic quartz glass. can be

The blue fluorescence of the entire surface of the present invention can be satisfied even in a quartz glass crucible having such a structure of an outer layer containing natural quartz glass and an inner layer containing synthetic quartz glass. The present invention can provide a quartz glass crucible having such a structure, in which the generation of air bubbles in the surface layer of the inner layer is satisfactorily suppressed over the entire surface.

Further, in the quartz glass crucible of the present invention, the inner layer may contain hydrogen-doped quartz glass or water vapor-introduced quartz glass.

Thus, the blanket blue fluorescence of the present invention can be achieved particularly well in quartz glass crucibles having an inner layer comprising hydrogen-doped quartz glass or water vapor-introduced quartz glass. Hydrogen-doped quartz glass and water vapor-introduced quartz glass are used to suppress the generation of bubbles, but if the quartz glass crucible in which blue fluorescence is observed over the entire surface like the present invention, the generation of bubbles in the surface layer of the inner layer is more reliable. can be a quartz glass crucible in which is well suppressed over the entire surface.

Further, in the quartz glass crucible of the present invention, the blue fluorescence can be fluorescence having a peak around a wavelength of 395 nm.

Further, in the quartz glass crucible of the present invention, the ultraviolet rays to be irradiated can be ultraviolet rays having a peak around a wavelength of 254 nm.

As described above, the blue fluorescence in the quartz glass crucible of the present invention can be determined by detecting the blue fluorescence generated as fluorescence having a peak around 395 nm by ultraviolet rays having a peak around 254 nm.

The quartz glass crucible of the present invention can be a quartz glass crucible in which the generation of air bubbles in the surface layer of the inner layer is satisfactorily suppressed over the entire surface by observing blue fluorescence over the entire surface.

1 is a schematic cross-sectional view showing parts of a common quartz glass crucible; FIG. 4 is a flow chart showing an outline of a method for detecting blue fluorescence in a quartz glass crucible.

As described above, conventionally, if the inner layer of the quartz glass crucible is not sufficiently hydrogen-doped, the effect of suppressing bubble expansion may not be sufficiently obtained. In particular, the state of hydrogen doping may vary depending on the location of the quartz glass crucible. That is, the state of bubbles contained in the inner layer of the quartz glass crucible was not uniform. Further, according to the studies of the present inventors, it has been found that there are sites where bubbles are likely to be included. The evaluation of each portion of the quartz glass crucible has been performed by performing cutting and vacuum heat treatment based on past experience. For example, according to “VBT” described in Patent Document 6, evaluation was performed under the conditions of 1650° C., 2 hours, 10 minutes holding, and 2×10 ⁻² Pa or less. So far, it has not been clarified what influences the bubbles contained in this synthetic transparent layer.

According to investigations by the present inventors, the "hydrogen" contained in the inner layer (often a synthetic transparent layer) made from hydrogen-doped silica powder is the outer layer (natural foam layer made from natural quartz powder). A thin natural layer with slightly fewer bubbles is formed by combining with oxygen abundantly present in the outer layer (hereinafter referred to as "natural transparent layer"). This natural transparent layer has oxygen-deficient defects, and blue fluorescence is emitted from the natural transparent layer when irradiated with ultraviolet rays of 254 nm.

The inventors of the present invention have found during their research that there are portions that emit blue fluorescence and portions that do not emit blue fluorescence in quartz glass crucibles. Then, when VBT is performed on the portion that emits blue fluorescence and the portion that does not emit blue fluorescence, the inventors discovered that the surface layer of the synthetic transparent layer is excellent in suppressing bubbles in the portion that emits fluorescence.

According to investigations by the present inventors, it is considered that portions where hydrogen doping is not sufficiently performed are caused by the following mechanism. When hydrogen-doped silica powder is sprinkled as a raw material powder using a spraying method and adhered to a quartz glass crucible substrate, a portion formed by direct adhesion of the raw material powder and a portion formed by inertia during melting (for example, , a portion where the raw material powder adhered and then moved in a glass state). It was found that the portion formed by this inertia has a low hydrogen concentration, and a sufficient foam suppressing effect cannot be obtained.

In order to solve this problem, the present inventors paid attention to oxygen-deficient defects that occur in the outer layer of a quartz glass crucible when hydrogen-doped silica powder is used as raw material powder for manufacturing quartz glass crucibles. By using hydrogen-doped silica powder, hydrogen diffuses from the inner layer (transparent silica glass layer) of the quartz glass crucible to the outer layer (opaque silica glass layer), and oxygen is taken into the silica, which is the main cause of bubbles in the outer layer, and from the melting atmosphere. Oxygen-deficient defects occur due to the combination of and hydrogen. Due to the existence of the oxygen-deficient defects, fluorescence (blue fluorescence) is generated by irradiating ultraviolet rays, and the state of the oxygen-deficient defects in the outer layer of the quartz glass crucible can be grasped, and the state of hydrogen doping can be grasped. Here, the site where blue fluorescence occurs, that is, where oxygen deficiency defects occur is a shallow portion on the outer layer side of the boundary portion between the inner layer and the outer layer. Blue fluorescence does not necessarily occur in the entire thickness direction of the outer layer. Based on these findings, the present inventors conceived of the present invention.

The present invention will be described in more detail below. The quartz glass crucible of the present invention is a quartz glass crucible comprising a bottom portion, a curved portion and a straight body portion, and has an outer layer made of opaque quartz glass containing air bubbles and an inner layer made of transparent quartz glass. When the glass crucible is irradiated with ultraviolet light as excitation light, blue fluorescence is generated in a boundary region between the outer layer and the inner layer of the quartz glass crucible, and the blue fluorescence is emitted from the bottom and the curved portion of the quartz glass crucible. and a quartz glass crucible characterized in that it occurs in the entirety of the straight body.

First, referring to FIG. 1, the parts of the quartz glass crucible of the present invention will be described. The quartz glass crucible 10 of FIG. 1 has an outer layer 21 made of opaque quartz glass containing air bubbles and an inner layer 22 made of transparent quartz glass. Further, as shown in FIG. 1, the crucible shape of the quartz glass crucible 10 typically consists of a bottom portion 12, a curved portion 13, and a straight body portion . There is a bottom center 11 at the center of the bottom portion 12, the bottom portion 12 is also called a large R portion, and the curved portion 13 is also called a small R portion.

As described above, the quartz glass crucible 10 of the present invention produces blue fluorescence in the boundary region between the outer layer 21 and the inner layer 22 of the quartz glass crucible 10 when irradiated with ultraviolet light as excitation light. , occur throughout the bottom portion 12 , the curved portion 13 and the straight body portion 14 of the quartz glass crucible 10 . Such a quartz glass crucible 10 becomes a quartz glass crucible in which the generation of air bubbles on the surface layer of the inner layer 22 is satisfactorily suppressed over the entire surface.

The quartz glass crucible 10 of the present invention can have an outer layer 21 containing natural quartz glass and an inner layer 22 containing synthetic quartz glass. A quartz glass crucible having such a structure is generally used, in particular, for pulling silicon single crystals. Moreover, in fused silica crucibles 10 having such a structure, blue fluorescence generally occurs in the region where natural fused silica contacts synthetic fused silica.

Further, in the quartz glass crucible 10 of the present invention, the inner layer 22 preferably contains hydrogen-doped quartz glass or water vapor-introduced quartz glass. The blanket blue fluorescence of the present invention can be fulfilled particularly well in fused silica crucibles having an inner layer comprising hydrogen-doped fused silica or water vapor-introduced fused silica. Hydrogen-doped quartz glass and water vapor-introduced quartz glass are used to suppress the generation of bubbles, but if the quartz glass crucible in which blue fluorescence is observed over the entire surface like the present invention, the generation of bubbles in the surface layer of the inner layer is more reliable. can be a quartz glass crucible in which is well suppressed over the entire surface.

[Method for detecting blue fluorescence]
In the quartz glass crucible of the present invention, blue fluorescence is detected, for example, as follows. First, as shown in step S1 of FIG. 2, a quartz glass crucible is prepared.

Next, as shown in step S2 in FIG. 2, the quartz glass crucible is irradiated with ultraviolet rays as excitation light. Next, as shown in step S3 in FIG. 2, blue fluorescence emitted from the quartz glass crucible irradiated with ultraviolet rays is detected. It is preferable to use ultraviolet rays having a peak around a wavelength of 254 nm as the ultraviolet rays to be irradiated here. Moreover, in that case, the blue fluorescence to be detected is fluorescence having a peak around a wavelength of 395 nm. Ultraviolet light with a wavelength of around 254 nm can be easily obtained from a mercury lamp. In this way, in the detection of blue fluorescence in quartz glass crucibles, ultraviolet light having a peak at a wavelength of 254 nm is used to detect blue fluorescence having a peak at a wavelength of around 395 nm. Deficiency defect status can be more easily assessed. In addition, in silica glass, it is known that the fluorescence having a peak around a wavelength of 395 nm is caused by an oxygen-deficient defect (B2β). Also, the fluorescence around a wavelength of 395 nm often has a peak at a wavelength of 394-396 nm.

If blue fluorescence is produced by the operations of steps S2 and S3, it means that an anoxia defect is present. Absence of blue fluorescence means absence or low density of oxygen-deficient defects.

Such a method for detecting blue fluorescence can easily evaluate a quartz glass crucible non-destructively. As described above, blue fluorescence occurs, that is, the site where oxygen deficiency defects occur is typically a shallow portion on the outer layer 21 side of the boundary portion between the inner layer 22 and the outer layer 21 . For example, when natural silica powder is used as the raw material silica powder for the outer layer 21 and synthetic silica powder is used as the raw material silica powder for the inner layer 22, the outer layer 21 becomes a natural silica glass layer. At this time, oxygen in the outer layer 21 (natural silica glass layer) and hydrogen introduced by hydrogen doping or introduction of water vapor combine to form a natural transparent layer with few bubbles and oxygen deficiency defects. This naturally transparent layer will generate blue fluorescence. Blue fluorescence does not necessarily occur in the entire thickness direction of the outer layer 21 .

In addition, blue fluorescence can be confirmed visually. Specifically, the quartz glass crucible is irradiated with ultraviolet rays in a dark room, and the generation of blue fluorescence can be confirmed. Also, the distribution of blue fluorescence in the outer layer of the quartz glass crucible can be visually confirmed.

Further, in the detection of blue fluorescence, it is possible to define that the blue fluorescence is quantitatively detected based on numerical values. Specifically, it is as follows. The peak intensity (peak height) of blue fluorescence generated when ultraviolet light is irradiated as excitation light is measured as peak intensity A. Also, the peak intensity (peak height) of the Rayleigh scattered light generated as a result of irradiation with ultraviolet rays is measured as the peak intensity B. Here, it can be defined that blue fluorescence is detected when the above A and B satisfy the following formula (1).
(A/B)×1000≧20 Formula (1)

In this way, blue fluorescence can be detected without relying on visual observation. The reason for using the above formula (1) is as follows.

Patent Documents 7 and 8 describe measuring red fluorescence in order to detect excess oxygen defects in quartz glass crucibles. In the case of red fluorescence, Raman scattered light and fluorescence are measured using an Ar laser with a wavelength of 514 nm as excitation light.

In the case of blue fluorescence, ultraviolet rays of 254 nm are used as excitation light and the fluorescence wavelength is 395 nm, so the same measurement method as for red fluorescence cannot be used. Since the fluorescence intensity depends on the excitation light intensity, it is preferable to standardize using the ratio of these. For normalization, it is necessary to know the excitation light intensity, but the excitation light intensity is not constant because it varies depending on the device and is accompanied by deterioration over time. Therefore, Rayleigh scattered light of the same wavelength generated by the excitation light is adopted as a reference. In principle, the Rayleigh scattered light has the same wavelength as the incident light, but it varies somewhat depending on the measurement device, and often has a peak near 253 nm to 256 nm.

However, as described above, even if Rayleigh scattered light is used as a reference, specularly reflected light of excitation light unnecessary for measurement may be mixed in the light receiving unit. Therefore, it is preferable to set the irradiation angle of the ultraviolet rays at an angle shifted from the vertical direction with respect to the inner surface of the quartz glass crucible, and to detect the blue fluorescence at an angle shifted from the specularly reflected light of the ultraviolet rays. For example, the irradiation surface of the quartz glass crucible can be tilted so that the incident angle of the excitation light is 60 degrees, and the measurement can be performed with a spectrofluorometer.

The relationship between the detection of blue fluorescence and the bubble density of the present invention will be described with reference to experimental examples.

[Experimental Examples 1-1 to 1-8]
A normal quartz glass crucible 10 shown in FIG. 1 was manufactured using hydrogen-doped synthetic quartz powder (hydrogen-doped synthetic quartz powder described in Patent Document 3) as raw material powder for the inner layer 22 . Samples were cut out from a plurality of portions of the manufactured quartz glass crucible 10 (Experimental Examples 1-1 to 1-8).

(Measurement of blue fluorescence)
Each sample was irradiated with ultraviolet light having a peak around a wavelength of 254 nm, and blue fluorescence having a peak around a wavelength of 395 nm was detected. As a result, samples in which blue fluorescence was detected were designated as Experimental Examples 1-1 to 1-4, and samples in which blue fluorescence was not detected were designated as Experimental Examples 1-5 to 1-8.

(Measurement of bubble density)
After measuring the blue fluorescence, the bubble density after VBT was measured for each sample of the quartz glass crucibles 10 of Experimental Examples 1-1 to 1-8 based on the evaluation method of Patent Document 6. Each sample was held at 1650° C. for 2 hours and 10 minutes with a degree of vacuum of 2×10 ⁻² Pa or less to generate air bubbles. After that, the density of air bubbles exposed on the surface of each sample was visually confirmed.

Table 1 shows the results of Experimental Examples 1-1 to 1-8.

As can be seen from Table 1, there was a difference in density of exposed bubbles on the inner surface depending on the degree of fluorescence. That is, it can be seen that the bubble density after VBT is greatly suppressed in the portion where the blue fluorescence is detected.

Furthermore, repeating the melting experiment suggested that it was important that the hydrogen-doped silica powder that had been sprayed was directly supplied to that portion. In other words, the effect of hydrogen disappears in the synthetic transparent layer formed by the dispersed hydrogen-doped silica powder not directly adhering, but flowing downward due to gravity or flowing in the circumferential direction due to centrifugal force. This can be explained by assuming that the underlying natural transparent layer does not fluoresce. Based on this hypothesis, the hydrogen-doped silica powder was supplied while moving the raw material powder supply port for supplying the hydrogen-doped silica powder from the bottom toward the straight body during melting of the quartz glass crucible. As a result, the hydrogen-doped silica powder could be directly adhered to the entire inner surface region to supply hydrogen, and a silica glass crucible was obtained in which the natural transparent thin layer on the entire surface of the silica glass crucible emitted blue fluorescence. Evaluation of the synthetic transparent layer at each part of the quartz glass crucible thus obtained showed that its bubble suppression was excellent. When the same quartz glass crucible was used for pulling a silicon single crystal, the silicon single crystal pulling performance (DF rate) was improved. In this way, by repeating melting experiments, we succeeded in fabricating a quartz glass crucible that emits blue fluorescence over the entire surface. This will be described with reference to Experimental Examples 2-1 to 2-8.

[Experimental example 2-1]
In the same manner as in Experimental Examples 1-1 to 1-8, except that the manufacturing conditions were changed, the ordinary silica glass crucible 10 shown in FIG. (Experimental Example 2-1).

(Sample preparation)
From each of the quartz glass crucibles 10 thus produced, samples of about 4 cm×about 8 cm were cut every 100 mm from the bottom center 11 to the straight body portion 14 . Among these, the distance 0 mm (bottom center) from the bottom center 11 is a portion including the bottom center 11 . The distances of 100 mm, 200 mm, and 300 mm from the bottom center 11 are located in the bottom portion 12 (that is, the large R portion). A curved portion 13 (that is, a small R portion) is located at a distance of 400 mm from the bottom center 11 . 500 mm, 600 mm, and 700 mm distances from the bottom center 11 are located in the straight body portion 14 . Among them, the portion at a distance of 500 mm from the bottom center 11 is located near the lower portion of the straight body portion 14 .

(Measurement of blue fluorescence)
Each sample was irradiated with ultraviolet light having a peak around a wavelength of 254 nm, and the presence or absence of blue fluorescence having a peak around a wavelength of 395 nm was visually confirmed.

(Measurement of bubble density)
After measuring the blue fluorescence described above, each sample of the quartz glass crucible 10 of Experimental Example 2-1 was measured for bubble density after VBT based on the evaluation method of Patent Document 6. Each sample was held at 1650° C. for 2 hours and 10 minutes with a degree of vacuum of 2×10 ⁻² Pa or less to generate air bubbles. After that, the density of air bubbles exposed on the surface of each sample was visually confirmed.

[Experimental Examples 2-2 to 2-8]
Experimental Examples 1-1 to 1-8 and Experimental Example 2-1 were carried out in the same manner as in Experimental Example 2-1 except that the production conditions were changed, and the ordinary silica glass crucible 10 shown in FIG. It was produced using doped synthetic quartz powder (Experimental Examples 2-2 to 2-8).

For the quartz glass crucibles 10 produced in Experimental Examples 2-2 to 2-8, sample preparation, blue fluorescence measurement, and bubble density measurement were performed in the same manner as in Experimental Example 2-1.

In Experimental Examples 2-2 and 2-3, as in Experimental Example 2-1, blue fluorescence was observed in all samples, and fluorescence was detected over the entire surface. Also, in the post-VBT bubble generation test, bubbles were suppressed in all samples.

On the other hand, in Experimental Examples 2-4 to 2-8, blue fluorescence was detected only in part, and blue fluorescence was not detected in part.

Table 2 shows the results of Experimental Examples 2-1 to 2-8.

Table 3 shows the density of air bubbles exposed on the inner surface of a unit area (1 cm ² ) after VBT.

As can be seen from Tables 2 and 3, blue fluorescence can be detected over the entire surface of the quartz glass crucible 10 depending on the manufacturing conditions. Such manufacturing conditions can be easily set by repeating melting experiments and detecting blue fluorescence for verification. Manufacturing conditions include, for example, changing the gas circulation position in the melting atmosphere and changing the supply position of the raw material quartz powder.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

[Comparative example]
Regarding quartz glass crucibles at the time when the relationship between blue fluorescence and the transparent layer had not been discovered, when investigating quartz glass crucibles that emit blue fluorescence in the entirety of the bottom, curved part and straight body part, the production rate was 0%. .

[Example]
During the spraying method, 200 g of hydrogen-doped silica powder was poured from the bottom of the quartz glass crucible toward the straight body using a raw material powder supply tube made of synthetic quartz with an inner diameter of 16 mm or less while adjusting the air current generated by arc discharge. /min or more, and melted so that the synthetic transparent layer has a thickness of 1 mm or more on the entire inner surface region of the quartz glass crucible. After confirming the blue fluorescence emission state of the quartz glass crucible, the position of the raw material powder supply pipe was adjusted and melted so that the hydrogen-doped silica powder adhered to the portion with no or weak emission. In this way, the melting experiment and condition adjustment were repeated until blue fluorescence was observed over the entire surface of the quartz glass crucible, and the manufacturing conditions for a quartz glass crucible exhibiting blue fluorescence over the entire surface were set. As a result of manufacturing quartz glass crucibles under these manufacturing conditions, the production ratio of quartz glass crucibles emitting blue fluorescence over the entire surface was increased to 93.8% (61 pieces/65 pieces), and stable supply became possible.

It should be noted that the present invention is not limited to the above embodiments. The above-described embodiment is merely an example, and any device that has substantially the same configuration as the technical idea described in the claims of the present invention and produces similar effects can be applied to the present invention. It is included in the technical scope of the invention.

10... quartz glass crucible,
11... Bottom center 12... Bottom part 13... Curved part 14... Straight body part
21... Outer layer, 22... Inner layer.

Claims (5)

A quartz glass crucible comprising a bottom portion, a curved portion and a straight body portion,
having an outer layer made of opaque quartz glass containing bubbles and an inner layer made of transparent quartz glass,
When the quartz glass crucible is irradiated with ultraviolet light as excitation light, blue fluorescence is generated in a boundary region between the outer layer and the inner layer of the quartz glass crucible,
A quartz glass crucible, wherein the blue fluorescence is generated in the entirety of the bottom portion, the curved portion and the straight body portion of the quartz glass crucible. wherein the outer layer comprises natural quartz glass;
wherein the inner layer comprises synthetic quartz glass;
2. The quartz glass crucible according to claim 1, wherein said blue fluorescence is generated in a region where said natural quartz glass contacts said synthetic quartz glass. 3. The quartz glass crucible according to claim 1, wherein the inner layer contains hydrogen-doped quartz glass or steam-introduced quartz glass. 4. The quartz glass crucible according to any one of claims 1 to 3, wherein the blue fluorescence has a peak around a wavelength of 395 nm. 5. The silica glass crucible according to any one of claims 1 to 4, characterized in that the ultraviolet rays to be irradiated are ultraviolet rays having a peak around a wavelength of 254 nm.

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