Abstract: There is provided a vitreous silica crucible whose strength at high temperature is high, and which allows easy taking-out from a susceptor after completion of pulling. The vitreous silica crucible 10 includes a vitreous silica outer layer 13a provided on the outer surface side of the crucible, a vitreous silica inner layer 13c provided on the inner surface side of the crucible, and an vitreous silica intermediate layer 13b provided between the vitreous silica outer layer 13a and the vitreous silica inner layer 13c. The vitreous silica outer layer 13a has a mineralizer concentration of 100 ppm or more, and the vitreous silica intermediate layer 13b and the vitreous silica inner layer 13c has a mineralizer concentration of 50 ppm or less. It is preferred that the vitreous silica outer layer 13a and the vitreous silica intermediate layer 13b are made of natural silica, and the vitreous silica inner layer 13c is made of high-purity natural silica or synthetic silica.

Abstract: The present invention provides a method of manufacturing a vitreous silica crucible having a transparent layer by use of waste vitreous silica, and silica powder suitable for the manufacturing. According to the present invention, there is provided a method of manufacturing granulated silica powder comprising a process for pulverizing waste vitreous silica generated in the manufacturing process of a crucible to form silica fine powder having an average particle diameter of 100 ?m or less, and a process for granulating the silica fine powder to obtain granulated silica powder having an average particle diameter of 50 ?m or more under helium atmosphere.

Abstract: There is provided a method of manufacturing a vitreous silica crucible having non-bubbles on the inner surface without necessitating new apparatuses for grinding and polishing and without damaging the productivity. According to the present invention, there is provided a method of manufacturing a vitreous silica crucible including the processes of: gathering a vitreous silica layer containing residual bubbles existing in a near-surface region of the transparent layer of the vitreous silica crucible by controlling the number of rotations applied to the vitreous silica crucible in a state that an inner surface side of the vitreous silica crucible is fused by arc heating; and moving a portion of a non-bubble layer in the surface of the transparent layer exposed by movement of the residual bubble-containing layer to cover a region in which bubbles have gathered with the non-bubble layer.

Abstract: The present invention provides a vitreous silica crucible which can suppress buckling and sidewall lowering of the crucible without fear of mixing of impurities into silicon melt. According to the present invention, provided is a vitreous silica crucible for pulling a silicon single crystal, wherein a ratio I2/I1 is 0.67 to 1.17, where I1 and I2 are area intensities of the peaks at 492 cm?1 and 606 cm?1, respectively, in Raman spectrum of vitreous silica of the region having a thickness of 2 mm from an outer surface to an inner surface of a wall of the crucible.

Abstract: There are provided an apparatus and a method for manufacturing a vitreous silica crucible which can prevent the deterioration of the inner surface property in the manufacturing process of a vitreous silica crucible. The apparatus includes a mold defining an outer shape of a vitreous silica crucible, and an arc discharge unit having electrodes and a power-supply unit, wherein each of the electrodes includes a tip end directed to the mold, the other end opposite to the tip end, and a bent portion provided between the tip end and the other end.

Abstract: Provided is a vitreous silica crucible having a reference point, which is capable of accurately detecting the location of a defect in the vitreous silica crucible used for pulling silicon single crystal, determining a defect generating site of silicon single crystal, and investigating the cause of the defect. The reference point used for specifying the position relationship with respect to a particular part is formed in at least one site of an end portion, an inner wall and an outer wall of the crucible.

Abstract: The arc discharge apparatus comprises a plurality of carbon electrodes connected to respective phases of a power supply for heating a silica powder and causing it to fuse by generating arc discharge between the carbon electrodes. All of the carbon electrodes have a density in a range from 1.30 g/cm3 to 1.80 g/cm3, and variability in density among the carbon electrodes is 0.2 g/cm3 or less. The carbon particles that constitute the carbon electrodes preferably have a particle diameter of 0.3 mm or less.

Abstract: A high-purity vitreous silica crucible used for pulling a large-diameter single-crystal silicon ingot, includes a double layered structure constituted by an outer layer composed of high-purity amorphous vitreous silica with a bubble content of 1 to 10% and a purity of 99.99% or higher, and an inner layer composed of high-purity amorphous vitreous silica s with a bubble content of 0.6% or less and a purity of 99.99% or higher, wherein, at least for an inner surface of the vitreous silica crucible between ingot-pulling start line and ingot-pulling end line of a silicon melt surface, a longitudinal section of the inner surface is shaped into a waveform, and depth and width of the ring grooves constituting the multi ring-groove patterned face are set in the range of 0.5 to 2 mm and 10 to 100 mm, respectively.

Abstract: A silica glass crucible causing fewer pinholes in silicon single crystals is provided by a method of preventing pinholes by performing the pulling up of a silicon single crystal while restraining the dissolution rate of the crucible inner surface to 20 ?m/hr or less, using a silica glass crucible for the pulling up of silicon single crystals, wherein the area of crystalline silica formed by crystallization of amorphous silica is restricted to 10% or less of the crucible inner surface area, or the density of pits formed from open bubbles on the crucible inner surface is restricted to 0.01 to 0.2 counts/mm2.

Abstract: Colored foreign particles contained in quartz powder material are detected in a high precision with the specified detection apparatus even when the colored foreign particles are pale colored foreign particles such as iron-based refuse, organic refuse and carbon-based refuse.

Abstract: A crucible lift device for taking a crucible out of a mold is provided with a lid member which closely contacts a limb portion defining an opening of a crucible; a decompressing mechanism which decompresses an internal space of the crucible sealed with the lid member; and a vertically-moving mechanism for the lid member. The crucible lift device includes a stand, and the vertically-moving mechanism includes a crane device which is fixed to a beam provided on an upper end of the stand and vertically moves the lid member. The decompressing mechanism includes a suction duct which penetrates the lid member to open into the internal space of crucible, and a decompressor which is connected to the suction duct. The vertically-moving mechanism can integrally lift the crucible in which the internal space is decompressed together with the lid member.

Abstract: A vitreous silica crucible for pulling single-crystal silicon, which is formed of vitreous silica and has a bottomed cylindrical shape, wherein, in a liquid-level movement range in the inner surface of the crucible, ranging from a position corresponding to the liquid surface level of a silicon melt at the time of stating the pulling of single-crystal silicon to a position corresponding to the liquid surface level of a silicon melt at the time of finishing the pulling of single-crystal silicon, the concentration of an OH group included in the vitreous silica is higher in an erosion thickness portion of the inner surface of the crucible than that in the range lower than the liquid surface level which is positioned below the liquid-level movement range.

Abstract: A mold for the production of a silica crucible by heat-fusing silica or quartz powder attached onto an inner wall of a rotating mold, wherein a ring-shaped heat insulating barrier material having a specified inner diameter is disposed on an inner peripheral wall of an upper opening portion of the mold corresponding to an upper region of the silica crucible.

Abstract: The present invention provides a method of evaluating silica powder which, enables precise prediction of easiness of crystallization of a vitreous silica crucible. According to the present invention, provided is a method of evaluating silica powder including a sample preparation process for preparing a vitrified sample by fusing silica powder at a fusing temperature of 1700 to 1900 deg. C., followed by cooling; a sample heat treatment process for retaining the sample for 30 minutes or more at a temperature of 1400 to 1750 deg. C., followed by cooling; and a sample evaluation process for evaluating a state of opacification of the sample after the sample heat treatment process.

Abstract: In a mold for use in the production of a silica crucible, a mold cover corresponding to a small-diameter thinned portion of an upper part of the silica crucible is detachably disposed on a mold substrate corresponding to a main body of the silica crucible, and the mold cover has a barrier function against arc heating, and an inner diameter of the mold cover is smaller than that of the mold substrate but larger than that of the silica crucible.

Abstract: The present invention provides a vitreous silica crucible which can suppress buckling and sidewall lowering of the crucible in multi-pulling. According to the present invention, provided is a vitreous silica crucible for pulling a silicon single crystal, comprising a mineralizer on an inner surface of the crucible, wherein the mineralizer contains at least one atoms selected from the group consisting of Ca, Sr, Ba, Ra, Ti, Zr, Cr, Mo, Fe, Co, Ni, Cu, and Ag, and the concentration of the mineralizer on the inner surface is 1.0×105 to 1.0×1017 atoms/cm2.

Abstract: There is provided a mold for use in the production of a silica crucible by heat-fusing silica or quartz powder attached onto an inner wall of a rotating mold, wherein an inner side of an upper opening portion of the mold corresponding to an upper part of the silica crucible is ground to obtain a step portion and a ring-shaped heat insulating barrier member having an inner diameter smaller than that of the mold is disposed on the step portion through a hollow disk-shaped support member having an inner diameter equal to or somewhat larger than that of the heat insulating barrier member.

Abstract: The disclosed is a method of manufacturing a silica glass crucible for pulling silicon single crystals. In the method, reduced pressure is imparted from the inner surface to the outer surface of a crucible-shaped molded product and the crucible-shaped molded product is arc-fused while rotating the same to form a silica glass crucible with a transparent layer on the inner surface side and a bubble layer on the outer surface side. The inner surface of the wall portion of the silica glass crucible is fused a second time by arc fusion to cause bubbles present in the transparent layer of the inner surface of the wall portion to be displaced toward the bottom portion of the inner surface of the wall portion. The inner surface of the bottom portion of the silica glass crucible is fuse a second time by arc fusion to cause bubbles present in the transparent layer of the inner surface of the bottom portion to be displaced toward the periphery of the inner surface of the bottom portion.

Abstract: Provided is a vitreous silica crucible which can suppress inward sagging and buckling of the sidewall effectively even when time for pulling silicon ingots is extremely long. According to the present invention, provided is a vitreous silica crucible for pulling a silicon single crystal, wherein the crucible has a wall comprising, from an inner surface toward an outer surface of the crucible, a transparent vitreous silica layer having a bubble content rate of less than 0.5%, a bubble-containing vitreous silica layer having a bubble content rate of 1% or more and less than 50%, a semi-transparent vitreous silica layer having a bubble content rate of 0.5% or more and less than 1.0% and having an OH group concentration of 35 ppm or more and less than 300 ppm.

Abstract: The present invention provides a vitreous silica crucible which can restrain deterioration of crystallinity of a silicon ingot in multi-pulling. Provided is a vitreous silica crucible for pulling a silicon single crystal, the crucible has a wall having, from an inner surface toward an outer surface of the crucible, a synthetic vitreous silica layer, a natural vitreous silica layer, an impurity-containing vitreous silica layer and a natural vitreous silica layer.