Abstract: A quartz glass crucible 1 having a cylindrical side wall portion 10a, a bottom portion 10b, and a corner portion 10c includes a transparent layer 11 as an innermost layer made of quartz glass, a semi-molten layer 13 as an outermost layer made of raw material silica powder solidified in a semi-molten state, and a bubble layer 12 made of quartz glass interposed therebetween. An infrared transmissivity of the corner portion 10c in a state where the semi-molten layer 13 is removed is 25 to 51%, the infrared transmissivity of the corner portion 10c in the state where the semi-molten layer 13 is removed is lower than an infrared transmissivity of the side wall portion 10a, and the infrared transmissivity of the side wall portion 10a in the state where the semi-molten layer 13 is removed is lower than an infrared transmissivity of the bottom portion 10b.

Abstract: A measurement method and a measurement apparatus are capable of measuring the transmittance of a quartz crucible accurately. A measurement method includes: emitting a parallel light from a light source disposed on a side of one wall surface of a quartz crucible toward a predetermined measurement point of the quartz crucible; measuring reception levels of light transmitted through the quartz crucible at a plurality of positions by disposing a detector at the plurality of positions on a circle centered around an exit point of the parallel light on the other wall surface of the quartz crucible; and calculating a transmittance of the quartz crucible at the predetermined measurement point based on a plurality of the reception levels of the transmitted light measured at the plurality of positions.

Abstract: A quartz glass crucible 1 having a cylindrical side wall portion 10a, a bottom portion 10b, and a corner portion 10c includes a transparent layer 11 as an innermost layer made of quartz glass, a semi-molten layer 13 as an outermost layer made of raw material silica powder solidified in a semi-molten state, and a bubble layer 12 made of quartz glass interposed therebetween. An infrared transmissivity of the corner portion 10c in a state where the semi-molten layer 13 is removed is 25 to 51%, the infrared transmissivity of the corner portion 10c in the state where the semi-molten layer 13 is removed is lower than an infrared transmissivity of the side wall portion 10a, and the infrared transmissivity of the side wall portion 10a in the state where the semi-molten layer 13 is removed is lower than an infrared transmissivity of the bottom portion 10b.

Abstract: An object is to provide an apparatus and a method for manufacturing a silica glass crucible, both allowing a stable silica powder layer to be formed in a mold in a short period of time. One embodiment of the present invention is an apparatus for manufacturing a silica glass crucible, by forming a silica powder layer on the inside of a rotating mold, which comprises a rotating means for rotating the mold as well as a supply means for feeding a silica powder to the inside of the mold. In this manufacturing apparatus, the supply means has a feeding part for feeding the silica powder in a manner releasing it to fall to a position away from the inner wall surface of the mold on the inside of the mold, as well as a dispersing part for changing, to one toward the inner wall surface side, at the fall position, the direction in which the silica powder fed from the feeding part moves, while also widening the angle at which the silica powder disperses toward the inner wall surface at the fall position.

Abstract: A measurement method and a measurement apparatus are capable of measuring the transmittance of a quartz crucible accurately. A measurement method includes: emitting a parallel light from a light source disposed on a side of one wall surface of a quartz crucible toward a predetermined measurement point of the quartz crucible; measuring reception levels of light transmitted through the quartz crucible at a plurality of positions by disposing a detector at the plurality of positions on a circle centered around an exit point of the parallel light on the other wall surface of the quartz crucible; and calculating a transmittance of the quartz crucible at the predetermined measurement point based on a plurality of the reception levels of the transmitted light measured at the plurality of positions.

Abstract: In an exemplary embodiment, a quartz glass crucible 1 includes: a high-aluminum-content layer 14B which is made of quartz glass having a relatively high average aluminum concentration and is provided to form an outer surface 10b of the quartz glass crucible 1; and a low-aluminum-content layer 14A which is made of quartz glass having a lower average aluminum concentration than that of the high-aluminum-content layer 14B and is provided on an inner side of the high-aluminum-content layer 14B, wherein the low-aluminum-content layer 14A includes an opaque layer 11 made of quartz glass containing a large number of minute bubbles, and the high-aluminum-content layer 14B is made of transparent or translucent quartz glass having a lower bubble content than that of the opaque layer 11. The quartz glass crucible is capable of withstanding a single crystal pull-up step undertaken for a very long period of time.

Abstract: In an exemplary embodiment, a quartz glass crucible 1 includes: a high-aluminum-content layer 14B which is made of quartz glass having a relatively high average aluminum concentration and is provided to form an outer surface 10b of the quartz glass crucible 1; and a low-aluminum-content layer 14A which is made of quartz glass having a lower average aluminum concentration than that of the high-aluminum-content layer 14B and is provided on an inner side of the high-aluminum-content layer 14B, wherein the low-aluminum-content layer 14A includes an opaque layer 11 made of quartz glass containing a large number of minute bubbles, and the high-aluminum-content layer 14B is made of transparent or translucent quartz glass having a lower bubble content than that of the opaque layer 11. The quartz glass crucible is capable of withstanding a single crystal pull-up step undertaken for a very long period of time.

Abstract: A semiconductor device includes, in a cell region thereof: a low resistance semiconductor layer; a drift layer; a base region; a high-concentration semiconductor region; and a gate electrode layer. The semiconductor device includes, in a peripheral region thereof: the low resistance semiconductor layer; the drift layer; which is formed over the low resistance semiconductor layer; a gate lead line; a gate finger; and a gate pad. The gate electrode layer and the gate lead line are electrically connected with each other by way of a resistor made of polysilicon containing an impurity, and an impurity concentration in polysilicon which forms the resistor is lower than an impurity concentration in polysilicon which forms the gate electrode layer.

Abstract: A semiconductor device includes, in a cell region thereof: a low resistance semiconductor layer; a drift layer; a base region; a high-concentration semiconductor region; and a gate electrode layer. The semiconductor device includes, in a peripheral region thereof: the low resistance semiconductor layer; the drift layer; which is formed over the low resistance semiconductor layer; a gate lead line; a gate finger; and a gate pad. The gate electrode layer and the gate lead line are electrically connected with each other by way of a resistor made of polysilicon containing an impurity, and an impurity concentration in polysilicon which forms the resistor is lower than an impurity concentration in polysilicon which forms the gate electrode layer.

Abstract: Leakage of silicon melt is monitored and touch of a seed crystal at the silicon melt is detected, and in addition, reinforcement of a vitreous silica crucible to be endurable during pulling for a long time and decrease of impurity concentration of a silicon single crystal can be expected. A method for manufacturing a silicon single crystal is provided.

Abstract: A method of manufacturing a fused silica crucible by heating and melting a vitreous silica powder compact shaped into a mold using arc discharge of electrodes arranged around a rotation shaft of the mold, includes the steps of: arranging the electrodes in a ring shape, and setting a ratio W/R of a horizontal distance W between the electrode front end and the surface of the vitreous silica powder compact to a vitreous silica powder compact opening radius R, for at least a predetermined time during arc heating, to be in the range of 0.002 to 0.98.

Abstract: A silica glass crucible for pulling up a silicon single crystal including a wall part and a bottom part is provided with a natural silica glass layer which forms at least one part of a an inner surface of the bottom part, and a synthetic silica glass layer which forms at least an inner surface of the wall part, wherein a concentration of Ca included in the natural silica glass layer is 0.5 ppm or less.

Abstract: A carbon electrode grinding apparatus for shaping a front end of an arc discharge carbon electrode is provided with front end grinding blades configured to grind a front end surface of the carbon electrode, lateral surface grinding blades configured to grind a surface from the front end surface to a base end of the carbon electrode, and rotation means configured to rotate and drive the front end grinding blades and the lateral surface grinding blades around a rotation axis line coincident with an axis line of the carbon electrode.

Abstract: A silica glass crucible having a sidewall portion and a bottom portion is provided with a first synthetic silica glass layer constituting an inner layer at least in the sidewall portion, a second synthetic silica glass layer constituting an inner layer at least in a region including a center of the bottom portion, and a natural silica glass layer constituting an outer layer in the sidewall portion and the bottom portion. A melting rate of the second synthetic silica glass layer with respect to a silicon melt is higher than that of the first synthetic silica glass layer. An aluminum concentration of the second synthetic silica glass layer is higher than that of the first synthetic silica glass layer.

Abstract: An arc discharge method includes the steps of heating and melting a non-conductive object by arc discharge using a plurality of carbon electrodes in a output range of 300 to 12,000 kVA; and setting a ratio of the distance between a contact position at which the carbon electrodes come in contact with each other and a front end to the diameter of the carbon electrode during the start of the arc discharge to be in the range of 0.001 and 0.9.

Abstract: A vitreous silica crucible manufacturing apparatus includes a plurality of carbon electrodes configured to heat and melt raw material powder by arc discharge, and a value of a ratio R2/R1 of a diameter R2 of a front end of each of the carbon electrodes to a diameter R1 of a base end is set in a range of 0.6 to 0.8. Each carbon electrode has a diameter reduction portion formed at a front end position and reduced in diameter from a diameter R3 of a base end side to the diameter R2 of the front end. When a length of the diameter reduction portion is L1, the diameter of the front end is R2, the diameter of the base end is R1, an angle between the axis lines of the carbon electrodes is ?1, and X=(R1?R2)/2, a value of L1?(X/tan(?1/2)) is set in a range of 50 to 150 mm.

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 modification process of the synthetic quartz powder, which can make a quartz glass product hardly having bubbles at the time of fusing, is provided, along with a modification process of the synthetic quartz powder and a glass product using said modified quartz powder are provided, wherein the synthetic quartz powder is kept in helium atmosphere at least in the temperature falling process, when the amorphous synthetic quartz powder produced by the sol-gel method is carried out by heat treatment in a vacuum furnace at more than the degas temperature and less than the baking temperature, wherein the highest temperature in the helium atmosphere is preferably set to from more than 700° C. to less than 1400° C., and the helium atmosphere is kept to less than 400° C.

Abstract: A semiconductor device which can make the generation of gate parasitic oscillations more difficult than a semiconductor device of the related art is provided.

Abstract: A reforming process of a quartz glass crucible in which the quartz glass crucible is reformed by an arc discharge generated by electrodes positioned around a rotational axis and configured to heat an inside surface of the crucible while the crucible is rotated. The process includes arranging electrodes in an electrode structure such that neighboring electrodes are positioned at regular intervals in a ring-like configuration; forming a stable ring-like arc between the neighboring electrodes, without generating a continuous arc between electrodes facing each other across a central portion of the ring-like configuration; heating the inside surface of the crucible; and removing a foreign substance located on the inside surface of the crucible or a bubble located under the inside surface of the crucible.