Shin-Etsu Quartz Products Co., Ltd.

Heraeus Quarzglas Gmbh & Co Kg

Heraeus Shin-Etsu America, Inc.

Shin-Estu Quartz Products Co., Ltd.

Yasuo Ohama

Katsuhiko Kemmochi

Shigeo Mizuno

Takayuki Togawa

Hiroshi Matsui

Tatsuhiro Sato

Robert O Mosier

Jiro Sawazaki

Katsumi Taniguchi

A mold for manufacturing a quartz glass crucible by a rotary molding method, having a plurality of grooves that are concentric with respect to a mold rotation axis in at least a straight body portion of an inner surface of the mold, wherein the plurality of concentric grooves are non-penetrating grooves that do not penetrate the mold. This provides a mold for manufacturing a quartz glass crucible by a rotary molding method, having an inner surface made so that it is difficult for quartz powder to slide down when forming a quartz powder compact.

Mold and method for manufacturing quartz glass crucible

A quartz glass crucible for silicon single crystal pulling operation that by a simple arrangement, attains prevention of any collapse onto the inside at a superior edge of straight trunk part; and a process for manufacturing the same. The quartz glass crucible for silicon single crystal pulling operation having a straight trunk part and a bottom part, is characterized in that at least the straight trunk part is provided with a gradient of fictive temperature so that the fictive temperature on the outermost side thereof is 25&#xb0; C. or more lower than the fictive temperature on the innermost side thereof.

Quartz glass crucible for silicon single crystal pulling operation and process for manufacturing the same

A fused glass crucible includes a collar of doped aluminum silica that defines uppermost and outermost surfaces of the crucible. The melt line that defines the surface of molten silicon in the crucible may be substantially at the lower end of the collar or slightly above it. Crystallization of the collar makes it hard and therefore supports the remaining uncrystallized portion of the crucible above the melt line. The melt line may also be below the lower end of the collar, especially if the melt is drawn down or poured early in the process. Because there is little or no overlap or because the overlap does not last long, the doped aluminum collar is not damaged by the heat of from the melt.

Crucible having a doped upper wall portion and method for making the same

A quartz glass crucible which has a non-transparent outer layer formed through melting a natural silica powder and a transparent layer formed in the inside of the outer layer, wherein the transparent layer comprises a natural quartz layer having a thickness of 0.4 to 5.0 mm transparent layer comprising a synthetic quarts glass is formed thereon in the inside of the crucible in the range of 0.15 to 0.55 L relative to L, which is the distance from the center of the bottom of the inner surface of the quartz glass crucible to the upper end thereof along the inner surface thereof. The quartz glass crucible can be suitably used for suppressing the occurrence of vibration and reducing the generation of roughened face in the surface of a crucible, and thus for pulling up a silicon single crystal with enhanced stability.

Quartz glass crucible for pulling up silicon single crystal and method for manufacture thereof

A rotating mold has a plurality of air channels that communicate with a cavity formed in the mold. Silica grain is deposited in the rotating mold and then formed into the shape of a crucible having a lower portion that comprises a substantially uniformly thick wall. An upper portion of the grain is formed into a substantially narrowed wall portion about the perimeter of the formed shape. The silica grain is heated, and a pump draws gas through the air channels while the silica fuses. There is a pressure drop across the narrowed wall portion. After fusing, the upper portion of the crucible, including the narrowed wall portion, is cut off.

Method for making a silica glass crucible

An object of the invention is to provide a quartz glass crucible reduced in the generation of vibration occurring on the surface of a silicon melt and free from the generation of rough surface and cristobalite spots, yet capable of pulling up single crystal silicon stably and at high yield even in long-term operations; it is also an object to provide a method for producing the same. In a quartz glass crucible for pulling up single crystal silicon comprising a crucible base body having a bottom part and a straight shell part with an inner layer provided to the inner surface thereof, the quartz glass crucible is characterized by that said inner layer comprises a synthetic quartz glass layer from the lowest end to at least a height of 0.25 H; a naturally occurring quartz glass layer or a mixed layer of naturally occurring quartz glass and synthetic quartz glass extended in a range of from at least 0.5 H to 0.8 H; and one selected from a synthetic quartz glass layer, a naturally occurring quartz glass layer, and a mixed quartz glass layer of naturally and synthetic quartz glass for the rest of the inner layer; wherein H represents the height from the lowest end of the bottom part to the upper end plane of the shell part. It also provides a method for producing the quartz glass crucible above.

Quartz glass crucible for pulling up silicon single crystal and method for producing the same

The present invention refers to a method for producing a quartz glass crucible for use in pulling silicon single crystal, said crucible having at least a double-layer structure comprising a pore-free transparent inner layer and an opaque base body or outer layer having pores, characterized in that at least the base body is formed with a silica powder maintained in a gas having a mixing ratio of 0.0005 to 0.0065 kg/kg (dry gas), and a quartz glass crucible produced by said production method. The obtained crucible has an average OH group concentration of 50 ppm or lower and is capable of suppressing the vibration occurring on the surface of silicon melt during pulling the silicon single crystal. Further the obtained crucible suffers less deformation of the crucible on pulling the silicon single crystal.

Method for producing quartz glass crucible for use in pulling silicon single crystal and quartz glass crucible produced by said method

A fused silica crucible having a nozzle is formed by first inserting a preformed silica glass tube into the lower portion of a graphite mold. The tube is aligned with a vertical axis about which the mold is rotated while silica grain is poured into the mold and shaped in the form of the crucible. A graphite plug inserted into the top of the tube keeps the grain out of the tube. Electrodes create a plasma gas ball that fuses the grain and forms it to the tube. Although the graphite plug is covered with grain, the molten silica recedes from the top of the plug during fusion thus forming the nozzle to the crucible.

Silica vessel with nozzle and method of making

A silica glass crucible includes a thin barium-doped inner layer, a stable, bubble-free intermediate layer, and a stable opaque outer layer. The fusion process of the present invention controls the dynamic gas balance at the fusion front where formed grain is melted to dense fused silica. The crucible demonstrates reduced bubble growth during a Czochralski process. As a result of the thin barium-doped layer and the reduced bubble growth, the inner surface of the crucible is uniformly minimally textured during a CZ process. The present crucible is especially suited for intense CZ processes for manufacturing silicon ingots used for solar cells or with silicon that is heavily doped with antimony, boron, or arsenic.

Silica glass crucible with barium-doped inner wall

A silica glass crucible includes a stable, bubble-free inner layer and an opaque outer layer, both layers demonstrating reduced bubble growth during a Czochralski process. When used in the CZ process, little volume change is observed in the crucible wall, and the crucible has little influence on melt level. The present crucible is especially suited for slow silicon ingot pulling with reduced crystalline defects. The fusion process of the present invention controls the dynamic gas balance at the fusion front where formed grain is melted to dense fused silica.

Silica glass crucible with bubble-free and reduced bubble growth wall

A quartz glass crucible for use in pulling up a silicon single crystal, wherein it has, at least in the curved portion thereof, a three-layer structure comprising a transparent inner layer being composed of a synthetic quartz glass and having a low Al concentration, a transparent or nontransparent intermediate layer being composed of a natural quartz glass or a mixture of natural and synthetic quartz glasses and having a high Al concentration, and a nontransparent outer layer being composed of a natural quartz glass and having an Al concentration higher than that of the intermediate layer. The quartz glass crucible is reduced in the deformation of the transparent inner layer, and allows the suppression of the change in the amount of dissolution of the quartz glass crucible associated with the pull-up of a single crystal and the achievement of the uniform oxygen concentration in the longitudinal direction of a single crystal.

Quartz glass crucible for the pulling up of silicon single crystal

It is an object of the present invention to provide a hydrogen-doped silica powder that is useful in the formation of a quartz glass crucible that is capable of pulling a silicon single crystal without causing a state having dislocations in the silicon single crystal due to peeling of quartz glass segment. It is a further object of the invention to provide a quartz glass crucible for use in pulling a silicon single crystal whose inner surface is formed by use of the hydrogen-doped silica powder and a producing method of the silica powder. In order to achieve the objects above, the present invention provides a hydrogen-doped silica powder for use in producing a quartz glass crucible for use in pulling a silicon single crystal, wherein the silica powder is made of synthetic silica powder, natural silica powder or a mixture thereof, with a hydrogen concentration being in the range of 1&#xd7;10to 5&#xd7;10molecules/cm, and a producing method thereof, and a quartz glass crucible for pulling a silicon single crystal whose inner surface is made of the silica powders.

Method for producing hydrogen-doped silica powder, hydrogen-doped silica powder obtained from that method for use in a quartz glass crucible

Problems the invention is to solve: An object of the present invention is to provide a method for producing a quartz glass crucible capable of pulling up a silicon single crystal at a highly improved yield, yet without generating oscillation at the surface of the melt on pulling up silicon single crystal, and free from generating dislocations due to the peeling off of quartz glass fractions. Means for solving the problems: In a method for producing a quartz glass comprising a step of forming a base body comprising supplying a powder of silicon dioxide inside a rotating mold and thereby obtaining a molded body in the shape of a crucible by taking advantage of the centrifugal force, followed by heating and fusing the resulting molded body to obtain a translucent quartz glass crucible base body, and a step of forming an inner layer by newly supplying a powder of silicon dioxide into the heated atmosphere inside said crucible base body during or after forming said crucible base body, thereby forming an inner layer of a transparent quartz glass on the inner plane of said crucible base body, claimed is a method in which water vapor is introduced into said crucible base body in at least a part of the step for forming the inner layer.

Method for producing quartz glass crucible

Disclosed is a multilayer structured quartz glass crucible, for pulling up silicon single crystal, whose structure has at least three layers comprising: a translucent outer layer made of naturally occurring quartz glass and having a large number of pores, a translucent intermediate layer, made of synthetic quartz glass and having a large number of pores, and a transparent inner layer substantially free from pores and made of a synthetic quartz glass. Thermal convection within the silicon melt is suppressed by use of the quartz glass crucible, thereby preventing oscillation on the surface of the silicon melt. A method for producing the quartz glas crucible is also disclosed.

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Fukui, Japan

Yasuo Ohama