Sumco Corporation

Tomokazu Katano

Ken Kitahara

Eriko Kitahara

Toshiaki Ono

Hiroshi Kishi

Masanori Fukui

Yasuo Koike

Hideki Tanaka

Yasuhiro Saito

Takeshi Fujita

Naoki Ikeda

Kazumi Tanabe

Kaoru Kajiwara

Takahiro Kanehara

An infrared transmissivity measurement method is for measuring an infrared transmissivity of a quartz glass crucible which includes a transparent layer made of quartz glass that does not contain bubbles, a bubble layer formed outside the transparent layer and made of quartz glass containing bubbles, and a semi-molten layer formed outside the bubble layer and made of raw material silica powder solidified in a semi-molten state. The infrared transmissivity measurement method includes processing an outer surface of the quartz glass crucible formed by the semi-molten layer to lower a surface roughness of the outer surface; and measuring an infrared transmissivity of the quartz glass crucible based on infrared light passing through the outer surface after processing the outer surface.

Infrared transmissivity measurement method of quartz glass crucible

A quartz glass cruciblehaving a cylindrical side wall portion, a bottom portion, and a corner portionconnecting the side wall portionand the bottom portionto each other includes a transparent layermade of quartz glass, and a bubble layermade of quartz glass and formed outside the transparent layer. A ratio of an infrared transmittance of the corner portionat a maximum thickness position of the corner portionto an infrared transmittance of the side wall portionis 0.3 or more and 0.99 or less, and an absolute value of a rate of change in infrared transmittance in a height direction along a wall surface of the crucible from a center of the bottom portiontoward an upper end of the side wall portionis 3%/cm or less.

Quartz glass crucible

A quartz glass cruciblehaving a cylindrical side wall portion, a bottom portion, and a corner portionincludes a transparent layeras an innermost layer made of quartz glass, a semi-molten layeras an outermost layer made of raw material silica powder solidified in a semi-molten state, and a bubble layermade of quartz glass interposed therebetween. An infrared transmissivity of the corner portionin a state where the semi-molten layeris removed is 25 to 51%, the infrared transmissivity of the corner portionin the state where the semi-molten layeris removed is lower than an infrared transmissivity of the side wall portion, and the infrared transmissivity of the side wall portionin the state where the semi-molten layeris removed is lower than an infrared transmissivity of the bottom portion

Quartz glass crucible, manufacturing method of silicon single crystal using the same, and infrared transmissivity measurement method and manufacturing method of quartz glass crucible

A method for producing a plurality of silicon single crystals using a single quartz crucible by repeating a step of heating a silicon material charged in the quartz crucible within a chamber and a step of pulling a silicon single crystal from the silicon melt in the quartz crucible includes a first melting step of melting the silicon material fed to the quartz crucible used to pull a first silicon single crystal, and a second melting step of melting an additional amount of the silicon material fed to the quartz crucible used to pull the second and subsequent silicon single crystals. The interior of the chamber is set to be a first furnace pressure during the first melting step and then set to be a second furnace pressure higher than the first furnace pressure during the second melting step.

Method for producing silicon single crystals

A silicon single crystal is pulled up such that nitrogen concentration of the crystal is 1&#xd7;10to 2&#xd7;10atoms/cm, the crystal cooling rate is about 4.2&#xb0; C./min at a temperature of a silicon melting point to 1350&#xb0; C. and is about 3.1&#xb0; C./min at a temperature of 1200&#xb0; C. to 1000&#xb0; C., and oxygen concentration of a wafer is 9.5&#xd7;10to 13.5&#xd7;10atoms/cm. After a heat treatment is performed on the wafer sliced from the silicon single crystal in a treatment condition of 875&#xb0; C. for about 30 min, growth of an epitaxial layer is caused. Thus, an epitaxial wafer in which the number of epitaxial defects is not increased while maintaining predetermined oxygen concentration and slips do not occur is produced.

Silicon epitaxial wafer and method of producing same

An epitaxial silicon wafer includes a silicon wafer consisting of a COP region in which a nitrogen concentration is 1&#xd7;10&#x2212;1&#xd7;10atoms/cm, and an epitaxial silicon film formed on the silicon wafer. When heat treatment for evaluation is applied, a density of BMD formed inside the silicon wafer is 1&#xd7;10&#x2212;3&#xd7;10atoms/cmover the entire radial direction of the silicon wafer. An average density of the BMD formed in an outer peripheral region of the silicon wafer which is a 1-10 mm range separated inward from an outermost periphery thereof is lower than the average density of the BMD formed in a center region. A variation in the BMD density in the outer peripheral region is 3 or less, and a residual oxygen concentration in the outer peripheral region is 8&#xd7;10atoms/cmor more.

Epitaxial silicon wafer

A method for manufacturing an epitaxial wafer includes: a step of pulling a single crystal from a boron-doped silicon melt in a chamber based on a Czochralski process; and a step of forming an epitaxial layer on a surface of a silicon wafer sliced from the single crystal. The single crystal is allowed to grow while passed through a temperature region of 800 to 600&#xb0; C. in the chamber in 250 to 180 minutes during the pulling step. The grown single crystal has an oxygen concentration of 10&#xd7;10to 12&#xd7;10atoms/cmand a resistivity of 0.03 to 0.01 &#x3a9;cm. The silicon wafer is subjected to pre-annealing prior to the step of forming the epitaxial layer on the surface of the silicon wafer, for 10 minutes to 4 hours at a predetermined temperature within a temperature region of 650 to 900&#xb0; C. in an inert gas atmosphere. The method is to fabricate an epitaxial wafer that has a diameter of 300 mm or more, and that attains a high IG effect, and involves few epitaxial defects.

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Tokyo, Japan

Tomokazu Katano