Sumitomo Metal Industries, Inc.

Sumitomo Mitsubishi Silicon Corporation

Sumco Corporation

Manabu Nishimoto

Takayuki Kubo

Masahiko Okui

Hiroshi Asano

Fumio Kawahigashi

Shingo Kizaki

Junji Horii

Hideki Fujiwara

Masataka Hourai

Wataru Takahashi

Shigeru Umeno

Makoto Ito

Kazuyuki Egashira

Tadami Tanaka

Hiroshi Morita

Yoshihito Sugimoto

Shiroh Kitayama

Shinichiro Miki

Shunji Kuragaki

Tatsuo Nagata

Isamu Miyamoto

A silicon wafer is produced through the steps of forming a silicon ingot by a CZ method with an interstitial oxygen concentration of not more than 7.0&#xd7;10atoms/cmand with a diameter of a COP occurring region not more than a diameter of a crystal, slicing a wafer from the silicon ingot after doping the silicon ingot with phosphorus, forming a polysilicon layer or a strained layer on one main surface of the wafer, and mirror polishing the other main surface of the wafer.

Silicon wafer and method for producing the same

In the CZ process using a cooling member surrounding a single crystal, the cooling member is permitted to effectively serve to increase a pulling speed. Cracks of the single crystal due to excessive cooling are prevented to occur. A high crystal quality is acquired. In order to realize these objects, the temperature of the inner peripheral surface of the cooling member opposing to the outer peripheral surface of the single crystal is restricted to 500&deg; C. or below, even in the lower end, the temperature of which becomes the highest. To achieve this restriction, the thickness T of the cooling member is 10 to 50 mm. The height H of the cooling member is 0.1 to 1.5 times the diameter D of the single crystal

Crystal growth method

An apparatus is provided which is to be used in producing single crystals for silicon wafers useful as semiconductor materials and which can stably produce large-diameter, long-length and high-quality single crystals from which wafers limited in the number of grown-in defects can be taken. This silicon single crystal production apparatus comprises a cooling member surrounding the single crystal to be pulled up and having an internal surface coaxial with the pulling axis and thermal insulating members disposed outside the outer surface and below the bottom surface of the cooling member, the cooling member having an internal surface diameter of 1.20D to 2.50D (D being the diameter of the single crystal to be pulled up) and a length of not less than 0.25D, the distance from the melt surface to the bottom surface of the cooling member being 0.30D to 0.85D and the bottom side of the thermal insulating member below the cooling member having an inside diameter smaller than the inside diameter of the bottom of the cooling member.

Production device for high-quality silicon single crystals

A method for producing a silicon single crystal, the method being capable of suppressing the dislocation of a single crystal. When a silicon single crystal is produced by a Czochralski method in which a horizontal magnetic field or a cusp magnetic field is applied and the single crystal during growth is dislocated, the single crystal with dislocations is dissolved in a nonmagnetic field condition and thereafter a magnetic field is applied again to pull up the silicon single crystal. The flow rate of argon gas is designed to be 100 L/min or more and the pressure in a furnace is designed to be 6700 pa or less when the single crystal with dislocations is dissolved.

Method for producing silicon single crystal

A method of producing a high-quality silicon single crystal of a large diameter and a long size in a good yield by controlling the positions where ring-like oxygen-induced stacking faults (R-OSF) occur in the crystal faces and minimizing grown-in defects such a dislocation clusters and infrared scattering bodies that are introduced in the pulling step. Wafers produced from the above-high-quality silicon single crystal contain little harmful defects that would deteriorate device characteristics and can be effectively adapted to larger scale integration and size reduction of the devices. Therefore, the method can be extensively utilized in the field of producing semiconductor silicon single crystals.

High-quality silicon single crystal and method of producing the same

The present invention was achieved in order to provide an apparatus for pulling a single crystal with which a single crystal having a low density of grown-in defects called infrared scatterers, dislocation clusters or the like can be grown. In the apparatus for pulling a single crystal having a crucible to be charged with a melt, a heater arranged around the crucible, a straightening vane in the shape of a side surface of an inverted truncated cone or a cylinder surrounding a pulled single crystal and a heat shield plate for inhibiting the radiant heat from diverging upward in the chamber from the side surface of the pulled single crystal located in the vicinity of the melt surface are arranged.

Single crystal pull-up apparatus

The machinability of titanium or a titanium alloy is improved without adversely affecting the hot workability and fatigue strength or corrosion resistance by addition of P: 0.01-1.0% along with one or both of S: 0.01-1.0% and Ni: 0.01-2.0%, or along with S: 0.01-1.0%, Ni: 0.01-2.0%, and REM: 0.01-5.0%, on a weight basis.

Method for improving machinability of titanium and titanium alloys and

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Saga, Japan

Manabu Nishimoto